Implement new score multipliers (#37967)

- Part of https://github.com/ppy/osu/issues/37818

Updates score multipliers to latest proposals, and bumps replay version
ready for recalculation.

---

For anyone following along, **please wait for the incoming news post
before sharing this publicly**. This is intended for internal
development use at this point. There's still some time before these go
live.

---------

Co-authored-by: Bartłomiej Dach <dach.bartlomiej@gmail.com>

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

osu.Android.props

@@ -10,7 +10,7 @@
     <EmbedAssembliesIntoApk>true</EmbedAssembliesIntoApk>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2026.513.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2026.527.0" />
   </ItemGroup>
   <PropertyGroup>
     <!-- Fody does not handle Android build well, and warns when unchanged.

osu.Game.Benchmarks/BenchmarkScoreMultiplierCalculator.cs

@@ -0,0 +1,67 @@
+// 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 BenchmarkDotNet.Attributes;
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu;
+using osu.Game.Rulesets.Osu.Mods;
+using osu.Game.Rulesets.Scoring;
+
+namespace osu.Game.Benchmarks
+{
+    public class BenchmarkScoreMultiplierCalculator : BenchmarkTest
+    {
+        private ScoreMultiplierCalculator calculator = null!;
+
+        [Params(1, 10, 100)]
+        public int Times { get; set; }
+
+        public record ModTestCase(string Description, IEnumerable<Mod> Mods)
+        {
+            public override string ToString() => Description;
+        }
+
+        public static IEnumerable<ModTestCase> ValuesForMods =>
+        [
+            new ModTestCase("no mods", []),
+            new ModTestCase("single mod", [new OsuModHardRock()]),
+            new ModTestCase("single mod 2", [new OsuModEasy()]),
+            new ModTestCase("multiple mods", [new OsuModHidden(), new OsuModHardRock(), new OsuModDoubleTime()]),
+            new ModTestCase("mods with adjusted settings", [
+                new OsuModDoubleTime { SpeedChange = { Value = 2 } },
+                new OsuModHidden { OnlyFadeApproachCircles = { Value = true } },
+                new OsuModHardRock()
+            ]),
+        ];
+
+        [ParamsSource(nameof(ValuesForMods))]
+        public ModTestCase Mods { get; set; } = null!;
+
+        public override void SetUp()
+        {
+            base.SetUp();
+            calculator = new OsuRuleset().CreateScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty()));
+        }
+
+        [Benchmark]
+        public double ViaCalculator()
+            => viaCalculator(Times, Mods);
+
+        [Test]
+        public void ViaCalculator([Values(100)] int times, [ValueSource(nameof(ValuesForMods))] ModTestCase mods)
+            => viaCalculator(times, mods);
+
+        private double viaCalculator(int times, ModTestCase mods)
+        {
+            double scoreMultiplier = 1;
+
+            for (int i = 0; i < times; ++i)
+                scoreMultiplier = calculator.CalculateFor(mods.Mods);
+
+            return scoreMultiplier;
+        }
+    }
+}

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

@@ -14,11 +14,11 @@ namespace osu.Game.Rulesets.Catch.Tests
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Catch.Tests";
 
-        [TestCase(4.039861734717169d, 127, "diffcalc-test")]
+        [TestCase(4.0505463516206195d, 127, "diffcalc-test")]
         public void Test(double expectedStarRating, int expectedMaxCombo, string name)
             => base.Test(expectedStarRating, expectedMaxCombo, name);
 
-        [TestCase(5.1527173897800873d, 127, "diffcalc-test")]
+        [TestCase(5.1696411260785498d, 127, "diffcalc-test")]
         public void TestClockRateAdjusted(double expectedStarRating, int expectedMaxCombo, string name)
             => Test(expectedStarRating, expectedMaxCombo, name, new CatchModDoubleTime());
 

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

@@ -0,0 +1,171 @@
+// 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 NUnit.Framework;
+using osu.Framework.Utils;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Mods;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+using osu.Game.Tests.Rulesets;
+
+namespace osu.Game.Rulesets.Catch.Tests
+{
+    public class CatchScoreMultiplierTest : RulesetScoreMultiplierTest
+    {
+        public CatchScoreMultiplierTest()
+            : base(new CatchRuleset())
+        {
+        }
+
+        private static readonly object[][] test_cases =
+        [
+            #region Difficulty Reduction
+
+            [new Mod[] { new CatchModEasy() }, 0.5],
+            [new Mod[] { new CatchModNoFail() }, 0.5],
+
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.50 } } }, 0.1],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.55 } } }, 0.1],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.60 } } }, 0.2],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.65 } } }, 0.2],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.70 } } }, 0.3],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.75 } } }, 0.3],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.80 } } }, 0.4],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.85 } } }, 0.4],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.90 } } }, 0.5],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.95 } } }, 0.5],
+            [new Mod[] { new CatchModHalfTime { SpeedChange = { Value = 0.99 } } }, 0.5],
+
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.50 } } }, 0.1],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.55 } } }, 0.1],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.60 } } }, 0.2],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.65 } } }, 0.2],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.70 } } }, 0.3],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.75 } } }, 0.3],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.80 } } }, 0.4],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.85 } } }, 0.4],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.90 } } }, 0.5],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.95 } } }, 0.5],
+            [new Mod[] { new CatchModDaycore { SpeedChange = { Value = 0.99 } } }, 0.5],
+
+            #endregion
+
+            #region Difficulty Increase
+
+            [new Mod[] { new CatchModHardRock() }, 1.12],
+            [new Mod[] { new CatchModSuddenDeath() }, 1],
+            [new Mod[] { new CatchModPerfect() }, 1],
+
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.01 } } }, 1.00],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.05 } } }, 1.00],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.10 } } }, 1.02],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.15 } } }, 1.02],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.20 } } }, 1.04],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.25 } } }, 1.04],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.30 } } }, 1.06],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.35 } } }, 1.06],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.40 } } }, 1.08],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.45 } } }, 1.08],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.50 } } }, 1.10],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.55 } } }, 1.10],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.60 } } }, 1.12],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.65 } } }, 1.12],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.70 } } }, 1.14],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.75 } } }, 1.14],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.80 } } }, 1.16],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.85 } } }, 1.16],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.90 } } }, 1.18],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 1.95 } } }, 1.18],
+            [new Mod[] { new CatchModDoubleTime { SpeedChange = { Value = 2.00 } } }, 1.20],
+
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.01 } } }, 1.00],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.05 } } }, 1.00],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.10 } } }, 1.02],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.15 } } }, 1.02],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.20 } } }, 1.04],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.25 } } }, 1.04],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.30 } } }, 1.06],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.35 } } }, 1.06],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.40 } } }, 1.08],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.45 } } }, 1.08],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.50 } } }, 1.10],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.55 } } }, 1.10],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.60 } } }, 1.12],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.65 } } }, 1.12],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.70 } } }, 1.14],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.75 } } }, 1.14],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.80 } } }, 1.16],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.85 } } }, 1.16],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.90 } } }, 1.18],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 1.95 } } }, 1.18],
+            [new Mod[] { new CatchModNightcore { SpeedChange = { Value = 2.00 } } }, 1.20],
+
+            [new Mod[] { new CatchModHidden() }, 1.06],
+
+            [new Mod[] { new CatchModFlashlight() }, 1.12],
+            [new Mod[] { new CatchModFlashlight { ComboBasedSize = { Value = false } } }, 1],
+
+            [new Mod[] { new ModAccuracyChallenge() }, 1],
+
+            #endregion
+
+            #region Conversion
+
+            [new Mod[] { new CatchModDifficultyAdjust() }, 0.5],
+            [new Mod[] { new CatchModClassic() }, 1],
+            [new Mod[] { new CatchModMirror() }, 1],
+
+            #endregion
+
+            #region Automation
+
+            [new Mod[] { new CatchModAutoplay() }, 1],
+            [new Mod[] { new CatchModCinema() }, 1],
+            [new Mod[] { new CatchModRelax() }, 0.1],
+
+            #endregion
+
+            #region Fun
+
+            [new Mod[] { new ModWindUp() }, 0.5],
+            [new Mod[] { new ModWindDown() }, 0.5],
+            [new Mod[] { new CatchModFloatingFruits() }, 1],
+            [new Mod[] { new CatchModMuted() }, 1],
+            [new Mod[] { new CatchModNoScope() }, 1],
+            [new Mod[] { new CatchModMovingFast() }, 1],
+            [new Mod[] { new CatchModSynesthesia() }, 0.8],
+
+            #endregion
+
+            #region System
+
+            [new Mod[] { new ModScoreV2() }, 1],
+
+            #endregion
+
+            #region Combinations
+
+            [new Mod[] { new CatchModHidden(), new CatchModHardRock() }, 1.06 * 1.12]
+
+            #endregion
+        ];
+
+        [TestCaseSource(nameof(test_cases))]
+        public void TestMultipliers(Mod[] mods, double expectedMultiplier)
+            => TestModCombination(mods, expectedMultiplier);
+
+        [TestCase(30000001, 0.96)]
+        [TestCase(30000009, 0.96)]
+        [TestCase(30000016, 0.96)]
+        [TestCase(30000017, 1)]
+        [TestCase(null, 1)]
+        public void TestClassicMultiplierVersioning(int? totalScoreVersion, double expectedMultiplier)
+        {
+            var scoreInfo = totalScoreVersion != null ? new ScoreInfo { TotalScoreVersion = totalScoreVersion.Value } : null;
+            var calculator = Ruleset.CreateScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty(), scoreInfo));
+            Assert.That(calculator.CalculateFor([new CatchModClassic()]), Is.EqualTo(expectedMultiplier).Within(Precision.DOUBLE_EPSILON));
+        }
+    }
+}

osu.Game.Rulesets.Catch/CatchRuleset.cs

@@ -169,6 +169,8 @@ namespace osu.Game.Rulesets.Catch
             }
         }
 
+        public override ScoreMultiplierCalculator CreateScoreMultiplierCalculator(ScoreMultiplierContext context) => new CatchScoreMultiplierCalculator(context);
+
         public override string Description => "osu!catch";
 
         public override string ShortName => SHORT_NAME;

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

@@ -15,7 +15,6 @@ 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
 {
@@ -23,6 +22,8 @@ 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)
@@ -30,7 +31,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new CatchDifficultyAttributes { Mods = mods };
@@ -45,19 +46,12 @@ namespace osu.Game.Rulesets.Catch.Difficulty
             return attributes;
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
         {
             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))
             {
@@ -74,11 +68,16 @@ namespace osu.Game.Rulesets.Catch.Difficulty
             return objects;
         }
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
         {
+            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),
+                new Movement(mods, halfCatcherWidth, clockRate),
             };
         }
 

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

@@ -11,16 +11,12 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Evaluators
     {
         private const double direction_change_bonus = 21.0;
 
-        public static double EvaluateDifficultyOf(DifficultyHitObject current)
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, double catcherSpeedMultiplier)
         {
             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);
@@ -44,30 +40,6 @@ 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

@@ -17,14 +17,28 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Skills
 
         protected override int SectionLength => 750;
 
-        public Movement(Mod[] mods)
+        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)
             : 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);
+            return MovementEvaluator.EvaluateDifficultyOf(current, catcherSpeedMultiplier);
         }
     }
 }

osu.Game.Rulesets.Catch/Edit/BananaShowerCompositionTool.cs

@@ -2,9 +2,9 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Graphics;
-using osu.Game.Beatmaps;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
-using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 
@@ -13,11 +13,11 @@ namespace osu.Game.Rulesets.Catch.Edit
     public class BananaShowerCompositionTool : CompositionTool
     {
         public BananaShowerCompositionTool()
-            : base(nameof(BananaShower))
+            : base("Banana shower")
         {
         }
 
-        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Spinners);
+        public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.EditorBananaShower };
 
         public override HitObjectPlacementBlueprint CreatePlacementBlueprint() => new BananaShowerPlacementBlueprint();
     }

osu.Game.Rulesets.Catch/Edit/CatchBlueprintContainer.cs

@@ -3,11 +3,16 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
 using osu.Framework.Input.Events;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Objects;
+using osu.Game.Screens.Edit.Components.TernaryButtons;
 using osu.Game.Screens.Edit.Compose.Components;
 using osuTK;
 
@@ -22,6 +27,29 @@ namespace osu.Game.Rulesets.Catch.Edit
         {
         }
 
+        protected override Drawable CreateNewComboButton() => new NewComboTernaryButton
+        {
+            Current = NewCombo,
+            CreateIcon = () => new Container
+            {
+                Children = new Drawable[]
+                {
+                    new SpriteIcon
+                    {
+                        Anchor = Anchor.BottomLeft,
+                        Origin = Anchor.BottomLeft,
+                        Icon = OsuIcon.EditorFruit,
+                        Size = new Vector2(15),
+                    },
+                    new SpriteIcon
+                    {
+                        Icon = OsuIcon.EditorNewComboSparkles,
+                        Size = new Vector2(20),
+                    }
+                },
+            },
+        };
+
         protected override SelectionHandler<HitObject> CreateSelectionHandler() => new CatchSelectionHandler();
 
         public override HitObjectSelectionBlueprint? CreateHitObjectBlueprintFor(HitObject hitObject)

osu.Game.Rulesets.Catch/Edit/FruitCompositionTool.cs

@@ -2,7 +2,8 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Graphics;
-using osu.Game.Beatmaps;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Edit;
@@ -17,7 +18,7 @@ namespace osu.Game.Rulesets.Catch.Edit
         {
         }
 
-        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles);
+        public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.EditorFruit };
 
         public override HitObjectPlacementBlueprint CreatePlacementBlueprint() => new FruitPlacementBlueprint();
     }

osu.Game.Rulesets.Catch/Edit/JuiceStreamCompositionTool.cs

@@ -2,9 +2,9 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Graphics;
-using osu.Game.Beatmaps;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
-using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 
@@ -13,11 +13,11 @@ namespace osu.Game.Rulesets.Catch.Edit
     public class JuiceStreamCompositionTool : CompositionTool
     {
         public JuiceStreamCompositionTool()
-            : base(nameof(JuiceStream))
+            : base("Juice stream")
         {
         }
 
-        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders);
+        public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.EditorJuiceStream };
 
         public override HitObjectPlacementBlueprint CreatePlacementBlueprint() => new JuiceStreamPlacementBlueprint();
     }

osu.Game.Rulesets.Catch/Mods/CatchModFlashlight.cs

@@ -13,8 +13,6 @@ namespace osu.Game.Rulesets.Catch.Mods
 {
     public partial class CatchModFlashlight : ModFlashlight<CatchHitObject>
     {
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.12 : 1;
-
         public override BindableFloat SizeMultiplier { get; } = new BindableFloat(1)
         {
             MinValue = 0.5f,

osu.Game.Rulesets.Catch/Mods/CatchModFloatingFruits.cs

@@ -16,7 +16,6 @@ namespace osu.Game.Rulesets.Catch.Mods
         public override string Name => "Floating Fruits";
         public override string Acronym => "FF";
         public override LocalisableString Description => "The fruits are... floating?";
-        public override double ScoreMultiplier => 1;
         public override IconUsage? Icon => OsuIcon.ModFloatingFruits;
 
         public void ApplyToDrawableRuleset(DrawableRuleset<CatchHitObject> drawableRuleset)

osu.Game.Rulesets.Catch/Mods/CatchModHardRock.cs

@@ -10,8 +10,6 @@ namespace osu.Game.Rulesets.Catch.Mods
 {
     public class CatchModHardRock : ModHardRock, IApplicableToBeatmapProcessor
     {
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.12 : 1;
-
         public void ApplyToBeatmapProcessor(IBeatmapProcessor beatmapProcessor)
         {
             var catchProcessor = (CatchBeatmapProcessor)beatmapProcessor;

osu.Game.Rulesets.Catch/Mods/CatchModHidden.cs

@@ -16,7 +16,6 @@ namespace osu.Game.Rulesets.Catch.Mods
     public class CatchModHidden : ModHidden, IApplicableToDrawableRuleset<CatchHitObject>
     {
         public override LocalisableString Description => @"Play with fading fruits.";
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.06 : 1;
 
         private const double fade_out_offset_multiplier = 0.6;
         private const double fade_out_duration_multiplier = 0.44;

osu.Game.Rulesets.Catch/Mods/CatchModMovingFast.cs

@@ -23,7 +23,6 @@ namespace osu.Game.Rulesets.Catch.Mods
         public override string Acronym => "MF";
         public override LocalisableString Description => "Dashing by default, slow down!";
         public override ModType Type => ModType.Fun;
-        public override double ScoreMultiplier => 1;
         public override IconUsage? Icon => OsuIcon.ModMovingFast;
         public override Type[] IncompatibleMods => new[] { typeof(ModAutoplay), typeof(ModRelax) };
 

osu.Game.Rulesets.Catch/Scoring/CatchScoreMultiplierCalculator.cs

@@ -0,0 +1,95 @@
+// 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.Game.Rulesets.Catch.Mods;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+
+namespace osu.Game.Rulesets.Catch.Scoring
+{
+    public class CatchScoreMultiplierCalculator : ScoreMultiplierCalculator
+    {
+        public CatchScoreMultiplierCalculator(ScoreMultiplierContext context)
+            : base(context)
+        {
+            #region Difficulty Reduction
+
+            Single<CatchModEasy>(hasMultiplier: 0.5);
+            Single<CatchModNoFail>(hasMultiplier: 0.5);
+            Single<CatchModHalfTime>(hasMultiplier: halfTime => rateAdjustMultiplier(halfTime.SpeedChange.Value));
+            Single<CatchModDaycore>(hasMultiplier: daycore => rateAdjustMultiplier(daycore.SpeedChange.Value));
+
+            #endregion
+
+            #region Difficulty Increase
+
+            Single<CatchModHardRock>(hasMultiplier: hardRock => hardRock.UsesDefaultConfiguration ? 1.12 : 1);
+            // Sudden Death
+            // Perfect
+            Single<CatchModDoubleTime>(hasMultiplier: doubleTime => rateAdjustMultiplier(doubleTime.SpeedChange.Value));
+            Single<CatchModNightcore>(hasMultiplier: nightcore => rateAdjustMultiplier(nightcore.SpeedChange.Value));
+            Single<CatchModHidden>(hasMultiplier: hidden => hidden.UsesDefaultConfiguration ? 1.06 : 1);
+            Single<CatchModFlashlight>(hasMultiplier: flashlight => flashlight.UsesDefaultConfiguration ? 1.12 : 1);
+            // Accuracy Challenge
+
+            #endregion
+
+            #region Conversion
+
+            Single<CatchModDifficultyAdjust>(hasMultiplier: 0.5);
+            Single<CatchModClassic>(hasMultiplier: _ => classicMultiplier(context.Score));
+            // Mirror
+
+            #endregion
+
+            #region Automation
+
+            // Autoplay
+            // Cinema
+            Single<CatchModRelax>(hasMultiplier: 0.1);
+
+            #endregion
+
+            #region Fun
+
+            Single<ModWindUp>(hasMultiplier: 0.5);
+            Single<ModWindDown>(hasMultiplier: 0.5);
+            // Floating Fruits
+            // Muted
+            // No Scope
+            // Moving Fast
+            Single<CatchModSynesthesia>(hasMultiplier: 0.8);
+
+            #endregion
+
+            #region System
+
+            // Score V2
+
+            #endregion
+        }
+
+        private static double rateAdjustMultiplier(double speedChange)
+        {
+            // Round to the nearest multiple of 0.1.
+            double value = (int)(speedChange * 10) / 10.0;
+
+            // Offset back to 0.
+            value -= 1;
+
+            if (speedChange >= 1)
+                return 1 + value / 5;
+            else
+                return 0.6 + value;
+        }
+
+        private static double classicMultiplier(ScoreInfo? score)
+        {
+            if (score != null && score.TotalScoreVersion < 30000017)
+                return 0.96;
+
+            return 1;
+        }
+    }
+}

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

@@ -36,8 +36,8 @@ namespace osu.Game.Rulesets.Mania.Tests
             var decoded = DecodeFromLegacy(beatmaps_resource_store.GetStream($"Resources/Testing/Beatmaps/{name}.osu"), beatmaps_resource_store, name);
             var decodedAfterEncode = DecodeFromLegacy(EncodeToLegacy(decoded), beatmaps_resource_store, name);
 
-            Sort(decoded.beatmap);
-            Sort(decodedAfterEncode.beatmap);
+            Sort(decoded.Beatmap);
+            Sort(decodedAfterEncode.Beatmap);
 
             CompareBeatmaps(decoded, decodedAfterEncode);
         }

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

@@ -0,0 +1,236 @@
+// 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 NUnit.Framework;
+using osu.Framework.Utils;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Mania.Mods;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+using osu.Game.Tests.Rulesets;
+
+namespace osu.Game.Rulesets.Mania.Tests
+{
+    public class ManiaScoreMultiplierTest : RulesetScoreMultiplierTest
+    {
+        public ManiaScoreMultiplierTest()
+            : base(new ManiaRuleset())
+        {
+        }
+
+        private static readonly object[][] test_cases =
+        [
+            #region Difficulty Reduction
+
+            [new Mod[] { new ManiaModEasy() }, 0.5],
+            [new Mod[] { new ManiaModNoFail() }, 0.5],
+
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.50 } } }, 0.1],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.55 } } }, 0.1],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.60 } } }, 0.2],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.65 } } }, 0.2],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.70 } } }, 0.3],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.75 } } }, 0.3],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.80 } } }, 0.4],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.85 } } }, 0.4],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.90 } } }, 0.5],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.95 } } }, 0.5],
+            [new Mod[] { new ManiaModHalfTime { SpeedChange = { Value = 0.99 } } }, 0.5],
+
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.50 } } }, 0.1],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.55 } } }, 0.1],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.60 } } }, 0.2],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.65 } } }, 0.2],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.70 } } }, 0.3],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.75 } } }, 0.3],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.80 } } }, 0.4],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.85 } } }, 0.4],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.90 } } }, 0.5],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.95 } } }, 0.5],
+            [new Mod[] { new ManiaModDaycore { SpeedChange = { Value = 0.99 } } }, 0.5],
+
+            [new Mod[] { new ManiaModNoRelease() }, 0.9],
+
+            #endregion
+
+            #region Difficulty Increase
+
+            [new Mod[] { new ManiaModHardRock() }, 1],
+            [new Mod[] { new ManiaModSuddenDeath() }, 1],
+            [new Mod[] { new ManiaModPerfect() }, 1],
+
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.01 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.05 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.10 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.15 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.20 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.25 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.30 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.35 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.40 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.45 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.50 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.55 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.60 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.65 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.70 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.75 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.80 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.85 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.90 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 1.95 } } }, 1],
+            [new Mod[] { new ManiaModDoubleTime { SpeedChange = { Value = 2.00 } } }, 1],
+
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.01 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.05 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.10 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.15 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.20 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.25 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.30 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.35 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.40 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.45 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.50 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.55 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.60 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.65 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.70 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.75 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.80 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.85 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.90 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 1.95 } } }, 1],
+            [new Mod[] { new ManiaModNightcore { SpeedChange = { Value = 2.00 } } }, 1],
+
+            [new Mod[] { new ManiaModFadeIn() }, 1],
+            [new Mod[] { new ManiaModHidden() }, 1],
+            [new Mod[] { new ManiaModCover() }, 1],
+
+            [new Mod[] { new ManiaModFlashlight() }, 1],
+            [new Mod[] { new ModAccuracyChallenge() }, 1],
+
+            #endregion
+
+            #region Conversion
+
+            [new Mod[] { new ManiaModRandom() }, 1],
+            [new Mod[] { new ManiaModDualStages() }, 1],
+            [new Mod[] { new ManiaModMirror() }, 1],
+            [new Mod[] { new ManiaModDifficultyAdjust() }, 0.5],
+            [new Mod[] { new ManiaModClassic() }, 1],
+            [new Mod[] { new ManiaModInvert() }, 1],
+            [new Mod[] { new ManiaModConstantSpeed() }, 0.9],
+            [new Mod[] { new ManiaModHoldOff() }, 0.9],
+            [new Mod[] { new ManiaModKey1() }, 0.9],
+            [new Mod[] { new ManiaModKey2() }, 0.9],
+            [new Mod[] { new ManiaModKey3() }, 0.9],
+            [new Mod[] { new ManiaModKey4() }, 0.9],
+            [new Mod[] { new ManiaModKey5() }, 0.9],
+            [new Mod[] { new ManiaModKey6() }, 0.9],
+            [new Mod[] { new ManiaModKey7() }, 0.9],
+            [new Mod[] { new ManiaModKey8() }, 0.9],
+            [new Mod[] { new ManiaModKey9() }, 0.9],
+            [new Mod[] { new ManiaModKey10() }, 0.9],
+
+            #endregion
+
+            #region Automation
+
+            [new Mod[] { new ManiaModAutoplay() }, 1],
+            [new Mod[] { new ManiaModCinema() }, 1],
+
+            #endregion
+
+            #region Fun
+
+            [new Mod[] { new ModWindUp() }, 0.5],
+            [new Mod[] { new ModWindDown() }, 0.5],
+            [new Mod[] { new ManiaModMuted() }, 1],
+            [new Mod[] { new ModAdaptiveSpeed() }, 0.5],
+
+            #endregion
+
+            #region System
+
+            [new Mod[] { new ManiaModScoreV2() }, 1],
+
+            #endregion
+
+            #region Combinations
+
+            [new Mod[] { new ManiaModEasy(), new ManiaModKey4() }, 0.5 * 0.9]
+
+            #endregion
+        ];
+
+        [TestCaseSource(nameof(test_cases))]
+        public void TestMultipliers(Mod[] mods, double expectedMultiplier)
+            => TestModCombination(mods, expectedMultiplier);
+
+        private static readonly object[][] key_mod_multiplier_test_cases =
+        [
+            // score end date, client version, expected multiplier
+
+            // scores verifiably from old clients.
+            [new DateTimeOffset(2024, 1, 31, 11, 0, 0, TimeSpan.Zero), "2024.130.2", 1],
+            [new DateTimeOffset(2024, 12, 9, 11, 0, 0, TimeSpan.Zero), "2024.1208.0", 1],
+            [new DateTimeOffset(2025, 6, 12, 11, 0, 0, TimeSpan.Zero), "2025.605.3", 1],
+            [new DateTimeOffset(2025, 6, 28, 11, 0, 0, TimeSpan.Zero), "2025.625.0-tachyon", 1],
+            [new DateTimeOffset(2025, 7, 11, 11, 0, 0, TimeSpan.Zero), "2025.710.0-lazer", 1],
+            [new DateTimeOffset(2025, 7, 15, 11, 0, 0, TimeSpan.Zero), "2025.711.0-tachyon", 1],
+
+            // scores without explicit client versions, predating the change of multiplier.
+            // those MUST have used the old multiplier.
+            [new DateTimeOffset(2024, 1, 31, 11, 0, 0, TimeSpan.Zero), "", 1],
+            [new DateTimeOffset(2024, 12, 9, 11, 0, 0, TimeSpan.Zero), "", 1],
+            [new DateTimeOffset(2025, 6, 12, 11, 0, 0, TimeSpan.Zero), "", 1],
+            [new DateTimeOffset(2025, 6, 28, 11, 0, 0, TimeSpan.Zero), "", 1],
+            [new DateTimeOffset(2025, 7, 11, 11, 0, 0, TimeSpan.Zero), "", 1],
+            [new DateTimeOffset(2025, 7, 15, 11, 0, 0, TimeSpan.Zero), "", 1],
+
+            // scores without explicit client versions, AFTER the change of multiplier.
+            // there is NO way of verifying whether these scores use the new or old multiplier, therefore GUESS that it's the new one.
+            // "thankfully" the window of opportunity for this occurring *should* be slim
+            // (from client release with new key mod multipliers on July 18, 2025
+            // until spectator server release which added client version writing to server-side replays on August 1, 2025).
+            [new DateTimeOffset(2025, 7, 19, 0, 20, 15, 0, TimeSpan.Zero), "", 0.9],
+            [new DateTimeOffset(2025, 7, 23, 0, 20, 15, 0, TimeSpan.Zero), "", 0.9],
+            [new DateTimeOffset(2025, 8, 19, 0, 20, 15, 0, TimeSpan.Zero), "", 0.9],
+            [new DateTimeOffset(2026, 6, 18, 0, 20, 15, 0, TimeSpan.Zero), "", 0.9],
+            [new DateTimeOffset(2026, 7, 18, 0, 20, 15, 0, TimeSpan.Zero), "", 0.9],
+
+            // scores verifiably from new clients.
+            [new DateTimeOffset(2025, 7, 19, 0, 20, 15, 0, TimeSpan.Zero), "2025.718.0-tachyon", 0.9],
+            [new DateTimeOffset(2025, 7, 23, 0, 20, 15, 0, TimeSpan.Zero), "2025.721.0-tachyon", 0.9],
+            [new DateTimeOffset(2025, 8, 19, 0, 20, 15, 0, TimeSpan.Zero), "2025.816.0-lazer", 0.9],
+            [new DateTimeOffset(2026, 6, 18, 0, 20, 15, 0, TimeSpan.Zero), "2026.518.0-lazer", 0.9],
+            [new DateTimeOffset(2026, 7, 18, 0, 20, 15, 0, TimeSpan.Zero), "2026.522.1-tachyon", 0.9],
+        ];
+
+        [TestCaseSource(nameof(key_mod_multiplier_test_cases))]
+        public void TestKeyModMultiplierCompatibility(DateTimeOffset endDate, string clientVersion, double expectedMultiplier)
+        {
+            var calculator = Ruleset.CreateScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty(), new ScoreInfo
+            {
+                Date = endDate,
+                ClientVersion = clientVersion
+            }));
+            Assert.That(calculator.CalculateFor([new ManiaModKey4()]), Is.EqualTo(expectedMultiplier).Within(Precision.DOUBLE_EPSILON));
+        }
+
+        [TestCase(30000001, 0.96)]
+        [TestCase(30000009, 0.96)]
+        [TestCase(30000016, 0.96)]
+        [TestCase(30000017, 1)]
+        [TestCase(null, 1)]
+        public void TestClassicMultiplierVersioning(int? totalScoreVersion, double expectedMultiplier)
+        {
+            var scoreInfo = totalScoreVersion != null ? new ScoreInfo { TotalScoreVersion = totalScoreVersion.Value } : null;
+            var calculator = Ruleset.CreateScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty(), scoreInfo));
+            Assert.That(calculator.CalculateFor([new ManiaModClassic()]), Is.EqualTo(expectedMultiplier).Within(Precision.DOUBLE_EPSILON));
+        }
+    }
+}

osu.Game.Rulesets.Mania.Tests/Mods/TestSceneManiaModDoubleTime.cs

@@ -8,8 +8,10 @@ using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Mania.Mods;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Replays;
+using osu.Game.Rulesets.Mania.Scoring;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Replays;
+using osu.Game.Rulesets.Scoring;
 using osu.Game.Tests.Visual;
 
 namespace osu.Game.Rulesets.Mania.Tests.Mods
@@ -54,7 +56,7 @@ namespace osu.Game.Rulesets.Mania.Tests.Mods
                 Mod = doubleTime,
                 PassCondition = () => Player.ScoreProcessor.JudgedHits > 0
                                       && Player.ScoreProcessor.Accuracy.Value == 1
-                                      && Player.ScoreProcessor.TotalScore.Value == (long)(1_000_000 * doubleTime.ScoreMultiplier),
+                                      && Player.ScoreProcessor.TotalScore.Value == (long)(1_000_000 * new ManiaScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty())).CalculateFor([doubleTime])),
                 Autoplay = false,
                 CreateBeatmap = () => new Beatmap
                 {

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

@@ -19,7 +19,6 @@ 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
 {
@@ -37,7 +36,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
             isForCurrentRuleset = beatmap.BeatmapInfo.Ruleset.MatchesOnlineID(ruleset);
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new ManiaDifficultyAttributes { Mods = mods };
@@ -63,13 +62,11 @@ namespace osu.Game.Rulesets.Mania.Difficulty
             return 1;
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
         {
             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>();
@@ -91,7 +88,7 @@ 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) => new Skill[]
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => new Skill[]
         {
             new Strain(mods, ((ManiaBeatmap)Beatmap).TotalColumns)
         };

osu.Game.Rulesets.Mania/Edit/Blueprints/ManiaPlacementBlueprint.cs

@@ -9,6 +9,8 @@ using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Mania.Skinning.Default;
 using osu.Game.Rulesets.Mania.UI;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.UI.Scrolling;
 using osuTK;
 using osuTK.Input;
@@ -90,5 +92,8 @@ namespace osu.Game.Rulesets.Mania.Edit.Blueprints
         private float getNoteHeight(Column resultPlayfield) =>
             resultPlayfield.ToScreenSpace(new Vector2(DefaultNotePiece.NOTE_HEIGHT)).Y -
             resultPlayfield.ToScreenSpace(Vector2.Zero).Y;
+
+        public override bool ReplacesExistingObject(HitObject existing)
+            => base.ReplacesExistingObject(existing) && HitObject.Column == ((IHasColumn)existing).Column;
     }
 }

osu.Game.Rulesets.Mania/Edit/HoldNoteCompositionTool.cs

@@ -2,7 +2,8 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Graphics;
-using osu.Game.Beatmaps;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mania.Edit.Blueprints;
@@ -16,7 +17,7 @@ namespace osu.Game.Rulesets.Mania.Edit
         {
         }
 
-        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders);
+        public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.EditorHoldNote };
 
         public override HitObjectPlacementBlueprint CreatePlacementBlueprint() => new HoldNotePlacementBlueprint();
     }

osu.Game.Rulesets.Mania/Edit/ManiaBlueprintContainer.cs

@@ -3,11 +3,16 @@
 
 using System.Collections.Generic;
 using System.Linq;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Sprites;
 using osu.Framework.Input.Events;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Mania.Edit.Blueprints;
 using osu.Game.Rulesets.Mania.Objects;
 using osu.Game.Rulesets.Objects;
+using osu.Game.Screens.Edit.Components.TernaryButtons;
 using osu.Game.Screens.Edit.Compose.Components;
 using osuTK;
 
@@ -22,6 +27,29 @@ namespace osu.Game.Rulesets.Mania.Edit
         {
         }
 
+        protected override Drawable CreateNewComboButton() => new NewComboTernaryButton
+        {
+            Current = NewCombo,
+            CreateIcon = () => new Container
+            {
+                Children = new Drawable[]
+                {
+                    new SpriteIcon
+                    {
+                        Anchor = Anchor.BottomLeft,
+                        Origin = Anchor.BottomLeft,
+                        Icon = OsuIcon.EditorNote,
+                        Size = new Vector2(15),
+                    },
+                    new SpriteIcon
+                    {
+                        Icon = OsuIcon.EditorNewComboSparkles,
+                        Size = new Vector2(20),
+                    }
+                },
+            },
+        };
+
         public override HitObjectSelectionBlueprint? CreateHitObjectBlueprintFor(HitObject hitObject)
         {
             switch (hitObject)

osu.Game.Rulesets.Mania/Edit/NoteCompositionTool.cs

@@ -2,7 +2,8 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Graphics;
-using osu.Game.Beatmaps;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Graphics;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mania.Edit.Blueprints;
@@ -17,7 +18,7 @@ namespace osu.Game.Rulesets.Mania.Edit
         {
         }
 
-        public override Drawable CreateIcon() => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles);
+        public override Drawable CreateIcon() => new SpriteIcon { Icon = OsuIcon.EditorNote };
 
         public override HitObjectPlacementBlueprint CreatePlacementBlueprint() => new NotePlacementBlueprint();
     }

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -307,6 +307,8 @@ namespace osu.Game.Rulesets.Mania
             }
         }
 
+        public override ScoreMultiplierCalculator CreateScoreMultiplierCalculator(ScoreMultiplierContext context) => new ManiaScoreMultiplierCalculator(context);
+
         public override string Description => "osu!mania";
 
         public override string ShortName => SHORT_NAME;

osu.Game.Rulesets.Mania/Mods/ManiaKeyMod.cs

@@ -14,7 +14,6 @@ namespace osu.Game.Rulesets.Mania.Mods
         public override string Acronym => Name;
         public abstract int KeyCount { get; }
         public override ModType Type => ModType.Conversion;
-        public override double ScoreMultiplier => 0.9;
         public override bool Ranked => UsesDefaultConfiguration;
 
         public void ApplyToBeatmapConverter(IBeatmapConverter beatmapConverter)

osu.Game.Rulesets.Mania/Mods/ManiaModConstantSpeed.cs

@@ -18,8 +18,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public override string Acronym => "CS";
 
-        public override double ScoreMultiplier => 0.9;
-
         public override LocalisableString Description => "No more tricky speed changes!";
 
         public override IconUsage? Icon => OsuIcon.ModConstantSpeed;

osu.Game.Rulesets.Mania/Mods/ManiaModCover.cs

@@ -20,8 +20,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public override LocalisableString Description => @"Decrease the playfield's viewing area.";
 
-        public override double ScoreMultiplier => 1;
-
         protected override CoverExpandDirection ExpandDirection => Direction.Value;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[]

osu.Game.Rulesets.Mania/Mods/ManiaModDoubleTime.cs

@@ -7,9 +7,5 @@ namespace osu.Game.Rulesets.Mania.Mods
 {
     public class ManiaModDoubleTime : ModDoubleTime, IManiaRateAdjustmentMod
     {
-        // For now, all rate-increasing mods should be given a 1x multiplier in mania because it doesn't always
-        // make the map harder and is more of a personal preference.
-        // In the future, we can consider adjusting this by experimenting with not applying the hitwindow leniency.
-        public override double ScoreMultiplier => 1;
     }
 }

osu.Game.Rulesets.Mania/Mods/ManiaModDualStages.cs

@@ -17,7 +17,6 @@ namespace osu.Game.Rulesets.Mania.Mods
         public override LocalisableString Description => @"Double the stages, double the fun!";
         public override IconUsage? Icon => OsuIcon.ModDualStages;
         public override ModType Type => ModType.Conversion;
-        public override double ScoreMultiplier => 1;
 
         private bool isForCurrentRuleset;
 

osu.Game.Rulesets.Mania/Mods/ManiaModFadeIn.cs

@@ -16,7 +16,6 @@ namespace osu.Game.Rulesets.Mania.Mods
         public override string Acronym => "FI";
         public override IconUsage? Icon => OsuIcon.ModFadeIn;
         public override LocalisableString Description => @"Keys appear out of nowhere!";
-        public override double ScoreMultiplier => 1;
         public override bool ValidForFreestyleAsRequiredMod => false;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[]

osu.Game.Rulesets.Mania/Mods/ManiaModFlashlight.cs

@@ -13,7 +13,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 {
     public partial class ManiaModFlashlight : ModFlashlight<ManiaHitObject>
     {
-        public override double ScoreMultiplier => 1;
         public override Type[] IncompatibleMods => new[] { typeof(ModHidden) };
 
         public override BindableFloat SizeMultiplier { get; } = new BindableFloat(1)

osu.Game.Rulesets.Mania/Mods/ManiaModHardRock.cs

@@ -10,7 +10,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 {
     public class ManiaModHardRock : ModHardRock, IApplicableToHitObject
     {
-        public override double ScoreMultiplier => 1;
         public override bool Ranked => false;
 
         public const double HIT_WINDOW_DIFFICULTY_MULTIPLIER = 1.4;

osu.Game.Rulesets.Mania/Mods/ManiaModHidden.cs

@@ -30,7 +30,6 @@ namespace osu.Game.Rulesets.Mania.Mods
         private const float coverage_increase_per_combo = 0.5f;
 
         public override LocalisableString Description => @"Keys fade out before you hit them!";
-        public override double ScoreMultiplier => 1;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[]
         {

osu.Game.Rulesets.Mania/Mods/ManiaModHoldOff.cs

@@ -21,8 +21,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public override string Acronym => "HO";
 
-        public override double ScoreMultiplier => 0.9;
-
         public override LocalisableString Description => @"Replaces all hold notes with normal notes.";
 
         public override IconUsage? Icon => OsuIcon.ModHoldOff;

osu.Game.Rulesets.Mania/Mods/ManiaModInvert.cs

@@ -20,7 +20,6 @@ namespace osu.Game.Rulesets.Mania.Mods
         public override string Name => "Invert";
 
         public override string Acronym => "IN";
-        public override double ScoreMultiplier => 1;
 
         public override LocalisableString Description => "Hold the keys. To the beat.";
 

osu.Game.Rulesets.Mania/Mods/ManiaModNightcore.cs

@@ -8,9 +8,5 @@ namespace osu.Game.Rulesets.Mania.Mods
 {
     public class ManiaModNightcore : ModNightcore<ManiaHitObject>, IManiaRateAdjustmentMod
     {
-        // For now, all rate-increasing mods should be given a 1x multiplier in mania because it doesn't always
-        // make the map any harder and is more of a personal preference.
-        // In the future, we can consider adjusting this by experimenting with not applying the hitwindow leniency.
-        public override double ScoreMultiplier => 1;
     }
 }

osu.Game.Rulesets.Mania/Mods/ManiaModNoRelease.cs

@@ -26,8 +26,6 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public override LocalisableString Description => "No more timing the end of hold notes.";
 
-        public override double ScoreMultiplier => 0.9;
-
         public override IconUsage? Icon => OsuIcon.ModNoRelease;
 
         public override ModType Type => ModType.DifficultyReduction;

osu.Game.Rulesets.Mania/Scoring/ManiaScoreMultiplierCalculator.cs

@@ -0,0 +1,154 @@
+// 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.Mania.Mods;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+
+namespace osu.Game.Rulesets.Mania.Scoring
+{
+    public class ManiaScoreMultiplierCalculator : ScoreMultiplierCalculator
+    {
+        public ManiaScoreMultiplierCalculator(ScoreMultiplierContext context)
+            : base(context)
+        {
+            #region Difficulty Reduction
+
+            Single<ManiaModEasy>(hasMultiplier: 0.5);
+            Single<ManiaModNoFail>(hasMultiplier: 0.5);
+            Single<ManiaModHalfTime>(hasMultiplier: halfTime => rateAdjustMultiplier(halfTime.SpeedChange.Value));
+            Single<ManiaModDaycore>(hasMultiplier: daycore => rateAdjustMultiplier(daycore.SpeedChange.Value));
+            Single<ManiaModNoRelease>(hasMultiplier: 0.9);
+
+            #endregion
+
+            #region Difficulty Increase
+
+            // Hard Rock
+            // Sudden Death
+            // Perfect
+            // Double Time
+            // Nightcore
+            // Fade In
+            // Hidden
+            // Cover
+            // Flashlight
+            // Accuracy Challenge
+
+            #endregion
+
+            #region Conversion
+
+            // Random
+            // Dual Stages
+            // Mirror
+            Single<ManiaModDifficultyAdjust>(hasMultiplier: 0.5);
+            Single<ManiaModClassic>(hasMultiplier: _ => classicMultiplier(Context.Score));
+            // Invert
+            Single<ManiaModConstantSpeed>(hasMultiplier: 0.9);
+            Single<ManiaModHoldOff>(hasMultiplier: 0.9);
+            Single<ManiaModKey1>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey2>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey3>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey4>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey5>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey6>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey7>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey8>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey9>(hasMultiplier: keyModMultiplier(Context.Score));
+            Single<ManiaModKey10>(hasMultiplier: keyModMultiplier(Context.Score));
+
+            #endregion
+
+            #region Automation
+
+            // Autoplay
+            // Cinema
+
+            #endregion
+
+            #region Fun
+
+            Single<ModWindUp>(hasMultiplier: 0.5);
+            Single<ModWindDown>(hasMultiplier: 0.5);
+            // Muted
+            Single<ModAdaptiveSpeed>(hasMultiplier: 0.5);
+
+            #endregion
+
+            #region System
+
+            // Score V2
+
+            #endregion
+        }
+
+        private static double rateAdjustMultiplier(double speedChange)
+        {
+            // Round to the nearest multiple of 0.1.
+            double value = (int)(speedChange * 10) / 10.0;
+
+            // Offset back to 0.
+            value -= 1;
+
+            if (speedChange >= 1)
+                return 1 + value / 5;
+            else
+                return 0.6 + value;
+        }
+
+        private const double old_key_mod_multiplier = 1;
+        private const double new_key_mod_multiplier = 0.9;
+
+        /// <summary>
+        /// <para>
+        /// The mod multiplier was changed from 1.0x to 0.9x in https://github.com/ppy/osu/pull/30506
+        /// which was included in the https://osu.ppy.sh/home/changelog/tachyon/2025.718.0 release.
+        /// The replay version was not bumped in the change, meaning that the only usable indicator
+        /// of the mod multiplier changing is the client version.
+        /// </para>
+        /// <para>
+        /// Unfortunately not even the client version is available on server-side recorded replays
+        /// recorded prior to https://github.com/ppy/osu-server-spectator/pull/290,
+        /// which does not appear to have been deployed until August 1
+        /// (https://github.com/ppy/osu-server-spectator/releases/tag/2025.801.0).
+        /// </para>
+        /// </summary>
+        private double keyModMultiplier(ScoreInfo? scoreInfo)
+        {
+            if (scoreInfo == null)
+                return new_key_mod_multiplier;
+
+            string clientVersion = scoreInfo.ClientVersion;
+
+            if (!string.IsNullOrEmpty(clientVersion))
+            {
+                string[] pieces = clientVersion.Split('.');
+
+                if (int.TryParse(pieces[0], out int year) && int.TryParse(pieces[1], out int monthDay))
+                {
+                    if (year < 2025 || (year == 2025 && monthDay < 718))
+                        return old_key_mod_multiplier;
+                }
+
+                return new_key_mod_multiplier;
+            }
+
+            // Client version not available, fallback to doing the best we can with the score's timestamp.
+            if (scoreInfo.Date < new DateTimeOffset(2025, 7, 18, 0, 0, 0, TimeSpan.Zero))
+                return old_key_mod_multiplier;
+
+            return new_key_mod_multiplier;
+        }
+
+        private static double classicMultiplier(ScoreInfo? score)
+        {
+            if (score != null && score.TotalScoreVersion < 30000017)
+                return 0.96;
+
+            return 1;
+        }
+    }
+}

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

@@ -33,7 +33,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
         [Test]
         public void TestTouchInputPlaceHitCircleDirectly()
         {
-            AddStep("tap circle", () => tap(this.ChildrenOfType<EditorRadioButton>().Single(b => b.Button.Label == "HitCircle")));
+            AddStep("tap circle", () => tap(this.ChildrenOfType<EditorRadioButton>().Single(b => b.Button.Label == "Hit circle")));
 
             AddStep("tap to place circle", () => tap(this.ChildrenOfType<Playfield>().Single()));
             AddAssert("circle placed correctly", () =>
@@ -52,7 +52,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
         [Test]
         public void TestTouchInputPlaceCircleAfterTouchingComposeArea()
         {
-            AddStep("tap circle", () => tap(this.ChildrenOfType<EditorRadioButton>().Single(b => b.Button.Label == "HitCircle")));
+            AddStep("tap circle", () => tap(this.ChildrenOfType<EditorRadioButton>().Single(b => b.Button.Label == "Hit circle")));
 
             AddStep("tap playfield", () => tap(this.ChildrenOfType<Playfield>().Single()));
             AddAssert("circle placed", () => EditorBeatmap.HitObjects.Single(h => h.StartTime == EditorClock.CurrentTimeAccurate) is HitCircle);

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

@@ -7,6 +7,9 @@ using osu.Framework.Input;
 using osu.Framework.Testing;
 using osu.Framework.Utils;
 using osu.Game.Beatmaps;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Osu.Edit;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.UI;
 using osu.Game.Screens.Edit;
@@ -130,5 +133,74 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
             AddAssert("slider has correct velocity", () => slider!.Velocity, () => Is.EqualTo(velocityBefore));
             AddAssert("slider has correct duration", () => slider!.Duration, () => Is.EqualTo(durationBefore));
         }
+
+        [Test]
+        public void TestVelocityToolbox()
+        {
+            ExpandableSlider<double> velocitySlider = null!;
+            ExpandableButton useLastSliderButton = null!;
+
+            AddStep("enter editor", () => Game.ScreenStack.Push(new EditorLoader()));
+            AddUntilStep("wait for editor load", () => editor?.ReadyForUse == true);
+            AddStep("retrieve controls", () =>
+            {
+                var toolbox = this.ChildrenOfType<OsuSliderVelocityToolboxGroup>().Single();
+                velocitySlider = toolbox.ChildrenOfType<ExpandableSlider<double>>().Single();
+                useLastSliderButton = toolbox.ChildrenOfType<ExpandableButton>().Single();
+            });
+
+            AddAssert("velocity slider at 1x", () => velocitySlider.Current.Value, () => Is.EqualTo(1));
+            AddStep("expand right toolbox", () => InputManager.MoveMouseTo(this.ChildrenOfType<ExpandingToolboxContainer>().Last()));
+            AddUntilStep("wait for expand", () => useLastSliderButton.Expanded.Value, () => Is.True);
+            AddAssert("use last slider button disabled", () => useLastSliderButton.Enabled.Value, () => Is.False);
+
+            AddStep("seek to 5000", () => editorClock.Seek(5000));
+            AddStep("set 2x velocity", () => velocitySlider.Current.Value = 2);
+            placeSlider();
+            AddAssert("placed slider has 2x velocity", () => editorBeatmap.HitObjects.OfType<Slider>().Last().SliderVelocityMultiplier, () => Is.EqualTo(2));
+            AddStep("expand right toolbox", () => InputManager.MoveMouseTo(this.ChildrenOfType<ExpandingToolboxContainer>().Last()));
+            AddUntilStep("wait for expand", () => useLastSliderButton.Expanded.Value, () => Is.True);
+            AddAssert("use last slider button enabled", () => useLastSliderButton.Enabled.Value, () => Is.True);
+
+            AddStep("seek to 6000", () => editorClock.Seek(6000));
+            placeSlider();
+            AddAssert("placed slider has 2x velocity", () => editorBeatmap.HitObjects.OfType<Slider>().Last().SliderVelocityMultiplier, () => Is.EqualTo(2));
+            AddStep("expand right toolbox", () => InputManager.MoveMouseTo(this.ChildrenOfType<ExpandingToolboxContainer>().Last()));
+            AddUntilStep("wait for expand", () => useLastSliderButton.Expanded.Value, () => Is.True);
+            AddAssert("use last slider button enabled", () => useLastSliderButton.Enabled.Value, () => Is.True);
+
+            AddStep("seek to 9000", () => editorClock.Seek(9000));
+            AddStep("set 3x velocity", () => velocitySlider.Current.Value = 3);
+            placeSlider();
+            AddAssert("placed slider has 3x velocity", () => editorBeatmap.HitObjects.OfType<Slider>().Last().SliderVelocityMultiplier, () => Is.EqualTo(3));
+            AddStep("expand right toolbox", () => InputManager.MoveMouseTo(this.ChildrenOfType<ExpandingToolboxContainer>().Last()));
+            AddUntilStep("wait for expand", () => useLastSliderButton.Expanded.Value, () => Is.True);
+            AddAssert("use last slider button enabled", () => useLastSliderButton.Enabled.Value, () => Is.True);
+
+            AddStep("seek to 10000", () => editorClock.Seek(10000));
+            AddStep("set 1x velocity", () => velocitySlider.Current.Value = 1);
+            AddStep("use last slider velocity instead", () => useLastSliderButton.TriggerClick());
+            placeSlider();
+            AddAssert("placed slider has 3x velocity", () => editorBeatmap.HitObjects.OfType<Slider>().Last().SliderVelocityMultiplier, () => Is.EqualTo(3));
+            AddStep("expand right toolbox", () => InputManager.MoveMouseTo(this.ChildrenOfType<ExpandingToolboxContainer>().Last()));
+            AddUntilStep("wait for expand", () => useLastSliderButton.Expanded.Value, () => Is.True);
+            AddAssert("use last slider button disabled", () => useLastSliderButton.Enabled.Value, () => Is.False);
+
+            AddStep("seek back to 7000", () => editorClock.Seek(7000));
+            placeSlider();
+            AddAssert("placed slider has 2x velocity", () => editorBeatmap.HitObjects.OfType<Slider>().ElementAt(2).SliderVelocityMultiplier, () => Is.EqualTo(2));
+            AddStep("expand right toolbox", () => InputManager.MoveMouseTo(this.ChildrenOfType<ExpandingToolboxContainer>().Last()));
+            AddUntilStep("wait for expand", () => useLastSliderButton.Expanded.Value, () => Is.True);
+            AddAssert("use last slider button disabled", () => useLastSliderButton.Enabled.Value, () => Is.False);
+
+            void placeSlider()
+            {
+                AddStep("enter slider placement mode", () => InputManager.Key(Key.Number3));
+                AddStep("move mouse to top left", () => InputManager.MoveMouseTo(editor.ChildrenOfType<Playfield>().First().ScreenSpaceDrawQuad.TopLeft + new Vector2(50)));
+                AddStep("start placement", () => InputManager.Click(MouseButton.Left));
+                AddStep("move mouse to bottom right", () => InputManager.MoveMouseTo(editor.ChildrenOfType<Playfield>().First().ScreenSpaceDrawQuad.BottomRight - new Vector2(50)));
+                AddStep("end placement", () => InputManager.Click(MouseButton.Right));
+            }
+        }
     }
 }

osu.Game.Rulesets.Osu.Tests/Mods/TestSceneOsuModDifficultyAdjust.cs

@@ -17,6 +17,8 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
 {
     public partial class TestSceneOsuModDifficultyAdjust : OsuModTestScene
     {
+        protected override bool AllowFail => true;
+
         [Test]
         public void TestNoAdjustment() => CreateModTest(new ModTestData
         {
@@ -72,6 +74,88 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
             PassCondition = () => checkSomeHit() && checkObjectsPreempt(450)
         });
 
+        [Test]
+        public void TestScoreMultiplierCorrectWithNoAdjustment() => CreateModTest(new ModTestData
+        {
+            Mod = new OsuModDifficultyAdjust(),
+            CreateBeatmap = () => new Beatmap
+            {
+                BeatmapInfo = new BeatmapInfo
+                {
+                    Difficulty = new BeatmapDifficulty
+                    {
+                        CircleSize = 8
+                    }
+                },
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 1000 },
+                    new HitCircle { StartTime = 2000 }
+                }
+            },
+            Autoplay = true,
+            PassCondition = () => Player.ScoreProcessor.TotalScore.Value == 1_000_000,
+        });
+
+        [Test]
+        public void TestScoreMultiplierCorrectWithSingleAdjustment() => CreateModTest(new ModTestData
+        {
+            Mod = new OsuModDifficultyAdjust
+            {
+                ApproachRate = { Value = 7.3f }
+            },
+            CreateBeatmap = () => new Beatmap
+            {
+                BeatmapInfo = new BeatmapInfo
+                {
+                    Difficulty = new BeatmapDifficulty
+                    {
+                        CircleSize = 8,
+                        ApproachRate = 7,
+                        OverallDifficulty = 6,
+                        DrainRate = 5,
+                    }
+                },
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 1000 },
+                    new HitCircle { StartTime = 2000 }
+                }
+            },
+            Autoplay = true,
+            PassCondition = () => Player.ScoreProcessor.TotalScore.Value == 850_000,
+        });
+
+        [Test]
+        public void TestScoreMultiplierCorrectWithMultipleAdjustments() => CreateModTest(new ModTestData
+        {
+            Mod = new OsuModDifficultyAdjust
+            {
+                ApproachRate = { Value = 6.8f },
+                OverallDifficulty = { Value = 6.6f }
+            },
+            CreateBeatmap = () => new Beatmap
+            {
+                BeatmapInfo = new BeatmapInfo
+                {
+                    Difficulty = new BeatmapDifficulty
+                    {
+                        CircleSize = 8,
+                        ApproachRate = 7,
+                        OverallDifficulty = 6,
+                        DrainRate = 5,
+                    }
+                },
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle { StartTime = 1000 },
+                    new HitCircle { StartTime = 2000 }
+                }
+            },
+            Autoplay = true,
+            PassCondition = () => Player.ScoreProcessor.TotalScore.Value == 630_000,
+        });
+
         private bool checkObjectsPreempt(double target)
         {
             var objects = Player.ChildrenOfType<DrawableHitCircle>();

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

@@ -15,49 +15,25 @@ namespace osu.Game.Rulesets.Osu.Tests
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Osu.Tests";
 
-        [TestCase(6.5243170265483581d, 239, "diffcalc-test")]
-        [TestCase(1.3280410795791415d, 54, "zero-length-sliders")]
-        [TestCase(0.40867325147697559d, 4, "very-fast-slider")]
-        [TestCase(0.87058175794353554d, 6, "nan-slider")]
+        [TestCase(6.6232533278125061d, 239, "diffcalc-test")]
+        [TestCase(1.5045783545699611d, 54, "zero-length-sliders")]
+        [TestCase(0.43333836671191595d, 4, "very-fast-slider")]
+        [TestCase(0.13841532030395723d, 2, "nan-slider")]
         public void Test(double expectedStarRating, int expectedMaxCombo, string name)
             => base.Test(expectedStarRating, expectedMaxCombo, name);
 
-        [TestCase(9.4677607900646308d, 239, "diffcalc-test")]
-        [TestCase(1.6856612715618886d, 54, "zero-length-sliders")]
-        [TestCase(0.53588473186572561d, 4, "very-fast-slider")]
+        [TestCase(9.6491691624112761d, 239, "diffcalc-test")]
+        [TestCase(1.756936832498702d, 54, "zero-length-sliders")]
+        [TestCase(0.57771197086735004d, 4, "very-fast-slider")]
         public void TestClockRateAdjusted(double expectedStarRating, int expectedMaxCombo, string name)
             => Test(expectedStarRating, expectedMaxCombo, name, new OsuModDoubleTime());
 
-        [TestCase(6.5243170265483581d, 239, "diffcalc-test")]
-        [TestCase(1.3280410795791415d, 54, "zero-length-sliders")]
-        [TestCase(0.40867325147697559d, 4, "very-fast-slider")]
+        [TestCase(6.6232533278125061d, 239, "diffcalc-test")]
+        [TestCase(1.5045783545699611d, 54, "zero-length-sliders")]
+        [TestCase(0.43333836671191595d, 4, "very-fast-slider")]
         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.Tests/OsuScoreMultiplierTest.cs

@@ -0,0 +1,297 @@
+// 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 NUnit.Framework;
+using osu.Framework.Utils;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Mods;
+using osu.Game.Rulesets.Scoring;
+using osu.Game.Scoring;
+using osu.Game.Tests.Rulesets;
+
+namespace osu.Game.Rulesets.Osu.Tests
+{
+    public class OsuScoreMultiplierTest : RulesetScoreMultiplierTest
+    {
+        public OsuScoreMultiplierTest()
+            : base(new OsuRuleset())
+        {
+        }
+
+        private static readonly object[][] test_cases =
+        [
+            #region Difficulty Reduction
+
+            [new Mod[] { new OsuModEasy() }, 0.8],
+            [new Mod[] { new OsuModEasy { Retries = { Value = 1 } } }, 0.8],
+            [new Mod[] { new OsuModEasy { Retries = { Value = 3 } } }, 0.7],
+            [new Mod[] { new OsuModEasy { Retries = { Value = 5 } } }, 0.5],
+            [new Mod[] { new OsuModEasy { Retries = { Value = 8 } } }, 0.4],
+
+            [new Mod[] { new OsuModNoFail() }, 0.5],
+
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.50 } } }, 0.20],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.55 } } }, 0.27],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.60 } } }, 0.34],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.65 } } }, 0.41],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.70 } } }, 0.48],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.75 } } }, 0.55],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.80 } } }, 0.62],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.85 } } }, 0.69],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.90 } } }, 0.76],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.95 } } }, 0.83],
+            [new Mod[] { new OsuModHalfTime { SpeedChange = { Value = 0.99 } } }, 0.83],
+
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.50 } } }, 0.20],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.55 } } }, 0.27],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.60 } } }, 0.34],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.65 } } }, 0.41],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.70 } } }, 0.48],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.75 } } }, 0.55],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.80 } } }, 0.62],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.85 } } }, 0.69],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.90 } } }, 0.76],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.95 } } }, 0.83],
+            [new Mod[] { new OsuModDaycore { SpeedChange = { Value = 0.99 } } }, 0.83],
+
+            #endregion
+
+            #region Difficulty Increase
+
+            [new Mod[] { new OsuModHardRock() }, 1.09],
+            [new Mod[] { new OsuModSuddenDeath() }, 1],
+            [new Mod[] { new OsuModPerfect() }, 1],
+
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.01 } } }, 1.000],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.05 } } }, 1.000],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.10 } } }, 1.036],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.15 } } }, 1.036],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.20 } } }, 1.082],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.25 } } }, 1.082],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.30 } } }, 1.128],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.35 } } }, 1.128],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.40 } } }, 1.174],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.45 } } }, 1.174],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.50 } } }, 1.230],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.55 } } }, 1.230],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.60 } } }, 1.266],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.65 } } }, 1.266],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.70 } } }, 1.312],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.75 } } }, 1.312],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.80 } } }, 1.358],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.85 } } }, 1.358],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.90 } } }, 1.404],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 1.95 } } }, 1.404],
+            [new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 2.00 } } }, 1.450],
+
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.01 } } }, 1.000],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.05 } } }, 1.000],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.10 } } }, 1.036],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.15 } } }, 1.036],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.20 } } }, 1.082],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.25 } } }, 1.082],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.30 } } }, 1.128],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.35 } } }, 1.128],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.40 } } }, 1.174],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.45 } } }, 1.174],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.50 } } }, 1.230],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.55 } } }, 1.230],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.60 } } }, 1.266],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.65 } } }, 1.266],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.70 } } }, 1.312],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.75 } } }, 1.312],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.80 } } }, 1.358],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.85 } } }, 1.358],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.90 } } }, 1.404],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 1.95 } } }, 1.404],
+            [new Mod[] { new OsuModNightcore { SpeedChange = { Value = 2.00 } } }, 1.450],
+
+            [new Mod[] { new OsuModHidden() }, 1.04],
+            [new Mod[] { new OsuModHidden { OnlyFadeApproachCircles = { Value = true } } }, 1.02],
+
+            [new Mod[] { new OsuModTraceable() }, 1.02],
+
+            [new Mod[] { new OsuModFlashlight() }, 1.2],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 0.5f } } }, 1.2],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 0.9f } } }, 1.2],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 1.1f } } }, 1.18],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 1.5f } } }, 1.1],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 1.9f } } }, 1.02],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 2f } } }, 1.02],
+            [new Mod[] { new OsuModFlashlight { ComboBasedSize = { Value = false } } }, 1.04],
+            [new Mod[] { new OsuModFlashlight { SizeMultiplier = { Value = 1.9f }, ComboBasedSize = { Value = false } } }, 1.004],
+
+            [new Mod[] { new OsuModBlinds() }, 1.24],
+            [new Mod[] { new OsuModStrictTracking() }, 1],
+            [new Mod[] { new OsuModAccuracyChallenge() }, 1],
+
+            #endregion
+
+            #region Conversion
+
+            [new Mod[] { new OsuModTargetPractice() }, 0.01],
+            [new Mod[] { new OsuModDifficultyAdjust() }, 1],
+
+            [new Mod[] { new OsuModClassic() }, 0.985],
+            [new Mod[] { new OsuModClassic { ClassicNoteLock = { Value = false } } }, 0.96],
+
+            [new Mod[] { new OsuModRandom() }, 0.7],
+            [new Mod[] { new OsuModMirror() }, 1],
+            [new Mod[] { new OsuModAlternate() }, 1],
+            [new Mod[] { new OsuModSingleTap() }, 1],
+
+            #endregion
+
+            #region Automation
+
+            [new Mod[] { new OsuModAutoplay() }, 1],
+            [new Mod[] { new OsuModCinema() }, 1],
+            [new Mod[] { new OsuModRelax() }, 0.1],
+            [new Mod[] { new OsuModAutopilot() }, 0.1],
+            [new Mod[] { new OsuModSpunOut() }, 0.95],
+
+            #endregion
+
+            #region Fun
+
+            [new Mod[] { new OsuModTransform() }, 1],
+            [new Mod[] { new OsuModWiggle() }, 1],
+            [new Mod[] { new OsuModSpinIn() }, 1],
+            [new Mod[] { new OsuModGrow() }, 1],
+
+            [new Mod[] { new OsuModDeflate() }, 1],
+            [new Mod[] { new OsuModDeflate { StartScale = { Value = 5 } } }, 0.94],
+
+            [new Mod[] { new ModWindUp() }, 0.8 * 1 + 0.2 * 1.230],
+            [new Mod[] { new ModWindUp { InitialRate = { Value = 0.7 }, FinalRate = { Value = 1.2 } } }, 0.8 * 0.48 + 0.2 * 1.082],
+            [new Mod[] { new ModWindUp { InitialRate = { Value = 0.7 }, FinalRate = { Value = 0.9 } } }, 0.8 * 0.48 + 0.2 * 0.76],
+            [new Mod[] { new ModWindUp { InitialRate = { Value = 1.1 }, FinalRate = { Value = 1.4 } } }, 0.8 * 1.036 + 0.2 * 1.174],
+
+            [new Mod[] { new ModWindDown() }, 0.8 * 0.55 + 0.2 * 1],
+            [new Mod[] { new ModWindDown { InitialRate = { Value = 1.2 }, FinalRate = { Value = 0.7 } } }, 0.8 * 0.48 + 0.2 * 1.082],
+            [new Mod[] { new ModWindDown { InitialRate = { Value = 0.9 }, FinalRate = { Value = 0.7 } } }, 0.8 * 0.48 + 0.2 * 0.76],
+            [new Mod[] { new ModWindDown { InitialRate = { Value = 1.4 }, FinalRate = { Value = 1.1 } } }, 0.8 * 1.036 + 0.2 * 1.174],
+
+            [new Mod[] { new OsuModBarrelRoll() }, 1],
+            [new Mod[] { new OsuModApproachDifferent() }, 0.7],
+            [new Mod[] { new OsuModMuted() }, 1],
+            [new Mod[] { new OsuModNoScope() }, 1],
+
+            [new Mod[] { new OsuModMagnetised() }, 0.4],
+            [new Mod[] { new OsuModMagnetised { AttractionStrength = { Value = 0.05f } } }, 0.67],
+            [new Mod[] { new OsuModMagnetised { AttractionStrength = { Value = 0.2f } } }, 0.58],
+            [new Mod[] { new OsuModMagnetised { AttractionStrength = { Value = 0.7f } } }, 0.28],
+            [new Mod[] { new OsuModMagnetised { AttractionStrength = { Value = 1 } } }, 0.1],
+
+            [new Mod[] { new OsuModRepel() }, 1],
+            [new Mod[] { new ModAdaptiveSpeed() }, 0.1],
+            [new Mod[] { new OsuModFreezeFrame() }, 1],
+            [new Mod[] { new OsuModBubbles() }, 1],
+            [new Mod[] { new OsuModSynesthesia() }, 0.99],
+            [new Mod[] { new OsuModDepth() }, 1],
+            [new Mod[] { new OsuModBloom() }, 1],
+
+            #endregion
+
+            #region System
+
+            [new Mod[] { new OsuModTouchDevice() }, 1],
+            [new Mod[] { new ModScoreV2() }, 1],
+
+            #endregion
+
+            #region Combinations
+
+            [new Mod[] { new OsuModHidden(), new OsuModHardRock() }, 1.04 * 1.09],
+
+            [new Mod[] { new OsuModHidden(), new OsuModWiggle() }, 1.02],
+            [new Mod[] { new OsuModHidden(), new OsuModGrow() }, 1.02],
+            [new Mod[] { new OsuModHidden(), new OsuModDeflate() }, 1.02],
+            [new Mod[] { new OsuModHidden(), new OsuModDeflate { StartScale = { Value = 4 } } }, 1.02 * 0.96],
+            [new Mod[] { new OsuModHidden(), new OsuModRepel() }, 1.02],
+            [new Mod[] { new OsuModHidden { OnlyFadeApproachCircles = { Value = true } }, new OsuModRepel() }, 1],
+            [new Mod[] { new OsuModHidden(), new OsuModDepth() }, 1.02],
+            [new Mod[] { new OsuModHidden(), new OsuModDepth(), new OsuModHardRock() }, 1.02 * 1.09],
+
+            [new Mod[] { new OsuModHidden(), new OsuModBlinds() }, 1.24],
+            [new Mod[] { new OsuModHidden(), new OsuModBlinds(), new OsuModHardRock() }, 1.24 * 1.09],
+
+            [new Mod[] { new OsuModTraceable(), new OsuModBlinds() }, 1.24],
+            [new Mod[] { new OsuModTraceable(), new OsuModBlinds(), new OsuModHardRock() }, 1.24 * 1.09],
+
+            [new Mod[] { new OsuModFlashlight(), new OsuModFreezeFrame() }, 1.1],
+
+            #endregion
+        ];
+
+        [TestCaseSource(nameof(test_cases))]
+        public void TestMultipliers(Mod[] mods, double expectedMultiplier)
+            => TestModCombination(mods, expectedMultiplier);
+
+        [TestCase(null, null, null, null, 1)]
+        [TestCase(2.9f, null, null, null, 0.95)]
+        [TestCase(3.1f, null, null, null, 0.95)]
+        [TestCase(null, 3.9f, null, null, 0.95)]
+        [TestCase(null, 4.1f, null, null, 0.95)]
+        [TestCase(null, null, 4.9f, null, 0.95)]
+        [TestCase(null, null, 5.1f, null, 0.95)]
+        [TestCase(null, null, null, 5.9f, 0.95)]
+        [TestCase(null, null, null, 6.1f, 0.95)]
+        [TestCase(2.9f, 3.9f, null, null, 0.95 * 0.95)]
+        [TestCase(2.9f, 3.9f, 4.9f, null, 0.95 * 0.95 * 0.95)]
+        [TestCase(2.9f, 3.9f, 4.9f, 5.9f, 0.95 * 0.95 * 0.95 * 0.95)]
+        [TestCase(0.0f, null, null, null, 0.1)]
+        [TestCase(0.0f, 0.0f, 0.0f, 0.0f, 0.1)]
+        public void TestDifficultyAdjust(float? cs, float? ar, float? od, float? hp, double expectedMultiplier)
+        {
+            var difficulty = new BeatmapDifficulty
+            {
+                CircleSize = 3,
+                ApproachRate = 4,
+                OverallDifficulty = 5,
+                DrainRate = 6,
+            };
+            var mod = new OsuModDifficultyAdjust
+            {
+                CircleSize = { Value = cs },
+                ApproachRate = { Value = ar },
+                OverallDifficulty = { Value = od },
+                DrainRate = { Value = hp },
+            };
+
+            var calculator = Ruleset.CreateScoreMultiplierCalculator(new ScoreMultiplierContext(difficulty));
+            Assert.That(calculator.CalculateFor([mod]), Is.EqualTo(expectedMultiplier).Within(Precision.FLOAT_EPSILON));
+        }
+
+        [TestCase(30000001, 0.96)]
+        [TestCase(30000009, 0.96)]
+        [TestCase(30000016, 0.96)]
+        [TestCase(30000017, 0.985)]
+        [TestCase(null, 0.985)]
+        public void TestClassicMultiplierVersioning(int? totalScoreVersion, double expectedMultiplier)
+        {
+            var scoreInfo = totalScoreVersion != null ? new ScoreInfo { TotalScoreVersion = totalScoreVersion.Value } : null;
+            var calculator = Ruleset.CreateScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty(), scoreInfo));
+            Assert.That(calculator.CalculateFor([new OsuModClassic()]), Is.EqualTo(expectedMultiplier).Within(Precision.DOUBLE_EPSILON));
+        }
+
+        [Test]
+        public void VerySmallModMultiplier()
+        {
+            var mods = new Mod[]
+            {
+                new OsuModEasy { Retries = { Value = 10 } },
+                new OsuModNoFail(),
+                new OsuModHalfTime { SpeedChange = { Value = 0.5 } },
+                new OsuModTargetPractice(),
+                new OsuModClassic { ClassicNoteLock = { Value = false } },
+                new OsuModDeflate { StartScale = { Value = 25 } },
+                new OsuModMagnetised { AttractionStrength = { Value = 1 } },
+                new OsuModSynesthesia(),
+            };
+            var calculator = Ruleset.CreateScoreMultiplierCalculator(new ScoreMultiplierContext(new BeatmapDifficulty()));
+            Assert.That(calculator.CalculateFor(mods), Is.GreaterThan(0));
+        }
+    }
+}

osu.Game.Rulesets.Osu.Tests/Resources/Testing/Beatmaps/nan-slider-expected-conversion.json

@@ -1 +1 @@
-{"Mappings":[{"StartTime":76911.0,"Objects":[{"StartTime":76911.0,"EndTime":76911.0,"X":283.402,"Y":275.402}]},{"StartTime":77053.0,"Objects":[{"StartTime":77053.0,"EndTime":77053.0,"X":287.0515,"Y":279.0515}]},{"StartTime":77196.0,"Objects":[{"StartTime":77196.0,"EndTime":77196.0,"X":290.701019,"Y":282.701019}]},{"StartTime":77339.0,"Objects":[{"StartTime":77339.0,"EndTime":77339.0,"X":294.3505,"Y":286.3505}]},{"StartTime":77497.0,"Objects":[{"StartTime":77497.0,"EndTime":77497.0,"X":298.0,"Y":290.0,"StackOffset":{"X":0.0,"Y":0.0}},{"StartTime":77533.0,"EndTime":77533.0,"X":276.162567,"Y":293.0336,"StackOffset":{"X":0.0,"Y":0.0}}]}]}
+{"Mappings":[{"StartTime":77497.0,"Objects":[{"StartTime":77497.0,"EndTime":77497.0,"X":298.0,"Y":290.0},{"StartTime":77533.0,"EndTime":77533.0,"X":276.162567,"Y":293.0336}]}]}

osu.Game.Rulesets.Osu.Tests/Resources/Testing/Beatmaps/nan-slider.osu

@@ -9,15 +9,10 @@ SliderMultiplier:2
 SliderTickRate:1
 
 [TimingPoints]
-76911,285.7142857142857,4,1,0,100,1,8
 77211,-100,4,3,50,70,0,0
 77497,8.40402703648439,4,3,51,70,1,8
 77497,NaN,4,3,51,70,0,8
 77498,285.714285714286,4,3,51,70,1,0
 
 [HitObjects]
-298,290,76911,5,0,1:0:0:0:
-298,290,77053,1,0,1:0:0:0:
-298,290,77196,1,0,1:0:0:0:
-298,290,77339,1,0,1:0:0:0:
 298,290,77497,6,0,B|234:298|192:279|192:279|180:299|180:299|205:311|238:318|238:318|230:347|217:371|217:371|137:370|80:340|80:340|65:259|73:143|102:68|102:68|149:49|199:34|199:34|213:54|213:54|267:38|324:40|324:40|332:18|332:18|385:20|435:27|435:27|480:93|517:204|521:286|521:286|474:329|396:350|396:350|377:329|363:302|363:302|393:287|415:271|415:271|398:254|398:254|362:282|299:290,1,1723.66345596313,10|0,1:0|3:0,3:0:0:0:

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

@@ -792,7 +792,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             {
                 AddStep("export beatmap", () =>
                 {
-                    var beatmapEncoder = new LegacyBeatmapEncoder(playableBeatmap, null);
+                    var beatmapEncoder = new LegacyBeatmapEncoder(playableBeatmap, null, null);
 
                     using (var stream = File.Open(Path.Combine(exportLocation, $"{testCaseName}.osu"), FileMode.Create))
                     {

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

@@ -1,42 +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.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

@@ -1,126 +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;
-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

@@ -1,220 +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.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

@@ -0,0 +1,172 @@
+// 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

@@ -2,12 +2,8 @@
 // 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
@@ -32,7 +28,7 @@ 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, IReadOnlyList<Mod> mods)
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, bool hidden)
         {
             if (current.BaseObject is Spinner)
                 return 0;
@@ -44,7 +40,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
             double smallDistNerf = 1.0;
             double cumulativeStrainTime = 0.0;
 
-            double flashlightDifficulty = 0.0;
+            double result = 0.0;
 
             OsuDifficultyHitObject lastObj = osuCurrent;
 
@@ -70,9 +66,9 @@ 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, mods.OfType<OsuModHidden>().Any(m => !m.OnlyFadeApproachCircles.Value)));
+                    double opacityBonus = 1.0 + max_opacity_bonus * (1.0 - osuCurrent.OpacityAt(currentHitObject.StartTime, hidden));
 
-                    flashlightDifficulty += stackNerf * opacityBonus * scalingFactor * jumpDistance / cumulativeStrainTime;
+                    result += stackNerf * opacityBonus * scalingFactor * jumpDistance / cumulativeStrainTime;
 
                     if (currentObj.Angle != null && osuCurrent.Angle != null)
                     {
@@ -85,14 +81,14 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                 lastObj = currentObj;
             }
 
-            flashlightDifficulty = Math.Pow(smallDistNerf * flashlightDifficulty, 2.0);
+            result = Math.Pow(smallDistNerf * result, 2.0);
 
             // Additional bonus for Hidden due to there being no approach circles.
-            if (mods.OfType<OsuModHidden>().Any())
-                flashlightDifficulty *= 1.0 + hidden_bonus;
+            if (hidden)
+                result *= 1.0 + hidden_bonus;
 
             // Nerf patterns with repeated angles.
-            flashlightDifficulty *= min_angle_multiplier + (1.0 - min_angle_multiplier) / (angleRepeatCount + 1.0);
+            result *= min_angle_multiplier + (1.0 - min_angle_multiplier) / (angleRepeatCount + 1.0);
 
             double sliderBonus = 0.0;
 
@@ -112,9 +108,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
                     sliderBonus /= (osuSlider.RepeatCount + 1);
             }
 
-            flashlightDifficulty += sliderBonus * slider_multiplier;
+            result += sliderBonus * slider_multiplier;
 
-            return flashlightDifficulty;
+            return result;
         }
     }
 }

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

@@ -1,272 +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.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/RhythmEvaluator.cs

@@ -8,16 +8,15 @@ 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.Speed
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
 {
     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 = 0.95;
-        private const double rhythm_ratio_multiplier = 26.0;
+        private const double rhythm_overall_multiplier = 1.0;
+        private const double rhythm_ratio_multiplier = 15.0;
 
         /// <summary>
         /// Calculates a rhythm multiplier for the difficulty of the tap associated with historic data of the current <see cref="OsuDifficultyHitObject"/>.
@@ -27,9 +26,11 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
             if (current.BaseObject is Spinner)
                 return 0;
 
+            var currentOsuObject = (OsuDifficultyHitObject)current;
+
             double rhythmComplexitySum = 0;
 
-            double deltaDifferenceEpsilon = ((OsuDifficultyHitObject)current).HitWindow(HitResult.Great) * 0.3;
+            double deltaDifferenceEpsilon = ((OsuDifficultyHitObject)current).HitWindowGreat * 0.3;
 
             var island = new Island(deltaDifferenceEpsilon);
             var previousIsland = new Island(deltaDifferenceEpsilon);
@@ -56,8 +57,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
             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;
@@ -65,56 +64,44 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
 
                 double currHistoricalDecay = Math.Min(noteDecay, timeDecay); // either we're limited by time or limited by object count.
 
-                // Use custom cap value to ensure that at this point delta time is actually zero
+                // Use custom cap value to ensure that 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 = 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);
-                }
+                double effectiveRatio = windowPenalty * currRatio * differenceMultiplier;
 
                 if (firstDeltaSwitch)
                 {
-                    if (Math.Abs(prevDelta - currDelta) > deltaDifferenceEpsilon)
+                    if (Math.Abs(prevDelta - currDelta) < deltaDifferenceEpsilon)
+                    {
+                        // island is still progressing
+                        island.AddDelta((int)currDelta);
+                    }
+                    else
                     {
                         // bpm change is into slider, this is easy acc window
                         if (currObj.BaseObject is Slider)
-                            effectiveRatio *= 0.5;
+                            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;
 
                         // repeated island polarity (2 -> 4, 3 -> 5)
                         if (island.IsSimilarPolarity(previousIsland))
@@ -129,9 +116,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
                         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)
@@ -150,10 +134,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
                         }
                         else
                         {
-                            if (island.DeltaCount > 0)
-                            {
-                                islandCounts.Add((island, 1));
-                            }
+                            islandCounts.Add((island, 1));
                         }
 
                         // scale down the difficulty if the object is doubletappable
@@ -195,18 +176,10 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
                 prevObj = currObj;
             }
 
-            // 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);
+            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));
 
-            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));
+            return rhythmDifficulty;
         }
 
         private class Island : IEquatable<Island>
@@ -238,12 +211,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
 
             public bool IsSimilarPolarity(Island other)
             {
-                // 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;
+                // 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;
             }
 
             public bool Equals(Island? other)

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

@@ -2,39 +2,47 @@
 // 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.Speed
+namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators
 {
     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)
+        public static double EvaluateDifficultyOf(DifficultyHitObject current, IReadOnlyList<Mod> mods)
         {
             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.HitWindow(HitResult.Great)) / 0.93, 0.92, 1);
+            strainTime /= Math.Clamp((strainTime / osuCurrObj.HitWindowGreat) / 0.93, 0.92, 1);
 
             // speedBonus will be 0.0 for BPM < 200
             double speedBonus = 0.0;
@@ -43,15 +51,26 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Evaluators.Speed
             if (DifficultyCalculationUtils.MillisecondsToBPM(strainTime) > min_speed_bonus)
                 speedBonus = 0.75 * Math.Pow((DifficultyCalculationUtils.BPMToMilliseconds(min_speed_bonus) - strainTime) / speed_balancing_factor, 2);
 
-            // Base difficulty with all bonuses
-            double speedDifficulty = (1 + speedBonus) * 1000 / strainTime;
+            double travelDistance = osuPrevObj?.TravelDistance ?? 0;
+            double distance = travelDistance + osuCurrObj.MinimumJumpDistance;
 
-            speedDifficulty *= highBpmBonus(osuCurrObj.AdjustedDeltaTime);
+            // 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;
 
             // Apply penalty if there's doubletappable doubles
-            return speedDifficulty * doubletapness;
+            return difficulty * doubletapness;
         }
-
-        private static double highBpmBonus(double ms) => 1 / (1 - Math.Pow(0.3, ms / 1000));
     }
 }

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

@@ -45,12 +45,6 @@ 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.
@@ -81,9 +75,6 @@ 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; }
 
@@ -93,6 +84,11 @@ 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>
@@ -115,7 +111,6 @@ 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())
@@ -132,7 +127,6 @@ 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)
@@ -141,7 +135,6 @@ 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];
@@ -154,7 +147,7 @@ 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];
-            ReadingDifficultNoteCount = values[ATTRIB_ID_READING_DIFFICULT_NOTE_COUNT];
+            DrainRate = onlineInfo.DrainRate;
             HitCircleCount = onlineInfo.CircleCount;
             SliderCount = onlineInfo.SliderCount;
             SpinnerCount = onlineInfo.SpinnerCount;

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

@@ -8,19 +8,21 @@ 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;
 using osu.Game.Rulesets.Osu.Difficulty.Utils;
 using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
-using osu.Game.Utils;
+using osu.Game.Rulesets.Osu.Scoring;
+using osu.Game.Rulesets.Scoring;
 
 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)
@@ -28,7 +30,23 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         {
         }
 
-        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills)
+        public static double CalculateRateAdjustedApproachRate(double approachRate, double clockRate)
+        {
+            double preempt = IBeatmapDifficultyInfo.DifficultyRange(approachRate, OsuHitObject.PREEMPT_MAX, OsuHitObject.PREEMPT_MID, OsuHitObject.PREEMPT_MIN) / clockRate;
+            return IBeatmapDifficultyInfo.InverseDifficultyRange(preempt, OsuHitObject.PREEMPT_MAX, OsuHitObject.PREEMPT_MID, OsuHitObject.PREEMPT_MIN);
+        }
+
+        public static double CalculateRateAdjustedOverallDifficulty(double overallDifficulty, double clockRate)
+        {
+            HitWindows hitWindows = new OsuHitWindows();
+            hitWindows.SetDifficulty(overallDifficulty);
+
+            double hitWindowGreat = hitWindows.WindowFor(HitResult.Great) / clockRate;
+
+            return (79.5 - hitWindowGreat) / 6;
+        }
+
+        protected override DifficultyAttributes CreateDifficultyAttributes(IBeatmap beatmap, Mod[] mods, Skill[] skills, double clockRate)
         {
             if (beatmap.HitObjects.Count == 0)
                 return new OsuDifficultyAttributes { Mods = mods };
@@ -37,61 +55,66 @@ 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 aimNoSlidersTopWeightedSliderCount = aimWithoutSliders.CountTopWeightedSliders(aimNoSlidersDifficultyValue);
-            double aimNoSlidersDifficultStrainCount = aimWithoutSliders.CountTopWeightedStrains(aimNoSlidersDifficultyValue);
+            double aimDifficultStrainCount = aim.CountTopWeightedStrains();
+            double speedDifficultStrainCount = speed.CountTopWeightedStrains();
+
+            double aimNoSlidersTopWeightedSliderCount = aimWithoutSliders.CountTopWeightedSliders();
+            double aimNoSlidersDifficultStrainCount = aimWithoutSliders.CountTopWeightedStrains();
 
             double aimTopWeightedSliderFactor = aimNoSlidersTopWeightedSliderCount / Math.Max(1, aimNoSlidersDifficultStrainCount - aimNoSlidersTopWeightedSliderCount);
 
-            double speedTopWeightedSliderCount = speed.CountTopWeightedSliders(speedDifficultyValue);
+            double speedTopWeightedSliderCount = speed.CountTopWeightedSliders();
             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);
+
             int hitCircleCount = beatmap.HitObjects.Count(h => h is HitCircle);
             int sliderCount = beatmap.HitObjects.Count(h => h is Slider);
             int spinnerCount = beatmap.HitObjects.Count(h => h is Spinner);
 
             int totalHits = beatmap.HitObjects.Count;
 
-            double sliderFactor = aimDifficultyValue > 0
-                ? calculateAimDifficultyRating(aimNoSlidersDifficultyValue) / calculateAimDifficultyRating(aimDifficultyValue)
-                : 1;
+            double drainRate = beatmap.Difficulty.DrainRate;
 
-            double aimRating = calculateAimDifficultyRating(aimDifficultyValue);
-            double speedRating = calculateDifficultyRating(speedDifficultyValue);
-            double readingRating = calculateDifficultyRating(readingDifficultyValue);
+            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);
+
+            double aimRating = osuRatingCalculator.ComputeAimRating(aimDifficultyValue);
+            double speedRating = osuRatingCalculator.ComputeSpeedRating(speedDifficultyValue);
 
             double flashlightRating = 0.0;
 
             if (flashlight is not null)
-                flashlightRating = calculateDifficultyRating(flashlight.DifficultyValue());
+                flashlightRating = osuRatingCalculator.ComputeFlashlightRating(flashlight.DifficultyValue());
 
             double sliderNestedScorePerObject = LegacyScoreUtils.CalculateNestedScorePerObject(beatmap, totalHits);
-            double legacyScoreBaseMultiplier = LegacyScoreUtils.CalculateDifficultyPeppyStars(WorkingBeatmap.Beatmap);
+            double legacyScoreBaseMultiplier = LegacyScoreUtils.CalculateDifficultyPeppyStars(beatmap);
 
             var simulator = new OsuLegacyScoreSimulator();
             var scoreAttributes = simulator.Simulate(WorkingBeatmap, beatmap);
 
-            double baseAimPerformance = OsuPerformanceCalculator.DifficultyToPerformance(aimRating);
-            double baseSpeedPerformance = HarmonicSkill.DifficultyToPerformance(speedRating);
-            double baseReadingPerformance = HarmonicSkill.DifficultyToPerformance(readingRating);
+            double baseAimPerformance = OsuStrainSkill.DifficultyToPerformance(aimRating);
+            double baseSpeedPerformance = OsuStrainSkill.DifficultyToPerformance(speedRating);
             double baseFlashlightPerformance = Flashlight.DifficultyToPerformance(flashlightRating);
-            double baseCognitionPerformance = SumCognitionDifficulty(baseReadingPerformance, baseFlashlightPerformance);
 
-            double basePerformance = DifficultyCalculationUtils.Norm(OsuPerformanceCalculator.PERFORMANCE_NORM_EXPONENT, baseAimPerformance, baseSpeedPerformance, baseCognitionPerformance);
+            double basePerformance =
+                Math.Pow(
+                    Math.Pow(baseAimPerformance, 1.1) +
+                    Math.Pow(baseSpeedPerformance, 1.1) +
+                    Math.Pow(baseFlashlightPerformance, 1.1), 1.0 / 1.1
+                );
 
             double starRating = calculateStarRating(basePerformance);
 
@@ -104,13 +127,12 @@ 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,
@@ -123,33 +145,28 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return attributes;
         }
 
-        public static double SumCognitionDifficulty(double reading, double flashlight)
+        private double calculateMechanicalDifficultyRating(double aimDifficultyValue, double speedDifficultyValue)
         {
-            if (reading <= 0)
-                return flashlight;
+            double aimValue = OsuStrainSkill.DifficultyToPerformance(OsuRatingCalculator.CalculateDifficultyRating(aimDifficultyValue));
+            double speedValue = OsuStrainSkill.DifficultyToPerformance(OsuRatingCalculator.CalculateDifficultyRating(speedDifficultyValue));
 
-            if (flashlight <= 0)
-                return reading;
+            double totalValue = Math.Pow(Math.Pow(aimValue, 1.1) + Math.Pow(speedValue, 1.1), 1 / 1.1);
 
-            // 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));
+            return calculateStarRating(totalValue);
         }
 
-        private double calculateAimDifficultyRating(double difficultyValue) => Math.Pow(difficultyValue, 0.63) * 0.02275;
-
-        private double calculateDifficultyRating(double difficultyValue) => Math.Sqrt(difficultyValue) * 0.0675;
-
         private double calculateStarRating(double basePerformance)
         {
-            return Math.Cbrt(basePerformance * OsuPerformanceCalculator.PERFORMANCE_BASE_MULTIPLIER);
+            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);
         }
 
-        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, Mod[] mods)
+        protected override IEnumerable<DifficultyHitObject> CreateDifficultyHitObjects(IBeatmap beatmap, double clockRate)
         {
             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++)
@@ -160,18 +177,17 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             return objects;
         }
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods)
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
         {
             var skills = new List<Skill>
             {
                 new Aim(mods, true),
                 new Aim(mods, false),
-                new Speed(mods),
-                new Reading(mods)
+                new Speed(mods)
             };
 
             if (mods.Any(h => h is OsuModFlashlight))
-                skills.Add(new Flashlight(mods, beatmap.HitObjects.Count));
+                skills.Add(new Flashlight(mods));
 
             return skills.ToArray();
         }

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

@@ -115,13 +115,9 @@ 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 it
-            double fullComboThreshold = attributes.MaxCombo - Math.Min(4 + likelyMissedSliderendPortion * attributes.SliderCount, attributes.SliderCount);
+            // 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;
 
             if (score.MaxCombo < fullComboThreshold)
                 missCount = Math.Pow(fullComboThreshold / Math.Max(1.0, score.MaxCombo), 2.5);

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

@@ -21,9 +21,6 @@ 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; }
 
@@ -51,7 +48,6 @@ 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

@@ -5,15 +5,12 @@ using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Extensions.IEnumerableExtensions;
-using osu.Game.Beatmaps;
-using osu.Game.Rulesets.Difficulty;
-using osu.Game.Rulesets.Difficulty.Skills;
 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.Osu.Difficulty.Skills;
 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.Scoring;
 using osu.Game.Utils;
@@ -22,8 +19,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 {
     public class OsuPerformanceCalculator : PerformanceCalculator
     {
-        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;
+        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.
 
         private bool usingClassicSliderAccuracy;
         private bool usingScoreV2;
@@ -54,18 +50,14 @@ 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())
         {
@@ -101,14 +93,13 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             okHitWindow = hitWindows.WindowFor(HitResult.Ok) / clockRate;
             mehHitWindow = hitWindows.WindowFor(HitResult.Meh) / clockRate;
 
-            approachRate = calculateRateAdjustedApproachRate(difficulty.ApproachRate, clockRate);
-            overallDifficulty = (79.5 - greatHitWindow) / 6;
-            drainRate = difficulty.DrainRate;
+            approachRate = OsuDifficultyCalculator.CalculateRateAdjustedApproachRate(difficulty.ApproachRate, clockRate);
+            overallDifficulty = OsuDifficultyCalculator.CalculateRateAdjustedOverallDifficulty(difficulty.OverallDifficulty, clockRate);
 
             double comboBasedEstimatedMissCount = calculateComboBasedEstimatedMissCount(osuAttributes);
             double? scoreBasedEstimatedMissCount = null;
 
-            if (usingClassicSliderAccuracy && !usingScoreV2 && score.LegacyTotalScore != null)
+            if (usingClassicSliderAccuracy && score.LegacyTotalScore != null)
             {
                 var legacyScoreMissCalculator = new OsuLegacyScoreMissCalculator(score, osuAttributes);
                 scoreBasedEstimatedMissCount = legacyScoreMissCalculator.Calculate();
@@ -124,12 +115,6 @@ 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))
@@ -155,12 +140,15 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             double aimValue = computeAimValue(score, osuAttributes);
             double speedValue = computeSpeedValue(score, osuAttributes);
             double accuracyValue = computeAccuracyValue(score, osuAttributes);
-
-            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;
+            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;
 
             return new OsuPerformanceAttributes
             {
@@ -168,7 +156,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 Speed = speedValue,
                 Accuracy = accuracyValue,
                 Flashlight = flashlightValue,
-                Reading = readingValue,
                 EffectiveMissCount = effectiveMissCount,
                 ComboBasedEstimatedMissCount = comboBasedEstimatedMissCount,
                 ScoreBasedEstimatedMissCount = scoreBasedEstimatedMissCount,
@@ -207,14 +194,16 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 aimDifficulty *= sliderNerfFactor;
             }
 
-            double aimValue = DifficultyToPerformance(aimDifficulty);
+            double aimValue = OsuStrainSkill.DifficultyToPerformance(aimDifficulty);
 
-            double lengthBonus = 0.95 + 0.35 * Math.Min(1.0, totalHits / 2000.0) +
+            double lengthBonus = 0.95 + 0.4 * 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);
@@ -222,10 +211,10 @@ 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 * drainRate * drainRate);
+                aimValue *= 1.3 + (totalHits * (0.0016 / (1 + 2 * effectiveMissCount)) * Math.Pow(accuracy, 16)) * (1 - 0.003 * attributes.DrainRate * attributes.DrainRate);
             else if (score.Mods.Any(m => m is OsuModTraceable))
             {
-                aimValue *= 1.0 + calculateTraceableBonus(attributes.SliderFactor);
+                aimValue *= 1.0 + OsuRatingCalculator.CalculateVisibilityBonus(score.Mods, approachRate, sliderFactor: attributes.SliderFactor);
             }
 
             aimValue *= accuracy;
@@ -238,33 +227,44 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             if (score.Mods.Any(h => h is OsuModRelax) || speedDeviation == null)
                 return 0.0;
 
-            double speedValue = HarmonicSkill.DifficultyToPerformance(attributes.SpeedDifficulty);
+            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;
 
             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;
 
-            // 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);
+            // 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);
 
-            // 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);
+            // Scale the speed value with accuracy and OD.
+            speedValue *= Math.Pow((accuracy + relevantAccuracy) / 2.0, (14.5 - overallDifficulty) / 2);
 
             return speedValue;
         }
@@ -294,19 +294,20 @@ 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 *= amountHitObjectsWithAccuracy < 1000
-                ? Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.3)
-                : Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.1);
+            accuracyValue *= Math.Min(1.15, Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.3));
 
             // 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 OsuModTraceable))
+            else if (score.Mods.Any(m => m is OsuModHidden || 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;
         }
 
@@ -329,19 +330,6 @@ 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)
@@ -351,13 +339,9 @@ 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 it
-                double fullComboThreshold = attributes.MaxCombo - Math.Min(4 + likelyMissedSliderendPortion * attributes.SliderCount, attributes.SliderCount);
+                // 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;
 
                 if (scoreMaxCombo < fullComboThreshold)
                     missCount = fullComboThreshold / Math.Max(1.0, scoreMaxCombo);
@@ -392,22 +376,19 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
         private double calculateEstimatedSliderBreaks(double topWeightedSliderFactor, OsuDifficultyAttributes attributes)
         {
-            int nonMissMistakes = countOk + countMeh;
-
-            if (!usingClassicSliderAccuracy || nonMissMistakes == 0)
+            if (!usingClassicSliderAccuracy || countOk == 0)
                 return 0;
 
             double missedComboPercent = 1.0 - (double)scoreMaxCombo / attributes.MaxCombo;
-            double estimatedSliderBreaks = Math.Min(nonMissMistakes, effectiveMissCount * topWeightedSliderFactor);
+            double estimatedSliderBreaks = Math.Min(countOk, effectiveMissCount * topWeightedSliderFactor);
 
-            // 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);
+            // Scores with more Oks are more likely to have slider breaks.
+            double okAdjustment = ((countOk - estimatedSliderBreaks) + 0.5) / countOk;
 
             // 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 * nonMissMistakeAdjustment * DifficultyCalculationUtils.Logistic(missedComboPercent, 0.33, 15);
+            return estimatedSliderBreaks * okAdjustment * DifficultyCalculationUtils.Logistic(missedComboPercent, 0.33, 15);
         }
 
         /// <summary>
@@ -489,7 +470,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             if (speedDeviation == null)
                 return 0;
 
-            double speedValue = HarmonicSkill.DifficultyToPerformance(attributes.SpeedDifficulty);
+            double speedValue = OsuStrainSkill.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.
@@ -508,42 +489,12 @@ 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) => 0.93 / (missCount / (4 * Math.Log(difficultStrainCount)) + 1);
+        private double calculateMissPenalty(double missCount, double difficultStrainCount) => 0.96 / ((missCount / (4 * Math.Pow(Math.Log(difficultStrainCount), 0.94))) + 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 double calculateRateAdjustedApproachRate(double approachRate, double clockRate)
-        {
-            double preempt = IBeatmapDifficultyInfo.DifficultyRange(approachRate, OsuHitObject.PREEMPT_MAX, OsuHitObject.PREEMPT_MID, OsuHitObject.PREEMPT_MIN) / clockRate;
-            return IBeatmapDifficultyInfo.InverseDifficultyRange(preempt, OsuHitObject.PREEMPT_MAX, OsuHitObject.PREEMPT_MID, OsuHitObject.PREEMPT_MIN);
-        }
-
         private int totalHits => countGreat + countOk + countMeh + countMiss;
         private int totalSuccessfulHits => countGreat + countOk + countMeh;
         private int totalImperfectHits => countOk + countMeh + countMiss;

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

@@ -0,0 +1,213 @@
+// 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.Linq;
+using osu.Game.Rulesets.Difficulty.Utils;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Mods;
+
+namespace osu.Game.Rulesets.Osu.Difficulty
+{
+    public class OsuRatingCalculator
+    {
+        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)
+        {
+            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 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;
+
+            return aimRating * Math.Cbrt(ratingMultiplier);
+        }
+
+        public double ComputeSpeedRating(double speedDifficultyValue)
+        {
+            if (mods.Any(m => m is OsuModRelax))
+                return 0;
+
+            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;
+            }
+
+            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);
+
+            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);
+        }
+
+        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.
+            ratingMultiplier *= 0.7 + 0.1 * Math.Min(1.0, totalHits / 200.0) +
+                                (totalHits > 200 ? 0.2 * Math.Min(1.0, (totalHits - 200) / 200.0) : 0.0);
+
+            // It is important to consider accuracy difficulty when scaling with accuracy.
+            ratingMultiplier *= 0.98 + Math.Pow(Math.Max(0, overallDifficulty), 2) / 2500;
+
+            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

@@ -5,7 +5,6 @@ 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;
@@ -36,22 +35,6 @@ 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>
@@ -118,29 +101,15 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
         public double? Angle { get; private set; }
 
         /// <summary>
-        /// Angle of the vector created between current and current-1
-        /// normalised to consider symmetrical vectors in any axis to be the same angle.
+        /// Retrieves the full hit window for a Great <see cref="HitResult"/>.
         /// </summary>
-        public double? NormalisedVectorAngle { get; private set; }
+        public double HitWindowGreat { get; private set; }
 
         /// <summary>
         /// Selective bonus for maps with higher circle size.
         /// </summary>
         public double SmallCircleBonus { get; private set; }
 
-        /// <summary>
-        /// Object's immediate OverallDifficulty value calculated from the raw hitwindow.
-        /// </summary>
-        public double OverallDifficulty
-        {
-            get
-            {
-                double hitWindowGreat = RawHitWindow(HitResult.Great) / ClockRate;
-
-                return (79.5 - hitWindowGreat) / 6;
-            }
-        }
-
         private readonly OsuDifficultyHitObject? lastLastDifficultyObject;
         private readonly OsuDifficultyHitObject? lastDifficultyObject;
 
@@ -152,11 +121,17 @@ 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) / 70);
+            SmallCircleBonus = Math.Max(1.0, 1.0 + (30 - BaseObject.Radius) / 40);
 
-            Preempt = BaseObject.TimePreempt / clockRate;
+            if (BaseObject is Slider sliderObject)
+            {
+                HitWindowGreat = 2 * sliderObject.HeadCircle.HitWindows.WindowFor(HitResult.Great) / clockRate;
+            }
+            else
+            {
+                HitWindowGreat = 2 * BaseObject.HitWindows.WindowFor(HitResult.Great) / clockRate;
+            }
 
             computeSliderCursorPosition();
             setDistances(clockRate);
@@ -173,9 +148,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
             }
 
             double fadeInStartTime = BaseObject.StartTime - BaseObject.TimePreempt;
-
-            // Equal to `OsuHitObject.TimeFadeIn` minus any adjustments from the HD mod.
-            double fadeInDuration = 400 * Math.Min(1, BaseObject.TimePreempt / OsuHitObject.PREEMPT_MIN);
+            double fadeInDuration = BaseObject.TimeFadeIn;
 
             if (hidden)
             {
@@ -202,16 +175,10 @@ 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 / 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));
+                double windowRatio = Math.Pow(Math.Min(1, currDeltaTime / HitWindowGreat), 2);
+                return 1.0 - Math.Pow(speedRatio, 1 - windowRatio);
             }
 
             return 0;
@@ -222,12 +189,10 @@ 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.Max(1, Math.Pow(currentSlider.RepeatCount, 0.3));
+                TravelDistance = LazyTravelDistance * Math.Pow(1 + currentSlider.RepeatCount / 2.5, 1.0 / 2.5);
                 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;
@@ -237,8 +202,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             Vector2 lastCursorPosition = lastDifficultyObject != null ? getEndCursorPosition(lastDifficultyObject) : LastObject.StackedPosition;
 
-            JumpDistance = (LastObject.StackedPosition - BaseObject.StackedPosition).Length * scalingFactor;
-            LazyJumpDistance = (BaseObject.StackedPosition - lastCursorPosition).Length * scalingFactor;
+            LazyJumpDistance = (BaseObject.StackedPosition * scalingFactor - lastCursorPosition * scalingFactor).Length;
+            MinimumJumpTime = AdjustedDeltaTime;
             MinimumJumpDistance = LazyJumpDistance;
 
             if (LastObject is Slider lastSlider && lastDifficultyObject != null)
@@ -274,18 +239,15 @@ 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);
 
-                double angle = calculateAngle(BaseObject.StackedPosition, lastCursorPosition, lastLastCursorPosition);
-                double sliderAngle = calculateSliderAngle(lastDifficultyObject!, lastLastCursorPosition);
+                Vector2 v1 = lastLastCursorPosition - LastObject.StackedPosition;
+                Vector2 v2 = BaseObject.StackedPosition - lastCursorPosition;
 
-                Vector2 v = BaseObject.StackedPosition - lastCursorPosition;
-                NormalisedVectorAngle = Math.Atan2(Math.Abs(v.Y), Math.Abs(v.X));
+                float dot = Vector2.Dot(v1, v2);
+                float det = v1.X * v2.Y - v1.Y * v2.X;
 
-                Angle = Math.Min(angle, sliderAngle);
+                Angle = Math.Abs(Math.Atan2(det, dot));
             }
         }
 
@@ -397,30 +359,6 @@ 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

@@ -4,14 +4,10 @@
 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.Aim;
-using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Osu.Mods;
+using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
+using osu.Game.Rulesets.Osu.Difficulty.Utils;
 using osu.Game.Rulesets.Osu.Objects;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
@@ -19,7 +15,7 @@ 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 : VariableLengthStrainSkill
+    public class Aim : OsuStrainSkill
     {
         public readonly bool IncludeSliders;
 
@@ -31,39 +27,19 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 
         private double currentStrain;
 
-        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 double skillMultiplier => 26;
+        private double strainDecayBase => 0.15;
 
         private readonly List<double> sliderStrains = new List<double>();
 
-        private double strainDecay(double ms) => Math.Pow(0.2, ms / 1000);
+        private double strainDecay(double ms) => Math.Pow(strainDecayBase, 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)
         {
-            if (Mods.Any(m => m is OsuModAutopilot))
-                return 0;
-
-            double decay = strainDecay(((OsuDifficultyHitObject)current).AdjustedDeltaTime);
-
-            currentStrain *= decay;
-            currentStrain += calculateAdjustedDifficulty(current) * (1 - decay);
+            currentStrain *= strainDecay(current.DeltaTime);
+            currentStrain += AimEvaluator.EvaluateDifficultyOf(current, IncludeSliders) * skillMultiplier;
 
             if (current.BaseObject is Slider)
                 sliderStrains.Add(currentStrain);
@@ -71,75 +47,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
             return currentStrain;
         }
 
-        private double calculateAdjustedDifficulty(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;
-            }
-
-            totalDifficulty *= 0.985 + Math.Pow(Math.Max(0, ((OsuDifficultyHitObject)current).OverallDifficulty), 2) / 4000;
-
-            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)
@@ -153,97 +60,6 @@ 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(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);
-        }
+        public double CountTopWeightedSliders() => OsuStrainUtils.CountTopWeightedSliders(sliderStrains, DifficultyValue());
     }
 }

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

@@ -5,10 +5,8 @@ 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.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Mods;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
@@ -18,15 +16,15 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
     /// </summary>
     public class Flashlight : StrainSkill
     {
-        private readonly int totalObjects;
+        private readonly bool hasHiddenMod;
 
-        public Flashlight(Mod[] mods, int totalObjects)
+        public Flashlight(Mod[] mods)
             : base(mods)
         {
-            this.totalObjects = totalObjects;
+            hasHiddenMod = mods.Any(m => m is OsuModHidden);
         }
 
-        private double skillMultiplier => 0.058;
+        private double skillMultiplier => 0.05512;
         private double strainDecayBase => 0.15;
 
         private double currentStrain;
@@ -37,55 +35,13 @@ 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 += calculateAdjustedDifficulty(current) * skillMultiplier;
+            currentStrain += FlashlightEvaluator.EvaluateDifficultyOf(current, hasHiddenMod) * skillMultiplier;
 
             return currentStrain;
         }
 
-        private double calculateAdjustedDifficulty(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;
-
-            difficulty *= 0.985 + Math.Pow(Math.Max(0, ((OsuDifficultyHitObject)current).OverallDifficulty), 2) / 4000;
-
-            return difficulty;
-        }
-
-        public override double DifficultyValue()
-        {
-            double sum = GetCurrentStrainPeaks().Sum();
-
-            // Account for shorter maps having a higher ratio of 0 combo/100 combo flashlight radius.
-            sum *= 0.7 + 0.1 * Math.Min(1.0, totalObjects / 200.0) +
-                   (totalObjects > 200 ? 0.2 * Math.Min(1.0, (totalObjects - 200) / 200.0) : 0.0);
-
-            return sum;
-        }
+        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

@@ -0,0 +1,62 @@
+// 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

@@ -1,124 +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 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.Preprocessing;
-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 += calculateAdjustedDifficulty(current) * (1 - decay) * skillMultiplier;
-
-            return currentStrain;
-        }
-
-        private double calculateAdjustedDifficulty(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;
-
-            difficulty *= 0.825 + Math.Pow(Math.Max(0, ((OsuDifficultyHitObject)current).OverallDifficulty), 2.2) / 1125.0;
-
-            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

@@ -3,33 +3,30 @@
 
 using System;
 using System.Collections.Generic;
-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.Speed;
+using osu.Game.Rulesets.Osu.Difficulty.Evaluators;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
-using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
+using System.Linq;
+using osu.Game.Rulesets.Osu.Difficulty.Utils;
 
 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 : HarmonicSkill
+    public class Speed : OsuStrainSkill
     {
-        private double skillMultiplier => 1.16;
+        private double skillMultiplier => 1.47;
+        private double strainDecayBase => 0.3;
+
+        private double currentStrain;
+        private double currentRhythm;
 
         private readonly List<double> sliderStrains = new List<double>();
 
-        private double currentStrain;
-
-        private double strainDecayBase => 0.3;
-
-        protected override double HarmonicScale => 20;
-        protected override double DecayExponent => 0.9;
+        protected override int ReducedSectionCount => 5;
 
         public Speed(Mod[] mods)
             : base(mods)
@@ -38,17 +35,14 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 
         private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
 
-        protected override double ObjectDifficultyOf(DifficultyHitObject current)
+        protected override double CalculateInitialStrain(double time, DifficultyHitObject current) => (currentStrain * currentRhythm) * strainDecay(time - current.Previous(0).StartTime);
+
+        protected override double StrainValueAt(DifficultyHitObject current)
         {
-            if (Mods.Any(m => m is OsuModRelax))
-                return 0;
+            currentStrain *= strainDecay(((OsuDifficultyHitObject)current).AdjustedDeltaTime);
+            currentStrain += SpeedEvaluator.EvaluateDifficultyOf(current, Mods) * skillMultiplier;
 
-            double decay = strainDecay(((OsuDifficultyHitObject)current).AdjustedDeltaTime);
-
-            currentStrain *= decay;
-            currentStrain += calculateAdjustedDifficulty(current) * (1 - decay) * skillMultiplier;
-
-            double currentRhythm = RhythmEvaluator.EvaluateDifficultyOf(current);
+            currentRhythm = RhythmEvaluator.EvaluateDifficultyOf(current);
 
             double totalStrain = currentStrain * currentRhythm;
 
@@ -58,44 +52,18 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
             return totalStrain;
         }
 
-        private double calculateAdjustedDifficulty(DifficultyHitObject current)
-        {
-            double difficulty = SpeedEvaluator.EvaluateDifficultyOf(current);
-
-            if (Mods.Any(m => m is OsuModAutopilot))
-                difficulty *= 0.5;
-
-            return difficulty;
-        }
-
         public double RelevantNoteCount()
         {
-            if (ObjectDifficulties.Count == 0)
+            if (ObjectStrains.Count == 0)
                 return 0;
 
-            double maxStrain = ObjectDifficulties.Max();
-
+            double maxStrain = ObjectStrains.Max();
             if (maxStrain == 0)
                 return 0;
 
-            return ObjectDifficulties.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxStrain * 12.0 - 6.0))));
+            return ObjectStrains.Sum(strain => 1.0 / (1.0 + Math.Exp(-(strain / maxStrain * 12.0 - 6.0))));
         }
 
-        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));
-        }
+        public double CountTopWeightedSliders() => OsuStrainUtils.CountTopWeightedSliders(sliderStrains, DifficultyValue());
     }
 }

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

@@ -0,0 +1,26 @@
+// 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.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs

@@ -54,6 +54,9 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
         [Resolved]
         private EditorClock? editorClock { get; set; }
 
+        [Resolved]
+        private OsuSliderVelocityToolboxGroup? sliderVelocityToolbox { get; set; }
+
         private Bindable<bool> limitedDistanceSnap { get; set; } = null!;
 
         private readonly IncrementalBSplineBuilder bSplineBuilder = new IncrementalBSplineBuilder { Degree = 4 };
@@ -111,9 +114,6 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
             }
         }
 
-        [Resolved]
-        private EditorBeatmap editorBeatmap { get; set; } = null!;
-
         public override SnapResult UpdateTimeAndPosition(Vector2 screenSpacePosition, double fallbackTime)
         {
             var result = composer?.TrySnapToNearbyObjects(screenSpacePosition, fallbackTime);
@@ -129,11 +129,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
                 case SliderPlacementState.Initial:
                     BeginPlacement();
 
-                    double? nearestSliderVelocity = (editorBeatmap
-                                                     .HitObjects
-                                                     .LastOrDefault(h => h is Slider && h.GetEndTime() < HitObject.StartTime) as Slider)?.SliderVelocityMultiplier;
-
-                    HitObject.SliderVelocityMultiplier = nearestSliderVelocity ?? 1;
+                    HitObject.SliderVelocityMultiplier = sliderVelocityToolbox?.SliderVelocity.Value ?? 1;
                     HitObject.Position = ToLocalSpace(result.ScreenSpacePosition);
 
                     // Replacing the DifficultyControlPoint above doesn't trigger any kind of invalidation.

osu.Game.Rulesets.Osu/Edit/FreehandSliderToolboxGroup.cs

@@ -15,7 +15,7 @@ namespace osu.Game.Rulesets.Osu.Edit
     public partial class FreehandSliderToolboxGroup : EditorToolboxGroup
     {
         public FreehandSliderToolboxGroup()
-            : base("slider")
+            : base("freehand")
         {
         }
 

osu.Game.Rulesets.Osu/Edit/HitCircleCompositionTool.cs

@@ -7,14 +7,13 @@ using osu.Game.Graphics;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles;
-using osu.Game.Rulesets.Osu.Objects;
 
 namespace osu.Game.Rulesets.Osu.Edit
 {
     public class HitCircleCompositionTool : CompositionTool
     {
         public HitCircleCompositionTool()
-            : base(nameof(HitCircle))
+            : base("Hit circle")
         {
         }
 

osu.Game.Rulesets.Osu/Edit/OsuHitObjectComposer.cs

@@ -75,6 +75,9 @@ namespace osu.Game.Rulesets.Osu.Edit
         [Cached(typeof(IDistanceSnapProvider))]
         public readonly OsuDistanceSnapProvider DistanceSnapProvider = new OsuDistanceSnapProvider();
 
+        [Cached]
+        private readonly OsuSliderVelocityToolboxGroup sliderVelocityToolboxGroup = new OsuSliderVelocityToolboxGroup();
+
         [Cached]
         protected readonly OsuGridToolboxGroup OsuGridToolboxGroup = new OsuGridToolboxGroup();
 
@@ -111,6 +114,7 @@ namespace osu.Game.Rulesets.Osu.Edit
 
             RightToolbox.AddRange(new Drawable[]
                 {
+                    sliderVelocityToolboxGroup,
                     OsuGridToolboxGroup,
                     new TransformToolboxGroup
                     {

osu.Game.Rulesets.Osu/Edit/OsuSliderVelocityToolboxGroup.cs

@@ -0,0 +1,213 @@
+// 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.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Caching;
+using osu.Framework.Extensions.LocalisationExtensions;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Localisation;
+using osu.Game.Graphics.UserInterface;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Screens.Edit;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public partial class OsuSliderVelocityToolboxGroup : EditorToolboxGroup
+    {
+        /// <summary>
+        /// Whether the last slider's velocity should be used (if available).
+        /// </summary>
+        private bool useLastSliderVelocity;
+
+        /// <summary>
+        /// The slider velocity to be used for new object placements.
+        /// </summary>
+        public IBindable<double> SliderVelocity => sliderVelocity;
+
+        private readonly BindableDouble sliderVelocity = new BindableDouble(1)
+        {
+            Precision = 0.01,
+            MinValue = 0.1,
+            MaxValue = 10,
+        };
+
+        private ExpandableSlider<double> slider = null!;
+        private ExpandableButton useLastSliderButton = null!;
+
+        [Resolved]
+        private EditorBeatmap editorBeatmap { get; set; } = null!;
+
+        [Resolved]
+        private EditorClock editorClock { get; set; } = null!;
+
+        private bool syncingBindables;
+        private double lastClockPosition = double.NegativeInfinity;
+        private readonly Cached<Slider?> sliderVelocitySourceObject = new Cached<Slider?>();
+
+        public OsuSliderVelocityToolboxGroup()
+            : base("velocity")
+        {
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Spacing = new Vector2(5);
+            Children = new Drawable[]
+            {
+                slider = new ExpandableSlider<double>
+                {
+                    ExpandedLabelText = "Slider velocity",
+                    Current = new BindableDouble(1)
+                    {
+                        Precision = 0.01,
+                        MinValue = 0.1,
+                        MaxValue = 10,
+                    },
+                    KeyboardStep = 0.1f,
+                },
+                useLastSliderButton = new ExpandableButton
+                {
+                    RelativeSizeAxes = Axes.X,
+                    Action = () =>
+                    {
+                        useLastSliderVelocity = true;
+                        sliderVelocitySourceObject.Invalidate();
+                    },
+                }
+            };
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            // set unconditionally to true initially.
+            // if there is no object available to get the slider velocity from, the code in `Update()` will handle that.
+            useLastSliderVelocity = true;
+
+            sliderVelocity.BindValueChanged(_ => updateSliderFromVelocity(), true);
+            slider.Current.BindValueChanged(_ =>
+            {
+                updateVelocityFromSlider();
+                updateContractedText();
+            });
+            updateContractedText();
+            useLastSliderButton.Expanded.BindValueChanged(_ => sliderVelocitySourceObject.Invalidate());
+
+            editorBeatmap.HitObjectAdded += invalidateSliderVelocitySourceObject;
+            editorBeatmap.HitObjectUpdated += invalidateSliderVelocitySourceObject;
+            editorBeatmap.HitObjectRemoved += invalidateSliderVelocitySourceObject;
+        }
+
+        private void updateContractedText()
+        {
+            slider.ContractedLabelText = LocalisableString.Interpolate($@"SV: {slider.Current.Value.ToLocalisableString("N2")}x");
+        }
+
+        /// <summary>
+        /// Updates the displayed value of this toolbox's slider from a change to <see cref="SliderVelocity"/>
+        /// (which is the source-of-truth used for new object placements).
+        /// This is only relevant when <see cref="useLastSliderVelocity"/> is true,
+        /// in which case this code is responsible for propagating the velocity from <see cref="sliderVelocitySourceObject"/> to the slider.
+        /// </summary>
+        private void updateSliderFromVelocity()
+        {
+            if (syncingBindables)
+                return;
+
+            if (!useLastSliderVelocity)
+                return;
+
+            syncingBindables = true;
+            slider.Current.Value = sliderVelocity.Value;
+            syncingBindables = false;
+        }
+
+        /// <summary>
+        /// Updates the value of <see cref="SliderVelocity"/> from a change to the slider's state.
+        /// This change is assumed to be user-provoked, and therefore <see cref="useLastSliderVelocity"/> is switched unconditionally off
+        /// as the presumed intent is to override the velocity from <see cref="sliderVelocitySourceObject"/>.
+        /// </summary>
+        private void updateVelocityFromSlider()
+        {
+            if (syncingBindables)
+                return;
+
+            syncingBindables = true;
+            useLastSliderVelocity = false;
+            sliderVelocity.Value = slider.Current.Value;
+            syncingBindables = false;
+            sliderVelocitySourceObject.Invalidate();
+        }
+
+        private void invalidateSliderVelocitySourceObject(HitObject _) => sliderVelocitySourceObject.Invalidate();
+
+        protected override void Update()
+        {
+            base.Update();
+
+            if (editorClock.CurrentTime != lastClockPosition)
+            {
+                sliderVelocitySourceObject.Invalidate();
+                lastClockPosition = editorClock.CurrentTime;
+            }
+
+            // Three possible causes of invalidation:
+            // - The user seeked the clock, which means a different velocity source object needs to be used.
+            // - Some change to the beatmap was made, which means the previously-used velocity source object may no longer be the most relevant one.
+            // - The user is interacting with the toolbox in a way that requires a visual state update
+            //   (hovered to expand it, clicked the button to use last slider's velocity, or dragged the manual velocity slider).
+            //   This is a procedural one, because `sliderVelocitySourceObject` will have been pointing at the correct object already,
+            //   but to decrease unnecessary work being done every frame, the invalidation is explicitly re-triggered to update the toolbox state.
+            if (!sliderVelocitySourceObject.IsValid)
+            {
+                var lastSlider = getLastSlider();
+                sliderVelocitySourceObject.Value = lastSlider;
+
+                if (lastSlider == null)
+                {
+                    useLastSliderButton.Enabled.Value = false;
+                    useLastSliderButton.ExpandedLabelText = "No sliders to get velocity from";
+                    useLastSliderButton.ContractedLabelText = default;
+                }
+                else
+                {
+                    useLastSliderButton.Enabled.Value = useLastSliderButton.Expanded.Value && !useLastSliderVelocity;
+                    useLastSliderButton.ExpandedLabelText = useLastSliderVelocity
+                        ? "Using last slider's velocity"
+                        : LocalisableString.Interpolate($@"Use last slider's velocity ({lastSlider.SliderVelocityMultiplier.ToLocalisableString("N2")}x)");
+                    useLastSliderButton.ContractedLabelText = $@"current {lastSlider.SliderVelocityMultiplier.ToLocalisableString("N2")}x";
+                    if (useLastSliderVelocity)
+                        sliderVelocity.Value = lastSlider.SliderVelocityMultiplier;
+                }
+            }
+        }
+
+        private Slider? getLastSlider()
+        {
+            return editorBeatmap
+                   .HitObjects
+                   .OfType<Slider>()
+                   .LastOrDefault(h => h.StartTime <= editorClock.CurrentTime);
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            if (editorBeatmap.IsNotNull())
+            {
+                editorBeatmap.HitObjectAdded -= invalidateSliderVelocitySourceObject;
+                editorBeatmap.HitObjectUpdated -= invalidateSliderVelocitySourceObject;
+                editorBeatmap.HitObjectRemoved -= invalidateSliderVelocitySourceObject;
+            }
+
+            base.Dispose(isDisposing);
+        }
+    }
+}

osu.Game.Rulesets.Osu/Mods/InputBlockingMod.cs

@@ -21,7 +21,6 @@ namespace osu.Game.Rulesets.Osu.Mods
 {
     public abstract partial class InputBlockingMod : Mod, IApplicableToDrawableRuleset<OsuHitObject>, IUpdatableByPlayfield
     {
-        public override double ScoreMultiplier => 1.0;
         public override Type[] IncompatibleMods => new[] { typeof(ModAutoplay), typeof(ModRelax), typeof(OsuModCinema) };
         public override ModType Type => ModType.Conversion;
 

osu.Game.Rulesets.Osu/Mods/OsuModApproachDifferent.cs

@@ -19,7 +19,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override string Name => "Approach Different";
         public override string Acronym => "AD";
         public override LocalisableString Description => "Never trust the approach circles...";
-        public override double ScoreMultiplier => 1;
         public override IconUsage? Icon => OsuIcon.ModApproachDifferent;
 
         public override Type[] IncompatibleMods => new[] { typeof(IHidesApproachCircles), typeof(OsuModFreezeFrame) };

osu.Game.Rulesets.Osu/Mods/OsuModAutopilot.cs

@@ -23,7 +23,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModAutopilot;
         public override ModType Type => ModType.Automation;
         public override LocalisableString Description => @"Automatic cursor movement - just follow the rhythm.";
-        public override double ScoreMultiplier => 0.1;
 
         public override Type[] IncompatibleMods => new[]
         {

osu.Game.Rulesets.Osu/Mods/OsuModBlinds.cs

@@ -30,7 +30,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModBlinds;
         public override ModType Type => ModType.DifficultyIncrease;
 
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.12 : 1;
         public override Type[] IncompatibleMods => new[] { typeof(OsuModFlashlight) };
         public override bool Ranked => true;
 

osu.Game.Rulesets.Osu/Mods/OsuModBloom.cs

@@ -26,7 +26,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModBloom;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "The cursor blooms into.. a larger cursor!";
-        public override double ScoreMultiplier => 1;
         protected const float MIN_SIZE = 1;
         protected const float TRANSITION_DURATION = 100;
         public override Type[] IncompatibleMods => new[] { typeof(OsuModFlashlight), typeof(OsuModNoScope), typeof(ModTouchDevice) };

osu.Game.Rulesets.Osu/Mods/OsuModBubbles.cs

@@ -34,8 +34,6 @@ namespace osu.Game.Rulesets.Osu.Mods
 
         public override LocalisableString Description => "Don't let their popping distract you!";
 
-        public override double ScoreMultiplier => 1;
-
         public override IconUsage? Icon => OsuIcon.ModBubbles;
 
         public override ModType Type => ModType.Fun;

osu.Game.Rulesets.Osu/Mods/OsuModDepth.cs

@@ -25,7 +25,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModDepth;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "3D. Almost.";
-        public override double ScoreMultiplier => 1;
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModMagnetised), typeof(OsuModRepel), typeof(OsuModFreezeFrame), typeof(ModWithVisibilityAdjustment) }).ToArray();
 
         private static readonly Vector3 camera_position = new Vector3(OsuPlayfield.BASE_SIZE.X * 0.5f, OsuPlayfield.BASE_SIZE.Y * 0.5f, -200);

osu.Game.Rulesets.Osu/Mods/OsuModFlashlight.cs

@@ -19,7 +19,6 @@ namespace osu.Game.Rulesets.Osu.Mods
 {
     public partial class OsuModFlashlight : ModFlashlight<OsuHitObject>, IApplicableToDrawableHitObject
     {
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.12 : 1;
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModBloom), typeof(OsuModBlinds) }).ToArray();
 
         private const double default_follow_delay = 120;

osu.Game.Rulesets.Osu/Mods/OsuModFreezeFrame.cs

@@ -23,8 +23,6 @@ namespace osu.Game.Rulesets.Osu.Mods
 
         public override IconUsage? Icon => OsuIcon.ModFreezeFrame;
 
-        public override double ScoreMultiplier => 1;
-
         public override LocalisableString Description => "Burn the notes into your memory.";
 
         /// <remarks>

osu.Game.Rulesets.Osu/Mods/OsuModHardRock.cs

@@ -13,8 +13,6 @@ namespace osu.Game.Rulesets.Osu.Mods
 {
     public class OsuModHardRock : ModHardRock, IApplicableToHitObject
     {
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.06 : 1;
-
         public override Type[] IncompatibleMods => base.IncompatibleMods.Append(typeof(ModMirror)).ToArray();
 
         public void ApplyToHitObject(HitObject hitObject)

osu.Game.Rulesets.Osu/Mods/OsuModHidden.cs

@@ -24,7 +24,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public Bindable<bool> OnlyFadeApproachCircles { get; } = new BindableBool();
 
         public override LocalisableString Description => @"Play with no approach circles and fading circles/sliders.";
-        public override double ScoreMultiplier => UsesDefaultConfiguration ? 1.06 : 1;
 
         public override Type[] IncompatibleMods => new[] { typeof(IRequiresApproachCircles), typeof(OsuModSpinIn), typeof(OsuModDepth), typeof(OsuModFreezeFrame) };
 

osu.Game.Rulesets.Osu/Mods/OsuModMagnetised.cs

@@ -27,7 +27,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModMagnetised;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "No need to chase the circles – your cursor is a magnet!";
-        public override double ScoreMultiplier => 0.5;
         public override Type[] IncompatibleMods => new[] { typeof(OsuModAutopilot), typeof(OsuModWiggle), typeof(OsuModTransform), typeof(ModAutoplay), typeof(OsuModRelax), typeof(OsuModRepel), typeof(OsuModBubbles), typeof(OsuModDepth) };
 
         [SettingSource("Attraction strength", "How strong the pull is.", 0)]

osu.Game.Rulesets.Osu/Mods/OsuModObjectScaleTween.cs

@@ -19,8 +19,6 @@ namespace osu.Game.Rulesets.Osu.Mods
     {
         public override ModType Type => ModType.Fun;
 
-        public override double ScoreMultiplier => 1;
-
         [SettingSource("Starting Size", "The initial size multiplier applied to all objects.")]
         public abstract BindableNumber<float> StartScale { get; }
 

osu.Game.Rulesets.Osu/Mods/OsuModRepel.cs

@@ -28,7 +28,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModRepel;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "Hit objects run away!";
-        public override double ScoreMultiplier => 1;
         public override Type[] IncompatibleMods => new[] { typeof(OsuModAutopilot), typeof(OsuModWiggle), typeof(OsuModTransform), typeof(ModAutoplay), typeof(OsuModMagnetised), typeof(OsuModBubbles), typeof(OsuModDepth) };
 
         [SettingSource("Repulsion strength", "How strong the repulsion is.", 0)]

osu.Game.Rulesets.Osu/Mods/OsuModSpinIn.cs

@@ -21,7 +21,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModSpinIn;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "Circles spin in. No approach circles.";
-        public override double ScoreMultiplier => 1;
 
         // todo: this mod needs to be incompatible with "hidden" due to forcing the circle to remain opaque,
         // further implementation will be required for supporting that.

osu.Game.Rulesets.Osu/Mods/OsuModSpunOut.cs

@@ -20,7 +20,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModSpunOut;
         public override ModType Type => ModType.Automation;
         public override LocalisableString Description => @"Spinners will be automatically completed.";
-        public override double ScoreMultiplier => 0.9;
         public override Type[] IncompatibleMods => new[] { typeof(ModAutoplay), typeof(OsuModAutopilot), typeof(OsuModTargetPractice) };
         public override bool Ranked => UsesDefaultConfiguration;
 

osu.Game.Rulesets.Osu/Mods/OsuModStrictTracking.cs

@@ -29,7 +29,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModStrictTracking;
         public override ModType Type => ModType.DifficultyIncrease;
         public override LocalisableString Description => @"Once you start a slider, follow precisely or get a miss.";
-        public override double ScoreMultiplier => 1.0;
         public override Type[] IncompatibleMods => new[] { typeof(ModClassic), typeof(OsuModTargetPractice) };
 
         public void ApplyToDrawableHitObject(DrawableHitObject drawable)

osu.Game.Rulesets.Osu/Mods/OsuModTargetPractice.cs

@@ -39,7 +39,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override ModType Type => ModType.Conversion;
         public override IconUsage? Icon => OsuIcon.ModTargetPractice;
         public override LocalisableString Description => @"Practice keeping up with the beat of the song.";
-        public override double ScoreMultiplier => 0.1;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[]
         {

osu.Game.Rulesets.Osu/Mods/OsuModTraceable.cs

@@ -23,7 +23,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModTraceable;
         public override ModType Type => ModType.DifficultyIncrease;
         public override LocalisableString Description => "Put your faith in the approach circles...";
-        public override double ScoreMultiplier => 1;
         public override bool Ranked => true;
 
         public override Type[] IncompatibleMods => new[] { typeof(IHidesApproachCircles), typeof(OsuModDepth) };

osu.Game.Rulesets.Osu/Mods/OsuModTransform.cs

@@ -22,7 +22,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModTransform;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "Everything rotates. EVERYTHING.";
-        public override double ScoreMultiplier => 1;
         public override Type[] IncompatibleMods => base.IncompatibleMods.Concat(new[] { typeof(OsuModWiggle), typeof(OsuModMagnetised), typeof(OsuModRepel), typeof(OsuModFreezeFrame), typeof(OsuModDepth) }).ToArray();
 
         private float theta;

osu.Game.Rulesets.Osu/Mods/OsuModWiggle.cs

@@ -23,7 +23,6 @@ namespace osu.Game.Rulesets.Osu.Mods
         public override IconUsage? Icon => OsuIcon.ModWiggle;
         public override ModType Type => ModType.Fun;
         public override LocalisableString Description => "They just won't stay still...";
-        public override double ScoreMultiplier => 1;
         public override Type[] IncompatibleMods => new[] { typeof(OsuModTransform), typeof(OsuModMagnetised), typeof(OsuModRepel), typeof(OsuModDepth) };
 
         private const int wiggle_duration = 100; // (ms) Higher = fewer wiggles