osu!taiko penalty for frequent rhythm changes with long gaps (#37200)

Co-authored-by: Jay Lawton <jaime@merkids.com>
Co-authored-by: James Wilson <tsunyoku@gmail.com>

.config/dotnet-tools.json

@@ -3,25 +3,28 @@
   "isRoot": true,
   "tools": {
     "jetbrains.resharper.globaltools": {
-      "version": "2025.2.3",
+      "version": "2023.3.3",
       "commands": [
         "jb"
-      ],
-      "rollForward": false
+      ]
+    },
+    "nvika": {
+      "version": "4.0.0",
+      "commands": [
+        "nvika"
+      ]
     },
     "codefilesanity": {
       "version": "0.0.37",
       "commands": [
         "CodeFileSanity"
-      ],
-      "rollForward": false
+      ]
     },
     "ppy.localisationanalyser.tools": {
       "version": "2025.1208.0",
       "commands": [
         "localisation"
-      ],
-      "rollForward": false
+      ]
     }
   }
-}
+}

.github/workflows/_diffcalc_processor.yml

@@ -44,7 +44,7 @@ jobs:
 
     steps:
       - name: Checkout diffcalc-sheet-generator
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           path: ${{ inputs.id }}
           repository: 'smoogipoo/diffcalc-sheet-generator'

.github/workflows/ci.yml

@@ -6,7 +6,6 @@ concurrency:
 
 permissions:
   contents: read # to fetch code (actions/checkout)
-  security-events: write # for reporting InspectCode issues
 
 jobs:
   inspect-code:
@@ -14,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Install .NET 8.0.x
-        uses: actions/setup-dotnet@v5
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
 
@@ -28,7 +27,7 @@ jobs:
         run: dotnet restore osu.Desktop.slnf
 
       - name: Restore inspectcode cache
-        uses: actions/cache@v5
+        uses: actions/cache@v4
         with:
           path: ${{ github.workspace }}/inspectcode
           key: inspectcode-${{ hashFiles('.config/dotnet-tools.json', '.github/workflows/ci.yml', 'osu.sln*', 'osu*.slnf', '.editorconfig', '.globalconfig', 'CodeAnalysis/*', '**/*.csproj', '**/*.props') }}
@@ -50,14 +49,10 @@ jobs:
           exit $exit_code
 
       - name: InspectCode
-        uses: JetBrains/ReSharper-InspectCode@v0.11
-        with:
-          # this is WTF tier but if you don't specify *both* of these the defaults assume `build: true`
-          build: false
-          no-build: true
-          solution: ./osu.Desktop.slnf
-          caches-home: inspectcode
-          verbosity: WARN
+        run: dotnet jb inspectcode $(pwd)/osu.Desktop.slnf --no-build --output="inspectcodereport.xml" --caches-home="inspectcode" --verbosity=WARN
+
+      - name: NVika
+        run: dotnet nvika parsereport "${{github.workspace}}/inspectcodereport.xml" --treatwarningsaserrors
 
   test:
     name: Test
@@ -76,10 +71,10 @@ jobs:
     timeout-minutes: 120
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Install .NET 8.0.x
-        uses: actions/setup-dotnet@v5
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
 
@@ -103,7 +98,7 @@ jobs:
       # Attempt to upload results even if test fails.
       # https://docs.github.com/en/actions/reference/context-and-expression-syntax-for-github-actions#always
       - name: Upload Test Results
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@v4
         if: ${{ always() }}
         with:
           name: osu-test-results-${{matrix.os.prettyname}}-${{matrix.threadingMode}}
@@ -115,16 +110,16 @@ jobs:
     timeout-minutes: 60
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Setup JDK 11
-        uses: actions/setup-java@v5
+        uses: actions/setup-java@v4
         with:
           distribution: microsoft
           java-version: 11
 
       - name: Install .NET 8.0.x
-        uses: actions/setup-dotnet@v5
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
 
@@ -140,10 +135,10 @@ jobs:
     timeout-minutes: 60
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Install .NET 8.0.x
-        uses: actions/setup-dotnet@v5
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
 

.github/workflows/deploy.yml

@@ -3,8 +3,7 @@ name: Pack and nuget
 on:
   push:
     tags:
-      - '*.*.*'
-      - '!*-*'
+      - '*'
 
 jobs:
   notify_pending_production_deploy:
@@ -44,14 +43,14 @@ jobs:
     environment: production
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
 
       - name: Set artifacts directory
         id: artifactsPath
         run: echo "::set-output name=nuget_artifacts::${{github.workspace}}/artifacts"
 
       - name: Install .NET 8.0.x
-        uses: actions/setup-dotnet@v5
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "8.0.x"
 
@@ -77,7 +76,7 @@ jobs:
           dotnet pack -c Release Templates /p:Version=${{ github.ref_name }} -o ${{steps.artifactsPath.outputs.nuget_artifacts}}
 
       - name: Upload artifacts
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@v4
         with:
           name: osu
           path: |

.github/workflows/report-nunit.yml

@@ -22,13 +22,13 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           repository: ${{ github.event.workflow_run.repository.full_name }}
           ref: ${{ github.event.workflow_run.head_sha }}
 
       - name: Download results
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@v4
         with:
           pattern: osu-test-results-*
           merge-multiple: true
@@ -36,7 +36,7 @@ jobs:
           github-token: ${{ github.token }}
 
       - name: Annotate CI run with test results
-        uses: dorny/test-reporter@v2.6.0
+        uses: dorny/test-reporter@v1.8.0
         with:
           name: Results
           path: "*.trx"

.github/workflows/sentry-release.yml

@@ -13,12 +13,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
 
       - name: Create Sentry release
-        uses: getsentry/action-release@v3
+        uses: getsentry/action-release@v1
         env:
           SENTRY_AUTH_TOKEN: ${{ secrets.SENTRY_AUTH_TOKEN }}
           SENTRY_ORG: ppy

Templates/Rulesets/ruleset-empty/osu.Game.Rulesets.EmptyFreeform/EmptyFreeformDifficultyCalculator.cs

@@ -19,13 +19,13 @@ namespace osu.Game.Rulesets.EmptyFreeform
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             return new DifficultyAttributes(mods, 0);
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods) => Enumerable.Empty<DifficultyHitObject>();
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => Array.Empty<Skill>();
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods) => Array.Empty<Skill>();
     }
 }

Templates/Rulesets/ruleset-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs

@@ -19,13 +19,13 @@ namespace osu.Game.Rulesets.Pippidon
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             return new DifficultyAttributes(mods, 0);
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods) => Enumerable.Empty<DifficultyHitObject>();
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => Array.Empty<Skill>();
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods) => Array.Empty<Skill>();
     }
 }

Templates/Rulesets/ruleset-scrolling-empty/osu.Game.Rulesets.EmptyScrolling/EmptyScrollingDifficultyCalculator.cs

@@ -19,13 +19,13 @@ namespace osu.Game.Rulesets.EmptyScrolling
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             return new DifficultyAttributes(mods, 0);
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods) => Enumerable.Empty<DifficultyHitObject>();
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => Array.Empty<Skill>();
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods) => Array.Empty<Skill>();
     }
 }

Templates/Rulesets/ruleset-scrolling-example/osu.Game.Rulesets.Pippidon/PippidonDifficultyCalculator.cs

@@ -19,13 +19,13 @@ namespace osu.Game.Rulesets.Pippidon
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             return new DifficultyAttributes(mods, 0);
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate) => Enumerable.Empty<DifficultyHitObject>();
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods) => Enumerable.Empty<DifficultyHitObject>();
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => Array.Empty<Skill>();
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods) => Array.Empty<Skill>();
     }
 }

osu.Android.props

@@ -10,7 +10,7 @@
     <EmbedAssembliesIntoApk>true</EmbedAssembliesIntoApk>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2026.318.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2026.310.0" />
   </ItemGroup>
   <PropertyGroup>
     <!-- Fody does not handle Android build well, and warns when unchanged.

osu.Desktop/DiscordRichPresence.cs

@@ -58,7 +58,6 @@ namespace osu.Desktop
         private readonly RichPresence presence = new RichPresence
         {
             Assets = new Assets { LargeImageKey = "osu_logo_lazer" },
-            Timestamps = Timestamps.Now,
             Secrets = new Secrets
             {
                 JoinSecret = null,

osu.Desktop/MacOS/MacOsAppLocationChecker.cs

@@ -1,55 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System;
-using System.IO;
-using osu.Framework;
-using osu.Framework.Allocation;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Sprites;
-using osu.Game.Graphics;
-using osu.Game.Localisation;
-using osu.Game.Overlays;
-using osu.Game.Overlays.Notifications;
-
-namespace osu.Desktop.MacOS
-{
-    /// <summary>
-    /// Checks if the game is located at `Applications` folder and displays a warning notification if not so.
-    /// </summary>
-    public partial class MacOSAppLocationChecker : Component
-    {
-        [Resolved]
-        private INotificationOverlay notification { get; set; } = null!;
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            string assemblyPath = RuntimeInfo.EntryAssembly.Location;
-
-            bool inRootApp = assemblyPath.StartsWith("/Applications/", StringComparison.Ordinal);
-            bool inUserApp = assemblyPath.StartsWith(Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "Applications/"), StringComparison.Ordinal);
-
-            if (!inRootApp && !inUserApp)
-                notification.Post(new MacOSAppLocationNotification());
-
-            Expire();
-        }
-
-        private partial class MacOSAppLocationNotification : SimpleNotification
-        {
-            public MacOSAppLocationNotification()
-            {
-                Text = NotificationsStrings.MacOSAppLocation(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile));
-            }
-
-            [BackgroundDependencyLoader]
-            private void load(OsuColour colours)
-            {
-                Icon = FontAwesome.Solid.ShieldAlt;
-                IconContent.Colour = colours.YellowDark;
-            }
-        }
-    }
-}

osu.Desktop/OsuGameDesktop.cs

@@ -5,6 +5,7 @@ using System;
 using System.IO;
 using System.Reflection;
 using System.Runtime.Versioning;
+using System.Threading.Tasks;
 using Microsoft.Win32;
 using osu.Desktop.Performance;
 using osu.Desktop.Security;
@@ -14,12 +15,12 @@ using osu.Desktop.Updater;
 using osu.Framework;
 using osu.Framework.Logging;
 using osu.Game.Updater;
-using osu.Desktop.MacOS;
 using osu.Desktop.Windows;
 using osu.Framework.Allocation;
 using osu.Game.Configuration;
 using osu.Game.IO;
 using osu.Game.IPC;
+using osu.Game.Online.Multiplayer;
 using osu.Game.Performance;
 using osu.Game.Utils;
 
@@ -122,7 +123,7 @@ namespace osu.Desktop
 
         public override bool RestartAppWhenExited()
         {
-            RestartOnExitAction = () => Velopack.UpdateExe.Start(waitPid: (uint)Environment.ProcessId);
+            Task.Run(() => Velopack.UpdateExe.Start(waitPid: (uint)Environment.ProcessId)).FireAndForget();
             return true;
         }
 
@@ -132,17 +133,8 @@ namespace osu.Desktop
 
             LoadComponentAsync(new DiscordRichPresence(), Add);
 
-            switch (RuntimeInfo.OS)
-            {
-                case RuntimeInfo.Platform.Windows:
-                    LoadComponentAsync(new GameplayWinKeyBlocker(), Add);
-                    break;
-
-                case RuntimeInfo.Platform.macOS when !IsPackageManaged && IsDeployedBuild:
-                    if (!IsPackageManaged && IsDeployedBuild)
-                        LoadComponentAsync(new MacOSAppLocationChecker(), Add);
-                    break;
-            }
+            if (RuntimeInfo.OS == RuntimeInfo.Platform.Windows)
+                LoadComponentAsync(new GameplayWinKeyBlocker(), Add);
 
             LoadComponentAsync(new ElevatedPrivilegesChecker(), Add);
 

osu.Desktop/Security/ElevatedPrivilegesChecker.cs

@@ -27,8 +27,6 @@ namespace osu.Desktop.Security
 
             if (Environment.IsPrivilegedProcess)
                 notifications.Post(new ElevatedPrivilegesNotification());
-
-            Expire();
         }
 
         private partial class ElevatedPrivilegesNotification : SimpleNotification

osu.Desktop/Updater/VelopackUpdateManager.cs

@@ -146,11 +146,11 @@ namespace osu.Desktop.Updater
             action();
         }
 
-        private void restartToApplyUpdate(Velopack.UpdateManager updateManager, UpdateInfo update)
+        private void restartToApplyUpdate(Velopack.UpdateManager updateManager, UpdateInfo update) => Task.Run(async () =>
         {
-            game.RestartOnExitAction = () => updateManager.WaitExitThenApplyUpdates(update.TargetFullRelease);
-            game.AttemptExit();
-        }
+            await updateManager.WaitExitThenApplyUpdatesAsync(update.TargetFullRelease).ConfigureAwait(false);
+            Schedule(() => game.AttemptExit());
+        });
 
         private static void log(string text) => Logger.Log($"VelopackUpdateManager: {text}");
     }

osu.Game.Rulesets.Catch.Tests/TestSceneHyperDashColouring.cs

@@ -193,20 +193,20 @@ namespace osu.Game.Rulesets.Catch.Tests
         {
             public Color4 HyperDashColour
             {
-                get => Configuration.CustomColours[nameof(CatchSkinColour.HyperDash)];
-                set => Configuration.CustomColours[nameof(CatchSkinColour.HyperDash)] = value;
+                get => Configuration.CustomColours[CatchSkinColour.HyperDash.ToString()];
+                set => Configuration.CustomColours[CatchSkinColour.HyperDash.ToString()] = value;
             }
 
             public Color4 HyperDashAfterImageColour
             {
-                get => Configuration.CustomColours[nameof(CatchSkinColour.HyperDashAfterImage)];
-                set => Configuration.CustomColours[nameof(CatchSkinColour.HyperDashAfterImage)] = value;
+                get => Configuration.CustomColours[CatchSkinColour.HyperDashAfterImage.ToString()];
+                set => Configuration.CustomColours[CatchSkinColour.HyperDashAfterImage.ToString()] = value;
             }
 
             public Color4 HyperDashFruitColour
             {
-                get => Configuration.CustomColours[nameof(CatchSkinColour.HyperDashFruit)];
-                set => Configuration.CustomColours[nameof(CatchSkinColour.HyperDashFruit)] = value;
+                get => Configuration.CustomColours[CatchSkinColour.HyperDashFruit.ToString()];
+                set => Configuration.CustomColours[CatchSkinColour.HyperDashFruit.ToString()] = value;
             }
 
             public TestSkin()

osu.Game.Rulesets.Catch/Difficulty/CatchDifficultyCalculator.cs

@@ -15,6 +15,7 @@ using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Utils;
 
 namespace osu.Game.Rulesets.Catch.Difficulty
 {
@@ -22,8 +23,6 @@ namespace osu.Game.Rulesets.Catch.Difficulty
     {
         private const double difficulty_multiplier = 4.59;
 
-        private float halfCatcherWidth;
-
         public override int Version => 20251020;
 
         public CatchDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
@@ -31,7 +30,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new CatchDifficultyAttributes { Mods = mods };
@@ -46,12 +45,19 @@ namespace osu.Game.Rulesets.Catch.Difficulty
             return attributes;
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
         {
             CatchHitObject? lastObject = null;
 
             List<DifficultyHitObject> objects = new List<DifficultyHitObject>();
 
+            double clockRate = ModUtils.CalculateRateWithMods(mods);
+
+            float halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.Difficulty) * 0.5f;
+
+            // For circle sizes above 5.5, reduce the catcher width further to simulate imperfect gameplay.
+            halfCatcherWidth *= 1 - (Math.Max(0, beatmap.Difficulty.CircleSize - 5.5f) * 0.0625f);
+
             // In 2B beatmaps, it is possible that a normal Fruit is placed in the middle of a JuiceStream.
             foreach (var hitObject in CatchBeatmap.GetPalpableObjects(beatmap.HitObjects))
             {
@@ -68,16 +74,11 @@ namespace osu.Game.Rulesets.Catch.Difficulty
             return objects;
         }
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
         {
-            halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.Difficulty) * 0.5f;
-
-            // For circle sizes above 5.5, reduce the catcher width further to simulate imperfect gameplay.
-            halfCatcherWidth *= 1 - (Math.Max(0, beatmap.Difficulty.CircleSize - 5.5f) * 0.0625f);
-
             return new Skill[]
             {
-                new Movement(mods, halfCatcherWidth, clockRate),
+                new Movement(mods),
             };
         }
 

osu.Game.Rulesets.Catch/Difficulty/Evaluators/MovementEvaluator.cs

@@ -11,12 +11,16 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Evaluators
     {
         private const double direction_change_bonus = 21.0;
 
-        public static double EvaluateDifficultyOf(DifficultyHitObject current, double catcherSpeedMultiplier)
+        public static double EvaluateDifficultyOf(DifficultyHitObject current)
         {
             var catchCurrent = (CatchDifficultyHitObject)current;
             var catchLast = (CatchDifficultyHitObject)current.Previous(0);
             var catchLastLast = (CatchDifficultyHitObject)current.Previous(1);
 
+            // In catch, clockrate adjustments do not only affect the timings of hitobjects,
+            // but also the speed of the player's catcher, which has an impact on difficulty
+            double catcherSpeedMultiplier = current.ClockRate;
+
             double weightedStrainTime = catchCurrent.StrainTime + 13 + (3 / catcherSpeedMultiplier);
 
             double distanceAddition = (Math.Pow(Math.Abs(catchCurrent.DistanceMoved), 1.3) / 510);
@@ -40,6 +44,30 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Evaluators
                                     / (CatchDifficultyHitObject.NORMALIZED_HALF_CATCHER_WIDTH * 6) / sqrtStrain;
             }
 
+            // Linear spacing nerf.
+            double linearSpacingCount = 0;
+
+            for (int i = 0; i < Math.Min(current.Index, 10); i++)
+            {
+                var catchPrevObj = (CatchDifficultyHitObject)catchCurrent.Previous(i);
+
+                // Only same direction movements matter as they do not take any additional inputs.
+                if (Math.Sign(catchCurrent.DistanceMoved) != Math.Sign(catchPrevObj.DistanceMoved) || catchCurrent.DistanceMoved == 0 || catchPrevObj.DistanceMoved == 0)
+                    break;
+
+                double currentSpacing = Math.Abs(catchCurrent.DistanceMoved / catchCurrent.StrainTime);
+                double prevSpacing = Math.Abs(catchPrevObj.DistanceMoved / catchPrevObj.StrainTime);
+
+                double relativeDifference = Math.Abs(currentSpacing / prevSpacing - 1);
+
+                if (relativeDifference > 0.05)
+                    break;
+
+                linearSpacingCount++;
+            }
+
+            distanceAddition *= Math.Pow(0.7, linearSpacingCount);
+
             // Bonus for edge dashes.
             if (catchCurrent.LastObject.DistanceToHyperDash <= 20.0f)
             {

osu.Game.Rulesets.Catch/Difficulty/Skills/Movement.cs

@@ -17,28 +17,14 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Skills
 
         protected override int SectionLength => 750;
 
-        protected readonly float HalfCatcherWidth;
-
-        /// <summary>
-        /// The speed multiplier applied to the player's catcher.
-        /// </summary>
-        private readonly double catcherSpeedMultiplier;
-
-        public Movement(Mod[] mods, float halfCatcherWidth, double clockRate)
+        public Movement(Mod[] mods)
             : base(mods)
         {
-            HalfCatcherWidth = halfCatcherWidth;
-
-            // In catch, clockrate adjustments do not only affect the timings of hitobjects,
-            // but also the speed of the player's catcher, which has an impact on difficulty
-            // TODO: Support variable clockrates caused by mods such as ModTimeRamp
-            //  (perhaps by using IApplicableToRate within the CatchDifficultyHitObject constructor to set a catcher speed for each object before processing)
-            catcherSpeedMultiplier = clockRate;
         }
 
         protected override double StrainValueOf(DifficultyHitObject current)
         {
-            return MovementEvaluator.EvaluateDifficultyOf(current, catcherSpeedMultiplier);
+            return MovementEvaluator.EvaluateDifficultyOf(current);
         }
     }
 }

osu.Game.Rulesets.Mania.Tests/TestSceneHoldNoteInput.cs

@@ -10,7 +10,6 @@ using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Replays;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Mania.Objects;
-using osu.Game.Rulesets.Mania.Objects.Drawables;
 using osu.Game.Rulesets.Mania.Replays;
 using osu.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Objects;
@@ -506,29 +505,6 @@ namespace osu.Game.Rulesets.Mania.Tests
                                                              .All(j => j.Type.IsHit()));
         }
 
-        /// <summary>
-        /// This ensures that the value of <see cref="DrawableHoldNote.MissingStartTime"/>
-        /// will be set correctly when the body receives a judgment during the hold.
-        ///
-        ///     -----[           ]-----
-        ///          x     o
-        /// </summary>
-        [Test]
-        public void TestReleaseDuringHoldMissingStartTime()
-        {
-            performTest([
-                new ManiaReplayFrame(time_head, ManiaAction.Key1),
-                new ManiaReplayFrame(time_during_hold_1)
-            ]);
-
-            assertHeadJudgement(HitResult.Perfect);
-            assertTailJudgement(HitResult.Miss);
-            assertNoteJudgement(HitResult.IgnoreMiss);
-
-            AddAssert("body judgement is miss", () => !judgementResults.Single(j => j.HitObject is HoldNoteBody).IsHit);
-            AddAssert("body judgement time indicates during hold", () => judgementResults.Single(j => j.HitObject is HoldNoteBody).TimeAbsolute, () => Is.EqualTo(time_during_hold_1).Within(100));
-        }
-
         private void assertHitObjectJudgement(HitObject hitObject, HitResult result)
             => AddAssert($"object judged as {result}", () => judgementResults.First(j => j.HitObject == hitObject).Type, () => Is.EqualTo(result));
 

osu.Game.Rulesets.Mania/Difficulty/ManiaDifficultyCalculator.cs

@@ -19,6 +19,7 @@ using osu.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Scoring;
+using osu.Game.Utils;
 
 namespace osu.Game.Rulesets.Mania.Difficulty
 {
@@ -36,7 +37,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
             isForCurrentRuleset = beatmap.BeatmapInfo.Ruleset.MatchesOnlineID(ruleset);
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new ManiaDifficultyAttributes { Mods = mods };
@@ -62,11 +63,13 @@ namespace osu.Game.Rulesets.Mania.Difficulty
             return 1;
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
         {
             var sortedObjects = beatmap.HitObjects.ToArray();
             int totalColumns = ((ManiaBeatmap)beatmap).TotalColumns;
 
+            double clockRate = ModUtils.CalculateRateWithMods(mods);
+
             LegacySortHelper<HitObject>.Sort(sortedObjects, Comparer<HitObject>.Create((a, b) => (int)Math.Round(a.StartTime) - (int)Math.Round(b.StartTime)));
 
             List<DifficultyHitObject> objects = new List<DifficultyHitObject>();
@@ -88,7 +91,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
         // Sorting is done in CreateDifficultyHitObjects, since the full list of hitobjects is required.
         protected override IEnumerable<DifficultyHitObject> SortObjects(IEnumerable<DifficultyHitObject> input) => input;
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => new Skill[]
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods) => new Skill[]
         {
             new Strain(mods, ((ManiaBeatmap)Beatmap).TotalColumns)
         };

osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNote.cs

@@ -31,21 +31,10 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
     {
         public override bool DisplayResult => false;
 
-        /// <summary>
-        /// Whether the user is currently pressing the hold note.
-        /// </summary>
         public IBindable<bool> IsHolding => isHolding;
 
         private readonly Bindable<bool> isHolding = new Bindable<bool>();
 
-        /// <summary>
-        /// The time at which the user starting missing the hold note.
-        /// This could be the time at which they missed the head, broke on the body, or missed the tail.
-        /// </summary>
-        public IBindable<double?> MissingStartTime => missingStartTime;
-
-        private readonly Bindable<double?> missingStartTime = new Bindable<double?>();
-
         public DrawableHoldNoteHead Head => headContainer.Child;
         public DrawableHoldNoteTail Tail => tailContainer.Child;
         public DrawableHoldNoteBody Body => bodyContainer.Child;
@@ -208,13 +197,11 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
         public override void OnKilled()
         {
             base.OnKilled();
-
             // flush the final state of holding on kill.
             // this matters because some skin implementations like legacy skin
             // insert drawables in the hierarchy that are not a child of this DHO
             // (see `LegacyBodyPiece` and related machinations with `lightContainer` being added at column level)
             isHolding.Value = Result.IsHolding(Time.Current);
-            missingStartTime.Value = null;
             (bodyPiece.Drawable as IHoldNoteBody)?.Recycle();
         }
 
@@ -222,13 +209,6 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
         {
             base.Update();
 
-            if (Head.Judged && !Head.IsHit)
-                missingStartTime.Value ??= Head.Result.TimeAbsolute;
-            if (Body.HasHoldBreak)
-                missingStartTime.Value ??= Body.Result.TimeAbsolute;
-            if (Tail.Judged && !Tail.IsHit)
-                missingStartTime.Value ??= Tail.Result.TimeAbsolute;
-
             isHolding.Value = Result.IsHolding(Time.Current);
 
             // Pad the full size container so its contents (i.e. the masking container) reach under the tail.

osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNoteHead.cs

@@ -3,7 +3,6 @@
 
 #nullable disable
 
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Input.Events;
 using osu.Game.Rulesets.Objects.Drawables;
@@ -15,12 +14,6 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
     /// </summary>
     public partial class DrawableHoldNoteHead : DrawableNote
     {
-        /// <summary>
-        /// The time at which the user starting missing the hold note.
-        /// This could be the time at which they missed the head, broke on the body, or missed the tail.
-        /// </summary>
-        public readonly IBindable<double?> MissingStartTime = new Bindable<double?>();
-
         protected override ManiaSkinComponents Component => ManiaSkinComponents.HoldNoteHead;
 
         public DrawableHoldNoteHead()
@@ -35,22 +28,6 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
             Origin = Anchor.TopCentre;
         }
 
-        protected override void OnApply()
-        {
-            base.OnApply();
-
-            if (ParentHitObject is DrawableHoldNote parentHold)
-                MissingStartTime.BindTo(parentHold.MissingStartTime);
-        }
-
-        protected override void OnFree()
-        {
-            base.OnFree();
-
-            if (ParentHitObject is DrawableHoldNote parentHold)
-                MissingStartTime.UnbindFrom(parentHold.MissingStartTime);
-        }
-
         public bool UpdateResult() => base.UpdateResult(true);
 
         protected override void UpdateHitStateTransforms(ArmedState state)

osu.Game.Rulesets.Mania/Objects/Drawables/DrawableHoldNoteTail.cs

@@ -3,7 +3,6 @@
 
 #nullable disable
 
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Input.Events;
 using osu.Game.Rulesets.Scoring;
@@ -15,12 +14,6 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
     /// </summary>
     public partial class DrawableHoldNoteTail : DrawableNote
     {
-        /// <summary>
-        /// The time at which the user starting missing the hold note.
-        /// This could be the time at which they missed the head, broke on the body, or missed the tail.
-        /// </summary>
-        public readonly IBindable<double?> MissingStartTime = new Bindable<double?>();
-
         protected override ManiaSkinComponents Component => ManiaSkinComponents.HoldNoteTail;
 
         protected internal DrawableHoldNote HoldNote => (DrawableHoldNote)ParentHitObject;
@@ -37,22 +30,6 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
             Origin = Anchor.TopCentre;
         }
 
-        protected override void OnApply()
-        {
-            base.OnApply();
-
-            if (ParentHitObject is DrawableHoldNote parentHold)
-                MissingStartTime.BindTo(parentHold.MissingStartTime);
-        }
-
-        protected override void OnFree()
-        {
-            base.OnFree();
-
-            if (ParentHitObject is DrawableHoldNote parentHold)
-                MissingStartTime.UnbindFrom(parentHold.MissingStartTime);
-        }
-
         public void UpdateResult() => base.UpdateResult(true);
 
         protected override void CheckForResult(bool userTriggered, double timeOffset) =>

osu.Game.Rulesets.Mania/Objects/HoldNote.cs

@@ -118,8 +118,7 @@ namespace osu.Game.Rulesets.Mania.Objects
             AddNested(Body = new HoldNoteBody
             {
                 StartTime = StartTime,
-                Column = Column,
-                Duration = Duration
+                Column = Column
             });
         }
 

osu.Game.Rulesets.Mania/Objects/HoldNoteBody.cs

@@ -3,7 +3,6 @@
 
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Mania.Judgements;
-using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Scoring;
 
 namespace osu.Game.Rulesets.Mania.Objects
@@ -14,11 +13,9 @@ namespace osu.Game.Rulesets.Mania.Objects
     /// On hit - the hold note was held correctly for the full duration.<br />
     /// On miss - the hold note was released at some point during its judgement period.
     /// </summary>
-    public class HoldNoteBody : ManiaHitObject, IHasDuration
+    public class HoldNoteBody : ManiaHitObject
     {
         public override Judgement CreateJudgement() => new HoldNoteBodyJudgement();
         protected override HitWindows CreateHitWindows() => HitWindows.Empty;
-        public double Duration { get; set; }
-        public double EndTime => StartTime + Duration;
     }
 }

osu.Game.Rulesets.Mania/Skinning/Legacy/LegacyBodyPiece.cs

@@ -25,10 +25,17 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
 
         private readonly IBindable<ScrollingDirection> direction = new Bindable<ScrollingDirection>();
         private readonly IBindable<bool> isHitting = new Bindable<bool>();
-        private readonly IBindable<double?> missingStartTime = new Bindable<double?>();
+
+        /// <summary>
+        /// Stores the start time of the fade animation that plays when any of the nested
+        /// hitobjects of the hold note are missed.
+        /// </summary>
+        private readonly Bindable<double?> missFadeTime = new Bindable<double?>();
 
         private Drawable? bodySprite;
+
         private Drawable? lightContainer;
+
         private Drawable? light;
         private LegacyNoteBodyStyle? bodyStyle;
 
@@ -80,7 +87,6 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
 
             direction.BindTo(scrollingInfo.Direction);
             isHitting.BindTo(holdNote.IsHolding);
-            missingStartTime.BindTo(holdNote.MissingStartTime);
 
             bodySprite = skin.GetAnimation(imageName, wrapMode, wrapMode, true, true, frameLength: 30)?.With(d =>
             {
@@ -103,9 +109,26 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
 
             direction.BindValueChanged(onDirectionChanged, true);
             isHitting.BindValueChanged(onIsHittingChanged, true);
-            missingStartTime.BindValueChanged(onMissingStartTimeChanged, true);
+            missFadeTime.BindValueChanged(onMissFadeTimeChanged, true);
 
-            holdNote.ApplyCustomUpdateState += onApplyCustomUpdateState;
+            holdNote.ApplyCustomUpdateState += applyCustomUpdateState;
+            applyCustomUpdateState(holdNote, holdNote.State.Value);
+        }
+
+        private void applyCustomUpdateState(DrawableHitObject hitObject, ArmedState state)
+        {
+            switch (hitObject)
+            {
+                // Ensure that the hold note is also faded out when the head/tail/body is missed.
+                // Importantly, we filter out unrelated objects like DrawableNotePerfectBonus.
+                case DrawableHoldNoteTail:
+                case DrawableHoldNoteHead:
+                case DrawableHoldNoteBody:
+                    if (state == ArmedState.Miss)
+                        missFadeTime.Value ??= hitObject.HitStateUpdateTime;
+
+                    break;
+            }
         }
 
         private void onIsHittingChanged(ValueChangedEvent<bool> isHitting)
@@ -164,19 +187,23 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
             }
         }
 
-        private void onMissingStartTimeChanged(ValueChangedEvent<double?> startTime)
-            => applyMissingDim();
-
-        private void onApplyCustomUpdateState(DrawableHitObject obj, ArmedState state)
-            => applyMissingDim();
-
-        private void applyMissingDim()
+        private void onMissFadeTimeChanged(ValueChangedEvent<double?> missFadeTimeChange)
         {
-            if (missingStartTime.Value == null)
+            if (missFadeTimeChange.NewValue == null)
                 return;
 
-            using (BeginAbsoluteSequence(missingStartTime.Value.Value))
-                this.FadeColour(Colour4.DarkGray, 60);
+            // this update could come from any nested object of the hold note (or even from an input).
+            // make sure the transforms are consistent across all affected parts.
+            using (BeginAbsoluteSequence(missFadeTimeChange.NewValue.Value))
+            {
+                // colour and duration matches stable
+                // transforms not applied to entire hold note in order to not affect hit lighting
+                const double fade_duration = 60;
+
+                holdNote.Head.FadeColour(Colour4.DarkGray, fade_duration);
+                holdNote.Tail.FadeColour(Colour4.DarkGray, fade_duration);
+                bodySprite?.FadeColour(Colour4.DarkGray, fade_duration);
+            }
         }
 
         protected override void Update()
@@ -186,6 +213,9 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
             if (!isHitting.Value)
                 (bodySprite as TextureAnimation)?.GotoFrame(0);
 
+            if (holdNote.Body.HasHoldBreak)
+                missFadeTime.Value = holdNote.Body.Result.TimeAbsolute;
+
             int scaleDirection = (direction.Value == ScrollingDirection.Down ? 1 : -1);
 
             // here we go...
@@ -221,7 +251,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
             base.Dispose(isDisposing);
 
             if (holdNote.IsNotNull())
-                holdNote.ApplyCustomUpdateState -= onApplyCustomUpdateState;
+                holdNote.ApplyCustomUpdateState -= applyCustomUpdateState;
 
             lightContainer?.Expire();
         }

osu.Game.Rulesets.Mania/Skinning/Legacy/LegacyHoldNoteHeadPiece.cs

@@ -1,61 +1,18 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
-using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
-using osu.Game.Rulesets.Mania.Objects.Drawables;
-using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Skinning;
 
 namespace osu.Game.Rulesets.Mania.Skinning.Legacy
 {
     public partial class LegacyHoldNoteHeadPiece : LegacyNotePiece
     {
-        private readonly IBindable<double?> missingStartTime = new Bindable<double?>();
-
-        [Resolved]
-        private DrawableHitObject drawableObject { get; set; } = null!;
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            missingStartTime.BindTo(((DrawableHoldNoteHead)drawableObject).MissingStartTime);
-            missingStartTime.BindValueChanged(onMissingStartTimeChanged, true);
-
-            drawableObject.ApplyCustomUpdateState += onApplyCustomUpdateState;
-        }
-
-        private void onMissingStartTimeChanged(ValueChangedEvent<double?> startTime)
-            => applyMissingDim();
-
-        private void onApplyCustomUpdateState(DrawableHitObject obj, ArmedState state)
-            => applyMissingDim();
-
-        private void applyMissingDim()
-        {
-            if (missingStartTime.Value == null)
-                return;
-
-            using (BeginAbsoluteSequence(missingStartTime.Value.Value))
-                this.FadeColour(Colour4.DarkGray, 60);
-        }
-
         protected override Drawable? GetAnimation(ISkinSource skin)
         {
             // TODO: Should fallback to the head from default legacy skin instead of note.
             return GetAnimationFromLookup(skin, LegacyManiaSkinConfigurationLookups.HoldNoteHeadImage)
                    ?? GetAnimationFromLookup(skin, LegacyManiaSkinConfigurationLookups.NoteImage);
         }
-
-        protected override void Dispose(bool isDisposing)
-        {
-            base.Dispose(isDisposing);
-
-            if (drawableObject.IsNotNull())
-                drawableObject.ApplyCustomUpdateState -= onApplyCustomUpdateState;
-        }
     }
 }

osu.Game.Rulesets.Mania/Skinning/Legacy/LegacyHoldNoteTailPiece.cs

@@ -1,12 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Allocation;
 using osu.Framework.Bindables;
-using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
-using osu.Game.Rulesets.Mania.Objects.Drawables;
-using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.UI.Scrolling;
 using osu.Game.Skinning;
 
@@ -14,36 +10,6 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
 {
     public partial class LegacyHoldNoteTailPiece : LegacyNotePiece
     {
-        private readonly IBindable<double?> missingStartTime = new Bindable<double?>();
-
-        [Resolved]
-        private DrawableHitObject drawableObject { get; set; } = null!;
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            missingStartTime.BindTo(((DrawableHoldNoteTail)drawableObject).MissingStartTime);
-            missingStartTime.BindValueChanged(onMissingStartTimeChanged, true);
-
-            drawableObject.ApplyCustomUpdateState += onApplyCustomUpdateState;
-        }
-
-        private void onMissingStartTimeChanged(ValueChangedEvent<double?> startTime)
-            => applyMissingDim();
-
-        private void onApplyCustomUpdateState(DrawableHitObject obj, ArmedState state)
-            => applyMissingDim();
-
-        private void applyMissingDim()
-        {
-            if (missingStartTime.Value == null)
-                return;
-
-            using (BeginAbsoluteSequence(missingStartTime.Value.Value))
-                this.FadeColour(Colour4.DarkGray, 60);
-        }
-
         protected override void OnDirectionChanged(ValueChangedEvent<ScrollingDirection> direction)
         {
             // Invert the direction
@@ -59,13 +25,5 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
                    ?? GetAnimationFromLookup(skin, LegacyManiaSkinConfigurationLookups.HoldNoteHeadImage)
                    ?? GetAnimationFromLookup(skin, LegacyManiaSkinConfigurationLookups.NoteImage);
         }
-
-        protected override void Dispose(bool isDisposing)
-        {
-            base.Dispose(isDisposing);
-
-            if (drawableObject.IsNotNull())
-                drawableObject.ApplyCustomUpdateState -= onApplyCustomUpdateState;
-        }
     }
 }

osu.Game.Rulesets.Osu.Tests/Editor/TestSceneSliderReversal.cs

@@ -73,7 +73,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
 
             Vector2 oldStartPos = default;
             Vector2 oldEndPos = default;
-            double oldDistance = 0;
+            double oldDistance = default;
             var oldControlPointTypes = controlPoints.Select(p => p.Type);
 
             AddStep("Add slider", () =>
@@ -255,7 +255,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
 
             Vector2 oldStartPos = default;
             Vector2 oldEndPos = default;
-            double oldDistance = 0;
+            double oldDistance = default;
 
             var oldControlPointTypes = segmentedSliderPath.Select(p => p.Type);
 

osu.Game.Rulesets.Osu.Tests/OsuDifficultyCalculatorTest.cs

@@ -34,6 +34,30 @@ namespace osu.Game.Rulesets.Osu.Tests
         public void TestClassicMod(double expectedStarRating, int expectedMaxCombo, string name)
             => Test(expectedStarRating, expectedMaxCombo, name, new OsuModClassic());
 
+        [TestCase(239, "diffcalc-test")]
+        [TestCase(54, "zero-length-sliders")]
+        [TestCase(4, "very-fast-slider")]
+        public void TestOffsetChanges(int expectedMaxCombo, string name)
+        {
+            const double offset_iterations = 400;
+            var beatmap = GetBeatmap(name);
+
+            var attributes = CreateDifficultyCalculator(beatmap).Calculate();
+            double expectedStarRating = attributes.StarRating;
+
+            for (int i = 0; i < offset_iterations; i++)
+            {
+                foreach (var beatmapHitObject in beatmap.Beatmap.HitObjects)
+                    beatmapHitObject.StartTime++;
+
+                attributes = CreateDifficultyCalculator(beatmap).Calculate();
+
+                // Platform-dependent math functions (Pow, Cbrt, Exp, etc) may result in minute differences.
+                Assert.That(attributes.StarRating, Is.EqualTo(expectedStarRating).Within(0.00001));
+                Assert.That(attributes.MaxCombo, Is.EqualTo(expectedMaxCombo));
+            }
+        }
+
         protected override DifficultyCalculator CreateDifficultyCalculator(IWorkingBeatmap beatmap) => new OsuDifficultyCalculator(new OsuRuleset().RulesetInfo, beatmap);
 
         protected override Ruleset CreateRuleset() => new OsuRuleset();

osu.Game.Rulesets.Osu/Difficulty/Evaluators/Aim/AgilityEvaluator.cs

@@ -0,0 +1,42 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Objects;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Aim
+{
+    public static class AgilityEvaluator
+    {
+        private const double distance_cap = OsuDifficultyHitObject.NORMALISED_DIAMETER * 1.2; // 1.2 circles distance between centers
+
+        /// <summary>
+        /// Evaluates the difficulty of fast aiming
+        /// </summary>
+        public static double EvaluateDifficultyOf(DifficultyHitObject current)
+        {
+            if (current.BaseObject is Spinner)
+                return 0;
+
+            var osuCurrObj = (OsuDifficultyHitObject)current;
+            var osuPrevObj = current.Index > 0 ? (OsuDifficultyHitObject)current.Previous(0) : null;
+
+            double travelDistance = osuPrevObj?.LazyTravelDistance ?? 0;
+            double distance = travelDistance + osuCurrObj.LazyJumpDistance;
+
+            double distanceScaled = Math.Min(distance, distance_cap) / distance_cap;
+
+            double agilityDifficulty = distanceScaled * 1000 / osuCurrObj.AdjustedDeltaTime;
+
+            agilityDifficulty *= Math.Pow(osuCurrObj.SmallCircleBonus, 1.5);
+
+            agilityDifficulty *= highBpmBonus(osuCurrObj.AdjustedDeltaTime);
+
+            return agilityDifficulty;
+        }
+
+        private static double highBpmBonus(double ms) => 1 / (1 - Math.Pow(0.2, ms / 1000));
+    }
+}

osu.Game.Rulesets.Osu/Difficulty/Evaluators/Aim/FlowAimEvaluator.cs

@@ -0,0 +1,126 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Objects;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Aim
+{
+    public static class FlowAimEvaluator
+    {
+        private const double velocity_change_multiplier = 0.52;
+
+        /// <summary>
+        /// Evaluates difficulty of "flow aim" - aiming pattern where player doesn't stop their cursor on every object and instead "flows" through them.
+        /// </summary>
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, bool withSliderTravelDistance)
+        {
+            if (current.BaseObject is Spinner || current.Index <= 1 || current.Previous(0).BaseObject is Spinner)
+                return 0;
+
+            var osuCurrObj = (OsuDifficultyHitObject)current;
+            var osuLastObj = (OsuDifficultyHitObject)current.Previous(0);
+            var osuLastLastObj = (OsuDifficultyHitObject)current.Previous(1);
+
+            double currDistance = withSliderTravelDistance ? osuCurrObj.LazyJumpDistance : osuCurrObj.JumpDistance;
+            double prevDistance = withSliderTravelDistance ? osuLastObj.LazyJumpDistance : osuLastObj.JumpDistance;
+
+            double currVelocity = currDistance / osuCurrObj.AdjustedDeltaTime;
+
+            if (osuLastObj.BaseObject is Slider && withSliderTravelDistance)
+            {
+                // If the last object is a slider, then we extend the travel velocity through the slider into the current object.
+                double sliderDistance = osuLastObj.LazyTravelDistance + osuCurrObj.LazyJumpDistance;
+                currVelocity = Math.Max(currVelocity, sliderDistance / osuCurrObj.AdjustedDeltaTime);
+            }
+
+            double prevVelocity = prevDistance / osuLastObj.AdjustedDeltaTime;
+
+            double flowDifficulty = currVelocity;
+
+            // Apply high circle size bonus to the base velocity.
+            // We use reduced CS bonus here because the bonus was made for an evaluator with a different d/t scaling
+            flowDifficulty *= Math.Sqrt(osuCurrObj.SmallCircleBonus);
+
+            // Rhythm changes are harder to flow
+            flowDifficulty *= 1 + Math.Min(0.25,
+                Math.Pow((Math.Max(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime) - Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime)) / 50, 4));
+
+            if (osuCurrObj.Angle != null && osuLastObj.Angle != null)
+            {
+                double angleDifference = Math.Abs(osuCurrObj.Angle.Value - osuLastObj.Angle.Value);
+                double angleDifferenceAdjusted = Math.Sin(angleDifference / 2) * 180.0;
+                double angularVelocity = angleDifferenceAdjusted / (osuCurrObj.AdjustedDeltaTime * 0.1);
+
+                // Low angular velocity flow (angles are consistent) is easier to follow than erratic flow
+                flowDifficulty *= 0.8 + Math.Sqrt(angularVelocity / 270.0);
+            }
+
+            // If all three notes are overlapping - don't reward bonuses as you don't have to do additional movement
+            double overlappedNotesWeight = 1;
+
+            if (current.Index > 2)
+            {
+                double o1 = calculateOverlapFactor(osuCurrObj, osuLastObj);
+                double o2 = calculateOverlapFactor(osuCurrObj, osuLastLastObj);
+                double o3 = calculateOverlapFactor(osuLastObj, osuLastLastObj);
+
+                overlappedNotesWeight = 1 - o1 * o2 * o3;
+            }
+
+            if (osuCurrObj.Angle != null)
+            {
+                // Acute angles are also hard to flow
+                flowDifficulty += currVelocity *
+                                  SnapAimEvaluator.CalcAngleAcuteness(osuCurrObj.Angle.Value) *
+                                  overlappedNotesWeight;
+            }
+
+            if (Math.Max(prevVelocity, currVelocity) != 0)
+            {
+                if (withSliderTravelDistance)
+                {
+                    currVelocity = currDistance / osuCurrObj.AdjustedDeltaTime;
+                }
+
+                // Scale with ratio of difference compared to 0.5 * max dist.
+                double distRatio = DifficultyCalculationUtils.Smoothstep(Math.Abs(prevVelocity - currVelocity) / Math.Max(prevVelocity, currVelocity), 0, 1);
+
+                // Reward for % distance up to 125 / strainTime for overlaps where velocity is still changing.
+                double overlapVelocityBuff = Math.Min(OsuDifficultyHitObject.NORMALISED_DIAMETER * 1.25 / Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime),
+                    Math.Abs(prevVelocity - currVelocity));
+
+                flowDifficulty += overlapVelocityBuff *
+                                  distRatio *
+                                  overlappedNotesWeight *
+                                  velocity_change_multiplier;
+            }
+
+            if (osuCurrObj.BaseObject is Slider && withSliderTravelDistance)
+            {
+                // Include slider velocity to make velocity more consistent with snap
+                flowDifficulty += osuCurrObj.TravelDistance / osuCurrObj.TravelTime;
+            }
+
+            // Final velocity is being raised to a power because flow difficulty scales harder with both high distance and time, and we want to account for that
+            flowDifficulty = Math.Pow(flowDifficulty, 1.45);
+
+            // Reduce difficulty for low spacing since spacing below radius is always to be flowed
+            return flowDifficulty * DifficultyCalculationUtils.Smootherstep(currDistance, 0, OsuDifficultyHitObject.NORMALISED_RADIUS);
+        }
+
+        private static double calculateOverlapFactor(OsuDifficultyHitObject first, OsuDifficultyHitObject second)
+        {
+            var firstBase = (OsuHitObject)first.BaseObject;
+            var secondBase = (OsuHitObject)second.BaseObject;
+            double objectRadius = firstBase.Radius;
+
+            double distance = Vector2.Distance(firstBase.StackedPosition, secondBase.StackedPosition);
+            return Math.Clamp(1 - Math.Pow(Math.Max(distance - objectRadius, 0) / objectRadius, 2), 0, 1);
+        }
+    }
+}

osu.Game.Rulesets.Osu/Difficulty/Evaluators/Aim/SnapAimEvaluator.cs

@@ -0,0 +1,220 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Objects;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Aim
+{
+    public static class SnapAimEvaluator
+    {
+        private const double wide_angle_multiplier = 9.67;
+        private const double acute_angle_multiplier = 2.41;
+        private const double slider_multiplier = 1.5;
+        private const double velocity_change_multiplier = 0.9;
+        private const double wiggle_multiplier = 1.02; // WARNING: Increasing this multiplier beyond 1.02 reduces difficulty as distance increases. Refer to the desmos link above the wiggle bonus calculation
+        private const double maximum_repetition_nerf = 0.15;
+        private const double maximum_vector_influence = 0.5;
+
+        /// <summary>
+        /// Evaluates the difficulty of aiming the current object, based on:
+        /// <list type="bullet">
+        /// <item><description>cursor velocity to the current object,</description></item>
+        /// <item><description>angle difficulty,</description></item>
+        /// <item><description>sharp velocity increases,</description></item>
+        /// <item><description>and slider difficulty.</description></item>
+        /// </list>
+        /// </summary>
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, bool withSliderTravelDistance)
+        {
+            if (current.BaseObject is Spinner || current.Index <= 1 || current.Previous(0).BaseObject is Spinner)
+                return 0;
+
+            var osuCurrObj = (OsuDifficultyHitObject)current;
+            var osuLastObj = (OsuDifficultyHitObject)current.Previous(0);
+            var osuLast2Obj = (OsuDifficultyHitObject)current.Previous(2);
+
+            const int radius = OsuDifficultyHitObject.NORMALISED_RADIUS;
+            const int diameter = OsuDifficultyHitObject.NORMALISED_DIAMETER;
+
+            // Calculate the velocity to the current hitobject, which starts with a base distance / time assuming the last object is a hitcircle.
+            double currDistance = withSliderTravelDistance ? osuCurrObj.LazyJumpDistance : osuCurrObj.JumpDistance;
+            double currVelocity = currDistance / osuCurrObj.AdjustedDeltaTime;
+
+            // But if the last object is a slider, then we extend the travel velocity through the slider into the current object.
+            if (osuLastObj.BaseObject is Slider && withSliderTravelDistance)
+            {
+                double sliderDistance = osuLastObj.LazyTravelDistance + osuCurrObj.LazyJumpDistance;
+                currVelocity = Math.Max(currVelocity, sliderDistance / osuCurrObj.AdjustedDeltaTime);
+            }
+
+            double prevDistance = withSliderTravelDistance ? osuLastObj.LazyJumpDistance : osuLastObj.JumpDistance;
+            double prevVelocity = prevDistance / osuLastObj.AdjustedDeltaTime;
+
+            double snapDifficulty = currVelocity; // Start difficulty with regular velocity.
+
+            // Penalize angle repetition.
+            snapDifficulty *= vectorAngleRepetition(osuCurrObj, osuLastObj);
+
+            if (osuCurrObj.Angle != null && osuLastObj.Angle != null)
+            {
+                double currAngle = osuCurrObj.Angle.Value;
+                double lastAngle = osuLastObj.Angle.Value;
+
+                // Rewarding angles, take the smaller velocity as base.
+                double velocityInfluence = Math.Min(currVelocity, prevVelocity);
+
+                double acuteAngleBonus = 0;
+
+                if (Math.Max(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime) < 1.25 * Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime)) // If rhythms are the same.
+                {
+                    acuteAngleBonus = CalcAngleAcuteness(currAngle);
+
+                    // Penalize angle repetition. It is important to do it _before_ multiplying by anything because we compare raw acuteness here
+                    acuteAngleBonus *= 0.08 + 0.92 * (1 - Math.Min(acuteAngleBonus, Math.Pow(CalcAngleAcuteness(lastAngle), 3)));
+
+                    // Apply acute angle bonus for BPM above 300 1/2 and distance more than one diameter
+                    acuteAngleBonus *= velocityInfluence * DifficultyCalculationUtils.Smootherstep(DifficultyCalculationUtils.MillisecondsToBPM(osuCurrObj.AdjustedDeltaTime, 2), 300, 400) *
+                                       DifficultyCalculationUtils.Smootherstep(currDistance, 0, diameter * 2);
+                }
+
+                double wideAngleBonus = calcAngleWideness(currAngle);
+
+                // Penalize angle repetition. It is important to do it _before_ multiplying by velocity because we compare raw wideness here
+                wideAngleBonus *= 0.25 + 0.75 * (1 - Math.Min(wideAngleBonus, Math.Pow(calcAngleWideness(lastAngle), 3)));
+
+                // Rescaling velocity for the wide angle bonus
+                const double wide_angle_time_scale = 1.45;
+                double wideAngleCurrVelocity = currDistance / Math.Pow(osuCurrObj.AdjustedDeltaTime, wide_angle_time_scale);
+                double wideAnglePrevVelocity = prevDistance / Math.Pow(osuLastObj.AdjustedDeltaTime, wide_angle_time_scale);
+
+                if (osuLastObj.BaseObject is Slider && withSliderTravelDistance)
+                {
+                    double sliderDistance = osuLastObj.LazyTravelDistance + osuCurrObj.LazyJumpDistance;
+                    wideAngleCurrVelocity = Math.Max(wideAngleCurrVelocity, sliderDistance / Math.Pow(osuCurrObj.AdjustedDeltaTime, wide_angle_time_scale));
+                }
+
+                wideAngleBonus *= Math.Min(wideAngleCurrVelocity, wideAnglePrevVelocity);
+
+                if (osuLast2Obj != null)
+                {
+                    // If objects just go back and forth through a middle point - don't give as much wide bonus
+                    // Use Previous(2) and Previous(0) because angles calculation is done prevprev-prev-curr, so any object's angle's center point is always the previous object
+                    var lastBaseObject = (OsuHitObject)osuLastObj.BaseObject;
+                    var last2BaseObject = (OsuHitObject)osuLast2Obj.BaseObject;
+
+                    float distance = (last2BaseObject.StackedPosition - lastBaseObject.StackedPosition).Length;
+
+                    if (distance < 1)
+                    {
+                        wideAngleBonus *= 1 - 0.55 * (1 - distance);
+                    }
+                }
+
+                // Add in acute angle bonus or wide angle bonus, whichever is larger.
+                snapDifficulty += Math.Max(acuteAngleBonus * acute_angle_multiplier, wideAngleBonus * wide_angle_multiplier);
+
+                // Apply wiggle bonus for jumps that are [radius, 3*diameter] in distance, with < 110 angle
+                // https://www.desmos.com/calculator/dp0v0nvowc
+                double wiggleBonus = velocityInfluence
+                                     * DifficultyCalculationUtils.Smootherstep(currDistance, radius, diameter)
+                                     * Math.Pow(DifficultyCalculationUtils.ReverseLerp(currDistance, diameter * 3, diameter), 1.8)
+                                     * DifficultyCalculationUtils.Smootherstep(currAngle, double.DegreesToRadians(110), double.DegreesToRadians(60))
+                                     * DifficultyCalculationUtils.Smootherstep(prevDistance, radius, diameter)
+                                     * Math.Pow(DifficultyCalculationUtils.ReverseLerp(prevDistance, diameter * 3, diameter), 1.8)
+                                     * DifficultyCalculationUtils.Smootherstep(lastAngle, double.DegreesToRadians(110), double.DegreesToRadians(60));
+
+                snapDifficulty += wiggleBonus * wiggle_multiplier;
+            }
+
+            if (Math.Max(prevVelocity, currVelocity) != 0)
+            {
+                if (withSliderTravelDistance)
+                {
+                    // We want to use just the object jump without slider velocity when awarding differences
+                    currVelocity = currDistance / osuCurrObj.AdjustedDeltaTime;
+                }
+
+                // Scale with ratio of difference compared to 0.5 * max dist.
+                double distRatio = DifficultyCalculationUtils.Smoothstep(Math.Abs(prevVelocity - currVelocity) / Math.Max(prevVelocity, currVelocity), 0, 1);
+
+                // Reward for % distance up to 125 / strainTime for overlaps where velocity is still changing.
+                double overlapVelocityBuff = Math.Min(diameter * 1.25 / Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime), Math.Abs(prevVelocity - currVelocity));
+
+                double velocityChangeBonus = overlapVelocityBuff * distRatio;
+
+                // Penalize for rhythm changes.
+                velocityChangeBonus *= Math.Pow(Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime) / Math.Max(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime), 2);
+
+                snapDifficulty += velocityChangeBonus * velocity_change_multiplier;
+            }
+
+            // Reward sliders based on velocity.
+            if (osuCurrObj.BaseObject is Slider && withSliderTravelDistance)
+            {
+                double sliderBonus = osuCurrObj.TravelDistance / osuCurrObj.TravelTime;
+                snapDifficulty += (sliderBonus < 1 ? sliderBonus : Math.Pow(sliderBonus, 0.75)) * slider_multiplier;
+            }
+
+            // Apply high circle size bonus
+            snapDifficulty *= osuCurrObj.SmallCircleBonus;
+
+            snapDifficulty *= highBpmBonus(osuCurrObj.AdjustedDeltaTime);
+
+            return snapDifficulty;
+        }
+
+        private static double highBpmBonus(double ms) => 1 / (1 - Math.Pow(0.03, Math.Pow(ms / 1000, 0.65)));
+
+        private static double vectorAngleRepetition(OsuDifficultyHitObject current, OsuDifficultyHitObject previous)
+        {
+            if (current.Angle == null || previous.Angle == null)
+                return 1;
+
+            const double note_limit = 6;
+
+            double constantAngleCount = 0;
+
+            for (int index = 0; index < note_limit; index++)
+            {
+                var loopObj = (OsuDifficultyHitObject)current.Previous(index);
+
+                if (loopObj.IsNull())
+                    break;
+
+                // Only consider vectors in the same jump section, stopping to change rhythm ruins momentum
+                if (Math.Max(current.AdjustedDeltaTime, loopObj.AdjustedDeltaTime) > 1.1 * Math.Min(current.AdjustedDeltaTime, loopObj.AdjustedDeltaTime))
+                    break;
+
+                if (loopObj.NormalisedVectorAngle.IsNotNull() && current.NormalisedVectorAngle.IsNotNull())
+                {
+                    double angleDifference = Math.Abs(current.NormalisedVectorAngle.Value - loopObj.NormalisedVectorAngle.Value);
+                    // Refer to this desmos for tuning, constants need to be precise so that values stay within the range of 0 and 1.
+                    // https://www.desmos.com/calculator/a8jesv5sv2
+                    constantAngleCount += Math.Cos(8 * Math.Min(double.DegreesToRadians(11.25), angleDifference));
+                }
+            }
+
+            double vectorRepetition = Math.Pow(Math.Min(0.5 / constantAngleCount, 1), 2);
+
+            double stackFactor = DifficultyCalculationUtils.Smootherstep(current.LazyJumpDistance, 0, OsuDifficultyHitObject.NORMALISED_DIAMETER);
+
+            double currAngle = current.Angle.Value;
+            double lastAngle = previous.Angle.Value;
+
+            double angleDifferenceAdjusted = Math.Cos(2 * Math.Min(double.DegreesToRadians(45), Math.Abs(currAngle - lastAngle) * stackFactor));
+
+            double baseNerf = 1 - maximum_repetition_nerf * CalcAngleAcuteness(lastAngle) * angleDifferenceAdjusted;
+
+            return Math.Pow(baseNerf + (1 - baseNerf) * vectorRepetition * maximum_vector_influence * stackFactor, 2);
+        }
+
+        private static double calcAngleWideness(double angle) => DifficultyCalculationUtils.Smoothstep(angle, double.DegreesToRadians(40), double.DegreesToRadians(140));
+
+        public static double CalcAngleAcuteness(double angle) => DifficultyCalculationUtils.Smoothstep(angle, double.DegreesToRadians(140), double.DegreesToRadians(40));
+    }
+}

osu.Game.Rulesets.Osu/Difficulty/Evaluators/AimEvaluator.cs

@@ -1,172 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System;
-using osu.Game.Rulesets.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Difficulty.Utils;
-using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Osu.Objects;
-
-namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
-{
-    public static class AimEvaluator
-    {
-        private const double wide_angle_multiplier = 1.5;
-        private const double acute_angle_multiplier = 2.55;
-        private const double slider_multiplier = 1.35;
-        private const double velocity_change_multiplier = 0.75;
-        private const double wiggle_multiplier = 1.02;
-
-        /// <summary>
-        /// Evaluates the difficulty of aiming the current object, based on:
-        /// <list type="bullet">
-        /// <item><description>cursor velocity to the current object,</description></item>
-        /// <item><description>angle difficulty,</description></item>
-        /// <item><description>sharp velocity increases,</description></item>
-        /// <item><description>and slider difficulty.</description></item>
-        /// </list>
-        /// </summary>
-        public static double EvaluateDifficultyOf(DifficultyHitObject current, bool withSliderTravelDistance)
-        {
-            if (current.BaseObject is Spinner || current.Index <= 1 || current.Previous(0).BaseObject is Spinner)
-                return 0;
-
-            var osuCurrObj = (OsuDifficultyHitObject)current;
-            var osuLastObj = (OsuDifficultyHitObject)current.Previous(0);
-            var osuLastLastObj = (OsuDifficultyHitObject)current.Previous(1);
-            var osuLast2Obj = (OsuDifficultyHitObject)current.Previous(2);
-
-            const int radius = OsuDifficultyHitObject.NORMALISED_RADIUS;
-            const int diameter = OsuDifficultyHitObject.NORMALISED_DIAMETER;
-
-            // Calculate the velocity to the current hitobject, which starts with a base distance / time assuming the last object is a hitcircle.
-            double currVelocity = osuCurrObj.LazyJumpDistance / osuCurrObj.AdjustedDeltaTime;
-
-            // But if the last object is a slider, then we extend the travel velocity through the slider into the current object.
-            if (osuLastObj.BaseObject is Slider && withSliderTravelDistance)
-            {
-                double travelVelocity = osuLastObj.TravelDistance / osuLastObj.TravelTime; // calculate the slider velocity from slider head to slider end.
-                double movementVelocity = osuCurrObj.MinimumJumpDistance / osuCurrObj.MinimumJumpTime; // calculate the movement velocity from slider end to current object
-
-                currVelocity = Math.Max(currVelocity, movementVelocity + travelVelocity); // take the larger total combined velocity.
-            }
-
-            // As above, do the same for the previous hitobject.
-            double prevVelocity = osuLastObj.LazyJumpDistance / osuLastObj.AdjustedDeltaTime;
-
-            if (osuLastLastObj.BaseObject is Slider && withSliderTravelDistance)
-            {
-                double travelVelocity = osuLastLastObj.TravelDistance / osuLastLastObj.TravelTime;
-                double movementVelocity = osuLastObj.MinimumJumpDistance / osuLastObj.MinimumJumpTime;
-
-                prevVelocity = Math.Max(prevVelocity, movementVelocity + travelVelocity);
-            }
-
-            double wideAngleBonus = 0;
-            double acuteAngleBonus = 0;
-            double sliderBonus = 0;
-            double velocityChangeBonus = 0;
-            double wiggleBonus = 0;
-
-            double aimStrain = currVelocity; // Start strain with regular velocity.
-
-            if (osuCurrObj.Angle != null && osuLastObj.Angle != null)
-            {
-                double currAngle = osuCurrObj.Angle.Value;
-                double lastAngle = osuLastObj.Angle.Value;
-
-                // Rewarding angles, take the smaller velocity as base.
-                double angleBonus = Math.Min(currVelocity, prevVelocity);
-
-                if (Math.Max(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime) < 1.25 * Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime)) // If rhythms are the same.
-                {
-                    acuteAngleBonus = calcAcuteAngleBonus(currAngle);
-
-                    // Penalize angle repetition.
-                    acuteAngleBonus *= 0.08 + 0.92 * (1 - Math.Min(acuteAngleBonus, Math.Pow(calcAcuteAngleBonus(lastAngle), 3)));
-
-                    // Apply acute angle bonus for BPM above 300 1/2 and distance more than one diameter
-                    acuteAngleBonus *= angleBonus *
-                                       DifficultyCalculationUtils.Smootherstep(DifficultyCalculationUtils.MillisecondsToBPM(osuCurrObj.AdjustedDeltaTime, 2), 300, 400) *
-                                       DifficultyCalculationUtils.Smootherstep(osuCurrObj.LazyJumpDistance, diameter, diameter * 2);
-                }
-
-                wideAngleBonus = calcWideAngleBonus(currAngle);
-
-                // Penalize angle repetition.
-                wideAngleBonus *= 1 - Math.Min(wideAngleBonus, Math.Pow(calcWideAngleBonus(lastAngle), 3));
-
-                // Apply full wide angle bonus for distance more than one diameter
-                wideAngleBonus *= angleBonus * DifficultyCalculationUtils.Smootherstep(osuCurrObj.LazyJumpDistance, 0, diameter);
-
-                // Apply wiggle bonus for jumps that are [radius, 3*diameter] in distance, with < 110 angle
-                // https://www.desmos.com/calculator/dp0v0nvowc
-                wiggleBonus = angleBonus
-                              * DifficultyCalculationUtils.Smootherstep(osuCurrObj.LazyJumpDistance, radius, diameter)
-                              * Math.Pow(DifficultyCalculationUtils.ReverseLerp(osuCurrObj.LazyJumpDistance, diameter * 3, diameter), 1.8)
-                              * DifficultyCalculationUtils.Smootherstep(currAngle, double.DegreesToRadians(110), double.DegreesToRadians(60))
-                              * DifficultyCalculationUtils.Smootherstep(osuLastObj.LazyJumpDistance, radius, diameter)
-                              * Math.Pow(DifficultyCalculationUtils.ReverseLerp(osuLastObj.LazyJumpDistance, diameter * 3, diameter), 1.8)
-                              * DifficultyCalculationUtils.Smootherstep(lastAngle, double.DegreesToRadians(110), double.DegreesToRadians(60));
-
-                if (osuLast2Obj != null)
-                {
-                    // If objects just go back and forth through a middle point - don't give as much wide bonus
-                    // Use Previous(2) and Previous(0) because angles calculation is done prevprev-prev-curr, so any object's angle's center point is always the previous object
-                    var lastBaseObject = (OsuHitObject)osuLastObj.BaseObject;
-                    var last2BaseObject = (OsuHitObject)osuLast2Obj.BaseObject;
-
-                    float distance = (last2BaseObject.StackedPosition - lastBaseObject.StackedPosition).Length;
-
-                    if (distance < 1)
-                    {
-                        wideAngleBonus *= 1 - 0.35 * (1 - distance);
-                    }
-                }
-            }
-
-            if (Math.Max(prevVelocity, currVelocity) != 0)
-            {
-                // We want to use the average velocity over the whole object when awarding differences, not the individual jump and slider path velocities.
-                prevVelocity = (osuLastObj.LazyJumpDistance + osuLastLastObj.TravelDistance) / osuLastObj.AdjustedDeltaTime;
-                currVelocity = (osuCurrObj.LazyJumpDistance + osuLastObj.TravelDistance) / osuCurrObj.AdjustedDeltaTime;
-
-                // Scale with ratio of difference compared to 0.5 * max dist.
-                double distRatio = DifficultyCalculationUtils.Smoothstep(Math.Abs(prevVelocity - currVelocity) / Math.Max(prevVelocity, currVelocity), 0, 1);
-
-                // Reward for % distance up to 125 / strainTime for overlaps where velocity is still changing.
-                double overlapVelocityBuff = Math.Min(diameter * 1.25 / Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime), Math.Abs(prevVelocity - currVelocity));
-
-                velocityChangeBonus = overlapVelocityBuff * distRatio;
-
-                // Penalize for rhythm changes.
-                velocityChangeBonus *= Math.Pow(Math.Min(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime) / Math.Max(osuCurrObj.AdjustedDeltaTime, osuLastObj.AdjustedDeltaTime), 2);
-            }
-
-            if (osuLastObj.BaseObject is Slider)
-            {
-                // Reward sliders based on velocity.
-                sliderBonus = osuLastObj.TravelDistance / osuLastObj.TravelTime;
-            }
-
-            aimStrain += wiggleBonus * wiggle_multiplier;
-            aimStrain += velocityChangeBonus * velocity_change_multiplier;
-
-            // Add in acute angle bonus or wide angle bonus, whichever is larger.
-            aimStrain += Math.Max(acuteAngleBonus * acute_angle_multiplier, wideAngleBonus * wide_angle_multiplier);
-
-            // Apply high circle size bonus
-            aimStrain *= osuCurrObj.SmallCircleBonus;
-
-            // Add in additional slider velocity bonus.
-            if (withSliderTravelDistance)
-                aimStrain += sliderBonus * slider_multiplier;
-
-            return aimStrain;
-        }
-
-        private static double calcWideAngleBonus(double angle) => DifficultyCalculationUtils.Smoothstep(angle, double.DegreesToRadians(40), double.DegreesToRadians(140));
-
-        private static double calcAcuteAngleBonus(double angle) => DifficultyCalculationUtils.Smoothstep(angle, double.DegreesToRadians(140), double.DegreesToRadians(40));
-    }
-}

osu.Game.Rulesets.Osu/Difficulty/Evaluators/FlashlightEvaluator.cs

@@ -2,8 +2,12 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.Collections.Generic;
+using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
@@ -28,7 +32,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
         /// <item><description>and whether the hidden mod is enabled.</description></item>
         /// </list>
         /// </summary>
-        public static double EvaluateDifficultyOf(DifficultyHitObject current, bool hidden)
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, IReadOnlyList<Mod> mods)
         {
             if (current.BaseObject is Spinner)
                 return 0;
@@ -40,7 +44,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             double smallDistNerf = 1.0;
             double cumulativeStrainTime = 0.0;
 
-            double result = 0.0;
+            double flashlightDifficulty = 0.0;
 
             OsuDifficultyHitObject lastObj = osuCurrent;
 
@@ -66,9 +70,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                     double stackNerf = Math.Min(1.0, (currentObj.LazyJumpDistance / scalingFactor) / 25.0);
 
                     // Bonus based on how visible the object is.
-                    double opacityBonus = 1.0 + max_opacity_bonus * (1.0 - osuCurrent.OpacityAt(currentHitObject.StartTime, hidden));
+                    double opacityBonus = 1.0 + max_opacity_bonus * (1.0 - osuCurrent.OpacityAt(currentHitObject.StartTime, mods.OfType<OsuModHidden>().Any(m => !m.OnlyFadeApproachCircles.Value)));
 
-                    result += stackNerf * opacityBonus * scalingFactor * jumpDistance / cumulativeStrainTime;
+                    flashlightDifficulty += stackNerf * opacityBonus * scalingFactor * jumpDistance / cumulativeStrainTime;
 
                     if (currentObj.Angle != null && osuCurrent.Angle != null)
                     {
@@ -81,14 +85,14 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                 lastObj = currentObj;
             }
 
-            result = Math.Pow(smallDistNerf * result, 2.0);
+            flashlightDifficulty = Math.Pow(smallDistNerf * flashlightDifficulty, 2.0);
 
             // Additional bonus for Hidden due to there being no approach circles.
-            if (hidden)
-                result *= 1.0 + hidden_bonus;
+            if (mods.OfType<OsuModHidden>().Any())
+                flashlightDifficulty *= 1.0 + hidden_bonus;
 
             // Nerf patterns with repeated angles.
-            result *= min_angle_multiplier + (1.0 - min_angle_multiplier) / (angleRepeatCount + 1.0);
+            flashlightDifficulty *= min_angle_multiplier + (1.0 - min_angle_multiplier) / (angleRepeatCount + 1.0);
 
             double sliderBonus = 0.0;
 
@@ -108,9 +112,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                     sliderBonus /= (osuSlider.RepeatCount + 1);
             }
 
-            result += sliderBonus * slider_multiplier;
+            flashlightDifficulty += sliderBonus * slider_multiplier;
 
-            return result;
+            return flashlightDifficulty;
         }
     }
 }

osu.Game.Rulesets.Osu/Difficulty/Evaluators/ReadingEvaluator.cs

@@ -0,0 +1,272 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Objects;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
+{
+    public static class ReadingEvaluator
+    {
+        private const double reading_window_size = 3000; // 3 seconds
+        private const double distance_influence_threshold = OsuDifficultyHitObject.NORMALISED_DIAMETER * 1.5; // 1.5 circles distance between centers
+        private const double hidden_multiplier = 0.28;
+        private const double density_multiplier = 2.4;
+        private const double density_difficulty_base = 2.5;
+        private const double preempt_balancing_factor = 140000;
+        private const double preempt_starting_point = 500; // AR 9.66 in milliseconds
+        private const double minimum_angle_relevancy_time = 2000; // 2 seconds
+        private const double maximum_angle_relevancy_time = 200;
+
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, bool hidden)
+        {
+            if (current.BaseObject is Spinner || current.Index == 0)
+                return 0;
+
+            var currObj = (OsuDifficultyHitObject)current;
+            var nextObj = (OsuDifficultyHitObject)current.Next(0);
+
+            double velocity = Math.Max(1, currObj.LazyJumpDistance / currObj.AdjustedDeltaTime); // Only allow velocity to buff
+
+            double currentVisibleObjectDensity = retrieveCurrentVisibleObjectDensity(currObj);
+            double pastObjectDifficultyInfluence = getPastObjectDifficultyInfluence(currObj);
+
+            double constantAngleNerfFactor = getConstantAngleNerfFactor(currObj);
+
+            double noteDensityDifficulty = calculateDensityDifficulty(nextObj, velocity, constantAngleNerfFactor, pastObjectDifficultyInfluence, currentVisibleObjectDensity);
+
+            double hiddenDifficulty = hidden
+                ? calculateHiddenDifficulty(currObj, pastObjectDifficultyInfluence, currentVisibleObjectDensity, velocity, constantAngleNerfFactor)
+                : 0;
+
+            double preemptDifficulty = calculatePreemptDifficulty(velocity, constantAngleNerfFactor, currObj.Preempt);
+
+            double readingDifficulty = DifficultyCalculationUtils.Norm(1.5, preemptDifficulty, hiddenDifficulty, noteDensityDifficulty);
+
+            // Having less time to process information is harder
+            readingDifficulty *= highBpmBonus(currObj.AdjustedDeltaTime);
+
+            return readingDifficulty;
+        }
+
+        /// <summary>
+        /// Calculates the density difficulty of the current object and how hard it is to aim it because of it based on:
+        /// <list type="bullet">
+        /// <item><description>cursor velocity to the current object,</description></item>
+        /// <item><description>how many times the current object's angle was repeated,</description></item>
+        /// <item><description>density of objects visible when the current object appears,</description></item>
+        /// <item><description>density of objects visible when the current object needs to be clicked,</description></item>
+        /// /// </list>
+        /// </summary>
+        private static double calculateDensityDifficulty(OsuDifficultyHitObject? nextObj, double velocity, double constantAngleNerfFactor,
+                                                         double pastObjectDifficultyInfluence, double currentVisibleObjectDensity)
+        {
+            // Consider future densities too because it can make the path the cursor takes less clear
+            double futureObjectDifficultyInfluence = Math.Sqrt(currentVisibleObjectDensity);
+
+            if (nextObj != null)
+            {
+                // Reduce difficulty if movement to next object is small
+                futureObjectDifficultyInfluence *= DifficultyCalculationUtils.Smootherstep(nextObj.LazyJumpDistance, 15, distance_influence_threshold);
+            }
+
+            // Value higher note densities exponentially
+            double noteDensityDifficulty = Math.Pow(pastObjectDifficultyInfluence + futureObjectDifficultyInfluence, 1.7) * 0.4 * constantAngleNerfFactor * velocity;
+
+            // Award only denser than average maps.
+            noteDensityDifficulty = Math.Max(0, noteDensityDifficulty - density_difficulty_base);
+
+            // Apply a soft cap to general density reading to account for partial memorization
+            noteDensityDifficulty = Math.Pow(noteDensityDifficulty, 0.45) * density_multiplier;
+
+            return noteDensityDifficulty;
+        }
+
+        /// <summary>
+        /// Calculates the difficulty of aiming the current object when the approach rate is very high based on:
+        /// <list type="bullet">
+        /// <item><description>cursor velocity to the current object,</description></item>
+        /// <item><description>how many times the current object's angle was repeated,</description></item>
+        /// <item><description>how many milliseconds elapse between the approach circle appearing and touching the inner circle</description></item>
+        /// </list>
+        /// </summary>
+        private static double calculatePreemptDifficulty(double velocity, double constantAngleNerfFactor, double preempt)
+        {
+            // Arbitrary curve for the base value preempt difficulty should have as approach rate increases.
+            // https://www.desmos.com/calculator/c175335a71
+            double preemptDifficulty = Math.Pow((preempt_starting_point - preempt + Math.Abs(preempt - preempt_starting_point)) / 2, 2.5) / preempt_balancing_factor;
+
+            preemptDifficulty *= constantAngleNerfFactor * velocity;
+
+            return preemptDifficulty;
+        }
+
+        /// <summary>
+        /// Calculates the difficulty of aiming the current object when the hidden mod is active based on:
+        /// <list type="bullet">
+        /// <item><description>cursor velocity to the current object,</description></item>
+        /// <item><description>time the current object spends invisible,</description></item>
+        /// <item><description>density of objects visible when the current object appears,</description></item>
+        /// <item><description>density of objects visible when the current object needs to be clicked,</description></item>
+        /// <item><description>how many times the current object's angle was repeated,</description></item>
+        /// <item><description>if the current object is perfectly stacked to the previous one</description></item>
+        /// </list>
+        /// </summary>
+        private static double calculateHiddenDifficulty(OsuDifficultyHitObject currObj, double pastObjectDifficultyInfluence, double currentVisibleObjectDensity, double velocity,
+                                                        double constantAngleNerfFactor)
+        {
+            // Higher preempt means that time spent invisible is higher too, we want to reward that
+            double preemptFactor = Math.Pow(currObj.Preempt, 2.2) * 0.01;
+
+            // Account for both past and current densities
+            double densityFactor = Math.Pow(currentVisibleObjectDensity + pastObjectDifficultyInfluence, 3.3) * 3;
+
+            double hiddenDifficulty = (preemptFactor + densityFactor) * constantAngleNerfFactor * velocity * 0.01;
+
+            // Apply a soft cap to general HD reading to account for partial memorization
+            hiddenDifficulty = Math.Pow(hiddenDifficulty, 0.4) * hidden_multiplier;
+
+            var previousObj = (OsuDifficultyHitObject)currObj.Previous(0);
+
+            // Buff perfect stacks only if current note is completely invisible at the time you click the previous note.
+            if (currObj.LazyJumpDistance == 0 && currObj.OpacityAt(previousObj.BaseObject.StartTime, true) == 0 && previousObj.StartTime > currObj.StartTime - currObj.Preempt)
+                hiddenDifficulty += hidden_multiplier * 2500 / Math.Pow(currObj.AdjustedDeltaTime, 1.5); // Perfect stacks are harder the less time between notes
+
+            return hiddenDifficulty;
+        }
+
+        private static double getPastObjectDifficultyInfluence(OsuDifficultyHitObject currObj)
+        {
+            double pastObjectDifficultyInfluence = 0;
+
+            foreach (var loopObj in retrievePastVisibleObjects(currObj))
+            {
+                double loopDifficulty = currObj.OpacityAt(loopObj.BaseObject.StartTime, false);
+
+                // When aiming an object small distances mean previous objects may be cheesed, so it doesn't matter whether they were arranged confusingly.
+                loopDifficulty *= DifficultyCalculationUtils.Smootherstep(loopObj.LazyJumpDistance, 15, distance_influence_threshold);
+
+                // Account less for objects close to the max reading window
+                double timeBetweenCurrAndLoopObj = currObj.StartTime - loopObj.StartTime;
+                double timeNerfFactor = getTimeNerfFactor(timeBetweenCurrAndLoopObj);
+
+                loopDifficulty *= timeNerfFactor;
+                pastObjectDifficultyInfluence += loopDifficulty;
+            }
+
+            return pastObjectDifficultyInfluence;
+        }
+
+        // Returns a list of objects that are visible on screen at the point in time the current object becomes visible.
+        private static IEnumerable<OsuDifficultyHitObject> retrievePastVisibleObjects(OsuDifficultyHitObject current)
+        {
+            for (int i = 0; i < current.Index; i++)
+            {
+                OsuDifficultyHitObject hitObject = (OsuDifficultyHitObject)current.Previous(i);
+
+                if (hitObject.IsNull() ||
+                    current.StartTime - hitObject.StartTime > reading_window_size ||
+                    hitObject.StartTime < current.StartTime - current.Preempt) // Current object not visible at the time object needs to be clicked
+                    break;
+
+                yield return hitObject;
+            }
+        }
+
+        // Returns the density of objects visible at the point in time the current object needs to be clicked capped by the reading window.
+        private static double retrieveCurrentVisibleObjectDensity(OsuDifficultyHitObject current)
+        {
+            double visibleObjectCount = 0;
+
+            OsuDifficultyHitObject? hitObject = (OsuDifficultyHitObject)current.Next(0);
+
+            while (hitObject != null)
+            {
+                if (hitObject.StartTime - current.StartTime > reading_window_size ||
+                    current.StartTime < hitObject.StartTime - hitObject.Preempt) // Object not visible at the time current object needs to be clicked.
+                    break;
+
+                double timeBetweenCurrAndLoopObj = hitObject.StartTime - current.StartTime;
+                double timeNerfFactor = getTimeNerfFactor(timeBetweenCurrAndLoopObj);
+
+                visibleObjectCount += hitObject.OpacityAt(current.BaseObject.StartTime, false) * timeNerfFactor;
+
+                hitObject = (OsuDifficultyHitObject?)hitObject.Next(0);
+            }
+
+            return visibleObjectCount;
+        }
+
+        // Returns a factor of how often the current object's angle has been repeated in a certain time frame.
+        // It does this by checking the difference in angle between current and past objects and sums them based on a range of similarity.
+        // https://www.desmos.com/calculator/eb057a4822
+        private static double getConstantAngleNerfFactor(OsuDifficultyHitObject current)
+        {
+            double constantAngleCount = 0;
+            int index = 0;
+            double currentTimeGap = 0;
+
+            OsuDifficultyHitObject loopObjPrev0 = current;
+            OsuDifficultyHitObject? loopObjPrev1 = null;
+            OsuDifficultyHitObject? loopObjPrev2 = null;
+
+            while (currentTimeGap < minimum_angle_relevancy_time)
+            {
+                var loopObj = (OsuDifficultyHitObject)current.Previous(index);
+
+                if (loopObj.IsNull())
+                    break;
+
+                // Account less for objects that are close to the time limit.
+                double longIntervalFactor = 1 - DifficultyCalculationUtils.ReverseLerp(loopObj.AdjustedDeltaTime, maximum_angle_relevancy_time, minimum_angle_relevancy_time);
+
+                if (loopObj.Angle.IsNotNull() && current.Angle.IsNotNull())
+                {
+                    double angleDifference = Math.Abs(current.Angle.Value - loopObj.Angle.Value);
+                    double angleDifferenceAlternating = Math.PI;
+
+                    if (loopObjPrev0.Angle != null && loopObjPrev1?.Angle != null && loopObjPrev2?.Angle != null)
+                    {
+                        angleDifferenceAlternating = Math.Abs(loopObjPrev1.Angle.Value - loopObj.Angle.Value);
+                        angleDifferenceAlternating += Math.Abs(loopObjPrev2.Angle.Value - loopObjPrev0.Angle.Value);
+
+                        double weight = 1.0;
+
+                        // Be sure that one of the angles is very sharp, when other is wide
+                        weight *= DifficultyCalculationUtils.ReverseLerp(Math.Min(loopObj.Angle.Value, loopObjPrev0.Angle.Value) * 180 / Math.PI, 20, 5);
+                        weight *= DifficultyCalculationUtils.ReverseLerp(Math.Max(loopObj.Angle.Value, loopObjPrev0.Angle.Value) * 180 / Math.PI, 60, 120);
+
+                        // Lerp between max angle difference and rescaled alternating difference, with more harsh scaling compared to normal difference
+                        angleDifferenceAlternating = double.Lerp(Math.PI, 0.1 * angleDifferenceAlternating, weight);
+                    }
+
+                    double stackFactor = DifficultyCalculationUtils.Smootherstep(loopObj.LazyJumpDistance, 0, OsuDifficultyHitObject.NORMALISED_RADIUS);
+
+                    constantAngleCount += Math.Cos(3 * Math.Min(double.DegreesToRadians(30), Math.Min(angleDifference, angleDifferenceAlternating) * stackFactor)) * longIntervalFactor;
+                }
+
+                currentTimeGap = current.StartTime - loopObj.StartTime;
+                index++;
+
+                loopObjPrev2 = loopObjPrev1;
+                loopObjPrev1 = loopObjPrev0;
+                loopObjPrev0 = loopObj;
+            }
+
+            return Math.Clamp(2 / constantAngleCount, 0.2, 1);
+        }
+
+        // Returns a nerfing factor for when objects are very distant in time, affecting reading less.
+        private static double getTimeNerfFactor(double deltaTime)
+        {
+            return Math.Clamp(2 - deltaTime / (reading_window_size / 2), 0, 1);
+        }
+
+        private static double highBpmBonus(double ms) => 1 / (1 - Math.Pow(0.8, ms / 1000));
+    }
+}

osu.Game.Rulesets.Osu/Difficulty/Evaluators/Speed/RhythmEvaluator.cs

@@ -8,15 +8,16 @@ using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Scoring;
 
-namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
 {
     public static class RhythmEvaluator
     {
         private const int history_time_max = 5 * 1000; // 5 seconds
         private const int history_objects_max = 32;
-        private const double rhythm_overall_multiplier = 1.0;
-        private const double rhythm_ratio_multiplier = 15.0;
+        private const double rhythm_overall_multiplier = 0.95;
+        private const double rhythm_ratio_multiplier = 26.0;
 
         /// <summary>
         /// Calculates a rhythm multiplier for the difficulty of the tap associated with historic data of the current <see cref="OsuDifficultyHitObject"/>.
@@ -26,11 +27,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             if (current.BaseObject is Spinner)
                 return 0;
 
-            var currentOsuObject = (OsuDifficultyHitObject)current;
-
             double rhythmComplexitySum = 0;
 
-            double deltaDifferenceEpsilon = ((OsuDifficultyHitObject)current).HitWindowGreat * 0.3;
+            double deltaDifferenceEpsilon = ((OsuDifficultyHitObject)current).HitWindow(HitResult.Great) * 0.3;
 
             var island = new Island(deltaDifferenceEpsilon);
             var previousIsland = new Island(deltaDifferenceEpsilon);
@@ -57,6 +56,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             for (int i = rhythmStart; i > 0; i--)
             {
                 OsuDifficultyHitObject currObj = (OsuDifficultyHitObject)current.Previous(i - 1);
+                if (currObj.BaseObject is Spinner)
+                    continue;
 
                 // scales note 0 to 1 from history to now
                 double timeDecay = (history_time_max - (current.StartTime - currObj.StartTime)) / history_time_max;
@@ -64,44 +65,56 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
 
                 double currHistoricalDecay = Math.Min(noteDecay, timeDecay); // either we're limited by time or limited by object count.
 
-                // Use custom cap value to ensure that that at this point delta time is actually zero
+                // Use custom cap value to ensure that at this point delta time is actually zero
                 double currDelta = Math.Max(currObj.DeltaTime, 1e-7);
                 double prevDelta = Math.Max(prevObj.DeltaTime, 1e-7);
                 double lastDelta = Math.Max(lastObj.DeltaTime, 1e-7);
 
+                // Make sure to always have the current island initialised - if we don't do it here it will only initialise on the next rhythm change
+                if (island.Delta == int.MaxValue)
+                    island = new Island((int)currDelta, deltaDifferenceEpsilon);
+
                 // calculate how much current delta difference deserves a rhythm bonus
                 // this function is meant to reduce rhythm bonus for deltas that are multiples of each other (i.e 100 and 200)
                 double deltaDifference = Math.Max(prevDelta, currDelta) / Math.Min(prevDelta, currDelta);
 
-                // Take only the fractional part of the value since we're only interested in punishing multiples
-                double deltaDifferenceFraction = deltaDifference - Math.Truncate(deltaDifference);
-
-                double currRatio = 1.0 + rhythm_ratio_multiplier * Math.Min(0.5, DifficultyCalculationUtils.SmoothstepBellCurve(deltaDifferenceFraction));
-
                 // reduce ratio bonus if delta difference is too big
                 double differenceMultiplier = Math.Clamp(2.0 - deltaDifference / 8.0, 0.0, 1.0);
 
                 double windowPenalty = Math.Min(1, Math.Max(0, Math.Abs(prevDelta - currDelta) - deltaDifferenceEpsilon) / deltaDifferenceEpsilon);
 
-                double effectiveRatio = windowPenalty * currRatio * differenceMultiplier;
+                double effectiveRatio = getEffectiveRatio(deltaDifference) * windowPenalty * differenceMultiplier;
+
+                // if previous object is a slider it might be easier to tap since you don't have to do a whole tapping motion
+                // while a full deltatime might end up some weird ratio the "unpress->tap" motion might be simple
+                // for example a slider-circle-circle pattern should be evaluated as a regular triple and not as a single->double
+                if (prevObj.BaseObject is Slider)
+                {
+                    double sliderLazyEndDelta = currObj.MinimumJumpTime;
+                    double sliderLazyDeltaDifference = Math.Max(sliderLazyEndDelta, currDelta) / Math.Min(sliderLazyEndDelta, currDelta);
+
+                    double sliderRealEndDelta = currObj.LastObjectEndDeltaTime;
+                    double sliderRealDeltaDifference = Math.Max(sliderRealEndDelta, currDelta) / Math.Min(sliderRealEndDelta, currDelta);
+
+                    double sliderEffectiveRatio = Math.Min(getEffectiveRatio(sliderLazyDeltaDifference), getEffectiveRatio(sliderRealDeltaDifference));
+                    effectiveRatio = Math.Min(sliderEffectiveRatio, effectiveRatio);
+                }
+
+                bool isSpeedingUp = prevDelta > currDelta + deltaDifferenceEpsilon;
+
+                if (Math.Abs(prevDelta - currDelta) < deltaDifferenceEpsilon)
+                {
+                    // island is still progressing
+                    island.AddDelta((int)currDelta);
+                }
 
                 if (firstDeltaSwitch)
                 {
-                    if (Math.Abs(prevDelta - currDelta) < deltaDifferenceEpsilon)
-                    {
-                        // island is still progressing
-                        island.AddDelta((int)currDelta);
-                    }
-                    else
+                    if (Math.Abs(prevDelta - currDelta) > deltaDifferenceEpsilon)
                     {
                         // bpm change is into slider, this is easy acc window
                         if (currObj.BaseObject is Slider)
-                            effectiveRatio *= 0.125;
-
-                        // bpm change was from a slider, this is easier typically than circle -> circle
-                        // unintentional side effect is that bursts with kicksliders at the ends might have lower difficulty than bursts without sliders
-                        if (prevObj.BaseObject is Slider)
-                            effectiveRatio *= 0.3;
+                            effectiveRatio *= 0.5;
 
                         // repeated island polarity (2 -> 4, 3 -> 5)
                         if (island.IsSimilarPolarity(previousIsland))
@@ -116,6 +129,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                         if (previousIsland.DeltaCount == island.DeltaCount)
                             effectiveRatio *= 0.5;
 
+                        if (isSpeedingUp)
+                            effectiveRatio *= 0.65;
+
                         var islandCount = islandCounts.FirstOrDefault(x => x.Island.Equals(island));
 
                         if (islandCount != default)
@@ -134,7 +150,10 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                         }
                         else
                         {
-                            islandCounts.Add((island, 1));
+                            if (island.DeltaCount > 0)
+                            {
+                                islandCounts.Add((island, 1));
+                            }
                         }
 
                         // scale down the difficulty if the object is doubletappable
@@ -176,10 +195,18 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                 prevObj = currObj;
             }
 
-            double rhythmDifficulty = Math.Sqrt(4 + rhythmComplexitySum * rhythm_overall_multiplier) / 2.0; // produces multiplier that can be applied to strain. range [1, infinity) (not really though)
-            rhythmDifficulty *= 1 - currentOsuObject.GetDoubletapness((OsuDifficultyHitObject)current.Next(0));
+            // If the current island is long we don't want the sum to have as big of an effect
+            rhythmComplexitySum *= DifficultyCalculationUtils.ReverseLerp(island.DeltaCount, 22, 3);
 
-            return rhythmDifficulty;
+            return Math.Sqrt(4 + rhythmComplexitySum * rhythm_overall_multiplier) / 2.0; // produces multiplier that can be applied to strain. range [1, infinity) (not really though);
+        }
+
+        private static double getEffectiveRatio(double deltaDifference)
+        {
+            // Take only the fractional part of the value since we're only interested in punishing multiples
+            double deltaDifferenceFraction = deltaDifference - Math.Truncate(deltaDifference);
+
+            return 1.0 + rhythm_ratio_multiplier * Math.Min(0.5, DifficultyCalculationUtils.SmoothstepBellCurve(deltaDifferenceFraction));
         }
 
         private class Island : IEquatable<Island>
@@ -211,9 +238,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
 
             public bool IsSimilarPolarity(Island other)
             {
-                // TODO: consider islands to be of similar polarity only if they're having the same average delta (we don't want to consider 3 singletaps similar to a triple)
-                //       naively adding delta check here breaks _a lot_ of maps because of the flawed ratio calculation
-                return DeltaCount % 2 == other.DeltaCount % 2;
+                // single delta islands shouldn't be compared
+                if (DeltaCount <= 1 || other.DeltaCount <= 1)
+                    return false;
+
+                return Math.Abs(Delta - other.Delta) < deltaDifferenceEpsilon &&
+                       DeltaCount % 2 == other.DeltaCount % 2;
             }
 
             public bool Equals(Island? other)

osu.Game.Rulesets.Osu/Difficulty/Evaluators/Speed/SpeedEvaluator.cs

@@ -2,47 +2,39 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using System.Collections.Generic;
-using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Utils;
-using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Scoring;
 
-namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
 {
     public static class SpeedEvaluator
     {
-        private const double single_spacing_threshold = OsuDifficultyHitObject.NORMALISED_DIAMETER * 1.25; // 1.25 circles distance between centers
         private const double min_speed_bonus = 200; // 200 BPM 1/4th
         private const double speed_balancing_factor = 40;
-        private const double distance_multiplier = 0.8;
 
         /// <summary>
         /// Evaluates the difficulty of tapping the current object, based on:
         /// <list type="bullet">
         /// <item><description>time between pressing the previous and current object,</description></item>
-        /// <item><description>distance between those objects,</description></item>
         /// <item><description>and how easily they can be cheesed.</description></item>
         /// </list>
         /// </summary>
-        public static double EvaluateDifficultyOf(DifficultyHitObject current, IReadOnlyList<Mod> mods)
+        public static double EvaluateDifficultyOf(DifficultyHitObject current)
         {
             if (current.BaseObject is Spinner)
                 return 0;
 
-            // derive strainTime for calculation
             var osuCurrObj = (OsuDifficultyHitObject)current;
-            var osuPrevObj = current.Index > 0 ? (OsuDifficultyHitObject)current.Previous(0) : null;
 
             double strainTime = osuCurrObj.AdjustedDeltaTime;
             double doubletapness = 1.0 - osuCurrObj.GetDoubletapness((OsuDifficultyHitObject?)osuCurrObj.Next(0));
 
             // Cap deltatime to the OD 300 hitwindow.
             // 0.93 is derived from making sure 260bpm OD8 streams aren't nerfed harshly, whilst 0.92 limits the effect of the cap.
-            strainTime /= Math.Clamp((strainTime / osuCurrObj.HitWindowGreat) / 0.93, 0.92, 1);
+            strainTime /= Math.Clamp((strainTime / osuCurrObj.HitWindow(HitResult.Great)) / 0.93, 0.92, 1);
 
             // speedBonus will be 0.0 for BPM < 200
             double speedBonus = 0.0;
@@ -51,26 +43,15 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             if (DifficultyCalculationUtils.MillisecondsToBPM(strainTime) > min_speed_bonus)
                 speedBonus = 0.75 * Math.Pow((DifficultyCalculationUtils.BPMToMilliseconds(min_speed_bonus) - strainTime) / speed_balancing_factor, 2);
 
-            double travelDistance = osuPrevObj?.TravelDistance ?? 0;
-            double distance = travelDistance + osuCurrObj.MinimumJumpDistance;
-
-            // Cap distance at single_spacing_threshold
-            distance = Math.Min(distance, single_spacing_threshold);
-
-            // Max distance bonus is 1 * `distance_multiplier` at single_spacing_threshold
-            double distanceBonus = Math.Pow(distance / single_spacing_threshold, 3.95) * distance_multiplier;
-
-            // Apply reduced small circle bonus because flow aim difficulty on small circles doesn't scale as hard as jumps
-            distanceBonus *= Math.Sqrt(osuCurrObj.SmallCircleBonus);
-
-            if (mods.OfType<OsuModAutopilot>().Any())
-                distanceBonus = 0;
-
             // Base difficulty with all bonuses
-            double difficulty = (1 + speedBonus + distanceBonus) * 1000 / strainTime;
+            double speedDifficulty = (1 + speedBonus) * 1000 / strainTime;
+
+            speedDifficulty *= highBpmBonus(osuCurrObj.AdjustedDeltaTime);
 
             // Apply penalty if there's doubletappable doubles
-            return difficulty * doubletapness;
+            return speedDifficulty * doubletapness;
         }
+
+        private static double highBpmBonus(double ms) => 1 / (1 - Math.Pow(0.3, ms / 1000));
     }
 }

osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyAttributes.cs

@@ -45,6 +45,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         [JsonProperty("flashlight_difficulty")]
         public double FlashlightDifficulty { get; set; }
 
+        /// <summary>
+        /// The difficulty corresponding to the reading skill.
+        /// </summary>
+        [JsonProperty("reading_difficulty")]
+        public double ReadingDifficulty { get; set; }
+
         /// <summary>
         /// Describes how much of <see cref="AimDifficulty"/> is contributed to by hitcircles or sliders.
         /// A value closer to 1.0 indicates most of <see cref="AimDifficulty"/> is contributed by hitcircles.
@@ -75,6 +81,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         [JsonProperty("speed_difficult_strain_count")]
         public double SpeedDifficultStrainCount { get; set; }
 
+        [JsonProperty("reading_difficult_note_count")]
+        public double ReadingDifficultNoteCount { get; set; }
+
         [JsonProperty("nested_score_per_object")]
         public double NestedScorePerObject { get; set; }
 
@@ -84,11 +93,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         [JsonProperty("maximum_legacy_combo_score")]
         public double MaximumLegacyComboScore { get; set; }
 
-        /// <summary>
-        /// The beatmap's drain rate. This doesn't scale with rate-adjusting mods.
-        /// </summary>
-        public double DrainRate { get; set; }
-
         /// <summary>
         /// The number of hitcircles in the beatmap.
         /// </summary>
@@ -111,6 +115,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             yield return (ATTRIB_ID_AIM, AimDifficulty);
             yield return (ATTRIB_ID_SPEED, SpeedDifficulty);
+            yield return (ATTRIB_ID_READING, ReadingDifficulty);
             yield return (ATTRIB_ID_DIFFICULTY, StarRating);
 
             if (ShouldSerializeFlashlightDifficulty())
@@ -127,6 +132,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             yield return (ATTRIB_ID_NESTED_SCORE_PER_OBJECT, NestedScorePerObject);
             yield return (ATTRIB_ID_LEGACY_SCORE_BASE_MULTIPLIER, LegacyScoreBaseMultiplier);
             yield return (ATTRIB_ID_MAXIMUM_LEGACY_COMBO_SCORE, MaximumLegacyComboScore);
+            yield return (ATTRIB_ID_READING_DIFFICULT_NOTE_COUNT, ReadingDifficultNoteCount);
         }
 
         public override void FromDatabaseAttributes(IReadOnlyDictionary<int, double> values, IBeatmapOnlineInfo onlineInfo)
@@ -135,6 +141,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             AimDifficulty = values[ATTRIB_ID_AIM];
             SpeedDifficulty = values[ATTRIB_ID_SPEED];
+            ReadingDifficulty = values[ATTRIB_ID_READING];
             StarRating = values[ATTRIB_ID_DIFFICULTY];
             FlashlightDifficulty = values.GetValueOrDefault(ATTRIB_ID_FLASHLIGHT);
             SliderFactor = values[ATTRIB_ID_SLIDER_FACTOR];
@@ -147,7 +154,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             NestedScorePerObject = values[ATTRIB_ID_NESTED_SCORE_PER_OBJECT];
             LegacyScoreBaseMultiplier = values[ATTRIB_ID_LEGACY_SCORE_BASE_MULTIPLIER];
             MaximumLegacyComboScore = values[ATTRIB_ID_MAXIMUM_LEGACY_COMBO_SCORE];
-            DrainRate = onlineInfo.DrainRate;
+            ReadingDifficultNoteCount = values[ATTRIB_ID_READING_DIFFICULT_NOTE_COUNT];
             HitCircleCount = onlineInfo.CircleCount;
             SliderCount = onlineInfo.SliderCount;
             SpinnerCount = onlineInfo.SpinnerCount;

osu.Game.Rulesets.Osu/Difficulty/OsuDifficultyCalculator.cs

@@ -8,6 +8,7 @@ using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
+using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Difficulty.Skills;
@@ -16,13 +17,12 @@ using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Osu.Scoring;
 using osu.Game.Rulesets.Scoring;
+using osu.Game.Utils;
 
 namespace osu.Game.Rulesets.Osu.Difficulty
 {
     public class OsuDifficultyCalculator : DifficultyCalculator
     {
-        private const double star_rating_multiplier = 0.0265;
-
         public override int Version => 20251020;
 
         public OsuDifficultyCalculator(IRulesetInfo ruleset, IWorkingBeatmap beatmap)
@@ -46,7 +46,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return (79.5 - hitWindowGreat) / 6;
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new OsuDifficultyAttributes { Mods = mods };
@@ -55,24 +55,30 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             var aimWithoutSliders = skills.OfType<Aim>().Single(a => !a.IncludeSliders);
             var speed = skills.OfType<Speed>().Single();
             var flashlight = skills.OfType<Flashlight>().SingleOrDefault();
+            var reading = skills.OfType<Reading>().Single();
+
+            double aimDifficultyValue = aim.DifficultyValue();
+            double aimNoSlidersDifficultyValue = aimWithoutSliders.DifficultyValue();
+            double speedDifficultyValue = speed.DifficultyValue();
+            double readingDifficultyValue = reading.DifficultyValue();
+
+            double aimDifficultStrainCount = aim.CountTopWeightedStrains(aimDifficultyValue);
+            double speedDifficultStrainCount = speed.CountTopWeightedObjectDifficulties(speedDifficultyValue);
+            double readingDifficultNoteCount = reading.CountTopWeightedObjectDifficulties(readingDifficultyValue);
 
             double speedNotes = speed.RelevantNoteCount();
 
-            double aimDifficultStrainCount = aim.CountTopWeightedStrains();
-            double speedDifficultStrainCount = speed.CountTopWeightedStrains();
-
-            double aimNoSlidersTopWeightedSliderCount = aimWithoutSliders.CountTopWeightedSliders();
-            double aimNoSlidersDifficultStrainCount = aimWithoutSliders.CountTopWeightedStrains();
+            double aimNoSlidersTopWeightedSliderCount = aimWithoutSliders.CountTopWeightedSliders(aimNoSlidersDifficultyValue);
+            double aimNoSlidersDifficultStrainCount = aimWithoutSliders.CountTopWeightedStrains(aimNoSlidersDifficultyValue);
 
             double aimTopWeightedSliderFactor = aimNoSlidersTopWeightedSliderCount / Math.Max(1, aimNoSlidersDifficultStrainCount - aimNoSlidersTopWeightedSliderCount);
 
-            double speedTopWeightedSliderCount = speed.CountTopWeightedSliders();
+            double speedTopWeightedSliderCount = speed.CountTopWeightedSliders(speedDifficultyValue);
             double speedTopWeightedSliderFactor = speedTopWeightedSliderCount / Math.Max(1, speedDifficultStrainCount - speedTopWeightedSliderCount);
 
             double difficultSliders = aim.GetDifficultSliders();
 
-            double approachRate = CalculateRateAdjustedApproachRate(beatmap.Difficulty.ApproachRate, clockRate);
-            double overallDifficulty = CalculateRateAdjustedOverallDifficulty(beatmap.Difficulty.OverallDifficulty, clockRate);
+            double overallDifficulty = CalculateRateAdjustedOverallDifficulty(beatmap.Difficulty.OverallDifficulty, ModUtils.CalculateRateWithMods(mods));
 
             int hitCircleCount = beatmap.HitObjects.Count(h => h is HitCircle);
             int sliderCount = beatmap.HitObjects.Count(h => h is Slider);
@@ -80,19 +86,15 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             int totalHits = beatmap.HitObjects.Count;
 
-            double drainRate = beatmap.Difficulty.DrainRate;
+            double sliderFactor = aimDifficultyValue > 0
+                ? OsuRatingCalculator.CalculateDifficultyRating(aimNoSlidersDifficultyValue) / OsuRatingCalculator.CalculateDifficultyRating(aimDifficultyValue)
+                : 1;
 
-            double aimDifficultyValue = aim.DifficultyValue();
-            double aimNoSlidersDifficultyValue = aimWithoutSliders.DifficultyValue();
-            double speedDifficultyValue = speed.DifficultyValue();
-
-            double mechanicalDifficultyRating = calculateMechanicalDifficultyRating(aimDifficultyValue, speedDifficultyValue);
-            double sliderFactor = aimDifficultyValue > 0 ? OsuRatingCalculator.CalculateDifficultyRating(aimNoSlidersDifficultyValue) / OsuRatingCalculator.CalculateDifficultyRating(aimDifficultyValue) : 1;
-
-            var osuRatingCalculator = new OsuRatingCalculator(mods, totalHits, approachRate, overallDifficulty, mechanicalDifficultyRating, sliderFactor);
+            var osuRatingCalculator = new OsuRatingCalculator(totalHits, overallDifficulty);
 
             double aimRating = osuRatingCalculator.ComputeAimRating(aimDifficultyValue);
             double speedRating = osuRatingCalculator.ComputeSpeedRating(speedDifficultyValue);
+            double readingRating = osuRatingCalculator.ComputeReadingRating(readingDifficultyValue);
 
             double flashlightRating = 0.0;
 
@@ -100,21 +102,18 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 flashlightRating = osuRatingCalculator.ComputeFlashlightRating(flashlight.DifficultyValue());
 
             double sliderNestedScorePerObject = LegacyScoreUtils.CalculateNestedScorePerObject(beatmap, totalHits);
-            double legacyScoreBaseMultiplier = LegacyScoreUtils.CalculateDifficultyPeppyStars(beatmap);
+            double legacyScoreBaseMultiplier = LegacyScoreUtils.CalculateDifficultyPeppyStars(WorkingBeatmap.Beatmap);
 
             var simulator = new OsuLegacyScoreSimulator();
             var scoreAttributes = simulator.Simulate(WorkingBeatmap, beatmap);
 
-            double baseAimPerformance = OsuStrainSkill.DifficultyToPerformance(aimRating);
-            double baseSpeedPerformance = OsuStrainSkill.DifficultyToPerformance(speedRating);
+            double baseAimPerformance = OsuPerformanceCalculator.DifficultyToPerformance(aimRating);
+            double baseSpeedPerformance = HarmonicSkill.DifficultyToPerformance(speedRating);
+            double baseReadingPerformance = HarmonicSkill.DifficultyToPerformance(readingRating);
             double baseFlashlightPerformance = Flashlight.DifficultyToPerformance(flashlightRating);
+            double baseCognitionPerformance = SumCognitionDifficulty(baseReadingPerformance, baseFlashlightPerformance);
 
-            double basePerformance =
-                Math.Pow(
-                    Math.Pow(baseAimPerformance, 1.1) +
-                    Math.Pow(baseSpeedPerformance, 1.1) +
-                    Math.Pow(baseFlashlightPerformance, 1.1), 1.0 / 1.1
-                );
+            double basePerformance = DifficultyCalculationUtils.Norm(OsuPerformanceCalculator.PERFORMANCE_NORM_EXPONENT, baseAimPerformance, baseSpeedPerformance, baseCognitionPerformance);
 
             double starRating = calculateStarRating(basePerformance);
 
@@ -127,12 +126,13 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 SpeedDifficulty = speedRating,
                 SpeedNoteCount = speedNotes,
                 FlashlightDifficulty = flashlightRating,
+                ReadingDifficulty = readingRating,
                 SliderFactor = sliderFactor,
                 AimDifficultStrainCount = aimDifficultStrainCount,
                 SpeedDifficultStrainCount = speedDifficultStrainCount,
+                ReadingDifficultNoteCount = readingDifficultNoteCount,
                 AimTopWeightedSliderFactor = aimTopWeightedSliderFactor,
                 SpeedTopWeightedSliderFactor = speedTopWeightedSliderFactor,
-                DrainRate = drainRate,
                 MaxCombo = beatmap.GetMaxCombo(),
                 HitCircleCount = hitCircleCount,
                 SliderCount = sliderCount,
@@ -145,28 +145,29 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return attributes;
         }
 
-        private double calculateMechanicalDifficultyRating(double aimDifficultyValue, double speedDifficultyValue)
+        public static double SumCognitionDifficulty(double reading, double flashlight)
         {
-            double aimValue = OsuStrainSkill.DifficultyToPerformance(OsuRatingCalculator.CalculateDifficultyRating(aimDifficultyValue));
-            double speedValue = OsuStrainSkill.DifficultyToPerformance(OsuRatingCalculator.CalculateDifficultyRating(speedDifficultyValue));
+            if (reading <= 0)
+                return flashlight;
 
-            double totalValue = Math.Pow(Math.Pow(aimValue, 1.1) + Math.Pow(speedValue, 1.1), 1 / 1.1);
+            if (flashlight <= 0)
+                return reading;
 
-            return calculateStarRating(totalValue);
+            // Nerf flashlight value in cognition sum when reading is greater than flashlight
+            return DifficultyCalculationUtils.Norm(OsuPerformanceCalculator.PERFORMANCE_NORM_EXPONENT, reading, flashlight * Math.Clamp(flashlight / reading, 0.25, 1.0));
         }
 
         private double calculateStarRating(double basePerformance)
         {
-            if (basePerformance <= 0.00001)
-                return 0;
-
-            return Math.Cbrt(OsuPerformanceCalculator.PERFORMANCE_BASE_MULTIPLIER) * star_rating_multiplier * (Math.Cbrt(100000 / Math.Pow(2, 1 / 1.1) * basePerformance) + 4);
+            return Math.Cbrt(basePerformance * OsuPerformanceCalculator.PERFORMANCE_BASE_MULTIPLIER);
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
         {
             List<DifficultyHitObject> objects = new List<DifficultyHitObject>();
 
+            double clockRate = ModUtils.CalculateRateWithMods(mods);
+
             // The first jump is formed by the first two hitobjects of the map.
             // If the map has less than two OsuHitObjects, the enumerator will not return anything.
             for (int i = 1; i < beatmap.HitObjects.Count; i++)
@@ -177,13 +178,14 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return objects;
         }
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
         {
             var skills = new List<Skill>
             {
                 new Aim(mods, true),
                 new Aim(mods, false),
-                new Speed(mods)
+                new Speed(mods),
+                new Reading(mods)
             };
 
             if (mods.Any(h => h is OsuModFlashlight))

osu.Game.Rulesets.Osu/Difficulty/OsuLegacyScoreMissCalculator.cs

@@ -115,9 +115,13 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             double missCount = 0;
 
+            // If sliders in the map are hard - it's likely for player to drop sliderends
+            // If map has easy sliders - it's more likely for player to sliderbreak
+            double likelyMissedSliderendPortion = 0.04 + 0.06 * Math.Pow(Math.Min(attributes.AimTopWeightedSliderFactor, 1), 2);
+
             // Consider that full combo is maximum combo minus dropped slider tails since they don't contribute to combo but also don't break it
-            // In classic scores we can't know the amount of dropped sliders so we estimate to 10% of all sliders on the map
-            double fullComboThreshold = attributes.MaxCombo - 0.1 * attributes.SliderCount;
+            // In classic scores we can't know the amount of dropped sliders so we estimate it
+            double fullComboThreshold = attributes.MaxCombo - Math.Min(4 + likelyMissedSliderendPortion * attributes.SliderCount, attributes.SliderCount);
 
             if (score.MaxCombo < fullComboThreshold)
                 missCount = Math.Pow(fullComboThreshold / Math.Max(1.0, score.MaxCombo), 2.5);

osu.Game.Rulesets.Osu/Difficulty/OsuPerformanceAttributes.cs

@@ -21,6 +21,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         [JsonProperty("flashlight")]
         public double Flashlight { get; set; }
 
+        [JsonProperty("reading")]
+        public double Reading { get; set; }
+
         [JsonProperty("effective_miss_count")]
         public double EffectiveMissCount { get; set; }
 
@@ -48,6 +51,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             yield return new PerformanceDisplayAttribute(nameof(Speed), "Speed", Speed);
             yield return new PerformanceDisplayAttribute(nameof(Accuracy), "Accuracy", Accuracy);
             yield return new PerformanceDisplayAttribute(nameof(Flashlight), "Flashlight Bonus", Flashlight);
+            yield return new PerformanceDisplayAttribute(nameof(Reading), "Reading", Reading);
         }
     }
 }

osu.Game.Rulesets.Osu/Difficulty/OsuPerformanceCalculator.cs

@@ -9,6 +9,7 @@ using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Scoring;
 using osu.Game.Rulesets.Difficulty;
+using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Osu.Difficulty.Skills;
 using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Scoring;
@@ -19,7 +20,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 {
     public class OsuPerformanceCalculator : PerformanceCalculator
     {
-        public const double PERFORMANCE_BASE_MULTIPLIER = 1.14; // This is being adjusted to keep the final pp value scaled around what it used to be when changing things.
+        public const double PERFORMANCE_BASE_MULTIPLIER = 1.12; // This is being adjusted to keep the final pp value scaled around what it used to be when changing things.
+        public const double PERFORMANCE_NORM_EXPONENT = 1.1;
 
         private bool usingClassicSliderAccuracy;
         private bool usingScoreV2;
@@ -50,14 +52,18 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         private double greatHitWindow;
         private double okHitWindow;
         private double mehHitWindow;
+
         private double overallDifficulty;
         private double approachRate;
+        private double drainRate;
 
         private double? speedDeviation;
 
         private double aimEstimatedSliderBreaks;
         private double speedEstimatedSliderBreaks;
 
+        public static double DifficultyToPerformance(double difficulty) => 4.0 * Math.Pow(difficulty, 3.0);
+
         public OsuPerformanceCalculator()
             : base(new OsuRuleset())
         {
@@ -95,11 +101,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             approachRate = OsuDifficultyCalculator.CalculateRateAdjustedApproachRate(difficulty.ApproachRate, clockRate);
             overallDifficulty = OsuDifficultyCalculator.CalculateRateAdjustedOverallDifficulty(difficulty.OverallDifficulty, clockRate);
+            drainRate = difficulty.DrainRate;
 
             double comboBasedEstimatedMissCount = calculateComboBasedEstimatedMissCount(osuAttributes);
             double? scoreBasedEstimatedMissCount = null;
 
-            if (usingClassicSliderAccuracy && score.LegacyTotalScore != null)
+            if (usingClassicSliderAccuracy && !usingScoreV2 && score.LegacyTotalScore != null)
             {
                 var legacyScoreMissCalculator = new OsuLegacyScoreMissCalculator(score, osuAttributes);
                 scoreBasedEstimatedMissCount = legacyScoreMissCalculator.Calculate();
@@ -115,6 +122,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             effectiveMissCount = Math.Max(countMiss, effectiveMissCount);
             effectiveMissCount = Math.Min(totalHits, effectiveMissCount);
 
+            if (effectiveMissCount > 0)
+            {
+                aimEstimatedSliderBreaks = calculateEstimatedSliderBreaks(osuAttributes.AimTopWeightedSliderFactor, osuAttributes);
+                speedEstimatedSliderBreaks = calculateEstimatedSliderBreaks(osuAttributes.SpeedTopWeightedSliderFactor, osuAttributes);
+            }
+
             double multiplier = PERFORMANCE_BASE_MULTIPLIER;
 
             if (score.Mods.Any(m => m is OsuModNoFail))
@@ -140,15 +153,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             double aimValue = computeAimValue(score, osuAttributes);
             double speedValue = computeSpeedValue(score, osuAttributes);
             double accuracyValue = computeAccuracyValue(score, osuAttributes);
-            double flashlightValue = computeFlashlightValue(score, osuAttributes);
 
-            double totalValue =
-                Math.Pow(
-                    Math.Pow(aimValue, 1.1) +
-                    Math.Pow(speedValue, 1.1) +
-                    Math.Pow(accuracyValue, 1.1) +
-                    Math.Pow(flashlightValue, 1.1), 1.0 / 1.1
-                ) * multiplier;
+            double readingValue = computeReadingValue(osuAttributes);
+            double flashlightValue = computeFlashlightValue(score, osuAttributes);
+            double cognitionValue = OsuDifficultyCalculator.SumCognitionDifficulty(readingValue, flashlightValue);
+
+            double totalValue = DifficultyCalculationUtils.Norm(PERFORMANCE_NORM_EXPONENT, aimValue, speedValue, accuracyValue, cognitionValue) * multiplier;
 
             return new OsuPerformanceAttributes
             {
@@ -156,6 +166,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 Speed = speedValue,
                 Accuracy = accuracyValue,
                 Flashlight = flashlightValue,
+                Reading = readingValue,
                 EffectiveMissCount = effectiveMissCount,
                 ComboBasedEstimatedMissCount = comboBasedEstimatedMissCount,
                 ScoreBasedEstimatedMissCount = scoreBasedEstimatedMissCount,
@@ -194,16 +205,14 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 aimDifficulty *= sliderNerfFactor;
             }
 
-            double aimValue = OsuStrainSkill.DifficultyToPerformance(aimDifficulty);
+            double aimValue = DifficultyToPerformance(aimDifficulty);
 
-            double lengthBonus = 0.95 + 0.4 * Math.Min(1.0, totalHits / 2000.0) +
+            double lengthBonus = 0.95 + 0.35 * Math.Min(1.0, totalHits / 2000.0) +
                                  (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
             aimValue *= lengthBonus;
 
             if (effectiveMissCount > 0)
             {
-                aimEstimatedSliderBreaks = calculateEstimatedSliderBreaks(attributes.AimTopWeightedSliderFactor, attributes);
-
                 double relevantMissCount = Math.Min(effectiveMissCount + aimEstimatedSliderBreaks, totalImperfectHits + countSliderTickMiss);
 
                 aimValue *= calculateMissPenalty(relevantMissCount, attributes.AimDifficultStrainCount);
@@ -211,10 +220,10 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             // TC bonuses are excluded when blinds is present as the increased visual difficulty is unimportant when notes cannot be seen.
             if (score.Mods.Any(m => m is OsuModBlinds))
-                aimValue *= 1.3 + (totalHits * (0.0016 / (1 + 2 * effectiveMissCount)) * Math.Pow(accuracy, 16)) * (1 - 0.003 * attributes.DrainRate * attributes.DrainRate);
+                aimValue *= 1.3 + (totalHits * (0.0016 / (1 + 2 * effectiveMissCount)) * Math.Pow(accuracy, 16)) * (1 - 0.003 * drainRate * drainRate);
             else if (score.Mods.Any(m => m is OsuModTraceable))
             {
-                aimValue *= 1.0 + OsuRatingCalculator.CalculateVisibilityBonus(score.Mods, approachRate, sliderFactor: attributes.SliderFactor);
+                aimValue *= 1.0 + calculateTraceableBonus(attributes.SliderFactor);
             }
 
             aimValue *= accuracy;
@@ -227,44 +236,33 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             if (score.Mods.Any(h => h is OsuModRelax) || speedDeviation == null)
                 return 0.0;
 
-            double speedValue = OsuStrainSkill.DifficultyToPerformance(attributes.SpeedDifficulty);
-
-            double lengthBonus = 0.95 + 0.4 * Math.Min(1.0, totalHits / 2000.0) +
-                                 (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
-            speedValue *= lengthBonus;
+            double speedValue = HarmonicSkill.DifficultyToPerformance(attributes.SpeedDifficulty);
 
             if (effectiveMissCount > 0)
             {
-                speedEstimatedSliderBreaks = calculateEstimatedSliderBreaks(attributes.SpeedTopWeightedSliderFactor, attributes);
-
                 double relevantMissCount = Math.Min(effectiveMissCount + speedEstimatedSliderBreaks, totalImperfectHits + countSliderTickMiss);
 
                 speedValue *= calculateMissPenalty(relevantMissCount, attributes.SpeedDifficultStrainCount);
             }
 
-            // TC bonuses are excluded when blinds is present as the increased visual difficulty is unimportant when notes cannot be seen.
             if (score.Mods.Any(m => m is OsuModBlinds))
             {
                 // Increasing the speed value by object count for Blinds isn't ideal, so the minimum buff is given.
                 speedValue *= 1.12;
             }
-            else if (score.Mods.Any(m => m is OsuModTraceable))
-            {
-                speedValue *= 1.0 + OsuRatingCalculator.CalculateVisibilityBonus(score.Mods, approachRate);
-            }
 
             double speedHighDeviationMultiplier = calculateSpeedHighDeviationNerf(attributes);
             speedValue *= speedHighDeviationMultiplier;
 
-            // Calculate accuracy assuming the worst case scenario
-            double relevantTotalDiff = Math.Max(0, totalHits - attributes.SpeedNoteCount);
-            double relevantCountGreat = Math.Max(0, countGreat - relevantTotalDiff);
-            double relevantCountOk = Math.Max(0, countOk - Math.Max(0, relevantTotalDiff - countGreat));
-            double relevantCountMeh = Math.Max(0, countMeh - Math.Max(0, relevantTotalDiff - countGreat - countOk));
-            double relevantAccuracy = attributes.SpeedNoteCount == 0 ? 0 : (relevantCountGreat * 6.0 + relevantCountOk * 2.0 + relevantCountMeh) / (attributes.SpeedNoteCount * 6.0);
+            // An effective hit window is created based on the speed SR. The higher the speed difficulty, the shorter the hit window.
+            // For example, a speed SR of 4.0 leads to an effective hit window of 20ms, which is OD 10.
+            double effectiveHitWindow = 20 * Math.Pow(4 / attributes.SpeedDifficulty, 0.35);
 
-            // Scale the speed value with accuracy and OD.
-            speedValue *= Math.Pow((accuracy + relevantAccuracy) / 2.0, (14.5 - overallDifficulty) / 2);
+            // Find the proportion of 300s on speed notes assuming the hit window was the effective hit window.
+            double effectiveAccuracy = DifficultyCalculationUtils.Erf(effectiveHitWindow / (double)speedDeviation);
+
+            // Scale speed value by normalized accuracy.
+            speedValue *= Math.Pow(effectiveAccuracy, 2);
 
             return speedValue;
         }
@@ -294,20 +292,19 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             double accuracyValue = Math.Pow(1.52163, overallDifficulty) * Math.Pow(betterAccuracyPercentage, 24) * 2.83;
 
             // Bonus for many hitcircles - it's harder to keep good accuracy up for longer.
-            accuracyValue *= Math.Min(1.15, Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.3));
+            accuracyValue *= amountHitObjectsWithAccuracy < 1000
+                ? Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.3)
+                : Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.1);
 
             // Increasing the accuracy value by object count for Blinds isn't ideal, so the minimum buff is given.
             if (score.Mods.Any(m => m is OsuModBlinds))
                 accuracyValue *= 1.14;
-            else if (score.Mods.Any(m => m is OsuModHidden || m is OsuModTraceable))
+            else if (score.Mods.Any(m => m is OsuModTraceable))
             {
                 // Decrease bonus for AR > 10
                 accuracyValue *= 1 + 0.08 * DifficultyCalculationUtils.ReverseLerp(approachRate, 11.5, 10);
             }
 
-            if (score.Mods.Any(m => m is OsuModFlashlight))
-                accuracyValue *= 1.02;
-
             return accuracyValue;
         }
 
@@ -330,6 +327,19 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return flashlightValue;
         }
 
+        private double computeReadingValue(OsuDifficultyAttributes attributes)
+        {
+            double readingValue = HarmonicSkill.DifficultyToPerformance(attributes.ReadingDifficulty);
+
+            if (effectiveMissCount > 0)
+                readingValue *= calculateMissPenalty(effectiveMissCount + aimEstimatedSliderBreaks, attributes.ReadingDifficultNoteCount);
+
+            // Scale the reading value with accuracy _harshly_.
+            readingValue *= Math.Pow(accuracy, 3);
+
+            return readingValue;
+        }
+
         private double calculateComboBasedEstimatedMissCount(OsuDifficultyAttributes attributes)
         {
             if (attributes.SliderCount <= 0)
@@ -339,9 +349,13 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             if (usingClassicSliderAccuracy)
             {
+                // If sliders in the map are hard - it's likely for player to drop sliderends
+                // If map has easy sliders - it's more likely for player to sliderbreak
+                double likelyMissedSliderendPortion = 0.04 + 0.06 * Math.Pow(Math.Min(attributes.AimTopWeightedSliderFactor, 1), 2);
+
                 // Consider that full combo is maximum combo minus dropped slider tails since they don't contribute to combo but also don't break it
-                // In classic scores we can't know the amount of dropped sliders so we estimate to 10% of all sliders on the map
-                double fullComboThreshold = attributes.MaxCombo - 0.1 * attributes.SliderCount;
+                // In classic scores we can't know the amount of dropped sliders so we estimate it
+                double fullComboThreshold = attributes.MaxCombo - Math.Min(4 + likelyMissedSliderendPortion * attributes.SliderCount, attributes.SliderCount);
 
                 if (scoreMaxCombo < fullComboThreshold)
                     missCount = fullComboThreshold / Math.Max(1.0, scoreMaxCombo);
@@ -376,19 +390,22 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
         private double calculateEstimatedSliderBreaks(double topWeightedSliderFactor, OsuDifficultyAttributes attributes)
         {
-            if (!usingClassicSliderAccuracy || countOk == 0)
+            int nonMissMistakes = countOk + countMeh;
+
+            if (!usingClassicSliderAccuracy || nonMissMistakes == 0)
                 return 0;
 
             double missedComboPercent = 1.0 - (double)scoreMaxCombo / attributes.MaxCombo;
-            double estimatedSliderBreaks = Math.Min(countOk, effectiveMissCount * topWeightedSliderFactor);
+            double estimatedSliderBreaks = Math.Min(nonMissMistakes, effectiveMissCount * topWeightedSliderFactor);
 
-            // Scores with more Oks are more likely to have slider breaks.
-            double okAdjustment = ((countOk - estimatedSliderBreaks) + 0.5) / countOk;
+            // Scores with more Oks and Mehs are more likely to have slider breaks.
+            // We add an arbitrary value to both sides of the division to make it more stable on extreme ends.
+            double nonMissMistakeAdjustment = (nonMissMistakes - estimatedSliderBreaks + 4.5) / (nonMissMistakes + 4);
 
             // There is a low probability of extra slider breaks on effective miss counts close to 1, as score based calculations are good at indicating if only a single break occurred.
             estimatedSliderBreaks *= DifficultyCalculationUtils.Smoothstep(effectiveMissCount, 1, 2);
 
-            return estimatedSliderBreaks * okAdjustment * DifficultyCalculationUtils.Logistic(missedComboPercent, 0.33, 15);
+            return estimatedSliderBreaks * nonMissMistakeAdjustment * DifficultyCalculationUtils.Logistic(missedComboPercent, 0.33, 15);
         }
 
         /// <summary>
@@ -470,7 +487,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             if (speedDeviation == null)
                 return 0;
 
-            double speedValue = OsuStrainSkill.DifficultyToPerformance(attributes.SpeedDifficulty);
+            double speedValue = HarmonicSkill.DifficultyToPerformance(attributes.SpeedDifficulty);
 
             // Decides a point where the PP value achieved compared to the speed deviation is assumed to be tapped improperly. Any PP above this point is considered "excess" speed difficulty.
             // This is used to cause PP above the cutoff to scale logarithmically towards the original speed value thus nerfing the value.
@@ -489,10 +506,34 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return adjustedSpeedValue / speedValue;
         }
 
+        /// <summary>
+        /// Calculates a visibility bonus that is applicable to Traceable.
+        /// </summary>
+        private double calculateTraceableBonus(double sliderFactor = 1)
+        {
+            // We want to reward slider aim less, more so at lower AR
+            double highApproachRateSliderVisibilityFactor = 0.5 + (Math.Pow(sliderFactor, 6) / 2);
+            double lowApproachRateSliderVisibilityFactor = Math.Pow(sliderFactor, 6);
+
+            // Start from normal curve, rewarding lower AR up to AR7
+            double traceableBonus = 0.0275;
+            traceableBonus += 0.025 * (12.0 - Math.Max(approachRate, 7)) * highApproachRateSliderVisibilityFactor;
+
+            // For AR up to 0 - reduce reward for very low ARs when object is visible
+            if (approachRate < 7)
+                traceableBonus += 0.025 * (7.0 - Math.Max(approachRate, 0)) * lowApproachRateSliderVisibilityFactor;
+
+            // Starting from AR0 - cap values so they won't grow to infinity
+            if (approachRate < 0)
+                traceableBonus += 0.025 * (1 - Math.Pow(1.5, approachRate)) * lowApproachRateSliderVisibilityFactor;
+
+            return traceableBonus;
+        }
+
         // Miss penalty assumes that a player will miss on the hardest parts of a map,
         // so we use the amount of relatively difficult sections to adjust miss penalty
         // to make it more punishing on maps with lower amount of hard sections.
-        private double calculateMissPenalty(double missCount, double difficultStrainCount) => 0.96 / ((missCount / (4 * Math.Pow(Math.Log(difficultStrainCount), 0.94))) + 1);
+        private double calculateMissPenalty(double missCount, double difficultStrainCount) => 0.93 / (missCount / (4 * Math.Log(difficultStrainCount)) + 1);
         private double getComboScalingFactor(OsuDifficultyAttributes attributes) => attributes.MaxCombo <= 0 ? 1.0 : Math.Min(Math.Pow(scoreMaxCombo, 0.8) / Math.Pow(attributes.MaxCombo, 0.8), 1.0);
 
         private int totalHits => countGreat + countOk + countMeh + countMiss;

osu.Game.Rulesets.Osu/Difficulty/OsuRatingCalculator.cs

@@ -2,10 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using System.Linq;
-using osu.Game.Rulesets.Difficulty.Utils;
-using osu.Game.Rulesets.Mods;
-using osu.Game.Rulesets.Osu.Mods;
 
 namespace osu.Game.Rulesets.Osu.Difficulty
 {
@@ -13,64 +9,21 @@ namespace osu.Game.Rulesets.Osu.Difficulty
     {
         private const double difficulty_multiplier = 0.0675;
 
-        private readonly Mod[] mods;
         private readonly int totalHits;
-        private readonly double approachRate;
         private readonly double overallDifficulty;
-        private readonly double mechanicalDifficultyRating;
-        private readonly double sliderFactor;
 
-        public OsuRatingCalculator(Mod[] mods, int totalHits, double approachRate, double overallDifficulty, double mechanicalDifficultyRating, double sliderFactor)
+        public OsuRatingCalculator(int totalHits, double overallDifficulty)
         {
-            this.mods = mods;
             this.totalHits = totalHits;
-            this.approachRate = approachRate;
             this.overallDifficulty = overallDifficulty;
-            this.mechanicalDifficultyRating = mechanicalDifficultyRating;
-            this.sliderFactor = sliderFactor;
         }
 
         public double ComputeAimRating(double aimDifficultyValue)
         {
-            if (mods.Any(m => m is OsuModAutopilot))
-                return 0;
-
-            double aimRating = CalculateDifficultyRating(aimDifficultyValue);
-
-            if (mods.Any(m => m is OsuModTouchDevice))
-                aimRating = Math.Pow(aimRating, 0.8);
-
-            if (mods.Any(m => m is OsuModRelax))
-                aimRating *= 0.9;
-
-            if (mods.Any(m => m is OsuModMagnetised))
-            {
-                float magnetisedStrength = mods.OfType<OsuModMagnetised>().First().AttractionStrength.Value;
-                aimRating *= 1.0 - magnetisedStrength;
-            }
+            double aimRating = Math.Pow(aimDifficultyValue, 0.63) * 0.02275;
 
             double ratingMultiplier = 1.0;
 
-            double approachRateLengthBonus = 0.95 + 0.4 * Math.Min(1.0, totalHits / 2000.0) +
-                                             (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
-
-            double approachRateFactor = 0.0;
-            if (approachRate > 10.33)
-                approachRateFactor = 0.3 * (approachRate - 10.33);
-            else if (approachRate < 8.0)
-                approachRateFactor = 0.05 * (8.0 - approachRate);
-
-            if (mods.Any(h => h is OsuModRelax))
-                approachRateFactor = 0.0;
-
-            ratingMultiplier += approachRateFactor * approachRateLengthBonus; // Buff for longer maps with high AR.
-
-            if (mods.Any(m => m is OsuModHidden))
-            {
-                double visibilityFactor = calculateAimVisibilityFactor(approachRate);
-                ratingMultiplier += CalculateVisibilityBonus(mods, approachRate, visibilityFactor, sliderFactor);
-            }
-
             // It is important to consider accuracy difficulty when scaling with accuracy.
             ratingMultiplier *= 0.98 + Math.Pow(Math.Max(0, overallDifficulty), 2) / 2500;
 
@@ -79,73 +32,24 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
         public double ComputeSpeedRating(double speedDifficultyValue)
         {
-            if (mods.Any(m => m is OsuModRelax))
-                return 0;
+            return CalculateDifficultyRating(speedDifficultyValue);
+        }
 
-            double speedRating = CalculateDifficultyRating(speedDifficultyValue);
-
-            if (mods.Any(m => m is OsuModAutopilot))
-                speedRating *= 0.5;
-
-            if (mods.Any(m => m is OsuModMagnetised))
-            {
-                // reduce speed rating because of the speed distance scaling, with maximum reduction being 0.7x
-                float magnetisedStrength = mods.OfType<OsuModMagnetised>().First().AttractionStrength.Value;
-                speedRating *= 1.0 - magnetisedStrength * 0.3;
-            }
+        public double ComputeReadingRating(double readingDifficultyValue)
+        {
+            double readingRating = CalculateDifficultyRating(readingDifficultyValue);
 
             double ratingMultiplier = 1.0;
 
-            double approachRateLengthBonus = 0.95 + 0.4 * Math.Min(1.0, totalHits / 2000.0) +
-                                             (totalHits > 2000 ? Math.Log10(totalHits / 2000.0) * 0.5 : 0.0);
+            ratingMultiplier *= 0.75 + Math.Pow(Math.Max(0, overallDifficulty), 2.2) / 800;
 
-            double approachRateFactor = 0.0;
-            if (approachRate > 10.33)
-                approachRateFactor = 0.3 * (approachRate - 10.33);
-
-            if (mods.Any(m => m is OsuModAutopilot))
-                approachRateFactor = 0.0;
-
-            ratingMultiplier += approachRateFactor * approachRateLengthBonus; // Buff for longer maps with high AR.
-
-            if (mods.Any(m => m is OsuModHidden))
-            {
-                double visibilityFactor = calculateSpeedVisibilityFactor(approachRate);
-                ratingMultiplier += CalculateVisibilityBonus(mods, approachRate, visibilityFactor);
-            }
-
-            ratingMultiplier *= 0.95 + Math.Pow(Math.Max(0, overallDifficulty), 2) / 750;
-
-            return speedRating * Math.Cbrt(ratingMultiplier);
+            return readingRating * Math.Cbrt(ratingMultiplier);
         }
 
         public double ComputeFlashlightRating(double flashlightDifficultyValue)
         {
-            if (!mods.Any(m => m is OsuModFlashlight))
-                return 0;
-
             double flashlightRating = CalculateDifficultyRating(flashlightDifficultyValue);
 
-            if (mods.Any(m => m is OsuModTouchDevice))
-                flashlightRating = Math.Pow(flashlightRating, 0.8);
-
-            if (mods.Any(m => m is OsuModRelax))
-                flashlightRating *= 0.7;
-            else if (mods.Any(m => m is OsuModAutopilot))
-                flashlightRating *= 0.4;
-
-            if (mods.Any(m => m is OsuModMagnetised))
-            {
-                float magnetisedStrength = mods.OfType<OsuModMagnetised>().First().AttractionStrength.Value;
-                flashlightRating *= 1.0 - magnetisedStrength;
-            }
-
-            if (mods.Any(m => m is OsuModDeflate))
-            {
-                float deflateInitialScale = mods.OfType<OsuModDeflate>().First().StartScale.Value;
-                flashlightRating *= Math.Clamp(DifficultyCalculationUtils.ReverseLerp(deflateInitialScale, 11, 1), 0.1, 1);
-            }
-
             double ratingMultiplier = 1.0;
 
             // Account for shorter maps having a higher ratio of 0 combo/100 combo flashlight radius.
@@ -158,56 +62,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return flashlightRating * Math.Sqrt(ratingMultiplier);
         }
 
-        private double calculateAimVisibilityFactor(double approachRate)
-        {
-            const double ar_factor_end_point = 11.5;
-
-            double mechanicalDifficultyFactor = DifficultyCalculationUtils.ReverseLerp(mechanicalDifficultyRating, 5, 10);
-            double arFactorStartingPoint = double.Lerp(9, 10.33, mechanicalDifficultyFactor);
-
-            return DifficultyCalculationUtils.ReverseLerp(approachRate, ar_factor_end_point, arFactorStartingPoint);
-        }
-
-        private double calculateSpeedVisibilityFactor(double approachRate)
-        {
-            const double ar_factor_end_point = 11.5;
-
-            double mechanicalDifficultyFactor = DifficultyCalculationUtils.ReverseLerp(mechanicalDifficultyRating, 5, 10);
-            double arFactorStartingPoint = double.Lerp(10, 10.33, mechanicalDifficultyFactor);
-
-            return DifficultyCalculationUtils.ReverseLerp(approachRate, ar_factor_end_point, arFactorStartingPoint);
-        }
-
-        /// <summary>
-        /// Calculates a visibility bonus that is applicable to Hidden and Traceable.
-        /// </summary>
-        public static double CalculateVisibilityBonus(Mod[] mods, double approachRate, double visibilityFactor = 1, double sliderFactor = 1)
-        {
-            // NOTE: TC's effect is only noticeable in performance calculations until lazer mods are accounted for server-side.
-            bool isAlwaysPartiallyVisible = mods.OfType<OsuModHidden>().Any(m => m.OnlyFadeApproachCircles.Value) || mods.OfType<OsuModTraceable>().Any();
-
-            // Start from normal curve, rewarding lower AR up to AR7
-            // TC forcefully requires a lower reading bonus for now as it's post-applied in PP which makes it multiplicative with the regular AR bonuses
-            // This means it has an advantage over HD, so we decrease the multiplier to compensate
-            // This should be removed once we're able to apply TC bonuses in SR (depends on real-time difficulty calculations being possible)
-            double readingBonus = (isAlwaysPartiallyVisible ? 0.025 : 0.04) * (12.0 - Math.Max(approachRate, 7));
-
-            readingBonus *= visibilityFactor;
-
-            // We want to reward slideraim on low AR less
-            double sliderVisibilityFactor = Math.Pow(sliderFactor, 3);
-
-            // For AR up to 0 - reduce reward for very low ARs when object is visible
-            if (approachRate < 7)
-                readingBonus += (isAlwaysPartiallyVisible ? 0.02 : 0.045) * (7.0 - Math.Max(approachRate, 0)) * sliderVisibilityFactor;
-
-            // Starting from AR0 - cap values so they won't grow to infinity
-            if (approachRate < 0)
-                readingBonus += (isAlwaysPartiallyVisible ? 0.01 : 0.1) * (1 - Math.Pow(1.5, approachRate)) * sliderVisibilityFactor;
-
-            return readingBonus;
-        }
-
         public static double CalculateDifficultyRating(double difficultyValue) => Math.Sqrt(difficultyValue) * difficulty_multiplier;
     }
 }

osu.Game.Rulesets.Osu/Difficulty/Preprocessing/OsuDifficultyHitObject.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
@@ -35,6 +36,22 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
         /// </summary>
         public readonly double AdjustedDeltaTime;
 
+        /// <summary>
+        /// Amount of time elapsed between lastDifficultyObject's <see cref="DifficultyHitObject.EndTime"/> and <see cref="DifficultyHitObject.StartTime"/> capped to a minimum of <see cref="MIN_DELTA_TIME"/>ms.
+        /// </summary>
+        public double LastObjectEndDeltaTime { get; private set; }
+
+        /// <summary>
+        /// Time (in ms) between the object first appearing and the time it needs to be clicked.
+        /// <see cref="OsuHitObject.TimePreempt"/> adjusted by clock rate.
+        /// </summary>
+        public readonly double Preempt;
+
+        /// <summary>
+        /// Normalised distance from the start position of the previous <see cref="OsuDifficultyHitObject"/> to the start position of this <see cref="OsuDifficultyHitObject"/>.
+        /// </summary>
+        public double JumpDistance { get; private set; }
+
         /// <summary>
         /// Normalised distance from the "lazy" end position of the previous <see cref="OsuDifficultyHitObject"/> to the start position of this <see cref="OsuDifficultyHitObject"/>.
         /// <para>
@@ -101,9 +118,10 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
         public double? Angle { get; private set; }
 
         /// <summary>
-        /// Retrieves the full hit window for a Great <see cref="HitResult"/>.
+        /// Angle of the vector created between current and current-1
+        /// normalised to consider symmetrical vectors in any axis to be the same angle.
         /// </summary>
-        public double HitWindowGreat { get; private set; }
+        public double? NormalisedVectorAngle { get; private set; }
 
         /// <summary>
         /// Selective bonus for maps with higher circle size.
@@ -121,17 +139,11 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             // Capped to 25ms to prevent difficulty calculation breaking from simultaneous objects.
             AdjustedDeltaTime = Math.Max(DeltaTime, MIN_DELTA_TIME);
+            LastObjectEndDeltaTime = lastDifficultyObject != null ? Math.Max(StartTime - lastDifficultyObject.EndTime, MIN_DELTA_TIME) : AdjustedDeltaTime;
 
-            SmallCircleBonus = Math.Max(1.0, 1.0 + (30 - BaseObject.Radius) / 40);
+            SmallCircleBonus = Math.Max(1.0, 1.0 + (30 - BaseObject.Radius) / 70);
 
-            if (BaseObject is Slider sliderObject)
-            {
-                HitWindowGreat = 2 * sliderObject.HeadCircle.HitWindows.WindowFor(HitResult.Great) / clockRate;
-            }
-            else
-            {
-                HitWindowGreat = 2 * BaseObject.HitWindows.WindowFor(HitResult.Great) / clockRate;
-            }
+            Preempt = BaseObject.TimePreempt / clockRate;
 
             computeSliderCursorPosition();
             setDistances(clockRate);
@@ -148,7 +160,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
             }
 
             double fadeInStartTime = BaseObject.StartTime - BaseObject.TimePreempt;
-            double fadeInDuration = BaseObject.TimeFadeIn;
+
+            // Equal to `OsuHitObject.TimeFadeIn` minus any adjustments from the HD mod.
+            double fadeInDuration = 400 * Math.Min(1, BaseObject.TimePreempt / OsuHitObject.PREEMPT_MIN);
 
             if (hidden)
             {
@@ -175,10 +189,16 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
             {
                 double currDeltaTime = Math.Max(1, DeltaTime);
                 double nextDeltaTime = Math.Max(1, osuNextObj.DeltaTime);
+
                 double deltaDifference = Math.Abs(nextDeltaTime - currDeltaTime);
+
                 double speedRatio = currDeltaTime / Math.Max(currDeltaTime, deltaDifference);
-                double windowRatio = Math.Pow(Math.Min(1, currDeltaTime / HitWindowGreat), 2);
-                return 1.0 - Math.Pow(speedRatio, 1 - windowRatio);
+                double windowRatio = Math.Pow(Math.Min(1, currDeltaTime / HitWindow(HitResult.Great)), 5);
+
+                // Can't doubletap if circles don't intersect
+                double distanceFactor = Math.Pow(DifficultyCalculationUtils.ReverseLerp(LazyJumpDistance, NORMALISED_DIAMETER, NORMALISED_RADIUS), 2);
+
+                return 1.0 - Math.Pow(speedRatio, distanceFactor * (1 - windowRatio));
             }
 
             return 0;
@@ -189,10 +209,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
             if (BaseObject is Slider currentSlider)
             {
                 // Bonus for repeat sliders until a better per nested object strain system can be achieved.
-                TravelDistance = LazyTravelDistance * Math.Pow(1 + currentSlider.RepeatCount / 2.5, 1.0 / 2.5);
+                TravelDistance = LazyTravelDistance * Math.Max(1, Math.Pow(currentSlider.RepeatCount, 0.3));
                 TravelTime = Math.Max(LazyTravelTime / clockRate, MIN_DELTA_TIME);
             }
 
+            MinimumJumpTime = AdjustedDeltaTime;
+
             // We don't need to calculate either angle or distance when one of the last->curr objects is a spinner
             if (BaseObject is Spinner || LastObject is Spinner)
                 return;
@@ -202,8 +224,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             Vector2 lastCursorPosition = lastDifficultyObject != null ? getEndCursorPosition(lastDifficultyObject) : LastObject.StackedPosition;
 
-            LazyJumpDistance = (BaseObject.StackedPosition * scalingFactor - lastCursorPosition * scalingFactor).Length;
-            MinimumJumpTime = AdjustedDeltaTime;
+            JumpDistance = (LastObject.StackedPosition - BaseObject.StackedPosition).Length * scalingFactor;
+            LazyJumpDistance = (BaseObject.StackedPosition - lastCursorPosition).Length * scalingFactor;
             MinimumJumpDistance = LazyJumpDistance;
 
             if (LastObject is Slider lastSlider && lastDifficultyObject != null)
@@ -239,15 +261,18 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             if (lastLastDifficultyObject != null && lastLastDifficultyObject.BaseObject is not Spinner)
             {
+                if (lastDifficultyObject!.BaseObject is Slider prevSlider && lastDifficultyObject.TravelDistance > 0)
+                    lastCursorPosition = prevSlider.HeadCircle.StackedPosition;
+
                 Vector2 lastLastCursorPosition = getEndCursorPosition(lastLastDifficultyObject);
 
-                Vector2 v1 = lastLastCursorPosition - LastObject.StackedPosition;
-                Vector2 v2 = BaseObject.StackedPosition - lastCursorPosition;
+                double angle = calculateAngle(BaseObject.StackedPosition, lastCursorPosition, lastLastCursorPosition);
+                double sliderAngle = calculateSliderAngle(lastDifficultyObject!, lastLastCursorPosition);
 
-                float dot = Vector2.Dot(v1, v2);
-                float det = v1.X * v2.Y - v1.Y * v2.X;
+                Vector2 v = BaseObject.StackedPosition - lastCursorPosition;
+                NormalisedVectorAngle = Math.Atan2(Math.Abs(v.Y), Math.Abs(v.X));
 
-                Angle = Math.Abs(Math.Atan2(det, dot));
+                Angle = Math.Min(angle, sliderAngle);
             }
         }
 
@@ -359,6 +384,30 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
             }
         }
 
+        private double calculateSliderAngle(OsuDifficultyHitObject lastDifficultyObject, Vector2 lastLastCursorPosition)
+        {
+            Vector2 lastCursorPosition = getEndCursorPosition(lastDifficultyObject);
+
+            if (lastDifficultyObject.BaseObject is Slider prevSlider && lastDifficultyObject.TravelDistance > 0)
+            {
+                OsuHitObject secondLastNestedObject = (OsuHitObject)prevSlider.NestedHitObjects[^2];
+                lastLastCursorPosition = secondLastNestedObject.StackedPosition;
+            }
+
+            return calculateAngle(BaseObject.StackedPosition, lastCursorPosition, lastLastCursorPosition);
+        }
+
+        private double calculateAngle(Vector2 currentPosition, Vector2 lastPosition, Vector2 lastLastPosition)
+        {
+            Vector2 v1 = lastLastPosition - lastPosition;
+            Vector2 v2 = currentPosition - lastPosition;
+
+            float dot = Vector2.Dot(v1, v2);
+            float det = v1.X * v2.Y - v1.Y * v2.X;
+
+            return Math.Abs(Math.Atan2(det, dot));
+        }
+
         private Vector2 getEndCursorPosition(OsuDifficultyHitObject difficultyHitObject)
         {
             return difficultyHitObject.LazyEndPosition ?? difficultyHitObject.BaseObject.StackedPosition;

osu.Game.Rulesets.Osu/Difficulty/Skills/Aim.cs

@@ -4,10 +4,14 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using osu.Framework.Utils;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Skills;
+using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Mods;
-using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
-using osu.Game.Rulesets.Osu.Difficulty.Utils;
+using osu.Game.Rulesets.Osu.Difficulty.Evaluators.Aim;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
@@ -15,7 +19,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
     /// <summary>
     /// Represents the skill required to correctly aim at every object in the map with a uniform CircleSize and normalized distances.
     /// </summary>
-    public class Aim : OsuStrainSkill
+    public class Aim : VariableLengthStrainSkill
     {
         public readonly bool IncludeSliders;
 
@@ -27,19 +31,39 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 
         private double currentStrain;
 
-        private double skillMultiplier => 26;
-        private double strainDecayBase => 0.15;
+        private double skillMultiplierSnap => 70.9;
+        private double skillMultiplierAgility => 2.35;
+        private double skillMultiplierFlow => 242.0;
+        private double skillMultiplierTotal => 1.12;
+        private double combinedSnapNormExponent => 1.2;
+
+        /// <summary>
+        /// The number of sections with the highest strains, which the peak strain reductions will apply to.
+        /// This is done in order to decrease their impact on the overall difficulty of the map for this skill.
+        /// </summary>
+        private int reducedSectionTime => 4000;
+
+        /// <summary>
+        /// The baseline multiplier applied to the section with the biggest strain.
+        /// </summary>
+        private double reducedStrainBaseline => 0.727;
 
         private readonly List<double> sliderStrains = new List<double>();
 
-        private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
+        private double strainDecay(double ms) => Math.Pow(0.2, ms / 1000);
 
-        protected override double CalculateInitialStrain(double time, DifficultyHitObject current) => currentStrain * strainDecay(time - current.Previous(0).StartTime);
+        protected override double CalculateInitialStrain(double time, DifficultyHitObject current) =>
+            currentStrain * strainDecay(time - current.Previous(0).StartTime);
 
         protected override double StrainValueAt(DifficultyHitObject current)
         {
-            currentStrain *= strainDecay(current.DeltaTime);
-            currentStrain += AimEvaluator.EvaluateDifficultyOf(current, IncludeSliders) * skillMultiplier;
+            if (Mods.Any(m => m is OsuModAutopilot))
+                return 0;
+
+            double decay = strainDecay(((OsuDifficultyHitObject)current).AdjustedDeltaTime);
+
+            currentStrain *= decay;
+            currentStrain += calculateModAdjustedDifficulty(current) * (1 - decay);
 
             if (current.BaseObject is Slider)
                 sliderStrains.Add(currentStrain);
@@ -47,6 +71,73 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
             return currentStrain;
         }
 
+        private double calculateModAdjustedDifficulty(DifficultyHitObject current)
+        {
+            double snapDifficulty = SnapAimEvaluator.EvaluateDifficultyOf(current, IncludeSliders) * skillMultiplierSnap;
+            double agilityDifficulty = AgilityEvaluator.EvaluateDifficultyOf(current) * skillMultiplierAgility;
+            double flowDifficulty = FlowAimEvaluator.EvaluateDifficultyOf(current, IncludeSliders) * skillMultiplierFlow;
+
+            double totalDifficulty = calculateTotalValue(snapDifficulty, agilityDifficulty, flowDifficulty);
+
+            if (Mods.Any(m => m is OsuModMagnetised))
+            {
+                float magnetisedStrength = Mods.OfType<OsuModMagnetised>().First().AttractionStrength.Value;
+                totalDifficulty *= 1.0 - magnetisedStrength;
+            }
+
+            return totalDifficulty;
+        }
+
+        private double calculateTotalValue(double snapDifficulty, double agilityDifficulty, double flowDifficulty)
+        {
+            // We compare flow to combined snap and agility because snap by itself doesn't have enough difficulty to be above flow on streams
+            // Agility on the other hand is supposed to measure the rate of cursor velocity changes while snapping
+            // So snapping every circle on a stream requires an enormous amount of agility at which point it's easier to flow
+            double combinedSnapDifficulty = DifficultyCalculationUtils.Norm(combinedSnapNormExponent, snapDifficulty, agilityDifficulty);
+
+            double pSnap = calculateSnapFlowProbability(flowDifficulty / combinedSnapDifficulty);
+            double pFlow = 1 - pSnap;
+
+            if (Mods.Any(m => m is OsuModTouchDevice))
+            {
+                // we don't adjust agility here since agility represents TD difficulty in a decent enough way
+                snapDifficulty = Math.Pow(snapDifficulty, 0.89);
+                combinedSnapDifficulty = DifficultyCalculationUtils.Norm(combinedSnapNormExponent, snapDifficulty, agilityDifficulty);
+            }
+
+            if (Mods.Any(m => m is OsuModRelax))
+            {
+                combinedSnapDifficulty *= 0.75;
+                flowDifficulty *= 0.6;
+            }
+
+            double totalDifficulty = combinedSnapDifficulty * pSnap + flowDifficulty * pFlow;
+
+            double totalStrain = totalDifficulty * skillMultiplierTotal;
+
+            return totalStrain;
+        }
+
+        // A function that turns the ratio of snap : flow into the probability of snapping/flowing
+        // It has the constraints:
+        // P(snap) + P(flow) = 1 (the object is always either snapped or flowed)
+        // P(snap) = f(snap/flow), P(flow) = f(flow/snap) (ie snap and flow are symmetric and reversible)
+        // Therefore: f(x) + f(1/x) = 1
+        // 0 <= f(x) <= 1 (cannot have negative or greater than 100% probability of snapping or flowing)
+        // This logistic function is a solution, which fits nicely with the general idea of interpolation and provides a tuneable constant
+        private static double calculateSnapFlowProbability(double ratio)
+        {
+            const double k = 7.27;
+
+            if (ratio == 0)
+                return 0;
+
+            if (double.IsNaN(ratio))
+                return 1;
+
+            return DifficultyCalculationUtils.Logistic(-k * Math.Log(ratio));
+        }
+
         public double GetDifficultSliders()
         {
             if (sliderStrains.Count == 0)
@@ -60,6 +151,97 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
             return sliderStrains.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxSliderStrain * 12.0 - 6.0))));
         }
 
-        public double CountTopWeightedSliders() => OsuStrainUtils.CountTopWeightedSliders(sliderStrains, DifficultyValue());
+        public double CountTopWeightedSliders(double difficultyValue)
+        {
+            if (sliderStrains.Count == 0)
+                return 0;
+
+            double consistentTopStrain = difficultyValue * (1 - DecayWeight); // What would the top strain be if all strain values were identical
+
+            if (consistentTopStrain == 0)
+                return 0;
+
+            // Use a weighted sum of all strains. Constants are arbitrary and give nice values
+            return sliderStrains.Sum(s => DifficultyCalculationUtils.Logistic(s / consistentTopStrain, 0.88, 10, 1.1));
+        }
+
+        public override double DifficultyValue()
+        {
+            double difficulty = 0;
+            double time = 0;
+
+            var strains = getReducedStrainPeaks();
+
+            // Difficulty is a continuous weighted sum of the sorted strains
+            foreach (StrainPeak strain in strains)
+            {
+                /* Weighting function can be thought of as:
+                        b
+                        ∫ DecayWeight^x dx
+                        a
+                    where a = startTime and b = endTime
+
+                    Technically, the function below has been slightly modified from the equation above.
+                    The real function would be
+                        double weight = Math.Pow(DecayWeight, startTime) - Math.Pow(DecayWeight, endTime);
+                        ...
+                        return difficulty / Math.Log(1 / DecayWeight);
+                    E.g. for a DecayWeight of 0.9, we're multiplying by 10 instead of 9.49122...
+
+                    This change makes it so that a map composed solely of MaxSectionLength chunks will have the exact same value when summed in this class and StrainSkill.
+                    Doing this ensures the relationship between strain values and difficulty values remains the same between the two classes.
+                */
+                double startTime = time;
+                double endTime = time + strain.SectionLength / MaxSectionLength;
+
+                double weight = Math.Pow(DecayWeight, startTime) - Math.Pow(DecayWeight, endTime);
+
+                difficulty += strain.Value * weight;
+                time = endTime;
+            }
+
+            return difficulty / (1 - DecayWeight);
+        }
+
+        /// <summary>
+        /// Returns a sorted enumerable of strain peaks with the highest values reduced.
+        /// </summary>
+        /// <returns></returns>
+        private IEnumerable<StrainPeak> getReducedStrainPeaks()
+        {
+            // Sections with 0 strain are excluded to avoid worst-case time complexity of the following sort (e.g. /b/2351871).
+            // These sections will not contribute to the difficulty.
+            var peaks = GetCurrentStrainPeaks().Where(p => p.Value > 0);
+
+            List<StrainPeak> strains = peaks.OrderByDescending(p => p.Value).ToList();
+
+            const int chunk_size = 20;
+            double time = 0;
+            int strainsToRemove = 0; // All strains are removed at the end for optimization purposes
+
+            // We are reducing the highest strains first to account for extreme difficulty spikes
+            // Strains are split into 20ms chunks to try to mitigate inconsistencies caused by reducing strains
+            while (strains.Count > strainsToRemove && time < reducedSectionTime)
+            {
+                StrainPeak strain = strains[strainsToRemove];
+
+                for (double addedTime = 0; addedTime < strain.SectionLength; addedTime += chunk_size)
+                {
+                    double scale = Math.Log10(Interpolation.Lerp(1, 10, Math.Clamp((time + addedTime) / reducedSectionTime, 0, 1)));
+
+                    strains.Add(new StrainPeak(
+                        strain.Value * Interpolation.Lerp(reducedStrainBaseline, 1.0, scale),
+                        Math.Min(chunk_size, strain.SectionLength - addedTime)
+                    ));
+                }
+
+                time += strain.SectionLength;
+                strainsToRemove++;
+            }
+
+            strains.RemoveRange(0, strainsToRemove);
+
+            return strains.OrderByDescending(p => p.Value);
+        }
     }
 }

osu.Game.Rulesets.Osu/Difficulty/Skills/Flashlight.cs

@@ -5,6 +5,7 @@ using System;
 using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
+using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
 using osu.Game.Rulesets.Osu.Mods;
@@ -16,15 +17,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
     /// </summary>
     public class Flashlight : StrainSkill
     {
-        private readonly bool hasHiddenMod;
-
         public Flashlight(Mod[] mods)
             : base(mods)
         {
-            hasHiddenMod = mods.Any(m => m is OsuModHidden);
         }
 
-        private double skillMultiplier => 0.05512;
+        private double skillMultiplier => 0.058;
         private double strainDecayBase => 0.15;
 
         private double currentStrain;
@@ -35,12 +33,43 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 
         protected override double StrainValueAt(DifficultyHitObject current)
         {
+            if (!Mods.Any(m => m is OsuModFlashlight))
+                return 0;
+
             currentStrain *= strainDecay(current.DeltaTime);
-            currentStrain += FlashlightEvaluator.EvaluateDifficultyOf(current, hasHiddenMod) * skillMultiplier;
+            currentStrain += calculateModAdjustedDifficulty(current) * skillMultiplier;
 
             return currentStrain;
         }
 
+        private double calculateModAdjustedDifficulty(DifficultyHitObject current)
+        {
+            double difficulty = FlashlightEvaluator.EvaluateDifficultyOf(current, Mods);
+
+            if (Mods.Any(m => m is OsuModTouchDevice))
+                difficulty = Math.Pow(difficulty, 0.9);
+
+            if (Mods.Any(m => m is OsuModMagnetised))
+            {
+                float magnetisedStrength = Mods.OfType<OsuModMagnetised>().First().AttractionStrength.Value;
+                difficulty *= 1.0 - magnetisedStrength;
+            }
+
+            if (Mods.Any(m => m is OsuModDeflate))
+            {
+                float deflateInitialScale = Mods.OfType<OsuModDeflate>().First().StartScale.Value;
+                difficulty *= Math.Clamp(DifficultyCalculationUtils.ReverseLerp(deflateInitialScale, 11, 1), 0.1, 1);
+            }
+
+            if (Mods.Any(m => m is OsuModRelax))
+                difficulty *= 0.7;
+
+            if (Mods.Any(m => m is OsuModAutopilot))
+                difficulty *= 0.4;
+
+            return difficulty;
+        }
+
         public override double DifficultyValue() => GetCurrentStrainPeaks().Sum();
 
         public static double DifficultyToPerformance(double difficulty) => 25 * Math.Pow(difficulty, 2);

osu.Game.Rulesets.Osu/Difficulty/Skills/OsuStrainSkill.cs

@@ -1,62 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System;
-using System.Collections.Generic;
-using osu.Game.Rulesets.Difficulty.Skills;
-using osu.Game.Rulesets.Mods;
-using System.Linq;
-using osu.Framework.Utils;
-
-namespace osu.Game.Rulesets.Osu.Difficulty.Skills
-{
-    public abstract class OsuStrainSkill : StrainSkill
-    {
-        /// <summary>
-        /// The number of sections with the highest strains, which the peak strain reductions will apply to.
-        /// This is done in order to decrease their impact on the overall difficulty of the map for this skill.
-        /// </summary>
-        protected virtual int ReducedSectionCount => 10;
-
-        /// <summary>
-        /// The baseline multiplier applied to the section with the biggest strain.
-        /// </summary>
-        protected virtual double ReducedStrainBaseline => 0.75;
-
-        protected OsuStrainSkill(Mod[] mods)
-            : base(mods)
-        {
-        }
-
-        public override double DifficultyValue()
-        {
-            double difficulty = 0;
-            double weight = 1;
-
-            // Sections with 0 strain are excluded to avoid worst-case time complexity of the following sort (e.g. /b/2351871).
-            // These sections will not contribute to the difficulty.
-            var peaks = GetCurrentStrainPeaks().Where(p => p > 0);
-
-            List<double> strains = peaks.OrderDescending().ToList();
-
-            // We are reducing the highest strains first to account for extreme difficulty spikes
-            for (int i = 0; i < Math.Min(strains.Count, ReducedSectionCount); i++)
-            {
-                double scale = Math.Log10(Interpolation.Lerp(1, 10, Math.Clamp((float)i / ReducedSectionCount, 0, 1)));
-                strains[i] *= Interpolation.Lerp(ReducedStrainBaseline, 1.0, scale);
-            }
-
-            // Difficulty is the weighted sum of the highest strains from every section.
-            // We're sorting from highest to lowest strain.
-            foreach (double strain in strains.OrderDescending())
-            {
-                difficulty += strain * weight;
-                weight *= DecayWeight;
-            }
-
-            return difficulty;
-        }
-
-        public static double DifficultyToPerformance(double difficulty) => Math.Pow(5.0 * Math.Max(1.0, difficulty / 0.0675) - 4.0, 3.0) / 100000.0;
-    }
-}

osu.Game.Rulesets.Osu/Difficulty/Skills/Reading.cs

@@ -0,0 +1,121 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using osu.Framework.Utils;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Skills;
+using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
+using osu.Game.Rulesets.Osu.Mods;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Skills
+{
+    public class Reading : HarmonicSkill
+    {
+        private readonly List<DifficultyHitObject> objectList = new List<DifficultyHitObject>();
+
+        private readonly bool hasHiddenMod;
+
+        public Reading(Mod[] mods)
+            : base(mods)
+        {
+            hasHiddenMod = mods.OfType<OsuModHidden>().Any(m => !m.OnlyFadeApproachCircles.Value);
+        }
+
+        private double currentStrain;
+
+        private double skillMultiplier => 2.5;
+        private double strainDecayBase => 0.8;
+
+        private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
+
+        protected override double ObjectDifficultyOf(DifficultyHitObject current)
+        {
+            objectList.Add(current);
+
+            double decay = strainDecay(current.DeltaTime);
+
+            currentStrain *= decay;
+            currentStrain += calculateModAdjustedDifficulty(current) * (1 - decay) * skillMultiplier;
+
+            return currentStrain;
+        }
+
+        private double calculateModAdjustedDifficulty(DifficultyHitObject current)
+        {
+            double difficulty = ReadingEvaluator.EvaluateDifficultyOf(current, hasHiddenMod);
+
+            if (Mods.Any(m => m is OsuModTouchDevice))
+                difficulty = Math.Pow(difficulty, 0.89);
+
+            if (Mods.Any(m => m is OsuModMagnetised))
+            {
+                float magnetisedStrength = Mods.OfType<OsuModMagnetised>().First().AttractionStrength.Value;
+                difficulty *= 1.0 - magnetisedStrength;
+            }
+
+            if (Mods.Any(m => m is OsuModRelax))
+                difficulty *= 0.4;
+
+            if (Mods.Any(m => m is OsuModAutopilot))
+                difficulty *= 0.1;
+
+            return difficulty;
+        }
+
+        protected override void ApplyDifficultyTransformation(double[] difficulties)
+        {
+            const double reduced_difficulty_base_line = 0.0; // Assume the first seconds are completely memorised
+
+            int reducedNoteCount = calculateReducedNoteCount();
+
+            for (int i = 0; i < Math.Min(difficulties.Length, reducedNoteCount); i++)
+            {
+                double scale = Math.Log10(Interpolation.Lerp(1, 10, Math.Clamp((double)i / reducedNoteCount, 0, 1)));
+                difficulties[i] *= Interpolation.Lerp(reduced_difficulty_base_line, 1.0, scale);
+            }
+        }
+
+        private int calculateReducedNoteCount()
+        {
+            const double reduced_difficulty_duration = 60 * 1000;
+
+            if (objectList.Count == 0)
+                return 0;
+
+            double reducedDuration = objectList.First().StartTime + reduced_difficulty_duration;
+
+            int reducedNoteCount = 0;
+
+            foreach (var hitObject in objectList)
+            {
+                if (hitObject.StartTime > reducedDuration)
+                    break;
+
+                reducedNoteCount++;
+            }
+
+            return reducedNoteCount;
+        }
+
+        public override double CountTopWeightedObjectDifficulties(double difficultyValue)
+        {
+            if (ObjectDifficulties.Count == 0)
+                return 0.0;
+
+            if (NoteWeightSum == 0)
+                return 0.0;
+
+            double consistentTopNote = difficultyValue / NoteWeightSum; // What would the top difficulty be if all object difficulties were identical
+
+            if (consistentTopNote == 0)
+                return 0;
+
+            return ObjectDifficulties.Sum(d => DifficultyCalculationUtils.Logistic(d / consistentTopNote, 1.15, 5, 1.1));
+        }
+    }
+}

osu.Game.Rulesets.Osu/Difficulty/Skills/Speed.cs

@@ -3,30 +3,33 @@
 
 using System;
 using System.Collections.Generic;
-using osu.Game.Rulesets.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Mods;
-using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
-using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Osu.Objects;
 using System.Linq;
-using osu.Game.Rulesets.Osu.Difficulty.Utils;
+using osu.Game.Rulesets.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Difficulty.Skills;
+using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Mods;
+using osu.Game.Rulesets.Osu.Objects;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 {
     /// <summary>
     /// Represents the skill required to press keys with regards to keeping up with the speed at which objects need to be hit.
     /// </summary>
-    public class Speed : OsuStrainSkill
+    public class Speed : HarmonicSkill
     {
-        private double skillMultiplier => 1.47;
-        private double strainDecayBase => 0.3;
-
-        private double currentStrain;
-        private double currentRhythm;
+        private double skillMultiplier => 1.16;
 
         private readonly List<double> sliderStrains = new List<double>();
 
-        protected override int ReducedSectionCount => 5;
+        private double currentStrain;
+
+        private double strainDecayBase => 0.3;
+
+        protected override double HarmonicScale => 20;
+        protected override double DecayExponent => 0.9;
 
         public Speed(Mod[] mods)
             : base(mods)
@@ -35,14 +38,17 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 
         private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
 
-        protected override double CalculateInitialStrain(double time, DifficultyHitObject current) => (currentStrain * currentRhythm) * strainDecay(time - current.Previous(0).StartTime);
-
-        protected override double StrainValueAt(DifficultyHitObject current)
+        protected override double ObjectDifficultyOf(DifficultyHitObject current)
         {
-            currentStrain *= strainDecay(((OsuDifficultyHitObject)current).AdjustedDeltaTime);
-            currentStrain += SpeedEvaluator.EvaluateDifficultyOf(current, Mods) * skillMultiplier;
+            if (Mods.Any(m => m is OsuModRelax))
+                return 0;
 
-            currentRhythm = RhythmEvaluator.EvaluateDifficultyOf(current);
+            double decay = strainDecay(((OsuDifficultyHitObject)current).AdjustedDeltaTime);
+
+            currentStrain *= decay;
+            currentStrain += calculateModAdjustedDifficulty(current) * (1 - decay) * skillMultiplier;
+
+            double currentRhythm = RhythmEvaluator.EvaluateDifficultyOf(current);
 
             double totalStrain = currentStrain * currentRhythm;
 
@@ -52,18 +58,44 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
             return totalStrain;
         }
 
+        private double calculateModAdjustedDifficulty(DifficultyHitObject current)
+        {
+            double difficulty = SpeedEvaluator.EvaluateDifficultyOf(current);
+
+            if (Mods.Any(m => m is OsuModAutopilot))
+                difficulty *= 0.5;
+
+            return difficulty;
+        }
+
         public double RelevantNoteCount()
         {
-            if (ObjectStrains.Count == 0)
+            if (ObjectDifficulties.Count == 0)
                 return 0;
 
-            double maxStrain = ObjectStrains.Max();
+            double maxStrain = ObjectDifficulties.Max();
+
             if (maxStrain == 0)
                 return 0;
 
-            return ObjectStrains.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxStrain * 12.0 - 6.0))));
+            return ObjectDifficulties.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxStrain * 12.0 - 6.0))));
         }
 
-        public double CountTopWeightedSliders() => OsuStrainUtils.CountTopWeightedSliders(sliderStrains, DifficultyValue());
+        public double CountTopWeightedSliders(double difficultyValue)
+        {
+            if (sliderStrains.Count == 0)
+                return 0;
+
+            if (NoteWeightSum == 0)
+                return 0.0;
+
+            double consistentTopNote = difficultyValue / NoteWeightSum; // What would the top note be if all note values were identical
+
+            if (consistentTopNote == 0)
+                return 0;
+
+            // Use a weighted sum of all notes. Constants are arbitrary and give nice values
+            return sliderStrains.Sum(s => DifficultyCalculationUtils.Logistic(s / consistentTopNote, 0.88, 10, 1.1));
+        }
     }
 }

osu.Game.Rulesets.Osu/Difficulty/Utils/OsuStrainUtils.cs

@@ -1,26 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System.Collections.Generic;
-using System.Linq;
-using osu.Game.Rulesets.Difficulty.Utils;
-
-namespace osu.Game.Rulesets.Osu.Difficulty.Utils
-{
-    public static class OsuStrainUtils
-    {
-        public static double CountTopWeightedSliders(IReadOnlyCollection<double> sliderStrains, double difficultyValue)
-        {
-            if (sliderStrains.Count == 0)
-                return 0;
-
-            double consistentTopStrain = difficultyValue / 10; // What would the top strain be if all strain values were identical
-
-            if (consistentTopStrain == 0)
-                return 0;
-
-            // Use a weighted sum of all strains. Constants are arbitrary and give nice values
-            return sliderStrains.Sum(s => DifficultyCalculationUtils.Logistic(s / consistentTopStrain, 0.88, 10, 1.1));
-        }
-    }
-}

osu.Game.Rulesets.Taiko/Difficulty/Evaluators/RhythmEvaluator.cs

@@ -5,9 +5,11 @@ using System;
 using System.Collections.Generic;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Rhythm;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Rhythm.Data;
+using osu.Game.Rulesets.Taiko.Objects;
 
 namespace osu.Game.Rulesets.Taiko.Difficulty.Evaluators
 {
@@ -16,25 +18,32 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Evaluators
         /// <summary>
         /// Evaluate the difficulty of a hitobject considering its interval change.
         /// </summary>
-        public static double EvaluateDifficultyOf(DifficultyHitObject hitObject, double hitWindow)
+        public static double EvaluateDifficultyOf(DifficultyHitObject hitObject)
         {
+            if (hitObject.BaseObject is not Hit)
+                return 0;
+
             TaikoRhythmData rhythmData = ((TaikoDifficultyHitObject)hitObject).RhythmData;
             double difficulty = 0.0d;
 
             double sameRhythm = 0;
             double samePattern = 0;
             double intervalPenalty = 0;
+            double gapPenalty = 0;
+
+            double hitWindow = hitObject.HitWindow(HitResult.Great);
 
             if (rhythmData.SameRhythmGroupedHitObjects?.FirstHitObject == hitObject) // Difficulty for SameRhythmGroupedHitObjects
             {
                 sameRhythm += 10.0 * evaluateDifficultyOf(rhythmData.SameRhythmGroupedHitObjects, hitWindow);
                 intervalPenalty = repeatedIntervalPenalty(rhythmData.SameRhythmGroupedHitObjects, hitWindow);
+                gapPenalty = longGapPenalty(rhythmData.SameRhythmGroupedHitObjects.Previous);
             }
 
             if (rhythmData.SamePatternsGroupedHitObjects?.FirstHitObject == hitObject) // Difficulty for SamePatternsGroupedHitObjects
                 samePattern += 1.15 * ratioDifficulty(rhythmData.SamePatternsGroupedHitObjects.IntervalRatio);
 
-            difficulty += Math.Max(sameRhythm, samePattern) * intervalPenalty;
+            difficulty += Math.Max(sameRhythm, samePattern) * intervalPenalty * gapPenalty;
 
             return difficulty;
         }
@@ -56,8 +65,8 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Evaluators
                 {
                     intervalDifficulty *= DifficultyCalculationUtils.Logistic(
                         durationDifference / hitWindow,
-                        midpointOffset: 0.7,
-                        multiplier: 1.0,
+                        midpointOffset: 0.35,
+                        multiplier: 2,
                         maxValue: 1);
                 }
             }
@@ -65,8 +74,8 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Evaluators
             // Penalise patterns that can be hit within a single hit window.
             intervalDifficulty *= DifficultyCalculationUtils.Logistic(
                 sameRhythmGroupedHitObjects.Duration / hitWindow,
-                midpointOffset: 0.6,
-                multiplier: 1,
+                midpointOffset: 0.3,
+                multiplier: 2,
                 maxValue: 1);
 
             return Math.Pow(intervalDifficulty, 0.75);
@@ -118,6 +127,32 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Evaluators
             }
         }
 
+        /// <summary>
+        /// Frequent rhythm changes containing long gaps (i.e. 1/4 + 1/6 with 1/2 gaps) award more difficulty than expected.
+        /// Due to limitations of the current rhythm evaluation, these cases are targeted and penalised.
+        /// The previous hit object grouping is used as often the rhythm change *two* rhythms after a long gap awards the unexpected difficulty.
+        /// </summary>
+        private static double longGapPenalty(SameRhythmHitObjectGrouping? previous)
+        {
+            if (previous == null)
+                return 1.0;
+
+            double gapInterval = previous.FirstHitObject.DeltaTime;
+            double rhythmInterval = previous.HitObjectInterval ?? gapInterval;
+            double rhythmLength = previous.HitObjects.Count;
+
+            // The ratio of the gap before this rhythm to the rhythm itself.
+            double gapRatio = gapInterval / Math.Max(rhythmInterval, 1);
+
+            // The gap ratio normalised to represent if the gap is long.
+            double gapFactor = DifficultyCalculationUtils.Logistic(gapRatio, 1.75, 20);
+
+            // The length in objects of this rhythm normalised to represent if the rhythm change is frequent enough to be penalised.
+            double lengthFactor = DifficultyCalculationUtils.ReverseLerp(rhythmLength, 8, 2);
+
+            return 1.0 - 0.75 * gapFactor * lengthFactor;
+        }
+
         /// <summary>
         /// Calculates the difficulty of a given ratio using a combination of periodic penalties and bonuses.
         /// </summary>

osu.Game.Rulesets.Taiko/Difficulty/Preprocessing/TaikoDifficultyHitObject.cs

@@ -7,10 +7,10 @@ using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Taiko.Difficulty.Evaluators;
-using osu.Game.Rulesets.Taiko.Objects;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Rhythm;
 using osu.Game.Rulesets.Taiko.Difficulty.Utils;
+using osu.Game.Rulesets.Taiko.Objects;
 
 namespace osu.Game.Rulesets.Taiko.Difficulty.Preprocessing
 {

osu.Game.Rulesets.Taiko/Difficulty/Skills/Rhythm.cs

@@ -17,17 +17,14 @@ namespace osu.Game.Rulesets.Taiko.Difficulty.Skills
         protected override double SkillMultiplier => 1.0;
         protected override double StrainDecayBase => 0.4;
 
-        private readonly double greatHitWindow;
-
-        public Rhythm(Mod[] mods, double greatHitWindow)
+        public Rhythm(Mod[] mods)
             : base(mods)
         {
-            this.greatHitWindow = greatHitWindow;
         }
 
         protected override double StrainValueOf(DifficultyHitObject current)
         {
-            double difficulty = RhythmEvaluator.EvaluateDifficultyOf(current, greatHitWindow);
+            double difficulty = RhythmEvaluator.EvaluateDifficultyOf(current);
 
             // To prevent abuse of exceedingly long intervals between awkward rhythms, we penalise its difficulty.
             double staminaDifficulty = StaminaEvaluator.EvaluateDifficultyOf(current) - 0.5; // Remove base strain

osu.Game.Rulesets.Taiko/Difficulty/TaikoDifficultyCalculator.cs

@@ -10,20 +10,19 @@ using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Skills;
 using osu.Game.Rulesets.Difficulty.Utils;
 using osu.Game.Rulesets.Mods;
-using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Colour;
 using osu.Game.Rulesets.Taiko.Difficulty.Preprocessing.Rhythm;
 using osu.Game.Rulesets.Taiko.Difficulty.Skills;
 using osu.Game.Rulesets.Taiko.Mods;
-using osu.Game.Rulesets.Taiko.Scoring;
+using osu.Game.Utils;
 
 namespace osu.Game.Rulesets.Taiko.Difficulty
 {
     public class TaikoDifficultyCalculator : DifficultyCalculator
     {
         private const double difficulty_multiplier = 0.084375;
-        private const double rhythm_skill_multiplier = 0.750 * difficulty_multiplier;
+        private const double rhythm_skill_multiplier = 0.770 * difficulty_multiplier;
         private const double reading_skill_multiplier = 0.100 * difficulty_multiplier;
         private const double colour_skill_multiplier = 0.375 * difficulty_multiplier;
         private const double stamina_skill_multiplier = 0.445 * difficulty_multiplier;
@@ -41,17 +40,14 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
         {
         }
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
         {
-            HitWindows hitWindows = new TaikoHitWindows();
-            hitWindows.SetDifficulty(beatmap.Difficulty.OverallDifficulty);
-
             isConvert = beatmap.BeatmapInfo.Ruleset.OnlineID == 0;
             isRelax = mods.Any(h => h is TaikoModRelax);
 
             return new Skill[]
             {
-                new Rhythm(mods, hitWindows.WindowFor(HitResult.Great) / clockRate),
+                new Rhythm(mods),
                 new Reading(mods),
                 new Colour(mods),
                 new Stamina(mods, false, isConvert),
@@ -67,13 +63,15 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
             new TaikoModHardRock(),
         };
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
         {
             var difficultyHitObjects = new List<DifficultyHitObject>();
             var centreObjects = new List<TaikoDifficultyHitObject>();
             var rimObjects = new List<TaikoDifficultyHitObject>();
             var noteObjects = new List<TaikoDifficultyHitObject>();
 
+            double clockRate = ModUtils.CalculateRateWithMods(mods);
+
             // Generate TaikoDifficultyHitObjects from the beatmap's hit objects.
             for (int i = 2; i < beatmap.HitObjects.Count; i++)
             {
@@ -97,7 +95,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
             return difficultyHitObjects;
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new TaikoDifficultyAttributes { Mods = mods };
@@ -108,14 +106,16 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
             var stamina = skills.OfType<Stamina>().Single(s => !s.SingleColourStamina);
             var singleColourStamina = skills.OfType<Stamina>().Single(s => s.SingleColourStamina);
 
+            double staminaDifficultyValue = stamina.DifficultyValue();
+
             double rhythmSkill = rhythm.DifficultyValue() * rhythm_skill_multiplier;
             double readingSkill = reading.DifficultyValue() * reading_skill_multiplier;
             double colourSkill = colour.DifficultyValue() * colour_skill_multiplier;
-            double staminaSkill = stamina.DifficultyValue() * stamina_skill_multiplier;
+            double staminaSkill = staminaDifficultyValue * stamina_skill_multiplier;
             double monoStaminaSkill = singleColourStamina.DifficultyValue() * stamina_skill_multiplier;
             double monoStaminaFactor = staminaSkill == 0 ? 1 : Math.Pow(monoStaminaSkill / staminaSkill, 5);
 
-            double staminaDifficultStrains = stamina.CountTopWeightedStrains();
+            double staminaDifficultStrains = stamina.CountTopWeightedStrains(staminaDifficultyValue);
 
             // As we don't have pattern integration in osu!taiko, we apply the other two skills relative to rhythm.
             patternMultiplier = Math.Pow(staminaSkill * colourSkill, 0.10);
@@ -184,10 +184,10 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
             }
 
             List<double> hitObjectStrainPeaks = combinePeaks(
-                rhythm.GetObjectStrains().ToList(),
-                reading.GetObjectStrains().ToList(),
-                colour.GetObjectStrains().ToList(),
-                stamina.GetObjectStrains().ToList()
+                rhythm.GetObjectDifficulties(),
+                reading.GetObjectDifficulties(),
+                colour.GetObjectDifficulties(),
+                stamina.GetObjectDifficulties()
             );
 
             if (hitObjectStrainPeaks.Count == 0)
@@ -209,7 +209,7 @@ namespace osu.Game.Rulesets.Taiko.Difficulty
         /// <summary>
         /// Combines lists of peak strains from multiple skills into a list of single peak strains for each section.
         /// </summary>
-        private List<double> combinePeaks(List<double> rhythmPeaks, List<double> readingPeaks, List<double> colourPeaks, List<double> staminaPeaks)
+        private List<double> combinePeaks(IReadOnlyList<double> rhythmPeaks, IReadOnlyList<double> readingPeaks, IReadOnlyList<double> colourPeaks, IReadOnlyList<double> staminaPeaks)
         {
             var combinedPeaks = new List<double>();
 

osu.Game.Tests/Beatmaps/IO/LegacyBeatmapExporterTest.cs

@@ -1,9 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using System.IO;
-using System.Linq;
 using System.Text;
 using NUnit.Framework;
 using osu.Framework.Allocation;
@@ -26,36 +24,6 @@ namespace osu.Game.Tests.Beatmaps.IO
         [Resolved]
         private BeatmapManager beatmaps { get; set; } = null!;
 
-        [TestCase(96, 32)]
-        [TestCase(32, 32)]
-        [TestCase(24, 32)]
-        [TestCase(23, 16)]
-        [TestCase(15, 16)]
-        [TestCase(12, 16)]
-        [TestCase(11, 8)]
-        [TestCase(6, 8)]
-        [TestCase(2, 4)]
-        public void TestGridSizeClampedToStableValues(int set, int expected)
-        {
-            IWorkingBeatmap beatmap = null!;
-            MemoryStream outStream = null!;
-
-            AddStep("import beatmap", () => beatmap = importBeatmapFromArchives(@"decimal-timing-beatmap.olz"));
-            AddStep("adjust grid", () => beatmap.Beatmap.GridSize = set);
-            AddStep("save", () => beatmaps.Save((beatmap.BeatmapInfo as BeatmapInfo)!, beatmap.Beatmap));
-
-            AddStep("export", () =>
-            {
-                outStream = new MemoryStream();
-
-                new LegacyBeatmapExporter(LocalStorage)
-                    .ExportToStream((BeatmapSetInfo)beatmap.BeatmapInfo.BeatmapSet!, outStream, null);
-            });
-
-            AddStep("import beatmap again", () => beatmap = importBeatmapFromStream(outStream));
-            AddAssert("grid clamped", () => beatmap.Beatmap.GridSize, () => Is.EqualTo(expected));
-        }
-
         [Test]
         public void TestObjectsSnappedAfterTruncatingExport()
         {
@@ -163,48 +131,6 @@ namespace osu.Game.Tests.Beatmaps.IO
             }
         }
 
-        [Test]
-        public void TestExportUsesCarriageReturnLineFeed()
-        {
-            IWorkingBeatmap beatmap = null!;
-            MemoryStream outStream = null!;
-
-            AddStep("import beatmap", () => beatmap = importBeatmapFromArchives(@"legacy-export-stability-test.olz"));
-            AddStep("export", () =>
-            {
-                outStream = new MemoryStream();
-
-                new LegacyBeatmapExporter(LocalStorage)
-                    .ExportToStream((BeatmapSetInfo)beatmap.BeatmapInfo.BeatmapSet!, outStream, null);
-            });
-
-            AddAssert(".osu file uses CRLF line endings",
-                () => hasBareLineFeed(outStream.GetBuffer()),
-                () => Is.False);
-
-            bool hasBareLineFeed(byte[] archiveBytes)
-            {
-                using var memoryStream = new MemoryStream(archiveBytes);
-                using var archiveReader = new ZipArchiveReader(memoryStream);
-
-                foreach (string filename in archiveReader.Filenames.Where(f => f.EndsWith(".osu", StringComparison.Ordinal)))
-                {
-                    byte[] content = archiveReader.GetStream(filename).ReadAllBytesToArray();
-
-                    for (int i = 0; i < content.Length; i++)
-                    {
-                        if (content[i] != '\n')
-                            continue;
-
-                        if (i == 0 || content[i - 1] != '\r')
-                            return true;
-                    }
-                }
-
-                return false;
-            }
-        }
-
         private IWorkingBeatmap importBeatmapFromStream(Stream stream)
         {
             var imported = beatmaps.Import(new ImportTask(stream, "filename.osz")).GetResultSafely();

osu.Game.Tests/Gameplay/TestSceneHitObjectSamples.cs

@@ -258,6 +258,6 @@ namespace osu.Game.Tests.Gameplay
         }
 
         private void disableLayeredHitSounds()
-            => AddStep("set LayeredHitSounds to false", () => Skin.Configuration.ConfigDictionary[nameof(LegacySetting.LayeredHitSounds)] = "0");
+            => AddStep("set LayeredHitSounds to false", () => Skin.Configuration.ConfigDictionary[LegacySetting.LayeredHitSounds.ToString()] = "0");
     }
 }

osu.Game.Tests/NonVisual/DifficultyAdjustmentModCombinationsTest.cs

@@ -223,17 +223,17 @@ namespace osu.Game.Tests.NonVisual
 
             protected override Mod[] DifficultyAdjustmentMods { get; }
 
-            protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+            protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
             {
                 throw new NotImplementedException();
             }
 
-            protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+            protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
             {
                 throw new NotImplementedException();
             }
 
-            protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
+            protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
             {
                 throw new NotImplementedException();
             }

osu.Game.Tests/NonVisual/Filtering/FilterMatchingTest.cs

@@ -219,46 +219,6 @@ namespace osu.Game.Tests.NonVisual.Filtering
             ClassicAssert.AreEqual(filtered, carouselItem.Filtered.Value);
         }
 
-        [Test]
-        [TestCase("\"quoted words\"", false)]
-        [TestCase("\"the artist\"", false)]
-        [TestCase("the artist \"quoted words\"", false)]
-        [TestCase("\"unknown\"", true)]
-        public void TestCriteriaMatchingTermsAdjacentToPunctuation(string terms, bool filtered)
-        {
-            var exampleBeatmapInfo = getExampleBeatmap();
-            exampleBeatmapInfo.Metadata.Title = "the artist \"quoted words\"";
-            var criteria = new FilterCriteria
-            {
-                Ruleset = new RulesetInfo { OnlineID = 6 },
-                AllowConvertedBeatmaps = true,
-                SearchText = terms
-            };
-            var carouselItem = new CarouselBeatmap(exampleBeatmapInfo);
-            carouselItem.Filter(criteria);
-            ClassicAssert.AreEqual(filtered, carouselItem.Filtered.Value);
-        }
-
-        [Test]
-        [TestCase("~quoted words~", false)]
-        [TestCase("the artist", false)]
-        [TestCase("the artist ~quoted words~", false)]
-        [TestCase("~unknown~", true)]
-        public void TestCriteriaMatchingTermsAdjacentToMathSymbols(string terms, bool filtered)
-        {
-            var exampleBeatmapInfo = getExampleBeatmap();
-            exampleBeatmapInfo.Metadata.Title = "the artist ~quoted words~";
-            var criteria = new FilterCriteria
-            {
-                Ruleset = new RulesetInfo { OnlineID = 6 },
-                AllowConvertedBeatmaps = true,
-                SearchText = terms
-            };
-            var carouselItem = new CarouselBeatmap(exampleBeatmapInfo);
-            carouselItem.Filter(criteria);
-            ClassicAssert.AreEqual(filtered, carouselItem.Filtered.Value);
-        }
-
         [Test]
         [TestCase("", false)]
         [TestCase("Goes", false)]

osu.Game.Tests/NonVisual/TestSceneTimedDifficultyCalculation.cs

@@ -15,6 +15,7 @@ using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.UI;
 using osu.Game.Tests.Beatmaps;
+using osu.Game.Utils;
 
 namespace osu.Game.Tests.NonVisual
 {
@@ -172,13 +173,15 @@ namespace osu.Game.Tests.NonVisual
             {
             }
 
-            protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+            protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
                 => new TestDifficultyAttributes { Objects = beatmap.HitObjects.ToArray() };
 
-            protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+            protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
             {
                 List<DifficultyHitObject> objects = new List<DifficultyHitObject>();
 
+                double clockRate = ModUtils.CalculateRateWithMods(mods);
+
                 foreach (var obj in beatmap.HitObjects.OfType<TestHitObject>())
                 {
                     if (!obj.Skip)
@@ -191,7 +194,7 @@ namespace osu.Game.Tests.NonVisual
                 return objects;
             }
 
-            protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => new Skill[] { new PassThroughSkill(mods) };
+            protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods) => new Skill[] { new PassThroughSkill(mods) };
 
             private class PassThroughSkill : Skill
             {
@@ -200,8 +203,9 @@ namespace osu.Game.Tests.NonVisual
                 {
                 }
 
-                public override void Process(DifficultyHitObject current)
+                protected override double ProcessInternal(DifficultyHitObject current)
                 {
+                    return 0;
                 }
 
                 public override double DifficultyValue() => 1;

osu.Game.Tests/Visual/Components/TestSceneFriendPresenceNotifier.cs

@@ -25,7 +25,6 @@ namespace osu.Game.Tests.Visual.Components
         private NotificationOverlay notificationOverlay = null!;
         private ChatOverlay chatOverlay = null!;
         private TestMetadataClient metadataClient = null!;
-        private FriendPresenceNotifier notifier = null!;
 
         [SetUp]
         public void Setup() => Schedule(() =>
@@ -46,11 +45,7 @@ namespace osu.Game.Tests.Visual.Components
                     notificationOverlay,
                     chatOverlay,
                     metadataClient,
-                    notifier = new FriendPresenceNotifier
-                    {
-                        // Speeds up tests that don't rely on this debounce a little bit.
-                        OfflineDebounceTime = 0
-                    }
+                    new FriendPresenceNotifier()
                 }
             };
 
@@ -132,27 +127,5 @@ namespace osu.Game.Tests.Visual.Components
 
             AddUntilStep("wait for notification", () => notificationOverlay.AllNotifications.Count(), () => Is.EqualTo(2));
         }
-
-        [Test]
-        public void TestOfflineDebounce()
-        {
-            AddStep("set debounce time", () =>
-            {
-                notifier.NotificationDebounceTime = 0;
-                notifier.OfflineDebounceTime = 5000;
-            });
-
-            AddStep("bring friend online", () => metadataClient.FriendPresenceUpdated(1, new UserPresence { Status = UserStatus.Online }));
-            AddUntilStep("online notification posted", () => notificationOverlay.AllNotifications.Count(), () => Is.EqualTo(1));
-
-            for (int i = 0; i < 3; i++)
-            {
-                AddStep("bring friend online", () => metadataClient.FriendPresenceUpdated(1, new UserPresence { Status = UserStatus.Online }));
-                AddStep("bring friend offline", () => metadataClient.FriendPresenceUpdated(1, null));
-            }
-
-            AddUntilStep("online notification posted", () => notificationOverlay.AllNotifications.Count(), () => Is.EqualTo(1));
-            AddUntilStep("offline notification posted", () => notificationOverlay.AllNotifications.Count(), () => Is.EqualTo(2));
-        }
     }
 }

osu.Game.Tests/Visual/Gameplay/TestSceneSkinEditor.cs

@@ -503,27 +503,27 @@ namespace osu.Game.Tests.Visual.Gameplay
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddStep("Click TopLeft anchor", () =>
+            AddStep("Right-click TopLeft anchor", () =>
             {
                 InputManager.MoveMouseTo(getMenuItemByText("TopLeft"));
-                InputManager.Click(MouseButton.Left);
+                InputManager.Click(MouseButton.Right);
             });
 
             AddAssert("TopLeft item checked", () => (getMenuItemByText("TopLeft").Item as TernaryStateRadioMenuItem)?.State.Value == TernaryState.True);
 
-            AddStep("Click Centre anchor", () =>
+            AddStep("Right-click Centre anchor", () =>
             {
                 InputManager.MoveMouseTo(getMenuItemByText("Centre"));
-                InputManager.Click(MouseButton.Left);
+                InputManager.Click(MouseButton.Right);
             });
 
             AddAssert("Centre item checked", () => (getMenuItemByText("Centre").Item as TernaryStateRadioMenuItem)?.State.Value == TernaryState.True);
             AddAssert("TopLeft item unchecked", () => (getMenuItemByText("TopLeft").Item as TernaryStateRadioMenuItem)?.State.Value == TernaryState.False);
 
-            AddStep("Click Closest anchor", () =>
+            AddStep("Right-click Closest anchor", () =>
             {
                 InputManager.MoveMouseTo(getMenuItemByText("Closest"));
-                InputManager.Click(MouseButton.Left);
+                InputManager.Click(MouseButton.Right);
             });
 
             AddAssert("Closest item checked", () => (getMenuItemByText("Closest").Item as TernaryStateRadioMenuItem)?.State.Value == TernaryState.True);

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerMatchSubScreen.cs

@@ -17,7 +17,6 @@ using osu.Game.Beatmaps;
 using osu.Game.Database;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Chat;
 using osu.Game.Online.Multiplayer;
 using osu.Game.Online.Rooms;
 using osu.Game.Overlays;
@@ -58,7 +57,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
             Dependencies.Cache(beatmaps = new BeatmapManager(LocalStorage, Realm, null, audio, Resources, host, Beatmap.Default));
             Dependencies.Cache(Realm);
             Dependencies.CacheAs<BeatmapStore>(new RealmDetachedBeatmapStore());
-            Dependencies.Cache(new ChannelManager(API));
 
             beatmaps.Import(TestResources.GetQuickTestBeatmapForImport()).WaitSafely();
 
@@ -441,27 +439,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("countdown started", () => MultiplayerClient.ServerRoom!.ActiveCountdowns.Any());
         }
 
-        [Test]
-        public void TestRoll()
-        {
-            AddStep("set playlist", () =>
-            {
-                room.Playlist =
-                [
-                    new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First()).BeatmapInfo)
-                    {
-                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                    }
-                ];
-            });
-            ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
-            AddStep("set channel", () => room.ChannelId = 1);
-
-            AddUntilStep("wait for room join", () => RoomJoined);
-
-            AddStep("roll", () => MultiplayerClient.SendMatchRequest(new RollRequest()));
-        }
-
         [Test]
         public void TestSettingsRemainsOpenOnRoomUpdate()
         {

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerParticipantsList.cs

@@ -56,25 +56,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddAssert("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 2);
         }
 
-        [Test]
-        public void TestAddReferee()
-        {
-            AddAssert("one unique panel", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 1);
-
-            AddStep("add user", () => MultiplayerClient.AddUser(new MultiplayerRoomUser(3)
-            {
-                User = new APIUser
-                {
-                    Id = 3,
-                    Username = "Second",
-                    CoverUrl = TestResources.COVER_IMAGE_3,
-                },
-                Role = MultiplayerRoomUserRole.Referee
-            }));
-
-            AddAssert("two unique panels", () => this.ChildrenOfType<ParticipantPanel>().Select(p => p.Current.Value).Distinct().Count() == 2);
-        }
-
         [Test]
         public void TestAddUnresolvedUser()
         {

osu.Game.Tests/Visual/Multiplayer/TestSceneTeamVersus.cs

@@ -116,55 +116,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("user still on team 0", () => (multiplayerClient.ClientRoom?.Users.FirstOrDefault()?.MatchState as TeamVersusUserState)?.TeamID == 0);
         }
 
-        [Test]
-        public void TestTeamChangesLocked()
-        {
-            createRoom(() => new Room
-            {
-                Name = "Test Room",
-                Type = MatchType.TeamVersus,
-                Playlist =
-                [
-                    new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
-                    {
-                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                    }
-                ]
-            });
-
-            AddUntilStep("user on team 0", () => (multiplayerClient.ClientRoom?.Users.FirstOrDefault()?.MatchState as TeamVersusUserState)?.TeamID == 0);
-            AddStep("add another user", () => multiplayerClient.AddUser(new APIUser { Username = "otheruser", Id = 44 }));
-
-            AddStep("lock room", () =>
-            {
-                var roomState = TeamVersusRoomState.CreateDefault();
-                roomState.Locked = true;
-                multiplayerClient.ChangeMatchRoomState(roomState).WaitSafely();
-            });
-            AddStep("press own button", () =>
-            {
-                InputManager.MoveMouseTo(multiplayerComponents.ChildrenOfType<TeamDisplay>().First());
-                InputManager.Click(MouseButton.Left);
-            });
-            AddUntilStep("user on team 0", () => (multiplayerClient.ClientRoom?.Users.FirstOrDefault()?.MatchState as TeamVersusUserState)?.TeamID == 0);
-
-            AddStep("unlock room", () =>
-            {
-                var roomState = TeamVersusRoomState.CreateDefault();
-                roomState.Locked = false;
-                multiplayerClient.ChangeMatchRoomState(roomState).WaitSafely();
-            });
-            AddStep("press own button", () =>
-            {
-                InputManager.MoveMouseTo(multiplayerComponents.ChildrenOfType<TeamDisplay>().First());
-                InputManager.Click(MouseButton.Left);
-            });
-            AddUntilStep("user on team 1", () => (multiplayerClient.ClientRoom?.Users.FirstOrDefault()?.MatchState as TeamVersusUserState)?.TeamID == 1);
-
-            AddStep("press own button again", () => InputManager.Click(MouseButton.Left));
-            AddUntilStep("user on team 0", () => (multiplayerClient.ClientRoom?.Users.FirstOrDefault()?.MatchState as TeamVersusUserState)?.TeamID == 0);
-        }
-
         [Test]
         public void TestSettingsUpdatedWhenChangingMatchType()
         {

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsRoomSubScreen.cs

@@ -140,14 +140,13 @@ namespace osu.Game.Tests.Visual.Playlists
                 room = new Room
                 {
                     RoomID = 1,
-                    MaxAttempts = 10,
                     Playlist =
                     [
                         // osu! beatmap
                         new PlaylistItem(importedSet.Beatmaps[0])
                         {
                             RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
-                            Freestyle = true,
+                            Freestyle = true
                         },
                         // osu! beatmap converted played in taiko
                         new PlaylistItem(importedSet.Beatmaps[1])

osu.Game.Tests/Visual/Settings/TestSceneRevertToDefaultButton.cs

@@ -18,7 +18,7 @@ namespace osu.Game.Tests.Visual.Settings
 
         private readonly Bindable<float> current = new Bindable<float>
         {
-            Default = 0,
+            Default = default,
             Value = 1,
         };
 
@@ -46,7 +46,7 @@ namespace osu.Game.Tests.Visual.Settings
                 foreach (var revertToDefaultButton in this.ChildrenOfType<RevertToDefaultButton<float>>())
                     revertToDefaultButton.Parent!.Scale = new Vector2(scale);
             });
-            AddToggleStep("toggle default state", state => current.Value = state ? 0 : 1);
+            AddToggleStep("toggle default state", state => current.Value = state ? default : 1);
             AddToggleStep("toggle disabled state", state => current.Disabled = state);
         }
     }

osu.Game.Tests/Visual/SongSelect/TestSceneManageCollectionsDialog.cs

@@ -17,7 +17,6 @@ using osu.Game.Graphics.UserInterface;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Dialog;
 using osu.Game.Rulesets;
-using osu.Game.Screens.Select;
 using osu.Game.Tests.Resources;
 using osuTK;
 using osuTK.Input;
@@ -28,9 +27,6 @@ namespace osu.Game.Tests.Visual.SongSelect
     {
         protected override Container<Drawable> Content { get; } = new Container { RelativeSizeAxes = Axes.Both };
 
-        [Cached]
-        private OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Aquamarine);
-
         private DialogOverlay dialogOverlay = null!;
         private RulesetStore rulesets = null!;
         private BeatmapManager beatmapManager = null!;

osu.Game.Tests/Visual/UserInterface/TestSceneBeatmapAttributeText.cs

@@ -208,13 +208,13 @@ namespace osu.Game.Tests.Visual.UserInterface
             {
             }
 
-            protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
+            protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
                 => new DifficultyAttributes(mods, mods.OfType<TestMod>().SingleOrDefault()?.Difficulty.Value ?? 0);
 
-            protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
+            protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
                 => Array.Empty<DifficultyHitObject>();
 
-            protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
+            protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
                 => Array.Empty<Skill>();
         }
 

osu.Game.Tests/Visual/UserInterface/TestSceneCollectionDropdown.cs

@@ -0,0 +1,283 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Extensions;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Localisation;
+using osu.Framework.Platform;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Collections;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Localisation;
+using osu.Game.Overlays;
+using osu.Game.Rulesets;
+using osu.Game.Tests.Resources;
+using osuTK.Input;
+using Realms;
+
+namespace osu.Game.Tests.Visual.UserInterface
+{
+    public partial class TestSceneCollectionDropdown : OsuManualInputManagerTestScene
+    {
+        private RulesetStore rulesets = null!;
+        private BeatmapManager beatmapManager = null!;
+        private CollectionDropdown dropdown = null!;
+
+        [Cached]
+        private readonly OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Aquamarine);
+
+        [BackgroundDependencyLoader]
+        private void load(GameHost host)
+        {
+            Dependencies.Cache(rulesets = new RealmRulesetStore(Realm));
+            Dependencies.Cache(beatmapManager = new BeatmapManager(LocalStorage, Realm, null, Audio, Resources, host, Beatmap.Default));
+            Dependencies.Cache(Realm);
+
+            beatmapManager.Import(TestResources.GetQuickTestBeatmapForImport()).WaitSafely();
+        }
+
+        [SetUp]
+        public void SetUp() => Schedule(() =>
+        {
+            writeAndRefresh(r => r.RemoveAll<BeatmapCollection>());
+
+            Child = new Container
+            {
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+                Child = dropdown = new CollectionDropdown
+                {
+                    Width = 300,
+                    Y = 100,
+                    Anchor = Anchor.TopCentre,
+                    Origin = Anchor.TopCentre,
+                },
+            };
+        });
+
+        [Test]
+        public void TestEmptyCollectionFilterContainsAllBeatmaps()
+        {
+            assertCollectionDropdownContains(CollectionsStrings.AllBeatmaps);
+            assertCollectionHeaderDisplays(CollectionsStrings.AllBeatmaps);
+        }
+
+        [Test]
+        public void TestCollectionAddedToDropdown()
+        {
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "2"))));
+            assertCollectionDropdownContains("1");
+            assertCollectionDropdownContains("2");
+        }
+
+        [Test]
+        public void TestCollectionsCleared()
+        {
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "2"))));
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "3"))));
+
+            AddUntilStep("check count 5", () => dropdown.ChildrenOfType<CollectionDropdown>().Single().ChildrenOfType<Menu.DrawableMenuItem>().Count(), () => Is.EqualTo(5));
+
+            AddStep("delete all collections", () => writeAndRefresh(r => r.RemoveAll<BeatmapCollection>()));
+
+            AddUntilStep("check count 2", () => dropdown.ChildrenOfType<CollectionDropdown>().Single().ChildrenOfType<Menu.DrawableMenuItem>().Count(), () => Is.EqualTo(2));
+        }
+
+        [Test]
+        public void TestCollectionRemovedFromDropdown()
+        {
+            BeatmapCollection first = null!;
+
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(first = new BeatmapCollection(name: "1"))));
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "2"))));
+            AddStep("remove collection", () => writeAndRefresh(r => r.Remove(first)));
+
+            assertCollectionDropdownContains("1", false);
+            assertCollectionDropdownContains("2");
+        }
+
+        [Test]
+        public void TestCollectionRenamed()
+        {
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            assertCollectionDropdownContains("1");
+            AddStep("select collection", () => dropdown.Current.Value = dropdown.ItemSource.ElementAt(1));
+
+            addExpandHeaderStep();
+
+            AddStep("change name", () => writeAndRefresh(_ => getFirstCollection().Name = "First"));
+
+            assertCollectionDropdownContains("First");
+            assertCollectionHeaderDisplays("First");
+        }
+
+        [Test]
+        public void TestAllBeatmapFilterDoesNotHaveAddButton()
+        {
+            addExpandHeaderStep();
+            AddStep("hover all beatmaps", () => InputManager.MoveMouseTo(getAddOrRemoveButton(0)));
+            AddAssert("'All beatmaps' filter does not have add button", () => !getAddOrRemoveButton(0).IsPresent);
+        }
+
+        [Test]
+        public void TestCollectionFilterHasAddButton()
+        {
+            addExpandHeaderStep();
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            assertCollectionDropdownContains("1");
+            AddStep("hover collection", () => InputManager.MoveMouseTo(getAddOrRemoveButton(1)));
+            AddAssert("collection has add button", () => getAddOrRemoveButton(1).IsPresent);
+        }
+
+        [Test]
+        public void TestButtonDisabledAndEnabledWithBeatmapChanges()
+        {
+            addExpandHeaderStep();
+
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            assertCollectionDropdownContains("1");
+
+            AddStep("select available beatmap", () => Beatmap.Value = beatmapManager.GetWorkingBeatmap(beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0]));
+            AddAssert("button enabled", () => getAddOrRemoveButton(1).Enabled.Value);
+
+            AddStep("set dummy beatmap", () => Beatmap.SetDefault());
+            AddAssert("button disabled", () => !getAddOrRemoveButton(1).Enabled.Value);
+        }
+
+        [Test]
+        public void TestButtonChangesWhenAddedAndRemovedFromCollection()
+        {
+            addExpandHeaderStep();
+
+            AddStep("select available beatmap", () => Beatmap.Value = beatmapManager.GetWorkingBeatmap(beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0]));
+
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            assertCollectionDropdownContains("1");
+
+            assertFirstButtonIs(FontAwesome.Solid.PlusSquare);
+
+            AddStep("add beatmap to collection", () => writeAndRefresh(r => getFirstCollection().BeatmapMD5Hashes.Add(Beatmap.Value.BeatmapInfo.MD5Hash)));
+            assertFirstButtonIs(FontAwesome.Solid.MinusSquare);
+
+            AddStep("remove beatmap from collection", () => writeAndRefresh(r => getFirstCollection().BeatmapMD5Hashes.Clear()));
+            assertFirstButtonIs(FontAwesome.Solid.PlusSquare);
+        }
+
+        [Test]
+        public void TestButtonAddsAndRemovesBeatmap()
+        {
+            addExpandHeaderStep();
+
+            AddStep("select available beatmap", () => Beatmap.Value = beatmapManager.GetWorkingBeatmap(beatmapManager.GetAllUsableBeatmapSets().First().Beatmaps[0]));
+
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1"))));
+            assertCollectionDropdownContains("1");
+            assertFirstButtonIs(FontAwesome.Solid.PlusSquare);
+
+            addClickAddOrRemoveButtonStep(1);
+            AddUntilStep("collection contains beatmap", () => getFirstCollection().BeatmapMD5Hashes.Contains(Beatmap.Value.BeatmapInfo.MD5Hash));
+            assertFirstButtonIs(FontAwesome.Solid.MinusSquare);
+
+            addClickAddOrRemoveButtonStep(1);
+            AddUntilStep("collection does not contain beatmap", () => !getFirstCollection().BeatmapMD5Hashes.Contains(Beatmap.Value.BeatmapInfo.MD5Hash));
+            assertFirstButtonIs(FontAwesome.Solid.PlusSquare);
+        }
+
+        [Test]
+        public void TestManageCollectionsFilterIsNotSelected()
+        {
+            bool received = false;
+
+            addExpandHeaderStep();
+
+            AddStep("add collection", () => writeAndRefresh(r => r.Add(new BeatmapCollection(name: "1", new List<string> { "abc" }))));
+            assertCollectionDropdownContains("1");
+
+            AddStep("select collection", () =>
+            {
+                InputManager.MoveMouseTo(getCollectionDropdownItemAt(1));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            addExpandHeaderStep();
+
+            AddStep("watch for filter requests", () =>
+            {
+                received = false;
+                dropdown.ChildrenOfType<CollectionDropdown>().First().RequestFilter = () => received = true;
+            });
+
+            AddStep("click manage collections filter", () =>
+            {
+                int lastItemIndex = dropdown.ChildrenOfType<CollectionDropdown>().Single().Items.Count() - 1;
+                InputManager.MoveMouseTo(getCollectionDropdownItemAt(lastItemIndex));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("collection filter still selected", () => dropdown.Current.Value.CollectionName == "1");
+
+            AddAssert("filter request not fired", () => !received);
+        }
+
+        private void writeAndRefresh(Action<Realm> action) => Realm.Write(r =>
+        {
+            action(r);
+            r.Refresh();
+        });
+
+        private BeatmapCollection getFirstCollection() => Realm.Run(r => r.All<BeatmapCollection>().First());
+
+        private void assertCollectionHeaderDisplays(LocalisableString collectionName, bool shouldDisplay = true)
+            => AddUntilStep($"collection dropdown header displays '{collectionName}'",
+                () => shouldDisplay == dropdown.ChildrenOfType<CollectionDropdown.OsuDropdownHeader>().Any(h => h.ChildrenOfType<SpriteText>().Any(t => t.Text == collectionName)));
+
+        private void assertFirstButtonIs(IconUsage icon) => AddUntilStep($"button is {icon.Icon.ToString()}", () => getAddOrRemoveButton(1).Icon.Equals(icon));
+
+        private void assertCollectionDropdownContains(LocalisableString collectionName, bool shouldContain = true) =>
+            AddUntilStep($"collection dropdown {(shouldContain ? "contains" : "does not contain")} '{collectionName}'",
+                // A bit of a roundabout way of going about this, see: https://github.com/ppy/osu-framework/issues/3871 + https://github.com/ppy/osu-framework/issues/3872
+                () => shouldContain == dropdown.ChildrenOfType<Menu.DrawableMenuItem>().Any(i => i.ChildrenOfType<CompositeDrawable>().OfType<IHasText>().First().Text == collectionName));
+
+        private IconButton getAddOrRemoveButton(int index)
+            => getCollectionDropdownItemAt(index).ChildrenOfType<IconButton>().Single();
+
+        private void addExpandHeaderStep() => AddStep("expand header", () =>
+        {
+            InputManager.MoveMouseTo(dropdown.ChildrenOfType<CollectionDropdown.OsuDropdownHeader>().Single());
+            InputManager.Click(MouseButton.Left);
+        });
+
+        private void addClickAddOrRemoveButtonStep(int index) => AddStep("click add or remove button", () =>
+        {
+            InputManager.MoveMouseTo(getAddOrRemoveButton(index));
+            InputManager.Click(MouseButton.Left);
+        });
+
+        private Menu.DrawableMenuItem getCollectionDropdownItemAt(int index)
+        {
+            // todo: we should be able to use Items, but apparently that's not guaranteed to be ordered... see: https://github.com/ppy/osu-framework/pull/6079
+            CollectionFilterMenuItem item = dropdown.ChildrenOfType<CollectionDropdown>().Single().ItemSource.ElementAt(index);
+            return dropdown.ChildrenOfType<Menu.DrawableMenuItem>().Single(i => i.Item.Text.Value == item.CollectionName);
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (rulesets.IsNotNull())
+                rulesets.Dispose();
+        }
+    }
+}

osu.Game.Tests/Visual/UserInterface/TestSceneStatefulMenuItem.cs

@@ -114,6 +114,51 @@ namespace osu.Game.Tests.Visual.UserInterface
                 => AddAssert($"state is {expected}", () => state.Value == expected);
         }
 
+        [Test]
+        public void TestItemRespondsToRightClick()
+        {
+            OsuMenu menu = null;
+
+            Bindable<TernaryState> state = new Bindable<TernaryState>(TernaryState.Indeterminate);
+
+            AddStep("create menu", () =>
+            {
+                state.Value = TernaryState.Indeterminate;
+
+                Child = menu = new OsuMenu(Direction.Vertical, true)
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Items = new[]
+                    {
+                        new TernaryStateToggleMenuItem("First"),
+                        new TernaryStateToggleMenuItem("Second") { State = { BindTarget = state } },
+                        new TernaryStateToggleMenuItem("Third") { State = { Value = TernaryState.True } },
+                    }
+                };
+            });
+
+            checkState(TernaryState.Indeterminate);
+
+            click();
+            checkState(TernaryState.True);
+
+            click();
+            checkState(TernaryState.False);
+
+            AddStep("change state via bindable", () => state.Value = TernaryState.True);
+
+            void click() =>
+                AddStep("click", () =>
+                {
+                    InputManager.MoveMouseTo(menu.ScreenSpaceDrawQuad.Centre);
+                    InputManager.Click(MouseButton.Right);
+                });
+
+            void checkState(TernaryState expected)
+                => AddAssert($"state is {expected}", () => state.Value == expected);
+        }
+
         [Test]
         public void TestCustomState()
         {

osu.Game.Tournament/osu.Game.Tournament.csproj

@@ -10,9 +10,5 @@
   </ItemGroup>
   <ItemGroup Label="Package References">
     <PackageReference Include="Microsoft.Win32.Registry" Version="5.0.0" />
-    <PackageReference Include="ppy.LocalisationAnalyser" Version="2025.1208.0">
-      <PrivateAssets>all</PrivateAssets>
-      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-    </PackageReference>
   </ItemGroup>
 </Project>

osu.Game/Beatmaps/BeatmapDifficultyCache.cs

@@ -424,7 +424,7 @@ namespace osu.Game.Beatmaps
             Stream IWorkingBeatmap.GetStream(string storagePath) => working.GetStream(storagePath);
             void IWorkingBeatmap.BeginAsyncLoad() => working.BeginAsyncLoad();
             void IWorkingBeatmap.CancelAsyncLoad() => working.CancelAsyncLoad();
-            void IWorkingBeatmap.PrepareTrackForPreview(bool looping, double? offsetFromPreviewPoint) => working.PrepareTrackForPreview(looping, offsetFromPreviewPoint);
+            void IWorkingBeatmap.PrepareTrackForPreview(bool looping, double offsetFromPreviewPoint) => working.PrepareTrackForPreview(looping, offsetFromPreviewPoint);
         }
     }
 }

osu.Game/Beatmaps/BeatmapManager.cs

@@ -296,7 +296,7 @@ namespace osu.Game.Beatmaps
             return Realm.Run(r =>
             {
                 r.Refresh();
-                return r.All<BeatmapSetInfo>().Where(b => !b.DeletePending).AsEnumerable().Detach();
+                return r.All<BeatmapSetInfo>().Where(b => !b.DeletePending).Detach();
             });
         }
 

osu.Game/Beatmaps/BeatmapUpdater.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Linq;
-using System.Threading;
 using System.Threading.Tasks;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Logging;
@@ -37,7 +36,7 @@ namespace osu.Game.Beatmaps
         public void Queue(Live<BeatmapSetInfo> beatmapSet, MetadataLookupScope lookupScope = MetadataLookupScope.LocalCacheFirst)
         {
             Logger.Log($"Queueing change for local beatmap {beatmapSet}");
-            Task.Factory.StartNew(() => beatmapSet.PerformRead(b => Process(b, lookupScope)), CancellationToken.None, TaskCreationOptions.HideScheduler | TaskCreationOptions.RunContinuationsAsynchronously,
+            Task.Factory.StartNew(() => beatmapSet.PerformRead(b => Process(b, lookupScope)), default, TaskCreationOptions.HideScheduler | TaskCreationOptions.RunContinuationsAsynchronously,
                 updateScheduler);
         }
 

osu.Game/Beatmaps/IWorkingBeatmap.cs

@@ -139,6 +139,6 @@ namespace osu.Game.Beatmaps
         /// <summary>
         /// Reads the correct track restart point from beatmap metadata and sets looping to enabled.
         /// </summary>
-        void PrepareTrackForPreview(bool looping, double? offsetFromPreviewPoint = null);
+        void PrepareTrackForPreview(bool looping, double offsetFromPreviewPoint = 0);
     }
 }

osu.Game/Beatmaps/StarDifficulty.cs

@@ -6,7 +6,7 @@ using osu.Game.Rulesets.Difficulty;
 
 namespace osu.Game.Beatmaps
 {
-    public readonly record struct StarDifficulty
+    public readonly struct StarDifficulty
     {
         /// <summary>
         /// The star difficulty rating for the given beatmap.

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -16,7 +16,6 @@ using osu.Framework.Audio.Track;
 using osu.Framework.Extensions;
 using osu.Framework.Graphics.Textures;
 using osu.Framework.Logging;
-using osu.Game.Overlays;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.UI;
@@ -120,7 +119,7 @@ namespace osu.Game.Beatmaps
             return track;
         }
 
-        public void PrepareTrackForPreview(bool looping, double? offsetFromPreviewPoint = null)
+        public void PrepareTrackForPreview(bool looping, double offsetFromPreviewPoint = 0)
         {
             Track.Looping = looping;
             Track.RestartPoint = Metadata.PreviewTime;
@@ -134,9 +133,7 @@ namespace osu.Game.Beatmaps
             if (Track.RestartPoint < 0 || Track.RestartPoint > Track.Length)
                 Track.RestartPoint = 0.4f * Track.Length;
 
-            offsetFromPreviewPoint ??= -MusicController.TRACK_FADE_IN_TIME;
-
-            Track.RestartPoint = Math.Clamp(Track.RestartPoint + offsetFromPreviewPoint.Value, 0, Track.Length);
+            Track.RestartPoint = Math.Clamp(Track.RestartPoint + offsetFromPreviewPoint, 0, Track.Length);
         }
 
         /// <summary>
@@ -265,7 +262,7 @@ namespace osu.Game.Beatmaps
                 using (var cancellationTokenSource = new CancellationTokenSource(10_000))
                 {
                     // don't apply the default timeout when debugger is attached (may be breakpointing / debugging).
-                    return GetPlayableBeatmap(ruleset, mods ?? Array.Empty<Mod>(), Debugger.IsAttached ? CancellationToken.None : cancellationTokenSource.Token);
+                    return GetPlayableBeatmap(ruleset, mods ?? Array.Empty<Mod>(), Debugger.IsAttached ? new CancellationToken() : cancellationTokenSource.Token);
                 }
             }
             catch (OperationCanceledException)

osu.Game/Collections/CollectionDropdown.cs

@@ -0,0 +1,283 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Input.Events;
+using osu.Framework.Localisation;
+using osu.Game.Beatmaps;
+using osu.Game.Database;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.UserInterface;
+using osuTK;
+using Realms;
+
+namespace osu.Game.Collections
+{
+    /// <summary>
+    /// A dropdown to select the collection to be used to filter results.
+    /// WARNING: TODO: we have TWO `CollectionDropdowns` with diverging functionality. This is not good.
+    /// </summary>
+    public partial class CollectionDropdown : OsuDropdown<CollectionFilterMenuItem>
+    {
+        /// <summary>
+        /// Whether to show the "manage collections..." menu item in the dropdown.
+        /// </summary>
+        protected virtual bool ShowManageCollectionsItem => true;
+
+        public Action? RequestFilter { private get; set; }
+
+        private readonly BindableList<CollectionFilterMenuItem> filters = new BindableList<CollectionFilterMenuItem>();
+
+        [Resolved]
+        private ManageCollectionsDialog? manageCollectionsDialog { get; set; }
+
+        [Resolved]
+        private RealmAccess realm { get; set; } = null!;
+
+        private IDisposable? realmSubscription;
+
+        private readonly CollectionFilterMenuItem allBeatmapsItem = new AllBeatmapsCollectionFilterMenuItem();
+
+        public CollectionDropdown()
+        {
+            ItemSource = filters;
+
+            Current.Value = allBeatmapsItem;
+            AlwaysShowSearchBar = true;
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            realmSubscription = realm.RegisterForNotifications(r => r.All<BeatmapCollection>().OrderBy(c => c.Name), collectionsChanged);
+
+            Current.BindValueChanged(selectionChanged);
+        }
+
+        private void collectionsChanged(IRealmCollection<BeatmapCollection> collections, ChangeSet? changes)
+        {
+            if (changes == null)
+            {
+                filters.Clear();
+                filters.Add(allBeatmapsItem);
+                filters.AddRange(collections.Select(c => new CollectionFilterMenuItem(c.ToLive(realm))));
+                if (ShowManageCollectionsItem)
+                    filters.Add(new ManageCollectionsFilterMenuItem());
+            }
+            else
+            {
+                foreach (int i in changes.DeletedIndices.OrderDescending())
+                    filters.RemoveAt(i + 1);
+
+                foreach (int i in changes.InsertedIndices)
+                    filters.Insert(i + 1, new CollectionFilterMenuItem(collections[i].ToLive(realm)));
+
+                var selectedItem = SelectedItem?.Value;
+
+                foreach (int i in changes.NewModifiedIndices)
+                {
+                    var updatedItem = collections[i];
+
+                    // This is responsible for updating the state of the +/- button and the collection's name.
+                    // TODO: we can probably make the menu items update with changes to avoid this.
+                    filters.RemoveAt(i + 1);
+                    filters.Insert(i + 1, new CollectionFilterMenuItem(updatedItem.ToLive(realm)));
+
+                    if (updatedItem.ID == selectedItem?.Collection?.ID)
+                    {
+                        // This current update and schedule is required to work around dropdown headers not updating text even when the selected item
+                        // changes. It's not great but honestly the whole dropdown menu structure isn't great. This needs to be fixed, but I'll issue
+                        // a warning that it's going to be a frustrating journey.
+                        Current.Value = allBeatmapsItem;
+                        Schedule(() =>
+                        {
+                            // current may have changed before the scheduled call is run.
+                            if (Current.Value != allBeatmapsItem)
+                                return;
+
+                            Current.Value = filters.SingleOrDefault(f => f.Collection?.ID == selectedItem.Collection?.ID) ?? filters[0];
+                        });
+
+                        // Trigger an external re-filter if the current item was in the change set.
+                        RequestFilter?.Invoke();
+                        break;
+                    }
+                }
+            }
+        }
+
+        private Live<BeatmapCollection>? lastFiltered;
+
+        private void selectionChanged(ValueChangedEvent<CollectionFilterMenuItem> filter)
+        {
+            // May be null during .Clear().
+            if (filter.NewValue.IsNull())
+                return;
+
+            // Never select the manage collection filter - rollback to the previous filter.
+            // This is done after the above since it is important that bindable is unbound from OldValue, which is lost after forcing it back to the old value.
+            if (filter.NewValue is ManageCollectionsFilterMenuItem)
+            {
+                Current.Value = filter.OldValue;
+                manageCollectionsDialog?.Show();
+                return;
+            }
+
+            var newCollection = filter.NewValue.Collection;
+
+            // This dropdown be weird.
+            // We only care about filtering if the actual collection has changed.
+            if (newCollection != lastFiltered)
+            {
+                RequestFilter?.Invoke();
+                lastFiltered = newCollection;
+            }
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            realmSubscription?.Dispose();
+        }
+
+        protected override LocalisableString GenerateItemText(CollectionFilterMenuItem item) => item.CollectionName;
+
+        protected sealed override DropdownHeader CreateHeader() => CreateCollectionHeader();
+
+        protected sealed override DropdownMenu CreateMenu() => CreateCollectionMenu();
+
+        protected virtual CollectionDropdownHeader CreateCollectionHeader() => new CollectionDropdownHeader();
+
+        protected virtual CollectionDropdownMenu CreateCollectionMenu() => new CollectionDropdownMenu();
+
+        public partial class CollectionDropdownHeader : OsuDropdownHeader
+        {
+            public CollectionDropdownHeader()
+            {
+                Height = 25;
+                Chevron.Size = new Vector2(12);
+                Foreground.Padding = new MarginPadding { Top = 4, Bottom = 4, Left = 8, Right = 8 };
+            }
+        }
+
+        protected partial class CollectionDropdownMenu : OsuDropdownMenu
+        {
+            public CollectionDropdownMenu()
+            {
+                MaxHeight = 200;
+            }
+
+            protected override DrawableDropdownMenuItem CreateDrawableDropdownMenuItem(MenuItem item) => new CollectionDropdownDrawableMenuItem(item)
+            {
+                BackgroundColourHover = HoverColour,
+                BackgroundColourSelected = SelectionColour
+            };
+        }
+
+        protected partial class CollectionDropdownDrawableMenuItem : OsuDropdownMenu.DrawableOsuDropdownMenuItem
+        {
+            private IconButton addOrRemoveButton = null!;
+
+            private bool beatmapInCollection;
+
+            private readonly Live<BeatmapCollection>? collection;
+
+            [Resolved]
+            private IBindable<WorkingBeatmap> beatmap { get; set; } = null!;
+
+            public CollectionDropdownDrawableMenuItem(MenuItem item)
+                : base(item)
+            {
+                collection = ((DropdownMenuItem<CollectionFilterMenuItem>)item).Value.Collection;
+            }
+
+            [BackgroundDependencyLoader]
+            private void load()
+            {
+                AddInternal(addOrRemoveButton = new NoFocusChangeIconButton
+                {
+                    Anchor = Anchor.CentreRight,
+                    Origin = Anchor.CentreRight,
+                    X = -OsuScrollContainer.SCROLL_BAR_WIDTH,
+                    Scale = new Vector2(0.65f),
+                    Action = addOrRemove,
+                });
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+
+                if (collection != null)
+                {
+                    beatmap.BindValueChanged(_ =>
+                    {
+                        beatmapInCollection = collection.PerformRead(c => c.BeatmapMD5Hashes.Contains(beatmap.Value.BeatmapInfo.MD5Hash));
+
+                        addOrRemoveButton.Enabled.Value = !beatmap.IsDefault;
+                        addOrRemoveButton.Icon = beatmapInCollection ? FontAwesome.Solid.MinusSquare : FontAwesome.Solid.PlusSquare;
+                        addOrRemoveButton.TooltipText = beatmapInCollection ? "Remove selected beatmap" : "Add selected beatmap";
+
+                        updateButtonVisibility();
+                    }, true);
+                }
+
+                updateButtonVisibility();
+            }
+
+            protected override bool OnHover(HoverEvent e)
+            {
+                updateButtonVisibility();
+                return base.OnHover(e);
+            }
+
+            protected override void OnHoverLost(HoverLostEvent e)
+            {
+                updateButtonVisibility();
+                base.OnHoverLost(e);
+            }
+
+            protected override void OnSelectChange()
+            {
+                base.OnSelectChange();
+                updateButtonVisibility();
+            }
+
+            private void updateButtonVisibility()
+            {
+                if (collection == null)
+                    addOrRemoveButton.Alpha = 0;
+                else
+                    addOrRemoveButton.Alpha = IsHovered || IsPreSelected || beatmapInCollection ? 1 : 0;
+            }
+
+            private void addOrRemove()
+            {
+                Debug.Assert(collection != null);
+
+                Task.Run(() => collection.PerformWrite(c =>
+                {
+                    if (!c.BeatmapMD5Hashes.Remove(beatmap.Value.BeatmapInfo.MD5Hash))
+                        c.BeatmapMD5Hashes.Add(beatmap.Value.BeatmapInfo.MD5Hash);
+                }));
+            }
+
+            protected override Drawable CreateContent() => (Content)base.CreateContent();
+
+            private partial class NoFocusChangeIconButton : IconButton
+            {
+                public override bool ChangeFocusOnClick => false;
+            }
+        }
+    }
+}

osu.Game/Database/LegacyBeatmapExporter.cs

@@ -71,15 +71,8 @@ namespace osu.Game.Database
 
             // Encode to legacy format
             var stream = new MemoryStream();
-
             using (var sw = new StreamWriter(stream, Encoding.UTF8, 1024, true))
-            {
-                // Maintain line endings in windows style.
-                // If we don't do that, uploads to BSS may show changes where there are none.
-                sw.NewLine = "\r\n";
-
                 new LegacyBeatmapEncoder(playableBeatmap, beatmapSkin).Encode(sw);
-            }
 
             stream.Seek(0, SeekOrigin.Begin);
 
@@ -88,16 +81,6 @@ namespace osu.Game.Database
 
         protected virtual void MutateBeatmap(BeatmapSetInfo beatmapSet, IBeatmap playableBeatmap)
         {
-            // Limit grid sizes to those which stable knows about.
-            if (playableBeatmap.GridSize >= 24)
-                playableBeatmap.GridSize = 32;
-            else if (playableBeatmap.GridSize >= 12)
-                playableBeatmap.GridSize = 16;
-            else if (playableBeatmap.GridSize >= 6)
-                playableBeatmap.GridSize = 8;
-            else
-                playableBeatmap.GridSize = 4;
-
             // Convert beatmap elements to be compatible with legacy format
             // So we truncate time and position values to integers, and convert paths with multiple segments to Bézier curves
 

osu.Game/Database/RealmAccess.cs

@@ -1227,7 +1227,7 @@ namespace osu.Game.Database
                         var oldKeyBindingsQuery = migration.NewRealm
                                                            .All<RealmKeyBinding>()
                                                            .Where(kb => kb.RulesetName == @"mania" && kb.Variant == variant);
-                        var oldKeyBindings = oldKeyBindingsQuery.AsEnumerable().Detach();
+                        var oldKeyBindings = oldKeyBindingsQuery.Detach();
 
                         migration.NewRealm.RemoveRange(oldKeyBindingsQuery);
 

osu.Game/Extensions/TaskExtensions.cs

@@ -55,9 +55,9 @@ namespace osu.Game.Extensions
                         {
                             tcs.TrySetResult(true);
                         }
-                    }, cancellationToken: CancellationToken.None);
+                    }, cancellationToken: default);
                 }
-            }, cancellationToken: CancellationToken.None);
+            }, cancellationToken: default);
 
             // importantly, we are not returning the continuation itself but rather a task which represents its status in sequential execution order.
             // this will not be cancelled or completed until the previous task has also.

osu.Game/Graphics/Backgrounds/BeatmapBackgroundWithStoryboard.cs

@@ -1,7 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Threading;
@@ -22,13 +21,10 @@ namespace osu.Game.Graphics.Backgrounds
     {
         private readonly InterpolatingFramedClock storyboardClock;
 
-        public readonly AudioContainer Storyboard;
-
+        private AudioContainer storyboardContainer = null!;
         private DrawableStoryboard? drawableStoryboard;
         private CancellationTokenSource? loadCancellationSource = new CancellationTokenSource();
 
-        public Action? StoryboardLoaded { get; set; }
-
         [Resolved(CanBeNull = true)]
         private MusicController? musicController { get; set; }
 
@@ -39,17 +35,17 @@ namespace osu.Game.Graphics.Backgrounds
             : base(beatmap, fallbackTextureName)
         {
             storyboardClock = new InterpolatingFramedClock();
-
-            AddInternal(Storyboard = new AudioContainer
-            {
-                RelativeSizeAxes = Axes.Both,
-                Volume = { Value = 0 },
-            });
         }
 
         [BackgroundDependencyLoader]
         private void load()
         {
+            AddInternal(storyboardContainer = new AudioContainer
+            {
+                RelativeSizeAxes = Axes.Both,
+                Volume = { Value = 0 },
+            });
+
             LoadStoryboard(false);
         }
 
@@ -78,10 +74,8 @@ namespace osu.Game.Graphics.Backgrounds
                 if (Beatmap.Storyboard.ReplacesBackground)
                     Sprite.FadeOut(BackgroundScreen.TRANSITION_LENGTH, Easing.InQuint);
 
-                Storyboard.FadeInFromZero(BackgroundScreen.TRANSITION_LENGTH, Easing.OutQuint);
-                Storyboard.Add(s);
-
-                StoryboardLoaded?.Invoke();
+                storyboardContainer.FadeInFromZero(BackgroundScreen.TRANSITION_LENGTH, Easing.OutQuint);
+                storyboardContainer.Add(s);
             }
         }
 
@@ -94,7 +88,7 @@ namespace osu.Game.Graphics.Backgrounds
             loadCancellationSource = null;
 
             // clear is intentionally used here for the storyboard to be disposed asynchronously.
-            Storyboard.Clear();
+            storyboardContainer.Clear();
 
             drawableStoryboard = null;
 

osu.Game/Graphics/Containers/UserTrackingScrollContainer.cs

@@ -35,7 +35,7 @@ namespace osu.Game.Graphics.Containers
         {
         }
 
-        protected override void OnUserScroll(double value, bool animated = true, double? distanceDecay = null)
+        protected override void OnUserScroll(double value, bool animated = true, double? distanceDecay = default)
         {
             UserScrolling = true;
             base.OnUserScroll(value, animated, distanceDecay);

osu.Game/Graphics/OsuIcon.cs

@@ -688,11 +688,11 @@ namespace osu.Game.Graphics
 
             public class Glyph : ITexturedCharacterGlyph
             {
-                public float XOffset => 0;
-                public float YOffset => 0;
-                public float XAdvance => 0;
-                public float Baseline => 0;
-                public char Character => '\0';
+                public float XOffset => default;
+                public float YOffset => default;
+                public float XAdvance => default;
+                public float Baseline => default;
+                public char Character => default;
 
                 public float GetKerning<T>(T lastGlyph) where T : ICharacterGlyph => throw new NotImplementedException();
 

osu.Game/Graphics/UserInterface/DrawableStatefulMenuItem.cs

@@ -4,7 +4,9 @@
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input.Events;
 using osuTK;
+using osuTK.Input;
 
 namespace osu.Game.Graphics.UserInterface
 {
@@ -12,8 +14,6 @@ namespace osu.Game.Graphics.UserInterface
     {
         protected new StatefulMenuItem Item => (StatefulMenuItem)base.Item;
 
-        public override bool CloseMenuOnClick => false;
-
         public DrawableStatefulMenuItem(StatefulMenuItem item)
             : base(item)
         {
@@ -21,6 +21,19 @@ namespace osu.Game.Graphics.UserInterface
 
         protected override TextContainer CreateTextContainer() => new ToggleTextContainer(Item);
 
+        protected override bool OnMouseDown(MouseDownEvent e)
+        {
+            // Right mouse button is a special case where we allow actioning without dismissing the menu.
+            // This is achieved by not calling `Clicked` (as done by the base implementation in OnClick).
+            if (IsActionable && e.Button == MouseButton.Right)
+            {
+                Item.Action.Value?.Invoke();
+                return true;
+            }
+
+            return false;
+        }
+
         private partial class ToggleTextContainer : TextContainer
         {
             private readonly StatefulMenuItem menuItem;

osu.Game/Graphics/UserInterface/Hotkey.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
-using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Input;
@@ -57,24 +55,5 @@ namespace osu.Game.Graphics.UserInterface
 
             return result;
         }
-
-        public bool Equals(Hotkey other)
-        {
-            if (KeyCombinations == null && other.KeyCombinations != null)
-                return false;
-
-            if (KeyCombinations != null && other.KeyCombinations == null)
-                return false;
-
-            bool result = (KeyCombinations == null && other.KeyCombinations == null) || KeyCombinations!.SequenceEqual(other.KeyCombinations!);
-            result &= GlobalAction == other.GlobalAction;
-            result &= PlatformAction == other.PlatformAction;
-            return result;
-        }
-
-        public override int GetHashCode()
-        {
-            return HashCode.Combine(StructuralComparisons.StructuralEqualityComparer.GetHashCode(KeyCombinations ?? []), GlobalAction, PlatformAction);
-        }
     }
 }

osu.Game/Graphics/UserInterface/SectionHeader.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
@@ -15,20 +14,8 @@ namespace osu.Game.Graphics.UserInterface
 {
     public partial class SectionHeader : CompositeDrawable
     {
-        /// <summary>
-        /// Extra text to be shown in brackets next to the header.
-        /// Unlike the header itself, this can be updated during runtime.
-        /// </summary>
-        public readonly Bindable<string> DetailsText = new Bindable<string>();
-
         private readonly LocalisableString text;
 
-        private OsuTextFlowContainer textFlow = null!;
-        private ITextPart? detailsPart;
-
-        [Resolved]
-        private OverlayColourProvider colourProvider { get; set; } = null!;
-
         public SectionHeader(LocalisableString text)
         {
             this.text = text;
@@ -40,7 +27,7 @@ namespace osu.Game.Graphics.UserInterface
         }
 
         [BackgroundDependencyLoader]
-        private void load()
+        private void load(OverlayColourProvider colourProvider)
         {
             InternalChild = new FillFlowContainer
             {
@@ -50,7 +37,7 @@ namespace osu.Game.Graphics.UserInterface
                 Spacing = new Vector2(2),
                 Children = new Drawable[]
                 {
-                    textFlow = new OsuTextFlowContainer(cp => cp.Font = OsuFont.Default.With(size: 16, weight: FontWeight.SemiBold))
+                    new OsuTextFlowContainer(cp => cp.Font = OsuFont.Default.With(size: 16, weight: FontWeight.SemiBold))
                     {
                         Text = text,
                         RelativeSizeAxes = Axes.X,
@@ -64,21 +51,5 @@ namespace osu.Game.Graphics.UserInterface
                 }
             };
         }
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            DetailsText.BindValueChanged(updateDetails, true);
-        }
-
-        private void updateDetails(ValueChangedEvent<string> details)
-        {
-            if (detailsPart != null)
-                textFlow.RemovePart(detailsPart);
-
-            if (!string.IsNullOrEmpty(details.NewValue))
-                detailsPart = textFlow.AddText($" ({details.NewValue})", t => t.Colour = colourProvider.Highlight1);
-        }
     }
 }

osu.Game/Input/Bindings/DatabasedKeyBindingContainer.cs

@@ -74,7 +74,7 @@ namespace osu.Game.Input.Bindings
         {
             var defaults = DefaultKeyBindings.ToList();
 
-            List<RealmKeyBinding> newBindings = realmKeyBindings.AsEnumerable().Detach()
+            List<RealmKeyBinding> newBindings = realmKeyBindings.Detach()
                                                                 // this ordering is important to ensure that we read entries from the database in the order
                                                                 // enforced by DefaultKeyBindings. allow for song select to handle actions that may otherwise
                                                                 // have been eaten by the music controller due to query order.

osu.Game/Localisation/NotificationsStrings.cs

@@ -235,11 +235,6 @@ Click to see what's new!", version);
         /// </summary>
         public static LocalisableString ElevatedPrivileges(LocalisableString user) => new TranslatableString(getKey(@"elevated_privileges"), @"Running osu! as {0} does not improve performance, may break integrations and poses a security risk. Please run the game as a normal user.", user);
 
-        /// <summary>
-        /// "On macOS, installing osu! to a directory other than /Applications or {0}/Applications can cause issues with updating the game. Please move your game installation to one of these locations."
-        /// </summary>
-        public static LocalisableString MacOSAppLocation(LocalisableString userProfile) => new TranslatableString(getKey(@"macos_app_location"), @"On macOS, installing osu! to a directory other than /Applications or {0}/Applications can cause issues with updating the game. Please move your game installation to one of these locations.", userProfile);
-
         /// <summary>
         /// "Screenshot saved! Click to view.
         /// {0}"

osu.Game/Localisation/OnlinePlayStrings.cs

@@ -49,31 +49,6 @@ namespace osu.Game.Localisation
         /// </summary>
         public static LocalisableString PlaylistTrayDescription => new TranslatableString(getKey(@"playlist_tray_description"), @"Manage items on previous screen");
 
-        /// <summary>
-        /// "Beatmap queue"
-        /// </summary>
-        public static LocalisableString MultiplayerBeatmapQueue => new TranslatableString(getKey(@"multiplayer_beatmap_queue"), @"Beatmap queue");
-
-        /// <summary>
-        /// "Progress"
-        /// </summary>
-        public static LocalisableString PlaylistProgress => new TranslatableString(getKey(@"playlist_progress"), @"Progress");
-
-        /// <summary>
-        /// "Leaderboard"
-        /// </summary>
-        public static LocalisableString PlaylistLeaderboard => new TranslatableString(getKey(@"playlist_leaderboard"), @"Leaderboard");
-
-        /// <summary>
-        /// "Difficulty"
-        /// </summary>
-        public static LocalisableString Difficulty => new TranslatableString(getKey(@"difficulty"), @"Difficulty");
-
-        /// <summary>
-        /// "Chat"
-        /// </summary>
-        public static LocalisableString Chat => new TranslatableString(getKey(@"chat"), @"Chat");
-
         private static string getKey(string key) => $@"{prefix}:{key}";
     }
 }

osu.Game/Localisation/PlayerLoaderStrings.cs

@@ -43,11 +43,6 @@ Leaderboards may be reset.");
         public static LocalisableString QualifiedBeatmapDisclaimerContent => new TranslatableString(getKey(@"qualified_beatmap_disclaimer_content"), @"No performance points will be awarded.
 Leaderboards will be reset when the beatmap is ranked.");
 
-        /// <summary>
-        /// "Loading paused..."
-        /// </summary>
-        public static LocalisableString LoadingPaused => new TranslatableString(getKey(@"loading_paused"), @"Loading paused...");
-
         private static string getKey(string key) => $@"{prefix}:{key}";
     }
 }

osu.Game/Online/API/Requests/Responses/SoloScoreInfo.cs

@@ -145,7 +145,7 @@ namespace osu.Game.Online.API.Requests.Responses
         // Generally this is required because this model may be used by server-side components, but
         // we don't want to bother sending these fields in score submission requests, for instance.
         public bool ShouldSerializeEndedAt() => EndedAt != default;
-        public bool ShouldSerializeStartedAt() => StartedAt != null;
+        public bool ShouldSerializeStartedAt() => StartedAt != default;
         public bool ShouldSerializeLegacyScoreId() => LegacyScoreId != null;
         public bool ShouldSerializeLegacyTotalScore() => LegacyTotalScore != null;
         public bool ShouldSerializeMods() => Mods.Length > 0;

osu.Game/Online/Chat/ChannelManager.cs

@@ -6,30 +6,19 @@
 using System;
 using System.Collections.Generic;
 using System.Collections.Specialized;
-using System.IO;
 using System.Linq;
-using System.Threading.Tasks;
-using JetBrains.Annotations;
-using Microsoft.AspNetCore.SignalR;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Logging;
-using osu.Framework.Platform;
 using osu.Framework.Threading;
 using osu.Game.Database;
-using osu.Game.Extensions;
-using osu.Game.IO;
-using osu.Game.Localisation;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests;
 using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Multiplayer;
-using osu.Game.Overlays;
 using osu.Game.Overlays.Chat.Listing;
-using osu.Game.Overlays.Notifications;
 
 namespace osu.Game.Online.Chat
 {
@@ -81,18 +70,6 @@ namespace osu.Game.Online.Chat
         [Resolved]
         private UserLookupCache users { get; set; }
 
-        [Resolved(CanBeNull = true)]
-        [CanBeNull]
-        private MultiplayerClient multiplayerClient { get; set; }
-
-        [Resolved(CanBeNull = true)]
-        [CanBeNull]
-        private Storage storage { get; set; }
-
-        [Resolved(CanBeNull = true)]
-        [CanBeNull]
-        private INotificationOverlay notifications { get; set; }
-
         private readonly IBindable<APIUser> localUser = new Bindable<APIUser>();
         private readonly IBindable<APIState> apiState = new Bindable<APIState>();
         private readonly IBindableList<APIRelation> localUserBlocks = new BindableList<APIRelation>();
@@ -287,11 +264,11 @@ namespace osu.Game.Online.Chat
 
             switch (command.ToLowerInvariant())
             {
-                case @"np":
+                case "np":
                     AddInternal(new NowPlayingCommand(target));
                     break;
 
-                case @"me":
+                case "me":
                     if (string.IsNullOrWhiteSpace(content))
                     {
                         target.AddNewMessages(new ErrorMessage("Usage: /me [action]"));
@@ -301,7 +278,7 @@ namespace osu.Game.Online.Chat
                     PostMessage(content, true, target);
                     break;
 
-                case @"join":
+                case "join":
                     if (string.IsNullOrWhiteSpace(content))
                     {
                         target.AddNewMessages(new ErrorMessage("Usage: /join [channel]"));
@@ -319,9 +296,9 @@ namespace osu.Game.Online.Chat
                     JoinChannel(channel);
                     break;
 
-                case @"chat":
-                case @"msg":
-                case @"query":
+                case "chat":
+                case "msg":
+                case "query":
                     if (string.IsNullOrWhiteSpace(content))
                     {
                         target.AddNewMessages(new ErrorMessage($"Usage: /{command} [user]"));
@@ -346,72 +323,8 @@ namespace osu.Game.Online.Chat
                     api.Queue(request);
                     break;
 
-                case @"roll":
-                    if (target.Type != ChannelType.Multiplayer || multiplayerClient?.Room?.ChannelID != target.Id)
-                    {
-                        target.AddNewMessages(new ErrorMessage("Cannot roll when not in a multiplayer room."));
-                        break;
-                    }
-
-                    uint max = 100;
-
-                    if (!string.IsNullOrEmpty(content))
-                    {
-                        if (!uint.TryParse(content, out max) || max < 2 || max > 100)
-                        {
-                            target.AddNewMessages(new ErrorMessage("Usage: /roll [2-100]"));
-                            break;
-                        }
-                    }
-
-                    var rollRequest = new RollRequest { Max = max };
-                    multiplayerClient.SendMatchRequest(rollRequest).FireAndForget(onError: ex =>
-                    {
-                        string message = ex is HubException
-                            ? $"Failed to roll: {ex.Message}"
-                            : "Failed to roll.";
-                        target.AddNewMessages(new ErrorMessage(message));
-                    });
-                    break;
-
-                case @"savelog":
-                    ProgressNotification notification = new ProgressNotification
-                    {
-                        State = ProgressNotificationState.Active,
-                        Text = NotificationsStrings.LogsExportOngoing,
-                    };
-                    notifications?.Post(notification);
-
-                    exportChannelLog(target).ContinueWith(t =>
-                    {
-                        if (t.Exception != null)
-                        {
-                            Logger.Log($@"Failed to export channel log: {t.Exception}");
-                            notification.State = ProgressNotificationState.Cancelled;
-                            return;
-                        }
-
-                        string result = t.GetResultSafely();
-
-                        if (result == null)
-                        {
-                            Logger.Log("Failed to export channel log due to missing storage.");
-                            notification.State = ProgressNotificationState.Cancelled;
-                            return;
-                        }
-
-                        notification.CompletionText = NotificationsStrings.FileExportFinished(result);
-                        notification.CompletionClickAction = () =>
-                        {
-                            (storage as OsuStorage)?.GetExportStorage().PresentFileExternally(result);
-                            return true;
-                        };
-                        notification.State = ProgressNotificationState.Completed;
-                    });
-                    break;
-
-                case @"help":
-                    target.AddNewMessages(new InfoMessage("Supported commands: /help, /me [action], /join [channel], /chat [user], /np, /savelog, /roll [2-100] (multiplayer only)"));
+                case "help":
+                    target.AddNewMessages(new InfoMessage("Supported commands: /help, /me [action], /join [channel], /chat [user], /np"));
                     break;
 
                 default:
@@ -766,26 +679,6 @@ namespace osu.Game.Online.Chat
             }
         }
 
-        [ItemCanBeNull]
-        private async Task<string> exportChannelLog(Channel channel)
-        {
-            if (storage is not OsuStorage osuStorage)
-                return null;
-
-            string filename = string.Format($@"chat-{channel.Name}-{DateTimeOffset.Now:yyyyMMdd-hhmmss}.txt").GetValidFilename();
-            var exportStorage = osuStorage.GetExportStorage();
-
-            using (var file = exportStorage.CreateFileSafely(filename))
-            {
-                using var textWriter = new StreamWriter(file);
-
-                foreach (var message in channel.Messages)
-                    await textWriter.WriteLineAsync($@"{message.Timestamp:yyyy-MM-dd HH:mm} {message.Sender.Username}: {message.Content}").ConfigureAwait(false);
-            }
-
-            return filename;
-        }
-
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);

osu.Game/Online/FriendPresenceNotifier.cs

@@ -25,16 +25,6 @@ namespace osu.Game.Online
 {
     public partial class FriendPresenceNotifier : Component
     {
-        /// <summary>
-        /// Minimum time between subsequent online/offline notifications.
-        /// </summary>
-        public double NotificationDebounceTime { get; set; } = 1000;
-
-        /// <summary>
-        /// Minimum time after a user has gone offline, before they're added to the offline alert queue.
-        /// </summary>
-        public double OfflineDebounceTime { get; set; } = 15000;
-
         [Resolved]
         private INotificationOverlay notifications { get; set; } = null!;
 
@@ -52,32 +42,14 @@ namespace osu.Game.Online
         private readonly IBindableList<APIRelation> friends = new BindableList<APIRelation>();
         private readonly IBindableDictionary<int, UserPresence> friendPresences = new BindableDictionary<int, UserPresence>();
 
-        /// <summary>
-        /// List of users that will be notified as having come online with the next notification.
-        /// </summary>
         private readonly HashSet<APIUser> onlineAlertQueue = new HashSet<APIUser>();
-
-        /// <summary>
-        /// List of users that will be notified as having gone offline with the next notification.
-        /// </summary>
         private readonly HashSet<APIUser> offlineAlertQueue = new HashSet<APIUser>();
 
-        /// <summary>
-        /// List of users that have gone offline, but we're waiting for them to potentially come online again before queueing them for notification.
-        /// For example, if a user is quickly toggling between the "Online" and "Appear Offline" states.
-        /// </summary>
-        private readonly HashSet<APIUser> pendingOfflineUsers = new HashSet<APIUser>();
-
-        /// <summary>
-        /// The post time for the next online notification.
-        /// </summary>
         private double? nextOnlineAlertTime;
-
-        /// <summary>
-        /// The post time for the next offline notification.
-        /// </summary>
         private double? nextOfflineAlertTime;
 
+        private const double debounce_time_before_notification = 1000;
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
@@ -161,55 +133,28 @@ namespace osu.Game.Online
                         APIRelation? friend = friends.FirstOrDefault(f => f.TargetID == friendId);
 
                         if (friend?.TargetUser is APIUser user)
-                            markUserOfflineDebounced(user);
+                            markUserOffline(user);
                     }
 
                     break;
             }
         }
 
-        /// <summary>
-        /// Immediately registers a user for the next online notification alert.
-        /// </summary>
         private void markUserOnline(APIUser user)
         {
-            if (pendingOfflineUsers.Remove(user))
-                return;
-
             if (!offlineAlertQueue.Remove(user))
             {
                 onlineAlertQueue.Add(user);
-                nextOnlineAlertTime ??= Time.Current + NotificationDebounceTime;
+                nextOnlineAlertTime ??= Time.Current + debounce_time_before_notification;
             }
         }
 
-        /// <summary>
-        /// Waits <see cref="OfflineDebounceTime"/> before adding a user to the next offline notification alert.
-        /// </summary>
-        /// <param name="user"></param>
-        private void markUserOfflineDebounced(APIUser user)
-        {
-            pendingOfflineUsers.Add(user);
-
-            Scheduler.AddDelayed(() =>
-            {
-                // Check if the friend has come back online.
-                if (!pendingOfflineUsers.Remove(user))
-                    return;
-
-                markUserOffline(user);
-            }, OfflineDebounceTime);
-        }
-
-        /// <summary>
-        /// Immediately registers a user for the next offline notification alert.
-        /// </summary>
         private void markUserOffline(APIUser user)
         {
             if (!onlineAlertQueue.Remove(user))
             {
                 offlineAlertQueue.Add(user);
-                nextOfflineAlertTime ??= Time.Current + NotificationDebounceTime;
+                nextOfflineAlertTime ??= Time.Current + debounce_time_before_notification;
             }
         }
 

osu.Game/Online/Metadata/OnlineMetadataClient.cs

@@ -175,7 +175,7 @@ namespace osu.Game.Online.Metadata
         public override Task<BeatmapUpdates> GetChangesSince(int queueId)
         {
             if (connector?.IsConnected.Value != true)
-                return Task.FromCanceled<BeatmapUpdates>(CancellationToken.None);
+                return Task.FromCanceled<BeatmapUpdates>(default);
 
             Logger.Log($"Requesting any changes since last known queue id {queueId}");
 

osu.Game/Online/Notifications/WebSocket/DummyNotificationsClient.cs

@@ -16,7 +16,7 @@ namespace osu.Game.Online.Notifications.WebSocket
 
         public Func<SocketMessage, bool>? HandleMessage;
 
-        public Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = null)
+        public Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = default)
         {
             if (HandleMessage?.Invoke(message) != true)
                 throw new InvalidOperationException($@"{nameof(DummyNotificationsClient)} cannot process this message.");

osu.Game/Online/Notifications/WebSocket/INotificationsClient.cs

@@ -26,6 +26,6 @@ namespace osu.Game.Online.Notifications.WebSocket
         /// <summary>
         /// Sends a <see cref="SocketMessage"/> to the notification server.
         /// </summary>
-        Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = null);
+        Task SendAsync(SocketMessage message, CancellationToken? cancellationToken = default);
     }
 }