Merge pull request #15307 from peppy/playlist-remaining-attempt-display

Show remaining attempts again on playlist screen

.editorconfig

@@ -113,7 +113,7 @@ dotnet_style_qualification_for_event = false:warning
 dotnet_style_predefined_type_for_locals_parameters_members = true:warning
 dotnet_style_predefined_type_for_member_access = true:warning
 csharp_style_var_when_type_is_apparent = true:none
-csharp_style_var_for_built_in_types = true:none
+csharp_style_var_for_built_in_types = false:warning
 csharp_style_var_elsewhere = true:silent
 
 #Style - modifiers

.github/FUNDING.yml

@@ -1 +1,2 @@
+github: ppy
 custom: https://osu.ppy.sh/home/support

.github/ISSUE_TEMPLATE/01-bug-issues.md

@@ -1,30 +0,0 @@
----
-name: Bug Report
-about: Report a bug or crash to desktop
----
-
-<!--
-IMPORTANT: Your issue may already be reported.
-
-Please check:
-- Pinned issues, at the top of https://github.com/ppy/osu/issues
-- Current priority 0 issues at https://github.com/ppy/osu/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3Apriority%3A0
-- Search for your issue. If you find that it already exists, please respond with a reaction or add any further information that may be helpful.
--->
-
-
-**Describe the bug:** 
-
-**Screenshots or videos showing encountered issue:** 
-
-**osu!lazer version:** 
-
-**Logs:**
-
-<!--
-*please attach logs here, which are located at:*
-- `%AppData%/osu/logs` *(on Windows),*
-- `~/.local/share/osu/logs` *(on Linux & macOS).*
-- `Android/data/sh.ppy.osulazer/files/logs` *(on Android)*,
-- on iOS they can be obtained by connecting your device to your desktop and copying the `logs` directory from the app's own document storage using iTunes. (https://support.apple.com/en-us/HT201301#copy-to-computer)
--->

.github/ISSUE_TEMPLATE/config.yml

@@ -1,12 +1,12 @@
 blank_issues_enabled: false
 contact_links:
-    - name: Suggestions or feature request
-      url: https://github.com/ppy/osu/discussions/categories/ideas
-      about: Got something you think should change or be added? Search for or start a new discussion!
     - name: Help
       url: https://github.com/ppy/osu/discussions/categories/q-a
       about: osu! not working as you'd expect? Not sure it's a bug? Check the Q&A section!
+    - name: Suggestions or feature request
+      url: https://github.com/ppy/osu/discussions/categories/ideas
+      about: Got something you think should change or be added? Search for or start a new discussion!
     - name: osu!stable issues
       url: https://github.com/ppy/osu-stable-issues
-      about: For osu!stable bugs (not osu!lazer), check out the dedicated repository. Note that we only accept serious bug reports.
+      about: For osu!(stable) - ie. the current "live" game version, check out the dedicated repository. Note that this is for serious bug reports only, not tech support.
 

.github/workflows/ci.yml

@@ -50,6 +50,48 @@ jobs:
           name: osu-test-results-${{matrix.os.prettyname}}-${{matrix.threadingMode}}
           path: ${{github.workspace}}/TestResults/TestResults-${{matrix.os.prettyname}}-${{matrix.threadingMode}}.trx
 
+  build-only-android:
+    name: Build only (Android)
+    runs-on: windows-latest
+    timeout-minutes: 60
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      - name: Setup MSBuild
+        uses: microsoft/setup-msbuild@v1
+
+      - name: Build
+        run: msbuild osu.Android.slnf /restore /p:Configuration=Debug
+
+  build-only-ios:
+    # While this workflow technically *can* run, it fails as iOS builds are blocked by multiple issues.
+    # See https://github.com/ppy/osu-framework/issues/4677 for the details.
+    # The job can be unblocked once those issues are resolved and game deployments can happen again.
+    if: false
+    name: Build only (iOS)
+    runs-on: macos-latest
+    timeout-minutes: 60
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Install .NET 5.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      # Contrary to seemingly any other msbuild, msbuild running on macOS/Mono
+      # cannot accept .sln(f) files as arguments.
+      # Build just the main game for now.
+      - name: Build
+        run: msbuild osu.iOS/osu.iOS.csproj /restore /p:Configuration=Debug
+
   inspect-code:
     name: Code Quality
     runs-on: ubuntu-latest
@@ -79,9 +121,14 @@ jobs:
         run: |
           # TODO: Add ignore filters and GitHub Workflow Command Reporting in CFS. That way we don't have to do this workaround.
           # FIXME: Suppress warnings from templates project
-          dotnet codefilesanity | while read -r line; do
-            echo "::warning::$line"
-          done
+          exit_code=0
+          while read -r line; do
+            if [[ ! -z "$line" ]]; then
+              echo "::error::$line"
+              exit_code=1
+            fi
+          done <<< $(dotnet codefilesanity)
+          exit $exit_code
 
       # Temporarily disabled due to test failures, but it won't work anyway until the tool is upgraded.
       # - name: .NET Format (Dry Run)

.github/workflows/diffcalc.yml

@@ -0,0 +1,206 @@
+# Listens for new PR comments containing !pp check [id], and runs a diffcalc comparison against master.
+# Usage:
+#   !pp check 0        | Runs only the osu! ruleset.
+#   !pp check 0 2      | Runs only the osu! and catch rulesets.
+#
+
+name: Difficulty Calculation
+on:
+  issue_comment:
+    types: [ created ]
+
+env:
+  CONCURRENCY: 4
+  ALLOW_DOWNLOAD: 1
+  SAVE_DOWNLOADED: 1
+  SKIP_INSERT_ATTRIBUTES: 1
+
+jobs:
+  metadata:
+    name: Check for requests
+    runs-on: self-hosted
+    if: github.event.issue.pull_request && contains(github.event.comment.body, '!pp check') && (github.event.comment.author_association == 'MEMBER' || github.event.comment.author_association == 'OWNER')
+    outputs:
+      matrix: ${{ steps.generate-matrix.outputs.matrix }}
+      continue: ${{ steps.generate-matrix.outputs.continue }}
+    steps:
+      - name: Construct build matrix
+        id: generate-matrix
+        run: |
+          if [[ "${{ github.event.comment.body }}" =~ "osu" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "osu", "id": 0 },'
+          fi
+          if [[ "${{ github.event.comment.body }}" =~ "taiko" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "taiko", "id": 1 },'
+          fi
+          if [[ "${{ github.event.comment.body }}" =~ "catch" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "catch", "id": 2 },'
+          fi
+          if [[ "${{ github.event.comment.body }}" =~ "mania" ]] ; then
+            MATRIX_PROJECTS_JSON+='{ "name": "mania", "id": 3 },'
+          fi
+
+          if [[ "${MATRIX_PROJECTS_JSON}" != "" ]]; then
+            MATRIX_JSON="{ \"ruleset\": [ ${MATRIX_PROJECTS_JSON} ] }"
+            echo "${MATRIX_JSON}"
+            CONTINUE="yes"
+          else
+            CONTINUE="no"
+          fi
+
+          echo "::set-output name=continue::${CONTINUE}"
+          echo "::set-output name=matrix::${MATRIX_JSON}"
+  diffcalc:
+    name: Run
+    runs-on: self-hosted
+    timeout-minutes: 1440
+    if: needs.metadata.outputs.continue == 'yes'
+    needs: metadata
+    strategy:
+      matrix: ${{ fromJson(needs.metadata.outputs.matrix) }}
+    steps:
+      - name: Verify MySQL connection from host
+        run: |
+          mysql -e "SHOW DATABASES"
+
+      - name: Drop previous databases
+        run: |
+          for db in osu_master osu_pr
+          do
+            mysql -e "DROP DATABASE IF EXISTS $db"
+          done
+
+      - name: Create directory structure
+        run: |
+          mkdir -p $GITHUB_WORKSPACE/master/
+          mkdir -p $GITHUB_WORKSPACE/pr/
+
+      - name: Get upstream branch # https://akaimo.hatenablog.jp/entry/2020/05/16/101251
+        id: upstreambranch
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          echo "::set-output name=branchname::$(curl -H "Authorization: token ${GITHUB_TOKEN}" ${{ github.event.issue.pull_request.url }} | jq '.head.ref' | sed 's/\"//g')"
+          echo "::set-output name=repo::$(curl -H "Authorization: token ${GITHUB_TOKEN}" ${{ github.event.issue.pull_request.url }} | jq '.head.repo.full_name' | sed 's/\"//g')"
+
+      # Checkout osu
+      - name: Checkout osu (master)
+        uses: actions/checkout@v2
+        with:
+          path: 'master/osu'
+      - name: Checkout osu (pr)
+        uses: actions/checkout@v2
+        with:
+          path: 'pr/osu'
+          repository: ${{ steps.upstreambranch.outputs.repo }}
+          ref: ${{ steps.upstreambranch.outputs.branchname }}
+
+      - name: Checkout osu-difficulty-calculator (master)
+        uses: actions/checkout@v2
+        with:
+          repository: ppy/osu-difficulty-calculator
+          path: 'master/osu-difficulty-calculator'
+      - name: Checkout osu-difficulty-calculator (pr)
+        uses: actions/checkout@v2
+        with:
+          repository: ppy/osu-difficulty-calculator
+          path: 'pr/osu-difficulty-calculator'
+
+      - name: Install .NET 5.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "5.0.x"
+
+      # Sanity checks to make sure diffcalc is not run when incompatible.
+      - name: Build diffcalc (master)
+        run: |
+          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator
+          ./UseLocalOsu.sh
+          dotnet build
+      - name: Build diffcalc (pr)
+        run: |
+          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator
+          ./UseLocalOsu.sh
+          dotnet build
+
+      - name: Download + import data
+        run: |
+          PERFORMANCE_DATA_NAME=$(curl https://data.ppy.sh/ | grep performance_${{ matrix.ruleset.name }}_top_1000 | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
+          BEATMAPS_DATA_NAME=$(curl https://data.ppy.sh/ | grep osu_files | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
+
+          # Set env variable for further steps.
+          echo "BEATMAPS_PATH=$GITHUB_WORKSPACE/$BEATMAPS_DATA_NAME" >> $GITHUB_ENV
+
+          cd $GITHUB_WORKSPACE
+
+          echo "Downloading database dump $PERFORMANCE_DATA_NAME.."
+          wget -q -nc https://data.ppy.sh/$PERFORMANCE_DATA_NAME.tar.bz2
+          echo "Extracting.."
+          tar -xf $PERFORMANCE_DATA_NAME.tar.bz2
+
+          echo "Downloading beatmap dump $BEATMAPS_DATA_NAME.."
+          wget -q -nc https://data.ppy.sh/$BEATMAPS_DATA_NAME.tar.bz2
+          echo "Extracting.."
+          tar -xf $BEATMAPS_DATA_NAME.tar.bz2
+
+          cd $PERFORMANCE_DATA_NAME
+
+          for db in osu_master osu_pr
+          do
+            echo "Setting up database $db.."
+
+            mysql -e "CREATE DATABASE $db"
+
+            echo "Importing beatmaps.."
+            cat osu_beatmaps.sql | mysql $db
+            echo "Importing beatmapsets.."
+            cat osu_beatmapsets.sql | mysql $db
+
+            echo "Creating table structure.."
+            mysql $db -e 'CREATE TABLE `osu_beatmap_difficulty` (
+                `beatmap_id` int unsigned NOT NULL,
+                `mode` tinyint NOT NULL DEFAULT 0,
+                `mods` int unsigned NOT NULL,
+                `diff_unified` float NOT NULL,
+                `last_update` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+                PRIMARY KEY (`beatmap_id`,`mode`,`mods`),
+                KEY `diff_sort` (`mode`,`mods`,`diff_unified`)
+              ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;'
+          done
+
+      - name: Run diffcalc (master)
+        env:
+          DB_NAME: osu_master
+        run: |
+          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator/osu.Server.DifficultyCalculator
+          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
+      - name: Run diffcalc (pr)
+        env:
+          DB_NAME: osu_pr
+        run: |
+          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator/osu.Server.DifficultyCalculator
+          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
+
+      - name: Print diffs
+        run: |
+          mysql -e "
+            SELECT
+              m.beatmap_id,
+              m.mods,
+              b.filename,
+              m.diff_unified as 'sr_master',
+              p.diff_unified as 'sr_pr',
+              (p.diff_unified - m.diff_unified) as 'diff'
+            FROM osu_master.osu_beatmap_difficulty m
+            JOIN osu_pr.osu_beatmap_difficulty p
+              ON m.beatmap_id = p.beatmap_id
+              AND m.mode = p.mode
+              AND m.mods = p.mods
+            JOIN osu_pr.osu_beatmaps b
+              ON b.beatmap_id = p.beatmap_id
+            WHERE abs(m.diff_unified - p.diff_unified) > 0.1
+            ORDER BY abs(m.diff_unified - p.diff_unified)
+              DESC
+            LIMIT 10000;"
+
+      # Todo: Run ppcalc

.github/workflows/report-nunit.yml

@@ -30,3 +30,5 @@ jobs:
           name: Test Results (${{matrix.os.prettyname}}, ${{matrix.threadingMode}})
           path: "*.trx"
           reporter: dotnet-trx
+          list-suites: 'failed'
+          list-tests: 'failed'

.github/workflows/test-diffcalc.yml

@@ -1,163 +0,0 @@
-# Listens for new PR comments containing !pp check [id], and runs a diffcalc comparison against master.
-# Usage:
-#   !pp check 0        | Runs only the osu! ruleset.
-#   !pp check 0 2      | Runs only the osu! and catch rulesets.
-#
-
-name: Diffcalc Consistency Checks
-on:
-  issue_comment:
-    types: [ created ]
-
-env:
-  DB_USER: root
-  DB_HOST: 127.0.0.1
-  CONCURRENCY: 4
-  ALLOW_DOWNLOAD: 1
-  SAVE_DOWNLOADED: 1
-
-jobs:
-  diffcalc:
-    name: Diffcalc
-    runs-on: ubuntu-latest
-    continue-on-error: true
-
-    if: |
-      github.event.issue.pull_request &&
-      contains(github.event.comment.body, '!pp check') &&
-      (github.event.comment.author_association == 'MEMBER' || github.event.comment.author_association == 'OWNER')
-
-    strategy:
-      fail-fast: false
-      matrix:
-        ruleset:
-          - { name: osu, id: 0 }
-          - { name: taiko, id: 1 }
-          - { name: catch, id: 2 }
-          - { name: mania, id: 3 }
-
-    services:
-      mysql:
-        image: mysql:8.0
-        env:
-          MYSQL_ALLOW_EMPTY_PASSWORD: yes
-        ports:
-          - 3306:3306
-        options: --health-cmd="mysqladmin ping" --health-interval=10s --health-timeout=5s --health-retries=3
-
-    steps:
-      - name: Verify ruleset
-        if: contains(github.event.comment.body, matrix.ruleset.id) == false
-        run: |
-          echo "${{ github.event.comment.body }} doesn't contain ${{ matrix.ruleset.id }}"
-          exit 1
-
-      - name: Verify MySQL connection from host
-        run: |
-          sudo apt-get install -y mysql-client
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "SHOW DATABASES"
-
-      - name: Create directory structure
-        run: |
-          mkdir -p $GITHUB_WORKSPACE/master/
-          mkdir -p $GITHUB_WORKSPACE/pr/
-
-      # Checkout osu
-      - name: Checkout osu (master)
-        uses: actions/checkout@v2
-        with:
-          repository: ppy/osu
-          path: 'master/osu'
-      - name: Checkout osu (pr)
-        uses: actions/checkout@v2
-        with:
-          path: 'pr/osu'
-
-      # Checkout osu-difficulty-calculator
-      - name: Checkout osu-difficulty-calculator (master)
-        uses: actions/checkout@v2
-        with:
-          repository: ppy/osu-difficulty-calculator
-          path: 'master/osu-difficulty-calculator'
-      - name: Checkout osu-difficulty-calculator (pr)
-        uses: actions/checkout@v2
-        with:
-          repository: ppy/osu-difficulty-calculator
-          path: 'pr/osu-difficulty-calculator'
-
-      - name: Install .NET 5.0.x
-        uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: "5.0.x"
-
-      # Sanity checks to make sure diffcalc is not run when incompatible.
-      - name: Build diffcalc (master)
-        run: |
-          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator
-          ./UseLocalOsu.sh
-          dotnet build
-      - name: Build diffcalc (pr)
-        run: |
-          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator
-          ./UseLocalOsu.sh
-          dotnet build
-
-      # Initial data imports
-      - name: Download + import data
-        run: |
-          PERFORMANCE_DATA_NAME=$(curl https://data.ppy.sh/ | grep performance_${{ matrix.ruleset.name }}_top | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
-          BEATMAPS_DATA_NAME=$(curl https://data.ppy.sh/ | grep osu_files | tail -1 | awk -F "\"" '{print $2}' | sed 's/\.tar\.bz2//g')
-
-          # Set env variable for further steps.
-          echo "BEATMAPS_PATH=$GITHUB_WORKSPACE/$BEATMAPS_DATA_NAME" >> $GITHUB_ENV
-
-          cd $GITHUB_WORKSPACE
-
-          wget https://data.ppy.sh/$PERFORMANCE_DATA_NAME.tar.bz2
-          wget https://data.ppy.sh/$BEATMAPS_DATA_NAME.tar.bz2
-          tar -xf $PERFORMANCE_DATA_NAME.tar.bz2
-          tar -xf $BEATMAPS_DATA_NAME.tar.bz2
-
-          cd $GITHUB_WORKSPACE/$PERFORMANCE_DATA_NAME
-
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "CREATE DATABASE osu_master"
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "CREATE DATABASE osu_pr"
-
-          cat *.sql | mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} --database=osu_master
-          cat *.sql | mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} --database=osu_pr
-
-      # Run diffcalc
-      - name: Run diffcalc (master)
-        env:
-          DB_NAME: osu_master
-        run: |
-          cd $GITHUB_WORKSPACE/master/osu-difficulty-calculator/osu.Server.DifficultyCalculator
-          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
-      - name: Run diffcalc (pr)
-        env:
-          DB_NAME: osu_pr
-        run: |
-          cd $GITHUB_WORKSPACE/pr/osu-difficulty-calculator/osu.Server.DifficultyCalculator
-          dotnet run -c:Release -- all -m ${{ matrix.ruleset.id }} -ac -c ${{ env.CONCURRENCY }}
-
-      # Print diffs
-      - name: Print diffs
-        run: |
-          mysql --host ${{ env.DB_HOST }} -u${{ env.DB_USER }} -e "
-            SELECT
-              m.beatmap_id,
-              m.mods,
-              m.diff_unified as 'sr_master',
-              p.diff_unified as 'sr_pr',
-              (p.diff_unified - m.diff_unified) as 'diff'
-            FROM osu_master.osu_beatmap_difficulty m
-            JOIN osu_pr.osu_beatmap_difficulty p
-              ON m.beatmap_id = p.beatmap_id
-              AND m.mode = p.mode
-              AND m.mods = p.mods
-            WHERE abs(m.diff_unified - p.diff_unified) > 0.1
-            ORDER BY abs(m.diff_unified - p.diff_unified)
-              DESC
-            LIMIT 10000;"
-
-      # Todo: Run ppcalc

.idea/.idea.osu/.idea/indexLayout.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ContentModelUserStore">
+  <component name="UserContentModel">
     <attachedFolders />
     <explicitIncludes />
     <explicitExcludes />

osu.Android.props

@@ -51,11 +51,11 @@
     <Reference Include="Java.Interop" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Game.Resources" Version="2021.913.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.916.1" />
+    <PackageReference Include="ppy.osu.Game.Resources" Version="2021.1026.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.1026.0" />
   </ItemGroup>
   <ItemGroup Label="Transitive Dependencies">
     <!-- Realm needs to be directly referenced in all Xamarin projects, as it will not pull in its transitive dependencies otherwise. -->
-    <PackageReference Include="Realm" Version="10.5.0" />
+    <PackageReference Include="Realm" Version="10.6.0" />
   </ItemGroup>
 </Project>

osu.Desktop/DiscordRichPresence.cs

@@ -140,10 +140,10 @@ namespace osu.Desktop
             switch (activity)
             {
                 case UserActivity.InGame game:
-                    return game.Beatmap.ToString();
+                    return game.BeatmapInfo.ToString();
 
                 case UserActivity.Editing edit:
-                    return edit.Beatmap.ToString();
+                    return edit.BeatmapInfo.ToString();
 
                 case UserActivity.InLobby lobby:
                     return privacyMode.Value == DiscordRichPresenceMode.Limited ? string.Empty : lobby.Room.Name.Value;

osu.Desktop/OsuGameDesktop.cs

@@ -156,7 +156,7 @@ namespace osu.Desktop
         {
             lock (importableFiles)
             {
-                var firstExtension = Path.GetExtension(filePaths.First());
+                string firstExtension = Path.GetExtension(filePaths.First());
 
                 if (filePaths.Any(f => Path.GetExtension(f) != firstExtension)) return;
 
@@ -177,7 +177,7 @@ namespace osu.Desktop
             {
                 Logger.Log($"Handling batch import of {importableFiles.Count} files");
 
-                var paths = importableFiles.ToArray();
+                string[] paths = importableFiles.ToArray();
                 importableFiles.Clear();
 
                 Task.Factory.StartNew(() => Import(paths), TaskCreationOptions.LongRunning);

osu.Desktop/Program.cs

@@ -22,17 +22,17 @@ namespace osu.Desktop
         public static int Main(string[] args)
         {
             // Back up the cwd before DesktopGameHost changes it
-            var cwd = Environment.CurrentDirectory;
+            string cwd = Environment.CurrentDirectory;
 
             string gameName = base_game_name;
             bool tournamentClient = false;
 
-            foreach (var arg in args)
+            foreach (string arg in args)
             {
-                var split = arg.Split('=');
+                string[] split = arg.Split('=');
 
-                var key = split[0];
-                var val = split.Length > 1 ? split[1] : string.Empty;
+                string key = split[0];
+                string val = split.Length > 1 ? split[1] : string.Empty;
 
                 switch (key)
                 {
@@ -62,7 +62,7 @@ namespace osu.Desktop
                     {
                         var importer = new ArchiveImportIPCChannel(host);
 
-                        foreach (var file in args)
+                        foreach (string file in args)
                         {
                             Console.WriteLine(@"Importing {0}", file);
                             if (!importer.ImportAsync(Path.GetFullPath(file, cwd)).Wait(3000))
@@ -74,7 +74,10 @@ namespace osu.Desktop
 
                     // we want to allow multiple instances to be started when in debug.
                     if (!DebugUtils.IsDebugBuild)
+                    {
+                        Logger.Log(@"osu! does not support multiple running instances.", LoggingTarget.Runtime, LogLevel.Error);
                         return 0;
+                    }
                 }
 
                 if (tournamentClient)

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";
 
-        [TestCase(4.050601681491468d, "diffcalc-test")]
+        [TestCase(4.0505463516206195d, "diffcalc-test")]
         public void Test(double expected, string name)
             => base.Test(expected, name);
 
-        [TestCase(5.169743871843191d, "diffcalc-test")]
+        [TestCase(5.1696411260785498d, "diffcalc-test")]
         public void TestClockRateAdjusted(double expected, string name)
             => Test(expected, name, new CatchModDoubleTime());
 

osu.Game.Rulesets.Catch.Tests/Editor/CatchSelectionBlueprintTestScene.cs

@@ -29,8 +29,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
 
         protected CatchSelectionBlueprintTestScene()
         {
-            EditorBeatmap = new EditorBeatmap(new CatchBeatmap());
-            EditorBeatmap.BeatmapInfo.BaseDifficulty.CircleSize = 0;
+            EditorBeatmap = new EditorBeatmap(new CatchBeatmap()) { Difficulty = { CircleSize = 0 } };
             EditorBeatmap.ControlPointInfo.Add(0, new TimingControlPoint
             {
                 BeatLength = 100

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneBananaShowerPlacementBlueprint.cs

@@ -5,6 +5,7 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Testing;
 using osu.Framework.Utils;
+using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
 using osu.Game.Rulesets.Catch.Edit.Blueprints.Components;
@@ -26,7 +27,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
         protected override void AddHitObject(DrawableHitObject hitObject)
         {
             // Create nested bananas (but positions are not randomized because beatmap processing is not done).
-            hitObject.HitObject.ApplyDefaults(new ControlPointInfo(), Beatmap.Value.BeatmapInfo.BaseDifficulty);
+            hitObject.HitObject.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty());
 
             base.AddHitObject(hitObject);
         }

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneCatchDistanceSnapGrid.cs

@@ -0,0 +1,91 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Input.Events;
+using osu.Framework.Timing;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Catch.Edit;
+using osu.Game.Rulesets.Catch.Edit.Blueprints.Components;
+using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.UI.Scrolling;
+using osu.Game.Tests.Visual;
+using osuTK;
+
+namespace osu.Game.Rulesets.Catch.Tests.Editor
+{
+    public class TestSceneCatchDistanceSnapGrid : OsuManualInputManagerTestScene
+    {
+        private readonly ManualClock manualClock = new ManualClock();
+
+        [Cached(typeof(Playfield))]
+        private readonly CatchPlayfield playfield;
+
+        private ScrollingHitObjectContainer hitObjectContainer => playfield.HitObjectContainer;
+
+        private readonly CatchDistanceSnapGrid distanceGrid;
+
+        private readonly FruitOutline fruitOutline;
+
+        private readonly Fruit fruit = new Fruit();
+
+        public TestSceneCatchDistanceSnapGrid()
+        {
+            Child = new Container
+            {
+                Anchor = Anchor.Centre,
+                Origin = Anchor.Centre,
+                RelativeSizeAxes = Axes.Y,
+                Width = 500,
+
+                Children = new Drawable[]
+                {
+                    new ScrollingTestContainer(ScrollingDirection.Down)
+                    {
+                        RelativeSizeAxes = Axes.Both,
+                        Child = playfield = new CatchPlayfield(new BeatmapDifficulty())
+                        {
+                            RelativeSizeAxes = Axes.Both,
+                            Clock = new FramedClock(manualClock)
+                        }
+                    },
+                    distanceGrid = new CatchDistanceSnapGrid(new double[] { 0, -1, 1 }),
+                    fruitOutline = new FruitOutline()
+                },
+            };
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            distanceGrid.StartTime = 100;
+            distanceGrid.StartX = 250;
+
+            Vector2 screenSpacePosition = InputManager.CurrentState.Mouse.Position;
+
+            var result = distanceGrid.GetSnappedPosition(screenSpacePosition);
+
+            if (result != null)
+            {
+                fruit.OriginalX = hitObjectContainer.ToLocalSpace(result.ScreenSpacePosition).X;
+
+                if (result.Time != null)
+                    fruit.StartTime = result.Time.Value;
+            }
+
+            fruitOutline.Position = CatchHitObjectUtils.GetStartPosition(hitObjectContainer, fruit);
+            fruitOutline.UpdateFrom(fruit);
+        }
+
+        protected override bool OnScroll(ScrollEvent e)
+        {
+            manualClock.CurrentTime -= e.ScrollDelta.Y * 50;
+            return true;
+        }
+    }
+}

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneJuiceStreamPlacementBlueprint.cs

@@ -4,9 +4,9 @@
 using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
-using osu.Framework.Allocation;
 using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Utils;
+using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Catch.Edit.Blueprints;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Catch.Objects.Drawables;
@@ -23,11 +23,12 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
 
         private JuiceStream lastObject => LastObject?.HitObject as JuiceStream;
 
-        [BackgroundDependencyLoader]
-        private void load()
+        protected override IBeatmap GetPlayableBeatmap()
         {
-            Beatmap.Value.BeatmapInfo.BaseDifficulty.SliderTickRate = 5;
-            Beatmap.Value.BeatmapInfo.BaseDifficulty.SliderMultiplier = velocity * 10;
+            var playable = base.GetPlayableBeatmap();
+            playable.Difficulty.SliderTickRate = 5;
+            playable.Difficulty.SliderMultiplier = velocity * 10;
+            return playable;
         }
 
         [Test]

osu.Game.Rulesets.Catch.Tests/Editor/TestSceneJuiceStreamSelectionBlueprint.cs

@@ -49,7 +49,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
 
             AddAssert("correct outline count", () =>
             {
-                var expected = hitObject.NestedHitObjects.Count(h => !(h is TinyDroplet));
+                int expected = hitObject.NestedHitObjects.Count(h => !(h is TinyDroplet));
                 return this.ChildrenOfType<FruitOutline>().Count() == expected;
             });
             AddAssert("correct vertex piece count", () =>
@@ -223,7 +223,7 @@ namespace osu.Game.Rulesets.Catch.Tests.Editor
                 X = x,
                 Path = sliderPath,
             };
-            EditorBeatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier = velocity;
+            EditorBeatmap.Difficulty.SliderMultiplier = velocity;
             EditorBeatmap.Add(hitObject);
             EditorBeatmap.Update(hitObject);
             Assert.That(hitObject.Velocity, Is.EqualTo(velocity));

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

@@ -103,7 +103,7 @@ namespace osu.Game.Rulesets.Catch.Tests
         [Test]
         public void TestCatcherCatchWidth()
         {
-            var halfWidth = Catcher.CalculateCatchWidth(new BeatmapDifficulty { CircleSize = 0 }) / 2;
+            float halfWidth = Catcher.CalculateCatchWidth(new BeatmapDifficulty { CircleSize = 0 }) / 2;
             AddStep("catch fruit", () =>
             {
                 attemptCatch(new Fruit { X = -halfWidth + 1 });
@@ -237,7 +237,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private void attemptCatch(Func<CatchHitObject> hitObject, int count)
         {
-            for (var i = 0; i < count; i++)
+            for (int i = 0; i < count; i++)
                 attemptCatch(hitObject(), out _, out _);
         }
 
@@ -290,7 +290,7 @@ namespace osu.Game.Rulesets.Catch.Tests
         {
             public IEnumerable<CaughtObject> CaughtObjects => this.ChildrenOfType<CaughtObject>();
 
-            public TestCatcher(DroppedObjectContainer droppedObjectTarget, BeatmapDifficulty difficulty)
+            public TestCatcher(DroppedObjectContainer droppedObjectTarget, IBeatmapDifficultyInfo difficulty)
                 : base(droppedObjectTarget, difficulty)
             {
             }
@@ -298,7 +298,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         public class TestKiaiFruit : Fruit
         {
-            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
             {
                 controlPointInfo.Add(0, new EffectControlPoint { KiaiMode = true });
                 base.ApplyDefaultsToSelf(controlPointInfo, difficulty);

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

@@ -34,7 +34,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private ScheduledDelegate addManyFruit;
 
-        private BeatmapDifficulty beatmapDifficulty;
+        private IBeatmapDifficultyInfo beatmapDifficulty;
 
         public TestSceneCatcherArea()
         {
@@ -120,7 +120,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private class TestCatcherArea : CatcherArea
         {
-            public TestCatcherArea(BeatmapDifficulty beatmapDifficulty)
+            public TestCatcherArea(IBeatmapDifficultyInfo beatmapDifficulty)
             {
                 var droppedObjectContainer = new DroppedObjectContainer();
                 Add(droppedObjectContainer);

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

@@ -118,7 +118,7 @@ namespace osu.Game.Rulesets.Catch.Tests
 
         private void spawnJuiceStream(bool hit = false)
         {
-            var xCoords = getXCoords(hit);
+            float xCoords = getXCoords(hit);
 
             var juice = new JuiceStream
             {

osu.Game.Rulesets.Catch/Beatmaps/CatchBeatmapProcessor.cs

@@ -211,7 +211,7 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
 
             palpableObjects.Sort((h1, h2) => h1.StartTime.CompareTo(h2.StartTime));
 
-            double halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.BeatmapInfo.BaseDifficulty) / 2;
+            double halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.Difficulty) / 2;
 
             // Todo: This is wrong. osu!stable calculated hyperdashes using the full catcher size, excluding the margins.
             // This should theoretically cause impossible scenarios, but practically, likely due to the size of the playfield, it doesn't seem possible.
@@ -233,7 +233,7 @@ namespace osu.Game.Rulesets.Catch.Beatmaps
                 int thisDirection = nextObject.EffectiveX > currentObject.EffectiveX ? 1 : -1;
                 double timeToNext = nextObject.StartTime - currentObject.StartTime - 1000f / 60f / 4; // 1/4th of a frame of grace time, taken from osu-stable
                 double distanceToNext = Math.Abs(nextObject.EffectiveX - currentObject.EffectiveX) - (lastDirection == thisDirection ? lastExcess : halfCatcherWidth);
-                float distanceToHyper = (float)(timeToNext * Catcher.BASE_SPEED - distanceToNext);
+                float distanceToHyper = (float)(timeToNext * Catcher.BASE_DASH_SPEED - distanceToNext);
 
                 if (distanceToHyper < 0)
                 {

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

@@ -34,7 +34,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
                 return new CatchDifficultyAttributes { Mods = mods, Skills = skills };
 
             // this is the same as osu!, so there's potential to share the implementation... maybe
-            double preempt = BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450) / clockRate;
+            double preempt = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.ApproachRate, 1800, 1200, 450) / clockRate;
 
             return new CatchDifficultyAttributes
             {
@@ -52,7 +52,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty
 
             // In 2B beatmaps, it is possible that a normal Fruit is placed in the middle of a JuiceStream.
             foreach (var hitObject in beatmap.HitObjects
-                                             .SelectMany(obj => obj is JuiceStream stream ? stream.NestedHitObjects : new[] { obj })
+                                             .SelectMany(obj => obj is JuiceStream stream ? stream.NestedHitObjects.AsEnumerable() : new[] { obj })
                                              .Cast<CatchHitObject>()
                                              .OrderBy(x => x.StartTime))
             {
@@ -69,10 +69,10 @@ namespace osu.Game.Rulesets.Catch.Difficulty
 
         protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
         {
-            halfCatcherWidth = Catcher.CalculateCatchWidth(beatmap.BeatmapInfo.BaseDifficulty) * 0.5f;
+            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.BeatmapInfo.BaseDifficulty.CircleSize - 5.5f) * 0.0625f);
+            halfCatcherWidth *= 1 - (Math.Max(0, beatmap.Difficulty.CircleSize - 5.5f) * 0.0625f);
 
             return new Skill[]
             {

osu.Game.Rulesets.Catch/Difficulty/Preprocessing/CatchDifficultyHitObject.cs

@@ -28,7 +28,7 @@ namespace osu.Game.Rulesets.Catch.Difficulty.Preprocessing
             : base(hitObject, lastObject, clockRate)
         {
             // We will scale everything by this factor, so we can assume a uniform CircleSize among beatmaps.
-            var scalingFactor = normalized_hitobject_radius / halfCatcherWidth;
+            float scalingFactor = normalized_hitobject_radius / halfCatcherWidth;
 
             NormalizedPosition = BaseObject.EffectiveX * scalingFactor;
             LastNormalizedPosition = LastObject.EffectiveX * scalingFactor;

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

@@ -0,0 +1,141 @@
+// 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 JetBrains.Annotations;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Lines;
+using osu.Framework.Graphics.Primitives;
+using osu.Game.Rulesets.Catch.UI;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.UI;
+using osu.Game.Rulesets.UI.Scrolling;
+using osuTK;
+
+namespace osu.Game.Rulesets.Catch.Edit
+{
+    /// <summary>
+    /// The guide lines used in the osu!catch editor to compose patterns that can be caught with constant speed.
+    /// Currently, only forward placement (an object is snapped based on the previous object, not the opposite) is supported.
+    /// </summary>
+    public class CatchDistanceSnapGrid : CompositeDrawable
+    {
+        public double StartTime { get; set; }
+
+        public float StartX { get; set; }
+
+        private const double max_vertical_line_length_in_time = CatchPlayfield.WIDTH / Catcher.BASE_WALK_SPEED;
+
+        private readonly double[] velocities;
+
+        private readonly List<Path> verticalPaths = new List<Path>();
+
+        private readonly List<Vector2[]> verticalLineVertices = new List<Vector2[]>();
+
+        [Resolved]
+        private Playfield playfield { get; set; }
+
+        private ScrollingHitObjectContainer hitObjectContainer => (ScrollingHitObjectContainer)playfield.HitObjectContainer;
+
+        public CatchDistanceSnapGrid(double[] velocities)
+        {
+            RelativeSizeAxes = Axes.Both;
+            Anchor = Anchor.BottomLeft;
+
+            this.velocities = velocities;
+
+            for (int i = 0; i < velocities.Length; i++)
+            {
+                verticalPaths.Add(new SmoothPath
+                {
+                    PathRadius = 2,
+                    Alpha = 0.5f,
+                });
+
+                verticalLineVertices.Add(new[] { Vector2.Zero, Vector2.Zero });
+            }
+
+            AddRangeInternal(verticalPaths);
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            double currentTime = hitObjectContainer.Time.Current;
+
+            for (int i = 0; i < velocities.Length; i++)
+            {
+                double velocity = velocities[i];
+
+                // The line ends at the top of the playfield.
+                double endTime = hitObjectContainer.TimeAtPosition(-hitObjectContainer.DrawHeight, currentTime);
+
+                // Non-vertical lines are cut at the sides of the playfield.
+                // Vertical lines are cut at some reasonable length.
+                if (velocity > 0)
+                    endTime = Math.Min(endTime, StartTime + (CatchPlayfield.WIDTH - StartX) / velocity);
+                else if (velocity < 0)
+                    endTime = Math.Min(endTime, StartTime + StartX / -velocity);
+                else
+                    endTime = Math.Min(endTime, StartTime + max_vertical_line_length_in_time);
+
+                Vector2[] lineVertices = verticalLineVertices[i];
+                lineVertices[0] = calculatePosition(velocity, StartTime);
+                lineVertices[1] = calculatePosition(velocity, endTime);
+
+                var verticalPath = verticalPaths[i];
+                verticalPath.Vertices = verticalLineVertices[i];
+                verticalPath.OriginPosition = verticalPath.PositionInBoundingBox(Vector2.Zero);
+            }
+
+            Vector2 calculatePosition(double velocity, double time)
+            {
+                // Don't draw inverted lines.
+                time = Math.Max(time, StartTime);
+
+                float x = StartX + (float)((time - StartTime) * velocity);
+                float y = hitObjectContainer.PositionAtTime(time, currentTime);
+                return new Vector2(x, y);
+            }
+        }
+
+        [CanBeNull]
+        public SnapResult GetSnappedPosition(Vector2 screenSpacePosition)
+        {
+            double time = hitObjectContainer.TimeAtScreenSpacePosition(screenSpacePosition);
+
+            // If the cursor is below the distance snap grid, snap to the origin.
+            // Not returning `null` to retain the continuous snapping behavior when the cursor is slightly below the origin.
+            // This behavior is not currently visible in the editor because editor chooses the snap start time based on the mouse position.
+            if (time <= StartTime)
+            {
+                float y = hitObjectContainer.PositionAtTime(StartTime);
+                Vector2 originPosition = hitObjectContainer.ToScreenSpace(new Vector2(StartX, y));
+                return new SnapResult(originPosition, StartTime);
+            }
+
+            return enumerateSnappingCandidates(time)
+                   .OrderBy(pos => Vector2.DistanceSquared(screenSpacePosition, pos.ScreenSpacePosition))
+                   .FirstOrDefault();
+        }
+
+        private IEnumerable<SnapResult> enumerateSnappingCandidates(double time)
+        {
+            float y = hitObjectContainer.PositionAtTime(time);
+
+            foreach (double velocity in velocities)
+            {
+                float x = (float)(StartX + (time - StartTime) * velocity);
+                Vector2 screenSpacePosition = hitObjectContainer.ToScreenSpace(new Vector2(x, y + hitObjectContainer.DrawHeight));
+                yield return new SnapResult(screenSpacePosition, time);
+            }
+        }
+
+        protected override bool ComputeIsMaskedAway(RectangleF maskingBounds) => false;
+    }
+}

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

@@ -9,7 +9,7 @@ namespace osu.Game.Rulesets.Catch.Edit
     public class CatchEditorPlayfield : CatchPlayfield
     {
         // TODO fixme: the size of the catcher is not changed when circle size is changed in setup screen.
-        public CatchEditorPlayfield(BeatmapDifficulty difficulty)
+        public CatchEditorPlayfield(IBeatmapDifficultyInfo difficulty)
             : base(difficulty)
         {
         }

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

@@ -2,14 +2,23 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using System.Linq;
+using JetBrains.Annotations;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Input;
 using osu.Game.Beatmaps;
+using osu.Game.Graphics.UserInterface;
 using osu.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.UI;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Edit.Tools;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.UI;
+using osu.Game.Screens.Edit.Components.TernaryButtons;
 using osu.Game.Screens.Edit.Compose.Components;
 using osuTK;
 
@@ -17,6 +26,14 @@ namespace osu.Game.Rulesets.Catch.Edit
 {
     public class CatchHitObjectComposer : HitObjectComposer<CatchHitObject>
     {
+        private const float distance_snap_radius = 50;
+
+        private CatchDistanceSnapGrid distanceSnapGrid;
+
+        private readonly Bindable<TernaryState> distanceSnapToggle = new Bindable<TernaryState>();
+
+        private InputManager inputManager;
+
         public CatchHitObjectComposer(CatchRuleset ruleset)
             : base(ruleset)
         {
@@ -30,6 +47,27 @@ namespace osu.Game.Rulesets.Catch.Edit
                 RelativeSizeAxes = Axes.Both,
                 PlayfieldBorderStyle = { Value = PlayfieldBorderStyle.Corners }
             });
+
+            LayerBelowRuleset.Add(distanceSnapGrid = new CatchDistanceSnapGrid(new[]
+            {
+                0.0,
+                Catcher.BASE_DASH_SPEED, -Catcher.BASE_DASH_SPEED,
+                Catcher.BASE_WALK_SPEED, -Catcher.BASE_WALK_SPEED,
+            }));
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            inputManager = GetContainingInputManager();
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            updateDistanceSnapGrid();
         }
 
         protected override DrawableRuleset<CatchHitObject> CreateDrawableRuleset(Ruleset ruleset, IBeatmap beatmap, IReadOnlyList<Mod> mods = null) =>
@@ -42,14 +80,95 @@ namespace osu.Game.Rulesets.Catch.Edit
             new BananaShowerCompositionTool()
         };
 
+        protected override IEnumerable<TernaryButton> CreateTernaryButtons() => base.CreateTernaryButtons().Concat(new[]
+        {
+            new TernaryButton(distanceSnapToggle, "Distance Snap", () => new SpriteIcon { Icon = FontAwesome.Solid.Ruler })
+        });
+
         public override SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition)
         {
             var result = base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
-            // TODO: implement position snap
             result.ScreenSpacePosition.X = screenSpacePosition.X;
+
+            if (distanceSnapGrid.IsPresent && distanceSnapGrid.GetSnappedPosition(result.ScreenSpacePosition) is SnapResult snapResult &&
+                Vector2.Distance(snapResult.ScreenSpacePosition, result.ScreenSpacePosition) < distance_snap_radius)
+            {
+                result = snapResult;
+            }
+
             return result;
         }
 
         protected override ComposeBlueprintContainer CreateBlueprintContainer() => new CatchBlueprintContainer(this);
+
+        [CanBeNull]
+        private PalpableCatchHitObject getLastSnappableHitObject(double time)
+        {
+            var hitObject = EditorBeatmap.HitObjects.OfType<CatchHitObject>().LastOrDefault(h => h.GetEndTime() < time && !(h is BananaShower));
+
+            switch (hitObject)
+            {
+                case Fruit fruit:
+                    return fruit;
+
+                case JuiceStream juiceStream:
+                    return juiceStream.NestedHitObjects.OfType<PalpableCatchHitObject>().LastOrDefault(h => !(h is TinyDroplet));
+
+                default:
+                    return null;
+            }
+        }
+
+        [CanBeNull]
+        private PalpableCatchHitObject getDistanceSnapGridSourceHitObject()
+        {
+            switch (BlueprintContainer.CurrentTool)
+            {
+                case SelectTool _:
+                    if (EditorBeatmap.SelectedHitObjects.Count == 0)
+                        return null;
+
+                    double minTime = EditorBeatmap.SelectedHitObjects.Min(hitObject => hitObject.StartTime);
+                    return getLastSnappableHitObject(minTime);
+
+                case FruitCompositionTool _:
+                case JuiceStreamCompositionTool _:
+                    if (!CursorInPlacementArea)
+                        return null;
+
+                    if (EditorBeatmap.PlacementObject.Value is JuiceStream)
+                    {
+                        // Juice stream path is not subject to snapping.
+                        return null;
+                    }
+
+                    double timeAtCursor = ((CatchPlayfield)Playfield).TimeAtScreenSpacePosition(inputManager.CurrentState.Mouse.Position);
+                    return getLastSnappableHitObject(timeAtCursor);
+
+                default:
+                    return null;
+            }
+        }
+
+        private void updateDistanceSnapGrid()
+        {
+            if (distanceSnapToggle.Value != TernaryState.True)
+            {
+                distanceSnapGrid.Hide();
+                return;
+            }
+
+            var sourceHitObject = getDistanceSnapGridSourceHitObject();
+
+            if (sourceHitObject == null)
+            {
+                distanceSnapGrid.Hide();
+                return;
+            }
+
+            distanceSnapGrid.Show();
+            distanceSnapGrid.StartTime = sourceHitObject.GetEndTime();
+            distanceSnapGrid.StartX = sourceHitObject.EffectiveX;
+        }
     }
 }

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

@@ -16,6 +16,6 @@ namespace osu.Game.Rulesets.Catch.Edit
         {
         }
 
-        protected override Playfield CreatePlayfield() => new CatchEditorPlayfield(Beatmap.BeatmapInfo.BaseDifficulty);
+        protected override Playfield CreatePlayfield() => new CatchEditorPlayfield(Beatmap.Difficulty);
     }
 }

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

@@ -52,8 +52,8 @@ namespace osu.Game.Rulesets.Catch.Mods
         {
             var hitObject = drawable.HitObject;
 
-            var offset = hitObject.TimePreempt * fade_out_offset_multiplier;
-            var duration = offset - hitObject.TimePreempt * fade_out_duration_multiplier;
+            double offset = hitObject.TimePreempt * fade_out_offset_multiplier;
+            double duration = offset - hitObject.TimePreempt * fade_out_duration_multiplier;
 
             using (drawable.BeginAbsoluteSequence(hitObject.StartTime - offset))
                 drawable.FadeOut(duration);

osu.Game.Rulesets.Catch/Objects/CatchHitObject.cs

@@ -128,11 +128,11 @@ namespace osu.Game.Rulesets.Catch.Objects
         /// </summary>
         public int RandomSeed => (int)StartTime;
 
-        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
         {
             base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
 
-            TimePreempt = (float)BeatmapDifficulty.DifficultyRange(difficulty.ApproachRate, 1800, 1200, 450);
+            TimePreempt = (float)IBeatmapDifficultyInfo.DifficultyRange(difficulty.ApproachRate, 1800, 1200, 450);
 
             Scale = (1.0f - 0.7f * (difficulty.CircleSize - 5) / 5) / 2;
         }

osu.Game.Rulesets.Catch/Objects/JuiceStream.cs

@@ -37,14 +37,13 @@ namespace osu.Game.Rulesets.Catch.Objects
         /// </summary>
         public double SpanDuration => Duration / this.SpanCount();
 
-        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
         {
             base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
 
             TimingControlPoint timingPoint = controlPointInfo.TimingPointAt(StartTime);
-            DifficultyControlPoint difficultyPoint = controlPointInfo.DifficultyPointAt(StartTime);
 
-            double scoringDistance = base_scoring_distance * difficulty.SliderMultiplier * difficultyPoint.SpeedMultiplier;
+            double scoringDistance = base_scoring_distance * difficulty.SliderMultiplier * DifficultyControlPoint.SliderVelocity;
 
             Velocity = scoringDistance / timingPoint.BeatLength;
             TickDistance = scoringDistance / difficulty.SliderTickRate;

osu.Game.Rulesets.Catch/Replays/CatchAutoGenerator.cs

@@ -26,9 +26,6 @@ namespace osu.Game.Rulesets.Catch.Replays
             if (Beatmap.HitObjects.Count == 0)
                 return;
 
-            // todo: add support for HT DT
-            const double dash_speed = Catcher.BASE_SPEED;
-            const double movement_speed = dash_speed / 2;
             float lastPosition = CatchPlayfield.CENTER_X;
             double lastTime = 0;
 
@@ -47,8 +44,8 @@ namespace osu.Game.Rulesets.Catch.Replays
                 // The case where positionChange > 0 and timeAvailable == 0 results in PositiveInfinity which provides expected beheaviour.
                 double speedRequired = positionChange == 0 ? 0 : positionChange / timeAvailable;
 
-                bool dashRequired = speedRequired > movement_speed;
-                bool impossibleJump = speedRequired > movement_speed * 2;
+                bool dashRequired = speedRequired > Catcher.BASE_WALK_SPEED;
+                bool impossibleJump = speedRequired > Catcher.BASE_DASH_SPEED;
 
                 // todo: get correct catcher size, based on difficulty CS.
                 const float catcher_width_half = Catcher.BASE_SIZE * 0.3f * 0.5f;
@@ -73,7 +70,7 @@ namespace osu.Game.Rulesets.Catch.Replays
                 else if (dashRequired)
                 {
                     // we do a movement in two parts - the dash part then the normal part...
-                    double timeAtNormalSpeed = positionChange / movement_speed;
+                    double timeAtNormalSpeed = positionChange / Catcher.BASE_WALK_SPEED;
                     double timeWeNeedToSave = timeAtNormalSpeed - timeAvailable;
                     double timeAtDashSpeed = timeWeNeedToSave / 2;
 
@@ -86,7 +83,7 @@ namespace osu.Game.Rulesets.Catch.Replays
                 }
                 else
                 {
-                    double timeBefore = positionChange / movement_speed;
+                    double timeBefore = positionChange / Catcher.BASE_WALK_SPEED;
 
                     addFrame(h.StartTime - timeBefore, lastPosition);
                     addFrame(h.StartTime, h.EffectiveX);

osu.Game.Rulesets.Catch/Replays/CatchFramedReplayInputHandler.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Rulesets.Catch.Replays
 
         public override void CollectPendingInputs(List<IInput> inputs)
         {
-            var position = Interpolation.ValueAt(CurrentTime, StartFrame.Position, EndFrame.Position, StartFrame.Time, EndFrame.Time);
+            float position = Interpolation.ValueAt(CurrentTime, StartFrame.Position, EndFrame.Position, StartFrame.Time, EndFrame.Time);
 
             inputs.Add(new CatchReplayState
             {

osu.Game.Rulesets.Catch/Skinning/Legacy/CatchLegacySkinTransformer.cs

@@ -66,7 +66,7 @@ namespace osu.Game.Rulesets.Catch.Skinning.Legacy
                         return null;
 
                     case CatchSkinComponents.Catcher:
-                        var version = GetConfig<LegacySkinConfiguration.LegacySetting, decimal>(LegacySkinConfiguration.LegacySetting.Version)?.Value ?? 1;
+                        decimal version = GetConfig<LegacySkinConfiguration.LegacySetting, decimal>(LegacySkinConfiguration.LegacySetting.Version)?.Value ?? 1;
 
                         if (version < 2.3m)
                         {

osu.Game.Rulesets.Catch/UI/CatchPlayfield.cs

@@ -34,9 +34,9 @@ namespace osu.Game.Rulesets.Catch.UI
 
         internal CatcherArea CatcherArea { get; private set; }
 
-        private readonly BeatmapDifficulty difficulty;
+        private readonly IBeatmapDifficultyInfo difficulty;
 
-        public CatchPlayfield(BeatmapDifficulty difficulty)
+        public CatchPlayfield(IBeatmapDifficultyInfo difficulty)
         {
             this.difficulty = difficulty;
         }

osu.Game.Rulesets.Catch/UI/Catcher.cs

@@ -57,14 +57,19 @@ namespace osu.Game.Rulesets.Catch.UI
         public bool CatchFruitOnPlate { get; set; } = true;
 
         /// <summary>
-        /// The relative space to cover in 1 millisecond. based on 1 game pixel per millisecond as in osu-stable.
+        /// The speed of the catcher when the catcher is dashing.
         /// </summary>
-        public const double BASE_SPEED = 1.0;
+        public const double BASE_DASH_SPEED = 1.0;
 
         /// <summary>
-        /// The current speed of the catcher.
+        /// The speed of the catcher when the catcher is not dashing.
         /// </summary>
-        public double Speed => (Dashing ? 1 : 0.5) * BASE_SPEED * hyperDashModifier;
+        public const double BASE_WALK_SPEED = 0.5;
+
+        /// <summary>
+        /// The current speed of the catcher with the hyper-dash modifier applied.
+        /// </summary>
+        public double Speed => (Dashing ? BASE_DASH_SPEED : BASE_WALK_SPEED) * hyperDashModifier;
 
         /// <summary>
         /// The amount by which caught fruit should be scaled down to fit on the plate.
@@ -124,7 +129,7 @@ namespace osu.Game.Rulesets.Catch.UI
         private readonly DrawablePool<CaughtBanana> caughtBananaPool;
         private readonly DrawablePool<CaughtDroplet> caughtDropletPool;
 
-        public Catcher([NotNull] DroppedObjectContainer droppedObjectTarget, BeatmapDifficulty difficulty = null)
+        public Catcher([NotNull] DroppedObjectContainer droppedObjectTarget, IBeatmapDifficultyInfo difficulty = null)
         {
             this.droppedObjectTarget = droppedObjectTarget;
 
@@ -172,7 +177,7 @@ namespace osu.Game.Rulesets.Catch.UI
         /// <summary>
         /// Calculates the scale of the catcher based off the provided beatmap difficulty.
         /// </summary>
-        private static Vector2 calculateScale(BeatmapDifficulty difficulty) => new Vector2(1.0f - 0.7f * (difficulty.CircleSize - 5) / 5);
+        private static Vector2 calculateScale(IBeatmapDifficultyInfo difficulty) => new Vector2(1.0f - 0.7f * (difficulty.CircleSize - 5) / 5);
 
         /// <summary>
         /// Calculates the width of the area used for attempting catches in gameplay.
@@ -184,7 +189,7 @@ namespace osu.Game.Rulesets.Catch.UI
         /// Calculates the width of the area used for attempting catches in gameplay.
         /// </summary>
         /// <param name="difficulty">The beatmap difficulty.</param>
-        public static float CalculateCatchWidth(BeatmapDifficulty difficulty) => CalculateCatchWidth(calculateScale(difficulty));
+        public static float CalculateCatchWidth(IBeatmapDifficultyInfo difficulty) => CalculateCatchWidth(calculateScale(difficulty));
 
         /// <summary>
         /// Determine if this catcher can catch a <see cref="CatchHitObject"/> in the current position.
@@ -226,11 +231,11 @@ namespace osu.Game.Rulesets.Catch.UI
             if (result.IsHit && hitObject.HyperDash)
             {
                 var target = hitObject.HyperDashTarget;
-                var timeDifference = target.StartTime - hitObject.StartTime;
+                double timeDifference = target.StartTime - hitObject.StartTime;
                 double positionDifference = target.EffectiveX - X;
-                var velocity = positionDifference / Math.Max(1.0, timeDifference - 1000.0 / 60.0);
+                double velocity = positionDifference / Math.Max(1.0, timeDifference - 1000.0 / 60.0);
 
-                SetHyperDashState(Math.Abs(velocity), target.EffectiveX);
+                SetHyperDashState(Math.Abs(velocity) / BASE_DASH_SPEED, target.EffectiveX);
             }
             else
                 SetHyperDashState();
@@ -266,7 +271,7 @@ namespace osu.Game.Rulesets.Catch.UI
         /// <param name="targetPosition">When this catcher crosses this position, this catcher ends hyper-dashing.</param>
         public void SetHyperDashState(double modifier = 1, float targetPosition = -1)
         {
-            var wasHyperDashing = HyperDashing;
+            bool wasHyperDashing = HyperDashing;
 
             if (modifier <= 1 || X == targetPosition)
             {

osu.Game.Rulesets.Catch/UI/DrawableCatchRuleset.cs

@@ -27,14 +27,14 @@ namespace osu.Game.Rulesets.Catch.UI
             : base(ruleset, beatmap, mods)
         {
             Direction.Value = ScrollingDirection.Down;
-            TimeRange.Value = BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450);
+            TimeRange.Value = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.ApproachRate, 1800, 1200, 450);
         }
 
         protected override ReplayInputHandler CreateReplayInputHandler(Replay replay) => new CatchFramedReplayInputHandler(replay);
 
         protected override ReplayRecorder CreateReplayRecorder(Score score) => new CatchReplayRecorder(score, (CatchPlayfield)Playfield);
 
-        protected override Playfield CreatePlayfield() => new CatchPlayfield(Beatmap.BeatmapInfo.BaseDifficulty);
+        protected override Playfield CreatePlayfield() => new CatchPlayfield(Beatmap.Difficulty);
 
         public override PlayfieldAdjustmentContainer CreatePlayfieldAdjustmentContainer() => new CatchPlayfieldAdjustmentContainer();
 

osu.Game.Rulesets.Mania.Tests/Editor/ManiaPlacementBlueprintTestScene.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Rulesets.Mania.Tests.Editor
 
         protected override SnapResult SnapForBlueprint(PlacementBlueprint blueprint)
         {
-            var time = column.TimeAtScreenSpacePosition(InputManager.CurrentState.Mouse.Position);
+            double time = column.TimeAtScreenSpacePosition(InputManager.CurrentState.Mouse.Position);
             var pos = column.ScreenSpacePositionAtTime(time);
 
             return new SnapResult(pos, time, column);

osu.Game.Rulesets.Mania.Tests/Editor/TestSceneManiaBeatSnapGrid.cs

@@ -13,6 +13,7 @@ using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Mania.Beatmaps;
 using osu.Game.Rulesets.Mania.Edit;
 using osu.Game.Rulesets.Mania.UI;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 using osu.Game.Rulesets.UI;
 using osu.Game.Rulesets.UI.Scrolling;
@@ -101,27 +102,27 @@ namespace osu.Game.Rulesets.Mania.Tests.Editor
             throw new System.NotImplementedException();
         }
 
-        public override float GetBeatSnapDistanceAt(double referenceTime)
+        public override float GetBeatSnapDistanceAt(HitObject referenceObject)
         {
             throw new System.NotImplementedException();
         }
 
-        public override float DurationToDistance(double referenceTime, double duration)
+        public override float DurationToDistance(HitObject referenceObject, double duration)
         {
             throw new System.NotImplementedException();
         }
 
-        public override double DistanceToDuration(double referenceTime, float distance)
+        public override double DistanceToDuration(HitObject referenceObject, float distance)
         {
             throw new System.NotImplementedException();
         }
 
-        public override double GetSnappedDurationFromDistance(double referenceTime, float distance)
+        public override double GetSnappedDurationFromDistance(HitObject referenceObject, float distance)
         {
             throw new System.NotImplementedException();
         }
 
-        public override float GetSnappedDistanceFromDistance(double referenceTime, float distance)
+        public override float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance)
         {
             throw new System.NotImplementedException();
         }

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

@@ -111,7 +111,7 @@ namespace osu.Game.Rulesets.Mania.Tests
 
         public int CompareTo(ConvertValue other)
         {
-            var result = StartTime.CompareTo(other.StartTime);
+            int result = StartTime.CompareTo(other.StartTime);
 
             if (result != 0)
                 return result;

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

@@ -43,7 +43,7 @@ namespace osu.Game.Rulesets.Mania.Tests
 
         private IEnumerable<ColumnType> getResults(StageDefinition definition)
         {
-            for (var i = 0; i < definition.Columns; i++)
+            for (int i = 0; i < definition.Columns; i++)
                 yield return definition.GetTypeOfColumn(i);
         }
     }

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

@@ -388,7 +388,7 @@ namespace osu.Game.Rulesets.Mania.Tests
                     },
                 };
 
-                beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
+                beatmap.ControlPointInfo.Add(0, new EffectControlPoint { ScrollSpeed = 0.1f });
             }
 
             AddStep("load player", () =>

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

@@ -148,7 +148,7 @@ namespace osu.Game.Rulesets.Mania.Tests
                     },
                 });
 
-                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
+                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new EffectControlPoint { ScrollSpeed = 0.1f });
 
                 var p = new ScoreAccessibleReplayPlayer(new Score { Replay = new Replay { Frames = frames } });
 

osu.Game.Rulesets.Mania/Beatmaps/ManiaBeatmapConverter.cs

@@ -42,8 +42,8 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
         {
             IsForCurrentRuleset = beatmap.BeatmapInfo.Ruleset.Equals(ruleset.RulesetInfo);
 
-            var roundedCircleSize = Math.Round(beatmap.BeatmapInfo.BaseDifficulty.CircleSize);
-            var roundedOverallDifficulty = Math.Round(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty);
+            double roundedCircleSize = Math.Round(beatmap.Difficulty.CircleSize);
+            double roundedOverallDifficulty = Math.Round(beatmap.Difficulty.OverallDifficulty);
 
             if (IsForCurrentRuleset)
             {
@@ -71,9 +71,9 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
             originalTargetColumns = TargetColumns;
         }
 
-        public static int GetColumnCountForNonConvert(BeatmapInfo beatmap)
+        public static int GetColumnCountForNonConvert(BeatmapInfo beatmapInfo)
         {
-            var roundedCircleSize = Math.Round(beatmap.BaseDifficulty.CircleSize);
+            double roundedCircleSize = Math.Round(beatmapInfo.BaseDifficulty.CircleSize);
             return (int)Math.Max(1, roundedCircleSize);
         }
 
@@ -81,7 +81,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps
 
         protected override Beatmap<ManiaHitObject> ConvertBeatmap(IBeatmap original, CancellationToken cancellationToken)
         {
-            BeatmapDifficulty difficulty = original.BeatmapInfo.BaseDifficulty;
+            IBeatmapDifficultyInfo difficulty = original.Difficulty;
 
             int seed = (int)MathF.Round(difficulty.DrainRate + difficulty.CircleSize) * 20 + (int)(difficulty.OverallDifficulty * 41.2) + (int)MathF.Round(difficulty.ApproachRate);
             Random = new FastRandom(seed);

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/DistanceObjectPatternGenerator.cs

@@ -47,7 +47,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
             Debug.Assert(distanceData != null);
 
             TimingControlPoint timingPoint = beatmap.ControlPointInfo.TimingPointAt(hitObject.StartTime);
-            DifficultyControlPoint difficultyPoint = beatmap.ControlPointInfo.DifficultyPointAt(hitObject.StartTime);
+            DifficultyControlPoint difficultyPoint = hitObject.DifficultyControlPoint;
 
             double beatLength;
 #pragma warning disable 618
@@ -55,13 +55,13 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 #pragma warning restore 618
                 beatLength = timingPoint.BeatLength * legacyDifficultyPoint.BpmMultiplier;
             else
-                beatLength = timingPoint.BeatLength / difficultyPoint.SpeedMultiplier;
+                beatLength = timingPoint.BeatLength / difficultyPoint.SliderVelocity;
 
             SpanCount = repeatsData?.SpanCount() ?? 1;
             StartTime = (int)Math.Round(hitObject.StartTime);
 
             // This matches stable's calculation.
-            EndTime = (int)Math.Floor(StartTime + distanceData.Distance * beatLength * SpanCount * 0.01 / beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier);
+            EndTime = (int)Math.Floor(StartTime + distanceData.Distance * beatLength * SpanCount * 0.01 / beatmap.Difficulty.SliderMultiplier);
 
             SegmentDuration = (EndTime - StartTime) / SpanCount;
         }
@@ -493,7 +493,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
             if (!(HitObject is IHasPathWithRepeats curveData))
                 return null;
 
-            var index = SegmentDuration == 0 ? 0 : (time - StartTime) / SegmentDuration;
+            int index = SegmentDuration == 0 ? 0 : (time - StartTime) / SegmentDuration;
 
             // avoid slicing the list & creating copies, if at all possible.
             return index == 0 ? curveData.NodeSamples : curveData.NodeSamples.Skip(index).ToList();

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/HitObjectPatternGenerator.cs

@@ -302,7 +302,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             var pattern = new Pattern();
 
-            int noteCount = getRandomNoteCountMirrored(centreProbability, p2, p3, out var addToCentre);
+            int noteCount = getRandomNoteCountMirrored(centreProbability, p2, p3, out bool addToCentre);
 
             int columnLimit = (TotalColumns % 2 == 0 ? TotalColumns : TotalColumns - 1) / 2;
             int nextColumn = GetRandomColumn(upperBound: columnLimit);

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Legacy/PatternGenerator.cs

@@ -111,7 +111,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
                 if (drainTime == 0)
                     drainTime = 10000;
 
-                BeatmapDifficulty difficulty = OriginalBeatmap.BeatmapInfo.BaseDifficulty;
+                IBeatmapDifficultyInfo difficulty = OriginalBeatmap.Difficulty;
                 conversionDifficulty = ((difficulty.DrainRate + Math.Clamp(difficulty.ApproachRate, 4, 7)) / 1.5 + (double)OriginalBeatmap.HitObjects.Count / drainTime * 9f) / 38f * 5f / 1.15;
                 conversionDifficulty = Math.Min(conversionDifficulty.Value, 12);
 
@@ -149,7 +149,7 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         {
             lowerBound ??= RandomStart;
             upperBound ??= TotalColumns;
-            nextColumn ??= (_ => GetRandomColumn(lowerBound, upperBound));
+            nextColumn ??= _ => GetRandomColumn(lowerBound, upperBound);
 
             // Check for the initial column
             if (isValid(initialColumn))
@@ -176,7 +176,19 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
 
             return initialColumn;
 
-            bool isValid(int column) => validation?.Invoke(column) != false && !patterns.Any(p => p.ColumnHasObject(column));
+            bool isValid(int column)
+            {
+                if (validation?.Invoke(column) == false)
+                    return false;
+
+                foreach (var p in patterns)
+                {
+                    if (p.ColumnHasObject(column))
+                        return false;
+                }
+
+                return true;
+            }
         }
 
         /// <summary>

osu.Game.Rulesets.Mania/Beatmaps/Patterns/Pattern.cs

@@ -12,46 +12,68 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns
     /// </summary>
     internal class Pattern
     {
-        private readonly List<ManiaHitObject> hitObjects = new List<ManiaHitObject>();
+        private List<ManiaHitObject> hitObjects;
+        private HashSet<int> containedColumns;
 
         /// <summary>
         /// All the hit objects contained in this pattern.
         /// </summary>
-        public IEnumerable<ManiaHitObject> HitObjects => hitObjects;
+        public IEnumerable<ManiaHitObject> HitObjects => hitObjects ?? Enumerable.Empty<ManiaHitObject>();
 
         /// <summary>
         /// Check whether a column of this patterns contains a hit object.
         /// </summary>
         /// <param name="column">The column index.</param>
         /// <returns>Whether the column with index <paramref name="column"/> contains a hit object.</returns>
-        public bool ColumnHasObject(int column) => hitObjects.Exists(h => h.Column == column);
+        public bool ColumnHasObject(int column) => containedColumns?.Contains(column) == true;
 
         /// <summary>
         /// Amount of columns taken up by hit objects in this pattern.
         /// </summary>
-        public int ColumnWithObjects => HitObjects.GroupBy(h => h.Column).Count();
+        public int ColumnWithObjects => containedColumns?.Count ?? 0;
 
         /// <summary>
         /// Adds a hit object to this pattern.
         /// </summary>
         /// <param name="hitObject">The hit object to add.</param>
-        public void Add(ManiaHitObject hitObject) => hitObjects.Add(hitObject);
+        public void Add(ManiaHitObject hitObject)
+        {
+            prepareStorage();
+
+            hitObjects.Add(hitObject);
+            containedColumns.Add(hitObject.Column);
+        }
 
         /// <summary>
         /// Copies hit object from another pattern to this one.
         /// </summary>
         /// <param name="other">The other pattern.</param>
-        public void Add(Pattern other) => hitObjects.AddRange(other.HitObjects);
+        public void Add(Pattern other)
+        {
+            prepareStorage();
+
+            if (other.hitObjects != null)
+            {
+                hitObjects.AddRange(other.hitObjects);
+
+                foreach (var h in other.hitObjects)
+                    containedColumns.Add(h.Column);
+            }
+        }
 
         /// <summary>
         /// Clears this pattern, removing all hit objects.
         /// </summary>
-        public void Clear() => hitObjects.Clear();
+        public void Clear()
+        {
+            hitObjects?.Clear();
+            containedColumns?.Clear();
+        }
 
-        /// <summary>
-        /// Removes a hit object from this pattern.
-        /// </summary>
-        /// <param name="hitObject">The hit object to remove.</param>
-        public bool Remove(ManiaHitObject hitObject) => hitObjects.Remove(hitObject);
+        private void prepareStorage()
+        {
+            hitObjects ??= new List<ManiaHitObject>();
+            containedColumns ??= new HashSet<int>();
+        }
     }
 }

osu.Game.Rulesets.Mania/Configuration/ManiaRulesetConfigManager.cs

@@ -28,7 +28,12 @@ namespace osu.Game.Rulesets.Mania.Configuration
         public override TrackedSettings CreateTrackedSettings() => new TrackedSettings
         {
             new TrackedSetting<double>(ManiaRulesetSetting.ScrollTime,
-                v => new SettingDescription(v, "Scroll Speed", $"{(int)Math.Round(DrawableManiaRuleset.MAX_TIME_RANGE / v)} ({v}ms)"))
+                scrollTime => new SettingDescription(
+                    rawValue: scrollTime,
+                    name: "Scroll Speed",
+                    value: $"{(int)Math.Round(DrawableManiaRuleset.MAX_TIME_RANGE / scrollTime)} ({scrollTime}ms)"
+                )
+            )
         };
     }
 

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

@@ -41,15 +41,14 @@ namespace osu.Game.Rulesets.Mania.Difficulty
                 return new ManiaDifficultyAttributes { Mods = mods, Skills = skills };
 
             HitWindows hitWindows = new ManiaHitWindows();
-            hitWindows.SetDifficulty(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty);
+            hitWindows.SetDifficulty(beatmap.Difficulty.OverallDifficulty);
 
             return new ManiaDifficultyAttributes
             {
                 StarRating = skills[0].DifficultyValue() * star_scaling_factor,
                 Mods = mods,
-                // Todo: This int cast is temporary to achieve 1:1 results with osu!stable, and should be removed in the future
-                GreatHitWindow = (int)Math.Ceiling(getHitWindow300(mods) / clockRate),
-                ScoreMultiplier = getScoreMultiplier(beatmap, mods),
+                GreatHitWindow = Math.Ceiling(getHitWindow300(mods) / clockRate),
+                ScoreMultiplier = getScoreMultiplier(mods),
                 MaxCombo = beatmap.HitObjects.Sum(h => h is HoldNote ? 2 : 1),
                 Skills = skills
             };
@@ -70,7 +69,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
 
         protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => new Skill[]
         {
-            new Strain(mods, ((ManiaBeatmap)beatmap).TotalColumns)
+            new Strain(mods, ((ManiaBeatmap)Beatmap).TotalColumns)
         };
 
         protected override Mod[] DifficultyAdjustmentMods
@@ -138,7 +137,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
             }
         }
 
-        private double getScoreMultiplier(IBeatmap beatmap, Mod[] mods)
+        private double getScoreMultiplier(Mod[] mods)
         {
             double scoreMultiplier = 1;
 
@@ -154,7 +153,7 @@ namespace osu.Game.Rulesets.Mania.Difficulty
                 }
             }
 
-            var maniaBeatmap = (ManiaBeatmap)beatmap;
+            var maniaBeatmap = (ManiaBeatmap)Beatmap;
             int diff = maniaBeatmap.TotalColumns - maniaBeatmap.OriginalTotalColumns;
 
             if (diff > 0)

osu.Game.Rulesets.Mania/Difficulty/Skills/Strain.cs

@@ -35,8 +35,8 @@ namespace osu.Game.Rulesets.Mania.Difficulty.Skills
         protected override double StrainValueOf(DifficultyHitObject current)
         {
             var maniaCurrent = (ManiaDifficultyHitObject)current;
-            var endTime = maniaCurrent.EndTime;
-            var column = maniaCurrent.BaseObject.Column;
+            double endTime = maniaCurrent.EndTime;
+            int column = maniaCurrent.BaseObject.Column;
 
             double holdFactor = 1.0; // Factor to all additional strains in case something else is held
             double holdAddition = 0; // Addition to the current note in case it's a hold and has to be released awkwardly

osu.Game.Rulesets.Mania/ManiaFilterCriteria.cs

@@ -13,9 +13,9 @@ namespace osu.Game.Rulesets.Mania
     {
         private FilterCriteria.OptionalRange<float> keys;
 
-        public bool Matches(BeatmapInfo beatmap)
+        public bool Matches(BeatmapInfo beatmapInfo)
         {
-            return !keys.HasFilter || (beatmap.RulesetID == new ManiaRuleset().LegacyID && keys.IsInRange(ManiaBeatmapConverter.GetColumnCountForNonConvert(beatmap)));
+            return !keys.HasFilter || (beatmapInfo.RulesetID == new ManiaRuleset().LegacyID && keys.IsInRange(ManiaBeatmapConverter.GetColumnCountForNonConvert(beatmapInfo)));
         }
 
         public bool TryParseCustomKeywordCriteria(string key, Operator op, string value)

osu.Game.Rulesets.Mania/ManiaRuleset.cs

@@ -316,7 +316,7 @@ namespace osu.Game.Rulesets.Mania
 
                 case PlayfieldType.Dual:
                 {
-                    var keys = getDualStageKeyCount(variant);
+                    int keys = getDualStageKeyCount(variant);
                     return $"{keys}K + {keys}K";
                 }
             }

osu.Game.Rulesets.Mania/MathUtils/LegacySortHelper.cs

@@ -62,9 +62,7 @@ namespace osu.Game.Rulesets.Mania.MathUtils
 
                     if (i < j)
                     {
-                        T key = keys[i];
-                        keys[i] = keys[j];
-                        keys[j] = key;
+                        (keys[i], keys[j]) = (keys[j], keys[i]);
                     }
 
                     i++;
@@ -122,7 +120,7 @@ namespace osu.Game.Rulesets.Mania.MathUtils
 
             while (i <= n / 2)
             {
-                var child = 2 * i;
+                int child = 2 * i;
 
                 if (child < n && comparer.Compare(keys[lo + child - 1], keys[lo + child]) < 0)
                 {
@@ -142,11 +140,7 @@ namespace osu.Game.Rulesets.Mania.MathUtils
         private static void swap(T[] a, int i, int j)
         {
             if (i != j)
-            {
-                T t = a[i];
-                a[i] = a[j];
-                a[j] = t;
-            }
+                (a[i], a[j]) = (a[j], a[i]);
         }
 
         private static void swapIfGreater(T[] keys, IComparer<T> comparer, int a, int b)
@@ -154,11 +148,7 @@ namespace osu.Game.Rulesets.Mania.MathUtils
             if (a != b)
             {
                 if (comparer.Compare(keys[a], keys[b]) > 0)
-                {
-                    T key = keys[a];
-                    keys[a] = keys[b];
-                    keys[b] = key;
-                }
+                    (keys[a], keys[b]) = (keys[b], keys[a]);
             }
         }
     }

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

@@ -16,7 +16,7 @@ namespace osu.Game.Rulesets.Mania.Mods
 
         public void ApplyToBeatmap(IBeatmap beatmap)
         {
-            var availableColumns = ((ManiaBeatmap)beatmap).TotalColumns;
+            int availableColumns = ((ManiaBeatmap)beatmap).TotalColumns;
 
             beatmap.HitObjects.OfType<ManiaHitObject>().ForEach(h => h.Column = availableColumns - 1 - h.Column);
         }

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

@@ -21,7 +21,7 @@ namespace osu.Game.Rulesets.Mania.Mods
             Seed.Value ??= RNG.Next();
             var rng = new Random((int)Seed.Value);
 
-            var availableColumns = ((ManiaBeatmap)beatmap).TotalColumns;
+            int availableColumns = ((ManiaBeatmap)beatmap).TotalColumns;
             var shuffledColumns = Enumerable.Range(0, availableColumns).OrderBy(item => rng.Next()).ToList();
 
             beatmap.HitObjects.OfType<ManiaHitObject>().ForEach(h => h.Column = shuffledColumns[h.Column]);

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

@@ -97,7 +97,7 @@ namespace osu.Game.Rulesets.Mania.Objects.Drawables
             if (Time.Current < HitObject.StartTime)
                 return;
 
-            var startTime = holdStartTime?.Invoke();
+            double? startTime = holdStartTime?.Invoke();
 
             if (startTime == null || startTime > HitObject.StartTime)
                 ApplyResult(r => r.Type = r.Judgement.MinResult);

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

@@ -84,7 +84,7 @@ namespace osu.Game.Rulesets.Mania.Objects
         /// </summary>
         private double tickSpacing = 50;
 
-        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+        protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
         {
             base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
 

osu.Game.Rulesets.Mania/Replays/ManiaAutoGenerator.cs

@@ -75,7 +75,7 @@ namespace osu.Game.Rulesets.Mania.Replays
             {
                 var currentObject = Beatmap.HitObjects[i];
                 var nextObjectInColumn = GetNextObject(i); // Get the next object that requires pressing the same button
-                var releaseTime = calculateReleaseTime(currentObject, nextObjectInColumn);
+                double releaseTime = calculateReleaseTime(currentObject, nextObjectInColumn);
 
                 yield return new HitPoint { Time = currentObject.StartTime, Column = currentObject.Column };
 

osu.Game.Rulesets.Mania/Resources/Testing/Beatmaps/mania-samples.osu

@@ -13,6 +13,7 @@ SliderTickRate:1
 
 [TimingPoints]
 0,500,4,1,0,100,1,0
+10000,-150,4,1,0,100,1,0
 
 [HitObjects]
 51,192,500,128,0,1500:1:0:0:0:

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

@@ -66,7 +66,7 @@ namespace osu.Game.Rulesets.Mania.Skinning.Legacy
             isLegacySkin = new Lazy<bool>(() => GetConfig<LegacySkinConfiguration.LegacySetting, decimal>(LegacySkinConfiguration.LegacySetting.Version) != null);
             hasKeyTexture = new Lazy<bool>(() =>
             {
-                var keyImage = this.GetManiaSkinConfig<string>(LegacyManiaSkinConfigurationLookups.KeyImage, 0)?.Value ?? "mania-key1";
+                string keyImage = this.GetManiaSkinConfig<string>(LegacyManiaSkinConfigurationLookups.KeyImage, 0)?.Value ?? "mania-key1";
                 return this.GetAnimation(keyImage, true, true) != null;
             });
         }

osu.Game.Rulesets.Mania/UI/DrawableManiaRuleset.cs

@@ -90,11 +90,11 @@ namespace osu.Game.Rulesets.Mania.UI
             {
                 // Mania doesn't care about global velocity
                 p.Velocity = 1;
-                p.BaseBeatLength *= Beatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier;
+                p.BaseBeatLength *= Beatmap.Difficulty.SliderMultiplier;
 
                 // For non-mania beatmap, speed changes should only happen through timing points
                 if (!isForCurrentRuleset)
-                    p.DifficultyPoint = new DifficultyControlPoint();
+                    p.EffectPoint = new EffectControlPoint();
             }
 
             BarLines.ForEach(Playfield.Add);

osu.Game.Rulesets.Osu.Tests/Editor/Checks/CheckTooShortSpinnersTest.cs

@@ -18,7 +18,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor.Checks
     public class CheckTooShortSpinnersTest
     {
         private CheckTooShortSpinners check;
-        private BeatmapDifficulty difficulty;
+        private IBeatmapDifficultyInfo difficulty;
 
         [SetUp]
         public void Setup()
@@ -81,12 +81,12 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor.Checks
             assertTooShort(new List<HitObject> { spinnerHighOd }, difficultyHighOd);
         }
 
-        private void assertOk(List<HitObject> hitObjects, BeatmapDifficulty beatmapDifficulty)
+        private void assertOk(List<HitObject> hitObjects, IBeatmapDifficultyInfo beatmapDifficulty)
         {
             Assert.That(check.Run(getContext(hitObjects, beatmapDifficulty)), Is.Empty);
         }
 
-        private void assertVeryShort(List<HitObject> hitObjects, BeatmapDifficulty beatmapDifficulty)
+        private void assertVeryShort(List<HitObject> hitObjects, IBeatmapDifficultyInfo beatmapDifficulty)
         {
             var issues = check.Run(getContext(hitObjects, beatmapDifficulty)).ToList();
 
@@ -94,7 +94,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor.Checks
             Assert.That(issues.First().Template is CheckTooShortSpinners.IssueTemplateVeryShort);
         }
 
-        private void assertTooShort(List<HitObject> hitObjects, BeatmapDifficulty beatmapDifficulty)
+        private void assertTooShort(List<HitObject> hitObjects, IBeatmapDifficultyInfo beatmapDifficulty)
         {
             var issues = check.Run(getContext(hitObjects, beatmapDifficulty)).ToList();
 
@@ -102,12 +102,12 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor.Checks
             Assert.That(issues.First().Template is CheckTooShortSpinners.IssueTemplateTooShort);
         }
 
-        private BeatmapVerifierContext getContext(List<HitObject> hitObjects, BeatmapDifficulty beatmapDifficulty)
+        private BeatmapVerifierContext getContext(List<HitObject> hitObjects, IBeatmapDifficultyInfo beatmapDifficulty)
         {
             var beatmap = new Beatmap<HitObject>
             {
                 HitObjects = hitObjects,
-                BeatmapInfo = new BeatmapInfo { BaseDifficulty = beatmapDifficulty }
+                BeatmapInfo = new BeatmapInfo { BaseDifficulty = new BeatmapDifficulty(beatmapDifficulty) }
             };
 
             return new BeatmapVerifierContext(beatmap, new TestWorkingBeatmap(beatmap));

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

@@ -11,6 +11,7 @@ using osu.Framework.Input.Events;
 using osu.Framework.Utils;
 using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Osu.Beatmaps;
 using osu.Game.Rulesets.Osu.Edit;
 using osu.Game.Rulesets.Osu.Objects;
@@ -45,7 +46,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
         [SetUp]
         public void Setup() => Schedule(() =>
         {
-            editorBeatmap.BeatmapInfo.BaseDifficulty.SliderMultiplier = 1;
+            editorBeatmap.Difficulty.SliderMultiplier = 1;
             editorBeatmap.ControlPointInfo.Clear();
             editorBeatmap.ControlPointInfo.Add(0, new TimingControlPoint { BeatLength = beat_length });
 
@@ -179,15 +180,15 @@ namespace osu.Game.Rulesets.Osu.Tests.Editor
 
             public SnapResult SnapScreenSpacePositionToValidTime(Vector2 screenSpacePosition) => new SnapResult(screenSpacePosition, 0);
 
-            public float GetBeatSnapDistanceAt(double referenceTime) => (float)beat_length;
+            public float GetBeatSnapDistanceAt(HitObject referenceObject) => (float)beat_length;
 
-            public float DurationToDistance(double referenceTime, double duration) => (float)duration;
+            public float DurationToDistance(HitObject referenceObject, double duration) => (float)duration;
 
-            public double DistanceToDuration(double referenceTime, float distance) => distance;
+            public double DistanceToDuration(HitObject referenceObject, float distance) => distance;
 
-            public double GetSnappedDurationFromDistance(double referenceTime, float distance) => 0;
+            public double GetSnappedDurationFromDistance(HitObject referenceObject, float distance) => 0;
 
-            public float GetSnappedDistanceFromDistance(double referenceTime, float distance) => 0;
+            public float GetSnappedDistanceFromDistance(HitObject referenceObject, float distance) => 0;
         }
     }
 }

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

@@ -0,0 +1,78 @@
+// 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 NUnit.Framework;
+using osu.Framework.Testing;
+using osu.Framework.Utils;
+using osu.Game.Rulesets.Osu.Edit;
+using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles;
+using osu.Game.Tests.Visual;
+using osuTK;
+using osuTK.Input;
+
+namespace osu.Game.Rulesets.Osu.Tests.Editor
+{
+    public class TestSceneOsuEditorGrids : EditorTestScene
+    {
+        protected override Ruleset CreateEditorRuleset() => new OsuRuleset();
+
+        [Test]
+        public void TestGridExclusivity()
+        {
+            AddStep("enable distance snap grid", () => InputManager.Key(Key.T));
+            AddStep("select second object", () => EditorBeatmap.SelectedHitObjects.Add(EditorBeatmap.HitObjects.ElementAt(1)));
+            AddUntilStep("distance snap grid visible", () => this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
+            rectangularGridActive(false);
+
+            AddStep("enable rectangular grid", () => InputManager.Key(Key.Y));
+            AddUntilStep("distance snap grid hidden", () => !this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
+            rectangularGridActive(true);
+
+            AddStep("enable distance snap grid", () => InputManager.Key(Key.T));
+            AddStep("select second object", () => EditorBeatmap.SelectedHitObjects.Add(EditorBeatmap.HitObjects.ElementAt(1)));
+            AddUntilStep("distance snap grid visible", () => this.ChildrenOfType<OsuDistanceSnapGrid>().Any());
+            rectangularGridActive(false);
+        }
+
+        private void rectangularGridActive(bool active)
+        {
+            AddStep("choose placement tool", () => InputManager.Key(Key.Number2));
+            AddStep("move cursor to (1, 1)", () =>
+            {
+                var composer = Editor.ChildrenOfType<OsuRectangularPositionSnapGrid>().Single();
+                InputManager.MoveMouseTo(composer.ToScreenSpace(new Vector2(1, 1)));
+            });
+
+            if (active)
+                AddAssert("placement blueprint at (0, 0)", () => Precision.AlmostEquals(Editor.ChildrenOfType<HitCirclePlacementBlueprint>().Single().HitObject.Position, new Vector2(0, 0)));
+            else
+                AddAssert("placement blueprint at (1, 1)", () => Precision.AlmostEquals(Editor.ChildrenOfType<HitCirclePlacementBlueprint>().Single().HitObject.Position, new Vector2(1, 1)));
+
+            AddStep("choose selection tool", () => InputManager.Key(Key.Number1));
+        }
+
+        [Test]
+        public void TestGridSizeToggling()
+        {
+            AddStep("enable rectangular grid", () => InputManager.Key(Key.Y));
+            AddUntilStep("rectangular grid visible", () => this.ChildrenOfType<OsuRectangularPositionSnapGrid>().Any());
+            gridSizeIs(4);
+
+            nextGridSizeIs(8);
+            nextGridSizeIs(16);
+            nextGridSizeIs(32);
+            nextGridSizeIs(4);
+        }
+
+        private void nextGridSizeIs(int size)
+        {
+            AddStep("toggle to next grid size", () => InputManager.Key(Key.G));
+            gridSizeIs(size);
+        }
+
+        private void gridSizeIs(int size)
+            => AddAssert($"grid size is {size}", () => this.ChildrenOfType<OsuRectangularPositionSnapGrid>().Single().Spacing == new Vector2(size)
+                                                       && EditorBeatmap.BeatmapInfo.GridSize == size);
+    }
+}

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

@@ -45,8 +45,8 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
                     {
                         new Spinner
                         {
-                            Duration = 2000,
-                            Position = OsuPlayfield.BASE_SIZE / 2
+                            Duration = 6000,
+                            Position = OsuPlayfield.BASE_SIZE / 2,
                         }
                     }
                 },

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

@@ -4,13 +4,11 @@
 using System.Collections.Generic;
 using System.Linq;
 using NUnit.Framework;
-using osu.Framework.Testing;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.Osu.Objects;
-using osu.Game.Screens.Play;
 using osuTK;
 
 namespace osu.Game.Rulesets.Osu.Tests.Mods
@@ -119,10 +117,46 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
             PassCondition = checkSomeHit
         });
 
+        [Test]
+        public void TestApproachCirclesOnly() => CreateModTest(new ModTestData
+        {
+            Mod = new OsuModHidden { OnlyFadeApproachCircles = { Value = true } },
+            Autoplay = true,
+            Beatmap = new Beatmap
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle
+                    {
+                        StartTime = 1000,
+                        Position = new Vector2(206, 142)
+                    },
+                    new HitCircle
+                    {
+                        StartTime = 2000,
+                        Position = new Vector2(306, 142)
+                    },
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = new Vector2(156, 242),
+                        Path = new SliderPath(PathType.Linear, new[] { Vector2.Zero, new Vector2(200, 0), })
+                    },
+                    new Spinner
+                    {
+                        Position = new Vector2(256, 192),
+                        StartTime = 7000,
+                        EndTime = 9000
+                    }
+                }
+            },
+            PassCondition = checkSomeHit
+        });
+
         private bool checkSomeHit() => Player.ScoreProcessor.JudgedHits >= 4;
 
         private bool objectWithIncreasedVisibilityHasIndex(int index)
-            => Player.Mods.Value.OfType<TestOsuModHidden>().Single().FirstObject == Player.ChildrenOfType<GameplayBeatmap>().Single().HitObjects[index];
+            => Player.GameplayState.Mods.OfType<TestOsuModHidden>().Single().FirstObject == Player.GameplayState.Beatmap.HitObjects[index];
 
         private class TestOsuModHidden : OsuModHidden
         {

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

@@ -0,0 +1,150 @@
+// 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 NUnit.Framework;
+using osu.Framework.Utils;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.Timing;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu.Mods;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Tests.Mods
+{
+    public class TestSceneOsuModNoScope : OsuModTestScene
+    {
+        [Test]
+        public void TestVisibleDuringBreak()
+        {
+            CreateModTest(new ModTestData
+            {
+                Mod = new OsuModNoScope
+                {
+                    HiddenComboCount = { Value = 0 },
+                },
+                Autoplay = true,
+                PassCondition = () => true,
+                Beatmap = new Beatmap
+                {
+                    HitObjects = new List<HitObject>
+                    {
+                        new HitCircle
+                        {
+                            Position = new Vector2(300, 192),
+                            StartTime = 1000,
+                        },
+                        new HitCircle
+                        {
+                            Position = new Vector2(300, 192),
+                            StartTime = 5000,
+                        }
+                    },
+                    Breaks = new List<BreakPeriod>
+                    {
+                        new BreakPeriod(2000, 4000),
+                    }
+                }
+            });
+
+            AddUntilStep("wait for cursor to hide", () => cursorAlphaAlmostEquals(0));
+            AddUntilStep("wait for start of break", isBreak);
+            AddUntilStep("wait for cursor to show", () => cursorAlphaAlmostEquals(1));
+            AddUntilStep("wait for end of break", () => !isBreak());
+            AddUntilStep("wait for cursor to hide", () => cursorAlphaAlmostEquals(0));
+        }
+
+        [Test]
+        public void TestVisibleDuringSpinner()
+        {
+            CreateModTest(new ModTestData
+            {
+                Mod = new OsuModNoScope
+                {
+                    HiddenComboCount = { Value = 0 },
+                },
+                Autoplay = true,
+                PassCondition = () => true,
+                Beatmap = new Beatmap
+                {
+                    HitObjects = new List<HitObject>
+                    {
+                        new HitCircle
+                        {
+                            Position = new Vector2(300, 192),
+                            StartTime = 1000,
+                        },
+                        new Spinner
+                        {
+                            Position = new Vector2(256, 192),
+                            StartTime = 2000,
+                            Duration = 2000,
+                        },
+                        new HitCircle
+                        {
+                            Position = new Vector2(300, 192),
+                            StartTime = 5000,
+                        }
+                    }
+                }
+            });
+
+            AddUntilStep("wait for cursor to hide", () => cursorAlphaAlmostEquals(0));
+            AddUntilStep("wait for start of spinner", isSpinning);
+            AddUntilStep("wait for cursor to show", () => cursorAlphaAlmostEquals(1));
+            AddUntilStep("wait for end of spinner", () => !isSpinning());
+            AddUntilStep("wait for cursor to hide", () => cursorAlphaAlmostEquals(0));
+        }
+
+        [Test]
+        public void TestVisibleAfterComboBreak()
+        {
+            CreateModTest(new ModTestData
+            {
+                Mod = new OsuModNoScope
+                {
+                    HiddenComboCount = { Value = 2 },
+                },
+                Autoplay = true,
+                PassCondition = () => true,
+                Beatmap = new Beatmap
+                {
+                    HitObjects = new List<HitObject>
+                    {
+                        new HitCircle
+                        {
+                            Position = new Vector2(100, 192),
+                            StartTime = 1000,
+                        },
+                        new HitCircle
+                        {
+                            Position = new Vector2(150, 192),
+                            StartTime = 3000,
+                        },
+                        new HitCircle
+                        {
+                            Position = new Vector2(200, 192),
+                            StartTime = 5000,
+                        },
+                    }
+                }
+            });
+
+            AddAssert("cursor must start visible", () => cursorAlphaAlmostEquals(1));
+            AddUntilStep("wait for combo", () => Player.ScoreProcessor.Combo.Value >= 2);
+            AddAssert("cursor must dim after combo", () => !cursorAlphaAlmostEquals(1));
+            AddStep("break combo", () => Player.ScoreProcessor.Combo.Set(0));
+            AddUntilStep("wait for cursor to show", () => cursorAlphaAlmostEquals(1));
+        }
+
+        private bool isSpinning() => Player.ChildrenOfType<DrawableSpinner>().SingleOrDefault()?.Progress > 0;
+
+        private bool isBreak() => Player.IsBreakTime.Value;
+
+        private bool cursorAlphaAlmostEquals(float alpha) => Precision.AlmostEquals(Player.DrawableRuleset.Cursor.Alpha, alpha);
+    }
+}

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

@@ -15,13 +15,13 @@ namespace osu.Game.Rulesets.Osu.Tests
     {
         protected override string ResourceAssembly => "osu.Game.Rulesets.Osu";
 
-        [TestCase(6.6634445062299665d, "diffcalc-test")]
-        [TestCase(1.0414203870195022d, "zero-length-sliders")]
+        [TestCase(6.5867229481955389d, "diffcalc-test")]
+        [TestCase(1.0416315570967911d, "zero-length-sliders")]
         public void Test(double expected, string name)
             => base.Test(expected, name);
 
-        [TestCase(8.3858089051603368d, "diffcalc-test")]
-        [TestCase(1.2723279173428435d, "zero-length-sliders")]
+        [TestCase(8.2730989071947896d, "diffcalc-test")]
+        [TestCase(1.2726413186221039d, "zero-length-sliders")]
         public void TestClockRateAdjusted(double expected, string name)
             => Test(expected, name, new OsuModDoubleTime());
 

osu.Game.Rulesets.Osu.Tests/Resources/special-skin/skin.ini

@@ -0,0 +1,3 @@
+[General]
+Version: latest
+HitCircleOverlayAboveNumber: 0

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

@@ -48,7 +48,7 @@ namespace osu.Game.Rulesets.Osu.Tests
                 {
                     Position = new Vector2(100, 300),
                 },
-                accuracyHeatmap = new TestAccuracyHeatmap(new ScoreInfo { Beatmap = new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo })
+                accuracyHeatmap = new TestAccuracyHeatmap(new ScoreInfo { BeatmapInfo = new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo })
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,

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

@@ -0,0 +1,175 @@
+// 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 NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.ControlPoints;
+using osu.Game.Beatmaps.Timing;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.Objects.Drawables;
+using osu.Game.Rulesets.Osu.Skinning.Legacy;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Skinning;
+using osuTK;
+using osuTK.Input;
+
+namespace osu.Game.Rulesets.Osu.Tests
+{
+    public class TestSceneCursorParticles : TestSceneOsuPlayer
+    {
+        protected override bool Autoplay => autoplay;
+        protected override bool HasCustomSteps => true;
+
+        private bool autoplay;
+        private IBeatmap currentBeatmap;
+
+        [Resolved]
+        private SkinManager skinManager { get; set; }
+
+        protected override IBeatmap CreateBeatmap(RulesetInfo ruleset) => currentBeatmap ?? base.CreateBeatmap(ruleset);
+
+        [Test]
+        public void TestLegacyBreakParticles()
+        {
+            LegacyCursorParticles cursorParticles = null;
+
+            createLegacyTest(false, () => new Beatmap
+            {
+                Breaks =
+                {
+                    new BreakPeriod(8500, 10000),
+                },
+                HitObjects =
+                {
+                    new HitCircle
+                    {
+                        StartTime = 8000,
+                        Position = OsuPlayfield.BASE_SIZE / 2,
+                    },
+                    new HitCircle
+                    {
+                        StartTime = 11000,
+                        Position = OsuPlayfield.BASE_SIZE / 2,
+                    },
+                }
+            });
+
+            AddUntilStep("fetch cursor particles", () =>
+            {
+                cursorParticles = this.ChildrenOfType<LegacyCursorParticles>().SingleOrDefault();
+                return cursorParticles != null;
+            });
+
+            AddStep("move mouse to centre", () => InputManager.MoveMouseTo(Player.ScreenSpaceDrawQuad.Centre));
+
+            AddAssert("particles are being spawned", () => cursorParticles.Active);
+
+            AddStep("press left mouse button", () => InputManager.PressButton(MouseButton.Left));
+            AddWaitStep("wait a bit", 5);
+            AddStep("press right mouse button", () => InputManager.PressButton(MouseButton.Right));
+            AddWaitStep("wait a bit", 5);
+            AddStep("release left mouse button", () => InputManager.ReleaseButton(MouseButton.Left));
+            AddWaitStep("wait a bit", 5);
+            AddStep("release right mouse button", () => InputManager.ReleaseButton(MouseButton.Right));
+
+            AddUntilStep("wait for beatmap start", () => !Player.IsBreakTime.Value);
+            AddAssert("particle spawning stopped", () => !cursorParticles.Active);
+
+            AddUntilStep("wait for break", () => Player.IsBreakTime.Value);
+            AddAssert("particles are being spawned", () => cursorParticles.Active);
+
+            AddUntilStep("wait for break end", () => !Player.IsBreakTime.Value);
+            AddAssert("particle spawning stopped", () => !cursorParticles.Active);
+        }
+
+        [Test]
+        public void TestLegacyKiaiParticles()
+        {
+            LegacyCursorParticles cursorParticles = null;
+            DrawableSpinner spinner = null;
+            DrawableSlider slider = null;
+
+            createLegacyTest(true, () =>
+                {
+                    var controlPointInfo = new ControlPointInfo();
+                    controlPointInfo.Add(0, new EffectControlPoint { KiaiMode = true });
+                    controlPointInfo.Add(5000, new EffectControlPoint { KiaiMode = false });
+
+                    return new Beatmap
+                    {
+                        ControlPointInfo = controlPointInfo,
+                        HitObjects =
+                        {
+                            new Spinner
+                            {
+                                StartTime = 0,
+                                Duration = 1000,
+                                Position = OsuPlayfield.BASE_SIZE / 2,
+                            },
+                            new Slider
+                            {
+                                StartTime = 2500,
+                                RepeatCount = 0,
+                                Position = OsuPlayfield.BASE_SIZE / 2,
+                                Path = new SliderPath(new[]
+                                {
+                                    new PathControlPoint(Vector2.Zero),
+                                    new PathControlPoint(new Vector2(100, 0)),
+                                })
+                            },
+                            new HitCircle
+                            {
+                                StartTime = 4500,
+                                Position = OsuPlayfield.BASE_SIZE / 2,
+                            },
+                        },
+                    };
+                }
+            );
+
+            AddUntilStep("fetch cursor particles", () =>
+            {
+                cursorParticles = this.ChildrenOfType<LegacyCursorParticles>().SingleOrDefault();
+                return cursorParticles != null;
+            });
+
+            AddUntilStep("wait for spinner tracking", () =>
+            {
+                spinner = this.ChildrenOfType<DrawableSpinner>().SingleOrDefault();
+                return spinner?.RotationTracker.Tracking == true;
+            });
+            AddAssert("particles are being spawned", () => cursorParticles.Active);
+
+            AddUntilStep("spinner tracking stopped", () => !spinner.RotationTracker.Tracking);
+            AddAssert("particle spawning stopped", () => !cursorParticles.Active);
+
+            AddUntilStep("wait for slider tracking", () =>
+            {
+                slider = this.ChildrenOfType<DrawableSlider>().SingleOrDefault();
+                return slider?.Tracking.Value == true;
+            });
+            AddAssert("particles are being spawned", () => cursorParticles.Active);
+
+            AddUntilStep("slider tracking stopped", () => !slider.Tracking.Value);
+            AddAssert("particle spawning stopped", () => !cursorParticles.Active);
+        }
+
+        private void createLegacyTest(bool autoplay, Func<IBeatmap> beatmap) => CreateTest(() =>
+        {
+            AddStep("set beatmap", () =>
+            {
+                this.autoplay = autoplay;
+                currentBeatmap = beatmap();
+            });
+            AddStep("setup default legacy skin", () =>
+            {
+                skinManager.CurrentSkinInfo.Value = skinManager.DefaultLegacySkin.SkinInfo;
+            });
+        });
+    }
+}

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

@@ -17,6 +17,7 @@ using osu.Framework.Testing.Input;
 using osu.Framework.Utils;
 using osu.Game.Audio;
 using osu.Game.Configuration;
+using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Skinning;
 using osu.Game.Rulesets.Osu.UI.Cursor;
 using osu.Game.Screens.Play;
@@ -29,7 +30,7 @@ namespace osu.Game.Rulesets.Osu.Tests
     public class TestSceneGameplayCursor : OsuSkinnableTestScene
     {
         [Cached]
-        private GameplayBeatmap gameplayBeatmap;
+        private GameplayState gameplayState;
 
         private OsuCursorContainer lastContainer;
 
@@ -40,7 +41,8 @@ namespace osu.Game.Rulesets.Osu.Tests
 
         public TestSceneGameplayCursor()
         {
-            gameplayBeatmap = new GameplayBeatmap(CreateBeatmap(new OsuRuleset().RulesetInfo));
+            var ruleset = new OsuRuleset();
+            gameplayState = new GameplayState(CreateBeatmap(ruleset.RulesetInfo), ruleset, Array.Empty<Mod>());
 
             AddStep("change background colour", () =>
             {
@@ -57,8 +59,8 @@ namespace osu.Game.Rulesets.Osu.Tests
             AddSliderStep("circle size", 0f, 10f, 0f, val =>
             {
                 config.SetValue(OsuSetting.AutoCursorSize, true);
-                gameplayBeatmap.BeatmapInfo.BaseDifficulty.CircleSize = val;
-                Scheduler.AddOnce(() => loadContent(false));
+                gameplayState.Beatmap.Difficulty.CircleSize = val;
+                Scheduler.AddOnce(loadContent);
             });
 
             AddStep("test cursor container", () => loadContent(false));
@@ -73,10 +75,10 @@ namespace osu.Game.Rulesets.Osu.Tests
         public void TestSizing(int circleSize, float userScale)
         {
             AddStep($"set user scale to {userScale}", () => config.SetValue(OsuSetting.GameplayCursorSize, userScale));
-            AddStep($"adjust cs to {circleSize}", () => gameplayBeatmap.BeatmapInfo.BaseDifficulty.CircleSize = circleSize);
+            AddStep($"adjust cs to {circleSize}", () => gameplayState.Beatmap.Difficulty.CircleSize = circleSize);
             AddStep("turn on autosizing", () => config.SetValue(OsuSetting.AutoCursorSize, true));
 
-            AddStep("load content", () => loadContent());
+            AddStep("load content", loadContent);
 
             AddUntilStep("cursor size correct", () => lastContainer.ActiveCursor.Scale.X == OsuCursorContainer.GetScaleForCircleSize(circleSize) * userScale);
 
@@ -96,7 +98,9 @@ namespace osu.Game.Rulesets.Osu.Tests
             AddStep("load content", () => loadContent(false, () => new SkinProvidingContainer(new TopLeftCursorSkin())));
         }
 
-        private void loadContent(bool automated = true, Func<SkinProvidingContainer> skinProvider = null)
+        private void loadContent() => loadContent(false);
+
+        private void loadContent(bool automated, Func<SkinProvidingContainer> skinProvider = null)
         {
             SetContents(_ =>
             {

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

@@ -97,7 +97,7 @@ namespace osu.Game.Rulesets.Osu.Tests
 
         private void scheduleHit() => AddStep("schedule action", () =>
         {
-            var delay = hitCircle.StartTime - hitCircle.HitWindows.WindowFor(HitResult.Great) - Time.Current;
+            double delay = hitCircle.StartTime - hitCircle.HitWindows.WindowFor(HitResult.Great) - Time.Current;
             Scheduler.AddDelayed(() => hitAreaReceptor.OnPressed(new KeyBindingPressEvent<OsuAction>(GetContainingInputManager().CurrentState, OsuAction.LeftButton)), delay);
         });
     }

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

@@ -32,7 +32,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             };
 
             var hitWindows = new OsuHitWindows();
-            hitWindows.SetDifficulty(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty);
+            hitWindows.SetDifficulty(beatmap.Difficulty.OverallDifficulty);
 
             CreateModTest(new ModTestData
             {
@@ -55,7 +55,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             };
 
             var hitWindows = new OsuHitWindows();
-            hitWindows.SetDifficulty(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty);
+            hitWindows.SetDifficulty(beatmap.Difficulty.OverallDifficulty);
 
             CreateModTest(new ModTestData
             {

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

@@ -400,15 +400,13 @@ namespace osu.Game.Rulesets.Osu.Tests
                 Beatmap.Value = CreateWorkingBeatmap(new Beatmap<OsuHitObject>
                 {
                     HitObjects = hitObjects,
+                    Difficulty = new BeatmapDifficulty { SliderTickRate = 3 },
                     BeatmapInfo =
                     {
-                        BaseDifficulty = new BeatmapDifficulty { SliderTickRate = 3 },
                         Ruleset = new OsuRuleset().RulesetInfo
                     },
                 });
 
-                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
-
                 SelectedMods.Value = new[] { new OsuModClassic() };
 
                 var p = new ScoreAccessibleReplayPlayer(new Score { Replay = new Replay { Frames = frames } });
@@ -439,6 +437,8 @@ namespace osu.Game.Rulesets.Osu.Tests
         {
             public TestSlider()
             {
+                DifficultyControlPoint = new DifficultyControlPoint { SliderVelocity = 0.1f };
+
                 DefaultsApplied += _ =>
                 {
                     HeadCircle.HitWindows = new TestHitWindows();
@@ -452,7 +452,7 @@ namespace osu.Game.Rulesets.Osu.Tests
 
         private class TestSpinner : Spinner
         {
-            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
             {
                 base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
                 SpinsRequired = 1;

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

@@ -13,6 +13,7 @@ using osuTK.Graphics;
 using osu.Game.Rulesets.Mods;
 using System.Linq;
 using NUnit.Framework;
+using osu.Game.Beatmaps.Legacy;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Rulesets.Judgements;
@@ -328,10 +329,14 @@ namespace osu.Game.Rulesets.Osu.Tests
 
         private Drawable createDrawable(Slider slider, float circleSize, double speedMultiplier)
         {
-            var cpi = new ControlPointInfo();
-            cpi.Add(0, new DifficultyControlPoint { SpeedMultiplier = speedMultiplier });
+            var cpi = new LegacyControlPointInfo();
+            cpi.Add(0, new DifficultyControlPoint { SliderVelocity = speedMultiplier });
 
-            slider.ApplyDefaults(cpi, new BeatmapDifficulty { CircleSize = circleSize, SliderTickRate = 3 });
+            slider.ApplyDefaults(cpi, new BeatmapDifficulty
+            {
+                CircleSize = circleSize,
+                SliderTickRate = 3
+            });
 
             var drawable = CreateDrawableSlider(slider);
 

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

@@ -348,6 +348,7 @@ namespace osu.Game.Rulesets.Osu.Tests
                         {
                             StartTime = time_slider_start,
                             Position = new Vector2(0, 0),
+                            DifficultyControlPoint = new DifficultyControlPoint { SliderVelocity = 0.1f },
                             Path = new SliderPath(PathType.PerfectCurve, new[]
                             {
                                 Vector2.Zero,
@@ -362,8 +363,6 @@ namespace osu.Game.Rulesets.Osu.Tests
                     },
                 });
 
-                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
-
                 var p = new ScoreAccessibleReplayPlayer(new Score { Replay = new Replay { Frames = frames } });
 
                 p.OnLoadComplete += _ =>

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

@@ -30,6 +30,9 @@ namespace osu.Game.Rulesets.Osu.Tests
 {
     public class TestSceneSpinnerRotation : TestSceneOsuPlayer
     {
+        private const double spinner_start_time = 100;
+        private const double spinner_duration = 6000;
+
         [Resolved]
         private AudioManager audioManager { get; set; }
 
@@ -77,7 +80,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             double finalTrackerRotation = 0, trackerRotationTolerance = 0;
             double finalSpinnerSymbolRotation = 0, spinnerSymbolRotationTolerance = 0;
 
-            addSeekStep(5000);
+            addSeekStep(spinner_start_time + 5000);
             AddStep("retrieve disc rotation", () =>
             {
                 finalTrackerRotation = drawableSpinner.RotationTracker.Rotation;
@@ -90,7 +93,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             });
             AddStep("retrieve cumulative disc rotation", () => finalCumulativeTrackerRotation = drawableSpinner.Result.RateAdjustedRotation);
 
-            addSeekStep(2500);
+            addSeekStep(spinner_start_time + 2500);
             AddAssert("disc rotation rewound",
                 // we want to make sure that the rotation at time 2500 is in the same direction as at time 5000, but about half-way in.
                 // due to the exponential damping applied we're allowing a larger margin of error of about 10%
@@ -102,7 +105,7 @@ namespace osu.Game.Rulesets.Osu.Tests
                 // cumulative rotation is not damped, so we're treating it as the "ground truth" and allowing a comparatively smaller margin of error.
                 () => Precision.AlmostEquals(drawableSpinner.Result.RateAdjustedRotation, finalCumulativeTrackerRotation / 2, 100));
 
-            addSeekStep(5000);
+            addSeekStep(spinner_start_time + 5000);
             AddAssert("is disc rotation almost same",
                 () => Precision.AlmostEquals(drawableSpinner.RotationTracker.Rotation, finalTrackerRotation, trackerRotationTolerance));
             AddAssert("is symbol rotation almost same",
@@ -140,12 +143,12 @@ namespace osu.Game.Rulesets.Osu.Tests
         [Test]
         public void TestSpinnerNormalBonusRewinding()
         {
-            addSeekStep(1000);
+            addSeekStep(spinner_start_time + 1000);
 
             AddAssert("player score matching expected bonus score", () =>
             {
                 // multipled by 2 to nullify the score multiplier. (autoplay mod selected)
-                var totalScore = ((ScoreExposedPlayer)Player).ScoreProcessor.TotalScore.Value * 2;
+                double totalScore = ((ScoreExposedPlayer)Player).ScoreProcessor.TotalScore.Value * 2;
                 return totalScore == (int)(drawableSpinner.Result.RateAdjustedRotation / 360) * new SpinnerTick().CreateJudgement().MaxNumericResult;
             });
 
@@ -201,24 +204,9 @@ namespace osu.Game.Rulesets.Osu.Tests
             AddAssert("spm almost same", () => Precision.AlmostEquals(expectedSpm, drawableSpinner.SpinsPerMinute.Value, 2.0));
         }
 
-        private Replay applyRateAdjustment(Replay scoreReplay, double rate) => new Replay
-        {
-            Frames = scoreReplay
-                     .Frames
-                     .Cast<OsuReplayFrame>()
-                     .Select(replayFrame =>
-                     {
-                         var adjustedTime = replayFrame.Time * rate;
-                         return new OsuReplayFrame(adjustedTime, replayFrame.Position, replayFrame.Actions.ToArray());
-                     })
-                     .Cast<ReplayFrame>()
-                     .ToList()
-        };
-
         private void addSeekStep(double time)
         {
             AddStep($"seek to {time}", () => Player.GameplayClockContainer.Seek(time));
-
             AddUntilStep("wait for seek to finish", () => Precision.AlmostEquals(time, Player.DrawableRuleset.FrameStableClock.CurrentTime, 100));
         }
 
@@ -241,7 +229,8 @@ namespace osu.Game.Rulesets.Osu.Tests
                 new Spinner
                 {
                     Position = new Vector2(256, 192),
-                    EndTime = 6000,
+                    StartTime = spinner_start_time,
+                    Duration = spinner_duration
                 },
             }
         };

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

@@ -369,8 +369,6 @@ namespace osu.Game.Rulesets.Osu.Tests
                     },
                 });
 
-                Beatmap.Value.Beatmap.ControlPointInfo.Add(0, new DifficultyControlPoint { SpeedMultiplier = 0.1f });
-
                 var p = new ScoreAccessibleReplayPlayer(new Score { Replay = new Replay { Frames = frames } });
 
                 p.OnLoadComplete += _ =>
@@ -399,6 +397,8 @@ namespace osu.Game.Rulesets.Osu.Tests
         {
             public TestSlider()
             {
+                DifficultyControlPoint = new DifficultyControlPoint { SliderVelocity = 0.1f };
+
                 DefaultsApplied += _ =>
                 {
                     HeadCircle.HitWindows = new TestHitWindows();
@@ -412,7 +412,7 @@ namespace osu.Game.Rulesets.Osu.Tests
 
         private class TestSpinner : Spinner
         {
-            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
+            protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, IBeatmapDifficultyInfo difficulty)
             {
                 base.ApplyDefaultsToSelf(controlPointInfo, difficulty);
                 SpinsRequired = 1;

osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmapConverter.cs

@@ -11,6 +11,7 @@ using System.Linq;
 using System.Threading;
 using osu.Game.Rulesets.Osu.UI;
 using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Game.Beatmaps.Legacy;
 
 namespace osu.Game.Rulesets.Osu.Beatmaps
 {
@@ -44,7 +45,7 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
                         LegacyLastTickOffset = (original as IHasLegacyLastTickOffset)?.LegacyLastTickOffset,
                         // prior to v8, speed multipliers don't adjust for how many ticks are generated over the same distance.
                         // this results in more (or less) ticks being generated in <v8 maps for the same time duration.
-                        TickDistanceMultiplier = beatmap.BeatmapInfo.BeatmapVersion < 8 ? 1f / beatmap.ControlPointInfo.DifficultyPointAt(original.StartTime).SpeedMultiplier : 1
+                        TickDistanceMultiplier = beatmap.BeatmapInfo.BeatmapVersion < 8 ? 1f / ((LegacyControlPointInfo)beatmap.ControlPointInfo).DifficultyPointAt(original.StartTime).SliderVelocity : 1
                     }.Yield();
 
                 case IHasDuration endTimeData:

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

@@ -9,9 +9,12 @@ namespace osu.Game.Rulesets.Osu.Difficulty
     {
         public double AimStrain { get; set; }
         public double SpeedStrain { get; set; }
+        public double FlashlightRating { get; set; }
         public double ApproachRate { get; set; }
         public double OverallDifficulty { get; set; }
+        public double DrainRate { get; set; }
         public int HitCircleCount { get; set; }
+        public int SliderCount { get; set; }
         public int SpinnerCount { get; set; }
     }
 }

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

@@ -21,6 +21,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
     public class OsuDifficultyCalculator : DifficultyCalculator
     {
         private const double difficulty_multiplier = 0.0675;
+        private double hitWindowGreat;
 
         public OsuDifficultyCalculator(Ruleset ruleset, WorkingBeatmap beatmap)
             : base(ruleset, beatmap)
@@ -34,24 +35,36 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             double aimRating = Math.Sqrt(skills[0].DifficultyValue()) * difficulty_multiplier;
             double speedRating = Math.Sqrt(skills[1].DifficultyValue()) * difficulty_multiplier;
+            double flashlightRating = Math.Sqrt(skills[2].DifficultyValue()) * difficulty_multiplier;
+
+            if (mods.Any(h => h is OsuModRelax))
+                speedRating = 0.0;
 
             double baseAimPerformance = Math.Pow(5 * Math.Max(1, aimRating / 0.0675) - 4, 3) / 100000;
             double baseSpeedPerformance = Math.Pow(5 * Math.Max(1, speedRating / 0.0675) - 4, 3) / 100000;
-            double basePerformance = Math.Pow(Math.Pow(baseAimPerformance, 1.1) + Math.Pow(baseSpeedPerformance, 1.1), 1 / 1.1);
+            double baseFlashlightPerformance = 0.0;
+
+            if (mods.Any(h => h is OsuModFlashlight))
+                baseFlashlightPerformance = Math.Pow(flashlightRating, 2.0) * 25.0;
+
+            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 = basePerformance > 0.00001 ? Math.Cbrt(1.12) * 0.027 * (Math.Cbrt(100000 / Math.Pow(2, 1 / 1.1) * basePerformance) + 4) : 0;
 
-            HitWindows hitWindows = new OsuHitWindows();
-            hitWindows.SetDifficulty(beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty);
-
-            // Todo: These int casts are temporary to achieve 1:1 results with osu!stable, and should be removed in the future
-            double hitWindowGreat = (int)(hitWindows.WindowFor(HitResult.Great)) / clockRate;
-            double preempt = (int)BeatmapDifficulty.DifficultyRange(beatmap.BeatmapInfo.BaseDifficulty.ApproachRate, 1800, 1200, 450) / clockRate;
+            double preempt = IBeatmapDifficultyInfo.DifficultyRange(beatmap.Difficulty.ApproachRate, 1800, 1200, 450) / clockRate;
+            double drainRate = beatmap.Difficulty.DrainRate;
 
             int maxCombo = beatmap.HitObjects.Count;
             // Add the ticks + tail of the slider. 1 is subtracted because the head circle would be counted twice (once for the slider itself in the line above)
             maxCombo += beatmap.HitObjects.OfType<Slider>().Sum(s => s.NestedHitObjects.Count - 1);
 
             int hitCirclesCount = 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);
 
             return new OsuDifficultyAttributes
@@ -60,10 +73,13 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 Mods = mods,
                 AimStrain = aimRating,
                 SpeedStrain = speedRating,
+                FlashlightRating = flashlightRating,
                 ApproachRate = preempt > 1200 ? (1800 - preempt) / 120 : (1200 - preempt) / 150 + 5,
                 OverallDifficulty = (80 - hitWindowGreat) / 6,
+                DrainRate = drainRate,
                 MaxCombo = maxCombo,
                 HitCircleCount = hitCirclesCount,
+                SliderCount = sliderCount,
                 SpinnerCount = spinnerCount,
                 Skills = skills
             };
@@ -83,11 +99,20 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             }
         }
 
-        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate) => new Skill[]
+        protected override Skill[] CreateSkills(IBeatmap beatmap, Mod[] mods, double clockRate)
         {
-            new Aim(mods),
-            new Speed(mods)
-        };
+            HitWindows hitWindows = new OsuHitWindows();
+            hitWindows.SetDifficulty(beatmap.Difficulty.OverallDifficulty);
+
+            hitWindowGreat = hitWindows.WindowFor(HitResult.Great) / clockRate;
+
+            return new Skill[]
+            {
+                new Aim(mods),
+                new Speed(mods, hitWindowGreat),
+                new Flashlight(mods)
+            };
+        }
 
         protected override Mod[] DifficultyAdjustmentMods => new Mod[]
         {
@@ -95,6 +120,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             new OsuModHalfTime(),
             new OsuModEasy(),
             new OsuModHardRock(),
+            new OsuModFlashlight(),
         };
     }
 }

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

@@ -25,6 +25,8 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         private int countMeh;
         private int countMiss;
 
+        private int effectiveMissCount;
+
         public OsuPerformanceCalculator(Ruleset ruleset, DifficultyAttributes attributes, ScoreInfo score)
             : base(ruleset, attributes, score)
         {
@@ -39,24 +41,33 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             countOk = Score.Statistics.GetValueOrDefault(HitResult.Ok);
             countMeh = Score.Statistics.GetValueOrDefault(HitResult.Meh);
             countMiss = Score.Statistics.GetValueOrDefault(HitResult.Miss);
+            effectiveMissCount = calculateEffectiveMissCount();
+
+            double multiplier = 1.12; // This is being adjusted to keep the final pp value scaled around what it used to be when changing things.
 
             // Custom multipliers for NoFail and SpunOut.
-            double multiplier = 1.12; // This is being adjusted to keep the final pp value scaled around what it used to be when changing things
-
             if (mods.Any(m => m is OsuModNoFail))
-                multiplier *= Math.Max(0.90, 1.0 - 0.02 * countMiss);
+                multiplier *= Math.Max(0.90, 1.0 - 0.02 * effectiveMissCount);
 
             if (mods.Any(m => m is OsuModSpunOut))
                 multiplier *= 1.0 - Math.Pow((double)Attributes.SpinnerCount / totalHits, 0.85);
 
+            if (mods.Any(h => h is OsuModRelax))
+            {
+                effectiveMissCount += countOk + countMeh;
+                multiplier *= 0.6;
+            }
+
             double aimValue = computeAimValue();
             double speedValue = computeSpeedValue();
             double accuracyValue = computeAccuracyValue();
+            double flashlightValue = computeFlashlightValue();
             double totalValue =
                 Math.Pow(
                     Math.Pow(aimValue, 1.1) +
                     Math.Pow(speedValue, 1.1) +
-                    Math.Pow(accuracyValue, 1.1), 1.0 / 1.1
+                    Math.Pow(accuracyValue, 1.1) +
+                    Math.Pow(flashlightValue, 1.1), 1.0 / 1.1
                 ) * multiplier;
 
             if (categoryRatings != null)
@@ -64,6 +75,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty
                 categoryRatings.Add("Aim", aimValue);
                 categoryRatings.Add("Speed", speedValue);
                 categoryRatings.Add("Accuracy", accuracyValue);
+                categoryRatings.Add("Flashlight", flashlightValue);
                 categoryRatings.Add("OD", Attributes.OverallDifficulty);
                 categoryRatings.Add("AR", Attributes.ApproachRate);
                 categoryRatings.Add("Max Combo", Attributes.MaxCombo);
@@ -81,17 +93,17 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             double aimValue = Math.Pow(5.0 * Math.Max(1.0, rawAim / 0.0675) - 4.0, 3.0) / 100000.0;
 
-            // Longer maps are worth more
+            // Longer maps are worth more.
             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;
 
             // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
-            if (countMiss > 0)
-                aimValue *= 0.97 * Math.Pow(1 - Math.Pow((double)countMiss / totalHits, 0.775), countMiss);
+            if (effectiveMissCount > 0)
+                aimValue *= 0.97 * Math.Pow(1 - Math.Pow((double)effectiveMissCount / totalHits, 0.775), effectiveMissCount);
 
-            // Combo scaling
+            // Combo scaling.
             if (Attributes.MaxCombo > 0)
                 aimValue *= Math.Min(Math.Pow(scoreMaxCombo, 0.8) / Math.Pow(Attributes.MaxCombo, 0.8), 1.0);
 
@@ -105,27 +117,19 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             double approachRateBonus = 1.0 + (0.03 + 0.37 * approachRateTotalHitsFactor) * approachRateFactor;
 
-            // We want to give more reward for lower AR when it comes to aim and HD. This nerfs high AR and buffs lower AR.
-            if (mods.Any(h => h is OsuModHidden))
-                aimValue *= 1.0 + 0.04 * (12.0 - Attributes.ApproachRate);
-
-            double flashlightBonus = 1.0;
-
-            if (mods.Any(h => h is OsuModFlashlight))
+            if (mods.Any(m => m is OsuModBlinds))
+                aimValue *= 1.3 + (totalHits * (0.0016 / (1 + 2 * effectiveMissCount)) * Math.Pow(accuracy, 16)) * (1 - 0.003 * Attributes.DrainRate * Attributes.DrainRate);
+            else if (mods.Any(h => h is OsuModHidden))
             {
-                // Apply object-based bonus for flashlight.
-                flashlightBonus = 1.0 + 0.35 * Math.Min(1.0, totalHits / 200.0) +
-                                  (totalHits > 200
-                                      ? 0.3 * Math.Min(1.0, (totalHits - 200) / 300.0) +
-                                        (totalHits > 500 ? (totalHits - 500) / 1200.0 : 0.0)
-                                      : 0.0);
+                // We want to give more reward for lower AR when it comes to aim and HD. This nerfs high AR and buffs lower AR.
+                aimValue *= 1.0 + 0.04 * (12.0 - Attributes.ApproachRate);
             }
 
-            aimValue *= Math.Max(flashlightBonus, approachRateBonus);
+            aimValue *= approachRateBonus;
 
-            // Scale the aim value with accuracy _slightly_
+            // Scale the aim value with accuracy _slightly_.
             aimValue *= 0.5 + accuracy / 2.0;
-            // It is important to also consider accuracy difficulty when doing that
+            // It is important to also consider accuracy difficulty when doing that.
             aimValue *= 0.98 + Math.Pow(Attributes.OverallDifficulty, 2) / 2500;
 
             return aimValue;
@@ -135,16 +139,16 @@ namespace osu.Game.Rulesets.Osu.Difficulty
         {
             double speedValue = Math.Pow(5.0 * Math.Max(1.0, Attributes.SpeedStrain / 0.0675) - 4.0, 3.0) / 100000.0;
 
-            // Longer maps are worth more
+            // Longer maps are worth more.
             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;
 
             // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
-            if (countMiss > 0)
-                speedValue *= 0.97 * Math.Pow(1 - Math.Pow((double)countMiss / totalHits, 0.775), Math.Pow(countMiss, .875));
+            if (effectiveMissCount > 0)
+                speedValue *= 0.97 * Math.Pow(1 - Math.Pow((double)effectiveMissCount / totalHits, 0.775), Math.Pow(effectiveMissCount, .875));
 
-            // Combo scaling
+            // Combo scaling.
             if (Attributes.MaxCombo > 0)
                 speedValue *= Math.Min(Math.Pow(scoreMaxCombo, 0.8) / Math.Pow(Attributes.MaxCombo, 0.8), 1.0);
 
@@ -156,11 +160,20 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
             speedValue *= 1.0 + (0.03 + 0.37 * approachRateTotalHitsFactor) * approachRateFactor;
 
-            if (mods.Any(m => m is OsuModHidden))
+            if (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 (mods.Any(m => m is OsuModHidden))
+            {
+                // We want to give more reward for lower AR when it comes to aim and HD. This nerfs high AR and buffs lower AR.
                 speedValue *= 1.0 + 0.04 * (12.0 - Attributes.ApproachRate);
+            }
 
-            // Scale the speed value with accuracy and OD
+            // Scale the speed value with accuracy and OD.
             speedValue *= (0.95 + Math.Pow(Attributes.OverallDifficulty, 2) / 750) * Math.Pow(accuracy, (14.5 - Math.Max(Attributes.OverallDifficulty, 8)) / 2);
+
             // Scale the speed value with # of 50s to punish doubletapping.
             speedValue *= Math.Pow(0.98, countMeh < totalHits / 500.0 ? 0 : countMeh - totalHits / 500.0);
 
@@ -169,7 +182,10 @@ namespace osu.Game.Rulesets.Osu.Difficulty
 
         private double computeAccuracyValue()
         {
-            // This percentage only considers HitCircles of any value - in this part of the calculation we focus on hitting the timing hit window
+            if (mods.Any(h => h is OsuModRelax))
+                return 0.0;
+
+            // This percentage only considers HitCircles of any value - in this part of the calculation we focus on hitting the timing hit window.
             double betterAccuracyPercentage;
             int amountHitObjectsWithAccuracy = Attributes.HitCircleCount;
 
@@ -178,25 +194,83 @@ namespace osu.Game.Rulesets.Osu.Difficulty
             else
                 betterAccuracyPercentage = 0;
 
-            // It is possible to reach a negative accuracy with this formula. Cap it at zero - zero points
+            // It is possible to reach a negative accuracy with this formula. Cap it at zero - zero points.
             if (betterAccuracyPercentage < 0)
                 betterAccuracyPercentage = 0;
 
             // Lots of arbitrary values from testing.
-            // Considering to use derivation from perfect accuracy in a probabilistic manner - assume normal distribution
+            // Considering to use derivation from perfect accuracy in a probabilistic manner - assume normal distribution.
             double accuracyValue = Math.Pow(1.52163, Attributes.OverallDifficulty) * Math.Pow(betterAccuracyPercentage, 24) * 2.83;
 
-            // Bonus for many hitcircles - it's harder to keep good accuracy up for longer
+            // Bonus for many hitcircles - it's harder to keep good accuracy up for longer.
             accuracyValue *= Math.Min(1.15, Math.Pow(amountHitObjectsWithAccuracy / 1000.0, 0.3));
 
-            if (mods.Any(m => m is OsuModHidden))
+            // Increasing the accuracy value by object count for Blinds isn't ideal, so the minimum buff is given.
+            if (mods.Any(m => m is OsuModBlinds))
+                accuracyValue *= 1.14;
+            else if (mods.Any(m => m is OsuModHidden))
                 accuracyValue *= 1.08;
+
             if (mods.Any(m => m is OsuModFlashlight))
                 accuracyValue *= 1.02;
 
             return accuracyValue;
         }
 
+        private double computeFlashlightValue()
+        {
+            if (!mods.Any(h => h is OsuModFlashlight))
+                return 0.0;
+
+            double rawFlashlight = Attributes.FlashlightRating;
+
+            if (mods.Any(m => m is OsuModTouchDevice))
+                rawFlashlight = Math.Pow(rawFlashlight, 0.8);
+
+            double flashlightValue = Math.Pow(rawFlashlight, 2.0) * 25.0;
+
+            // Add an additional bonus for HDFL.
+            if (mods.Any(h => h is OsuModHidden))
+                flashlightValue *= 1.3;
+
+            // Penalize misses by assessing # of misses relative to the total # of objects. Default a 3% reduction for any # of misses.
+            if (effectiveMissCount > 0)
+                flashlightValue *= 0.97 * Math.Pow(1 - Math.Pow((double)effectiveMissCount / totalHits, 0.775), Math.Pow(effectiveMissCount, .875));
+
+            // Combo scaling.
+            if (Attributes.MaxCombo > 0)
+                flashlightValue *= Math.Min(Math.Pow(scoreMaxCombo, 0.8) / Math.Pow(Attributes.MaxCombo, 0.8), 1.0);
+
+            // Account for shorter maps having a higher ratio of 0 combo/100 combo flashlight radius.
+            flashlightValue *= 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);
+
+            // Scale the flashlight value with accuracy _slightly_.
+            flashlightValue *= 0.5 + accuracy / 2.0;
+            // It is important to also consider accuracy difficulty when doing that.
+            flashlightValue *= 0.98 + Math.Pow(Attributes.OverallDifficulty, 2) / 2500;
+
+            return flashlightValue;
+        }
+
+        private int calculateEffectiveMissCount()
+        {
+            // guess the number of misses + slider breaks from combo
+            double comboBasedMissCount = 0.0;
+
+            if (Attributes.SliderCount > 0)
+            {
+                double fullComboThreshold = Attributes.MaxCombo - 0.1 * Attributes.SliderCount;
+                if (scoreMaxCombo < fullComboThreshold)
+                    comboBasedMissCount = fullComboThreshold / Math.Max(1.0, scoreMaxCombo);
+            }
+
+            // we're clamping misscount because since its derived from combo it can be higher than total hits and that breaks some calculations
+            comboBasedMissCount = Math.Min(comboBasedMissCount, totalHits);
+
+            return Math.Max(countMiss, (int)Math.Floor(comboBasedMissCount));
+        }
+
         private int totalHits => countGreat + countOk + countMeh + countMiss;
         private int totalSuccessfulHits => countGreat + countOk + countMeh;
     }

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

@@ -16,6 +16,11 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
         protected new OsuHitObject BaseObject => (OsuHitObject)base.BaseObject;
 
+        /// <summary>
+        /// Milliseconds elapsed since the start time of the previous <see cref="OsuDifficultyHitObject"/>, with a minimum of 25ms to account for simultaneous <see cref="OsuDifficultyHitObject"/>s.
+        /// </summary>
+        public double StrainTime { get; private set; }
+
         /// <summary>
         /// Normalized distance from the end position of the previous <see cref="OsuDifficultyHitObject"/> to the start position of this <see cref="OsuDifficultyHitObject"/>.
         /// </summary>
@@ -32,11 +37,6 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
         /// </summary>
         public double? Angle { get; private set; }
 
-        /// <summary>
-        /// Milliseconds elapsed since the start time of the previous <see cref="OsuDifficultyHitObject"/>, with a minimum of 50ms.
-        /// </summary>
-        public readonly double StrainTime;
-
         private readonly OsuHitObject lastLastObject;
         private readonly OsuHitObject lastObject;
 
@@ -48,12 +48,16 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             setDistances();
 
-            // Every strain interval is hard capped at the equivalent of 375 BPM streaming speed as a safety measure
-            StrainTime = Math.Max(50, DeltaTime);
+            // Capped to 25ms to prevent difficulty calculation breaking from simulatenous objects.
+            StrainTime = Math.Max(DeltaTime, 25);
         }
 
         private void setDistances()
         {
+            // 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;
+
             // We will scale distances by this factor, so we can assume a uniform CircleSize among beatmaps.
             float scalingFactor = normalized_radius / (float)BaseObject.Radius;
 
@@ -71,11 +75,9 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             Vector2 lastCursorPosition = getEndCursorPosition(lastObject);
 
-            // Don't need to jump to reach spinners
-            if (!(BaseObject is Spinner))
-                JumpDistance = (BaseObject.StackedPosition * scalingFactor - lastCursorPosition * scalingFactor).Length;
+            JumpDistance = (BaseObject.StackedPosition * scalingFactor - lastCursorPosition * scalingFactor).Length;
 
-            if (lastLastObject != null)
+            if (lastLastObject != null && !(lastLastObject is Spinner))
             {
                 Vector2 lastLastCursorPosition = getEndCursorPosition(lastLastObject);
 
@@ -121,7 +123,7 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Preprocessing
 
             // Skip the head circle
             var scoringTimes = slider.NestedHitObjects.Skip(1).Select(t => t.StartTime);
-            foreach (var time in scoringTimes)
+            foreach (double time in scoringTimes)
                 computeVertex(time);
         }
 

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

@@ -22,17 +22,19 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
         {
         }
 
-        protected override double SkillMultiplier => 26.25;
-        protected override double StrainDecayBase => 0.15;
+        private double currentStrain = 1;
 
-        protected override double StrainValueOf(DifficultyHitObject current)
+        private double skillMultiplier => 26.25;
+        private double strainDecayBase => 0.15;
+
+        private double strainValueOf(DifficultyHitObject current)
         {
             if (current.BaseObject is Spinner)
                 return 0;
 
             var osuCurrent = (OsuDifficultyHitObject)current;
 
-            double result = 0;
+            double aimStrain = 0;
 
             if (Previous.Count > 0)
             {
@@ -42,11 +44,11 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
                 {
                     const double scale = 90;
 
-                    var angleBonus = Math.Sqrt(
+                    double angleBonus = Math.Sqrt(
                         Math.Max(osuPrevious.JumpDistance - scale, 0)
                         * Math.Pow(Math.Sin(osuCurrent.Angle.Value - angle_bonus_begin), 2)
                         * Math.Max(osuCurrent.JumpDistance - scale, 0));
-                    result = 1.4 * applyDiminishingExp(Math.Max(0, angleBonus)) / Math.Max(timing_threshold, osuPrevious.StrainTime);
+                    aimStrain = 1.4 * applyDiminishingExp(Math.Max(0, angleBonus)) / Math.Max(timing_threshold, osuPrevious.StrainTime);
                 }
             }
 
@@ -54,11 +56,23 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
             double travelDistanceExp = applyDiminishingExp(osuCurrent.TravelDistance);
 
             return Math.Max(
-                result + (jumpDistanceExp + travelDistanceExp + Math.Sqrt(travelDistanceExp * jumpDistanceExp)) / Math.Max(osuCurrent.StrainTime, timing_threshold),
+                aimStrain + (jumpDistanceExp + travelDistanceExp + Math.Sqrt(travelDistanceExp * jumpDistanceExp)) / Math.Max(osuCurrent.StrainTime, timing_threshold),
                 (Math.Sqrt(travelDistanceExp * jumpDistanceExp) + jumpDistanceExp + travelDistanceExp) / osuCurrent.StrainTime
             );
         }
 
         private double applyDiminishingExp(double val) => Math.Pow(val, 0.99);
+
+        private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
+
+        protected override double CalculateInitialStrain(double time) => currentStrain * strainDecay(time - Previous[0].StartTime);
+
+        protected override double StrainValueAt(DifficultyHitObject current)
+        {
+            currentStrain *= strainDecay(current.DeltaTime);
+            currentStrain += strainValueOf(current) * skillMultiplier;
+
+            return currentStrain;
+        }
     }
 }

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

@@ -0,0 +1,79 @@
+// 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.Mods;
+using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
+using osu.Game.Rulesets.Osu.Objects;
+
+namespace osu.Game.Rulesets.Osu.Difficulty.Skills
+{
+    /// <summary>
+    /// Represents the skill required to memorise and hit every object in a map with the Flashlight mod enabled.
+    /// </summary>
+    public class Flashlight : OsuStrainSkill
+    {
+        public Flashlight(Mod[] mods)
+            : base(mods)
+        {
+        }
+
+        private double skillMultiplier => 0.15;
+        private double strainDecayBase => 0.15;
+        protected override double DecayWeight => 1.0;
+        protected override int HistoryLength => 10; // Look back for 10 notes is added for the sake of flashlight calculations.
+        private double currentStrain = 1;
+
+        private double strainValueOf(DifficultyHitObject current)
+        {
+            if (current.BaseObject is Spinner)
+                return 0;
+
+            var osuCurrent = (OsuDifficultyHitObject)current;
+            var osuHitObject = (OsuHitObject)(osuCurrent.BaseObject);
+
+            double scalingFactor = 52.0 / osuHitObject.Radius;
+            double smallDistNerf = 1.0;
+            double cumulativeStrainTime = 0.0;
+
+            double result = 0.0;
+
+            for (int i = 0; i < Previous.Count; i++)
+            {
+                var osuPrevious = (OsuDifficultyHitObject)Previous[i];
+                var osuPreviousHitObject = (OsuHitObject)(osuPrevious.BaseObject);
+
+                if (!(osuPrevious.BaseObject is Spinner))
+                {
+                    double jumpDistance = (osuHitObject.StackedPosition - osuPreviousHitObject.EndPosition).Length;
+
+                    cumulativeStrainTime += osuPrevious.StrainTime;
+
+                    // We want to nerf objects that can be easily seen within the Flashlight circle radius.
+                    if (i == 0)
+                        smallDistNerf = Math.Min(1.0, jumpDistance / 75.0);
+
+                    // We also want to nerf stacks so that only the first object of the stack is accounted for.
+                    double stackNerf = Math.Min(1.0, (osuPrevious.JumpDistance / scalingFactor) / 25.0);
+
+                    result += Math.Pow(0.8, i) * stackNerf * scalingFactor * jumpDistance / cumulativeStrainTime;
+                }
+            }
+
+            return Math.Pow(smallDistNerf * result, 2.0);
+        }
+
+        private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
+
+        protected override double CalculateInitialStrain(double time) => currentStrain * strainDecay(time - Previous[0].StartTime);
+
+        protected override double StrainValueAt(DifficultyHitObject current)
+        {
+            currentStrain *= strainDecay(current.DeltaTime);
+            currentStrain += strainValueOf(current) * skillMultiplier;
+
+            return currentStrain;
+        }
+    }
+}

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

@@ -10,7 +10,7 @@ using osu.Framework.Utils;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 {
-    public abstract class OsuStrainSkill : StrainDecaySkill
+    public abstract class OsuStrainSkill : StrainSkill
     {
         /// <summary>
         /// The number of sections with the highest strains, which the peak strain reductions will apply to.

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

@@ -6,6 +6,7 @@ using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Osu.Objects;
+using osu.Framework.Utils;
 
 namespace osu.Game.Rulesets.Osu.Difficulty.Skills
 {
@@ -15,56 +16,161 @@ namespace osu.Game.Rulesets.Osu.Difficulty.Skills
     public class Speed : OsuStrainSkill
     {
         private const double single_spacing_threshold = 125;
-
-        private const double angle_bonus_begin = 5 * Math.PI / 6;
-        private const double pi_over_4 = Math.PI / 4;
-        private const double pi_over_2 = Math.PI / 2;
-
-        protected override double SkillMultiplier => 1400;
-        protected override double StrainDecayBase => 0.3;
-        protected override int ReducedSectionCount => 5;
-        protected override double DifficultyMultiplier => 1.04;
-
+        private const double rhythm_multiplier = 0.75;
+        private const int history_time_max = 5000; // 5 seconds of calculatingRhythmBonus max.
         private const double min_speed_bonus = 75; // ~200BPM
-        private const double max_speed_bonus = 45; // ~330BPM
         private const double speed_balancing_factor = 40;
 
-        public Speed(Mod[] mods)
+        private double skillMultiplier => 1375;
+        private double strainDecayBase => 0.3;
+
+        private double currentStrain = 1;
+        private double currentRhythm = 1;
+
+        protected override int ReducedSectionCount => 5;
+        protected override double DifficultyMultiplier => 1.04;
+        protected override int HistoryLength => 32;
+
+        private readonly double greatWindow;
+
+        public Speed(Mod[] mods, double hitWindowGreat)
             : base(mods)
         {
+            greatWindow = hitWindowGreat;
         }
 
-        protected override double StrainValueOf(DifficultyHitObject current)
+        /// <summary>
+        /// Calculates a rhythm multiplier for the difficulty of the tap associated with historic data of the current <see cref="OsuDifficultyHitObject"/>.
+        /// </summary>
+        private double calculateRhythmBonus(DifficultyHitObject current)
         {
             if (current.BaseObject is Spinner)
                 return 0;
 
-            var osuCurrent = (OsuDifficultyHitObject)current;
+            int previousIslandSize = 0;
 
-            double distance = Math.Min(single_spacing_threshold, osuCurrent.TravelDistance + osuCurrent.JumpDistance);
-            double deltaTime = Math.Max(max_speed_bonus, current.DeltaTime);
+            double rhythmComplexitySum = 0;
+            int islandSize = 1;
+            double startRatio = 0; // store the ratio of the current start of an island to buff for tighter rhythms
 
-            double speedBonus = 1.0;
-            if (deltaTime < min_speed_bonus)
-                speedBonus = 1 + Math.Pow((min_speed_bonus - deltaTime) / speed_balancing_factor, 2);
+            bool firstDeltaSwitch = false;
 
-            double angleBonus = 1.0;
-
-            if (osuCurrent.Angle != null && osuCurrent.Angle.Value < angle_bonus_begin)
+            for (int i = Previous.Count - 2; i > 0; i--)
             {
-                angleBonus = 1 + Math.Pow(Math.Sin(1.5 * (angle_bonus_begin - osuCurrent.Angle.Value)), 2) / 3.57;
+                OsuDifficultyHitObject currObj = (OsuDifficultyHitObject)Previous[i - 1];
+                OsuDifficultyHitObject prevObj = (OsuDifficultyHitObject)Previous[i];
+                OsuDifficultyHitObject lastObj = (OsuDifficultyHitObject)Previous[i + 1];
 
-                if (osuCurrent.Angle.Value < pi_over_2)
+                double currHistoricalDecay = Math.Max(0, (history_time_max - (current.StartTime - currObj.StartTime))) / history_time_max; // scales note 0 to 1 from history to now
+
+                if (currHistoricalDecay != 0)
                 {
-                    angleBonus = 1.28;
-                    if (distance < 90 && osuCurrent.Angle.Value < pi_over_4)
-                        angleBonus += (1 - angleBonus) * Math.Min((90 - distance) / 10, 1);
-                    else if (distance < 90)
-                        angleBonus += (1 - angleBonus) * Math.Min((90 - distance) / 10, 1) * Math.Sin((pi_over_2 - osuCurrent.Angle.Value) / pi_over_4);
+                    currHistoricalDecay = Math.Min((double)(Previous.Count - i) / Previous.Count, currHistoricalDecay); // either we're limited by time or limited by object count.
+
+                    double currDelta = currObj.StrainTime;
+                    double prevDelta = prevObj.StrainTime;
+                    double lastDelta = lastObj.StrainTime;
+                    double currRatio = 1.0 + 6.0 * Math.Min(0.5, Math.Pow(Math.Sin(Math.PI / (Math.Min(prevDelta, currDelta) / Math.Max(prevDelta, currDelta))), 2)); // fancy function to calculate rhythmbonuses.
+
+                    double windowPenalty = Math.Min(1, Math.Max(0, Math.Abs(prevDelta - currDelta) - greatWindow * 0.6) / (greatWindow * 0.6));
+
+                    windowPenalty = Math.Min(1, windowPenalty);
+
+                    double effectiveRatio = windowPenalty * currRatio;
+
+                    if (firstDeltaSwitch)
+                    {
+                        if (!(prevDelta > 1.25 * currDelta || prevDelta * 1.25 < currDelta))
+                        {
+                            if (islandSize < 7)
+                                islandSize++; // island is still progressing, count size.
+                        }
+                        else
+                        {
+                            if (Previous[i - 1].BaseObject is Slider) // bpm change is into slider, this is easy acc window
+                                effectiveRatio *= 0.125;
+
+                            if (Previous[i].BaseObject is Slider) // bpm change was from a slider, this is easier typically than circle -> circle
+                                effectiveRatio *= 0.25;
+
+                            if (previousIslandSize == islandSize) // repeated island size (ex: triplet -> triplet)
+                                effectiveRatio *= 0.25;
+
+                            if (previousIslandSize % 2 == islandSize % 2) // repeated island polartiy (2 -> 4, 3 -> 5)
+                                effectiveRatio *= 0.50;
+
+                            if (lastDelta > prevDelta + 10 && prevDelta > currDelta + 10) // previous increase happened a note ago, 1/1->1/2-1/4, dont want to buff this.
+                                effectiveRatio *= 0.125;
+
+                            rhythmComplexitySum += Math.Sqrt(effectiveRatio * startRatio) * currHistoricalDecay * Math.Sqrt(4 + islandSize) / 2 * Math.Sqrt(4 + previousIslandSize) / 2;
+
+                            startRatio = effectiveRatio;
+
+                            previousIslandSize = islandSize; // log the last island size.
+
+                            if (prevDelta * 1.25 < currDelta) // we're slowing down, stop counting
+                                firstDeltaSwitch = false; // if we're speeding up, this stays true and  we keep counting island size.
+
+                            islandSize = 1;
+                        }
+                    }
+                    else if (prevDelta > 1.25 * currDelta) // we want to be speeding up.
+                    {
+                        // Begin counting island until we change speed again.
+                        firstDeltaSwitch = true;
+                        startRatio = effectiveRatio;
+                        islandSize = 1;
+                    }
                 }
             }
 
-            return (1 + (speedBonus - 1) * 0.75) * angleBonus * (0.95 + speedBonus * Math.Pow(distance / single_spacing_threshold, 3.5)) / osuCurrent.StrainTime;
+            return Math.Sqrt(4 + rhythmComplexitySum * rhythm_multiplier) / 2; //produces multiplier that can be applied to strain. range [1, infinity) (not really though)
+        }
+
+        private double strainValueOf(DifficultyHitObject current)
+        {
+            if (current.BaseObject is Spinner)
+                return 0;
+
+            // derive strainTime for calculation
+            var osuCurrObj = (OsuDifficultyHitObject)current;
+            var osuPrevObj = Previous.Count > 0 ? (OsuDifficultyHitObject)Previous[0] : null;
+
+            double strainTime = osuCurrObj.StrainTime;
+            double greatWindowFull = greatWindow * 2;
+            double speedWindowRatio = strainTime / greatWindowFull;
+
+            // Aim to nerf cheesy rhythms (Very fast consecutive doubles with large deltatimes between)
+            if (osuPrevObj != null && strainTime < greatWindowFull && osuPrevObj.StrainTime > strainTime)
+                strainTime = Interpolation.Lerp(osuPrevObj.StrainTime, strainTime, speedWindowRatio);
+
+            // 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 / greatWindowFull) / 0.93, 0.92, 1);
+
+            // derive speedBonus for calculation
+            double speedBonus = 1.0;
+
+            if (strainTime < min_speed_bonus)
+                speedBonus = 1 + 0.75 * Math.Pow((min_speed_bonus - strainTime) / speed_balancing_factor, 2);
+
+            double distance = Math.Min(single_spacing_threshold, osuCurrObj.TravelDistance + osuCurrObj.JumpDistance);
+
+            return (speedBonus + speedBonus * Math.Pow(distance / single_spacing_threshold, 3.5)) / strainTime;
+        }
+
+        private double strainDecay(double ms) => Math.Pow(strainDecayBase, ms / 1000);
+
+        protected override double CalculateInitialStrain(double time) => (currentStrain * currentRhythm) * strainDecay(time - Previous[0].StartTime);
+
+        protected override double StrainValueAt(DifficultyHitObject current)
+        {
+            currentStrain *= strainDecay(current.DeltaTime);
+            currentStrain += strainValueOf(current) * skillMultiplier;
+
+            currentRhythm = calculateRhythmBonus(current);
+
+            return currentStrain * currentRhythm;
         }
     }
 }

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/Components/PathControlPointPiece.cs

@@ -184,7 +184,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
         {
             Vector2[] oldControlPoints = slider.Path.ControlPoints.Select(cp => cp.Position).ToArray();
             var oldPosition = slider.Position;
-            var oldStartTime = slider.StartTime;
+            double oldStartTime = slider.StartTime;
 
             if (ControlPoint == slider.Path.ControlPoints[0])
             {
@@ -205,7 +205,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
 
             if (!slider.Path.HasValidLength)
             {
-                for (var i = 0; i < slider.Path.ControlPoints.Count; i++)
+                for (int i = 0; i < slider.Path.ControlPoints.Count; i++)
                     slider.Path.ControlPoints[i].Position = oldControlPoints[i];
 
                 slider.Position = oldPosition;

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderPlacementBlueprint.cs

@@ -8,12 +8,14 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Input;
 using osu.Framework.Input.Events;
+using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Graphics;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Types;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles.Components;
 using osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components;
+using osu.Game.Screens.Edit;
 using osuTK;
 using osuTK.Input;
 
@@ -67,6 +69,9 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
             inputManager = GetContainingInputManager();
         }
 
+        [Resolved]
+        private EditorBeatmap editorBeatmap { get; set; }
+
         public override void UpdateTimeAndPosition(SnapResult result)
         {
             base.UpdateTimeAndPosition(result);
@@ -75,6 +80,10 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
             {
                 case SliderPlacementState.Initial:
                     BeginPlacement();
+
+                    var nearestDifficultyPoint = editorBeatmap.HitObjects.LastOrDefault(h => h.GetEndTime() < HitObject.StartTime)?.DifficultyControlPoint?.DeepClone() as DifficultyControlPoint;
+
+                    HitObject.DifficultyControlPoint = nearestDifficultyPoint ?? new DifficultyControlPoint();
                     HitObject.Position = ToLocalSpace(result.ScreenSpacePosition);
                     break;
 
@@ -212,7 +221,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
 
         private void updateSlider()
         {
-            HitObject.Path.ExpectedDistance.Value = composer?.GetSnappedDistanceFromDistance(HitObject.StartTime, (float)HitObject.Path.CalculatedDistance) ?? (float)HitObject.Path.CalculatedDistance;
+            HitObject.Path.ExpectedDistance.Value = composer?.GetSnappedDistanceFromDistance(HitObject, (float)HitObject.Path.CalculatedDistance) ?? (float)HitObject.Path.CalculatedDistance;
 
             bodyPiece.UpdateFrom(HitObject);
             headCirclePiece.UpdateFrom(HitObject.HeadCircle);

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderSelectionBlueprint.cs

@@ -230,7 +230,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders
 
         private void updatePath()
         {
-            HitObject.Path.ExpectedDistance.Value = composer?.GetSnappedDistanceFromDistance(HitObject.StartTime, (float)HitObject.Path.CalculatedDistance) ?? (float)HitObject.Path.CalculatedDistance;
+            HitObject.Path.ExpectedDistance.Value = composer?.GetSnappedDistanceFromDistance(HitObject, (float)HitObject.Path.CalculatedDistance) ?? (float)HitObject.Path.CalculatedDistance;
             editorBeatmap?.Update(HitObject);
         }
 

osu.Game.Rulesets.Osu/Edit/Checks/CheckLowDiffOverlaps.cs

@@ -47,14 +47,14 @@ namespace osu.Game.Rulesets.Osu.Edit.Checks
                 if (!(hitObjects[i + 1] is OsuHitObject nextHitObject) || nextHitObject is Spinner)
                     continue;
 
-                var deltaTime = nextHitObject.StartTime - hitObject.GetEndTime();
+                double deltaTime = nextHitObject.StartTime - hitObject.GetEndTime();
                 if (deltaTime >= hitObject.TimeFadeIn + hitObject.TimePreempt)
                     // The objects are not visible at the same time (without mods), hence skipping.
                     continue;
 
-                var distanceSq = (hitObject.StackedEndPosition - nextHitObject.StackedPosition).LengthSquared;
-                var diameter = (hitObject.Radius - overlap_leniency) * 2;
-                var diameterSq = diameter * diameter;
+                float distanceSq = (hitObject.StackedEndPosition - nextHitObject.StackedPosition).LengthSquared;
+                double diameter = (hitObject.Radius - overlap_leniency) * 2;
+                double diameterSq = diameter * diameter;
 
                 bool areOverlapping = distanceSq < diameterSq;
 

osu.Game.Rulesets.Osu/Edit/Checks/CheckTimeDistanceEquality.cs

@@ -88,21 +88,21 @@ namespace osu.Game.Rulesets.Osu.Edit.Checks
                 if (!(hitObjects[i + 1] is OsuHitObject nextHitObject) || nextHitObject is Spinner)
                     continue;
 
-                var deltaTime = nextHitObject.StartTime - hitObject.GetEndTime();
+                double deltaTime = nextHitObject.StartTime - hitObject.GetEndTime();
 
                 // Ignore objects that are far enough apart in time to not be considered the same pattern.
                 if (deltaTime > pattern_lifetime)
                     continue;
 
                 // Relying on FastInvSqrt is probably good enough here. We'll be taking the difference between distances later, hence square not being sufficient.
-                var distance = (hitObject.StackedEndPosition - nextHitObject.StackedPosition).LengthFast;
+                float distance = (hitObject.StackedEndPosition - nextHitObject.StackedPosition).LengthFast;
 
                 // Ignore stacks and half-stacks, as these are close enough to where they can't be confused for being time-distanced.
                 if (distance < stack_leniency)
                     continue;
 
                 var observedTimeDistance = new ObservedTimeDistance(nextHitObject.StartTime, deltaTime, distance);
-                var expectedDistance = getExpectedDistance(prevObservedTimeDistances, observedTimeDistance);
+                double expectedDistance = getExpectedDistance(prevObservedTimeDistances, observedTimeDistance);
 
                 if (expectedDistance == 0)
                 {
@@ -125,7 +125,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Checks
 
         private double getExpectedDistance(IEnumerable<ObservedTimeDistance> prevObservedTimeDistances, ObservedTimeDistance observedTimeDistance)
         {
-            var observations = prevObservedTimeDistances.Count();
+            int observations = prevObservedTimeDistances.Count();
 
             int count = 0;
             double sum = 0;

osu.Game.Rulesets.Osu/Edit/Checks/CheckTooShortSpinners.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Checks
 
         public IEnumerable<Issue> Run(BeatmapVerifierContext context)
         {
-            double od = context.Beatmap.BeatmapInfo.BaseDifficulty.OverallDifficulty;
+            double od = context.Beatmap.Difficulty.OverallDifficulty;
 
             // These are meant to reflect the duration necessary for auto to score at least 1000 points on the spinner.
             // It's difficult to eliminate warnings here, as auto achieving 1000 points depends on the approach angle on some spinners.

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

@@ -11,7 +11,7 @@ namespace osu.Game.Rulesets.Osu.Edit
     public class OsuDistanceSnapGrid : CircularDistanceSnapGrid
     {
         public OsuDistanceSnapGrid(OsuHitObject hitObject, [CanBeNull] OsuHitObject nextHitObject = null)
-            : base(hitObject.StackedEndPosition, hitObject.GetEndTime(), nextHitObject?.StartTime)
+            : base(hitObject, hitObject.StackedEndPosition, hitObject.GetEndTime(), nextHitObject?.StartTime)
         {
             Masking = true;
         }

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

@@ -42,10 +42,12 @@ namespace osu.Game.Rulesets.Osu.Edit
         };
 
         private readonly Bindable<TernaryState> distanceSnapToggle = new Bindable<TernaryState>();
+        private readonly Bindable<TernaryState> rectangularGridSnapToggle = new Bindable<TernaryState>();
 
         protected override IEnumerable<TernaryButton> CreateTernaryButtons() => base.CreateTernaryButtons().Concat(new[]
         {
-            new TernaryButton(distanceSnapToggle, "Distance Snap", () => new SpriteIcon { Icon = FontAwesome.Solid.Ruler })
+            new TernaryButton(distanceSnapToggle, "Distance Snap", () => new SpriteIcon { Icon = FontAwesome.Solid.Ruler }),
+            new TernaryButton(rectangularGridSnapToggle, "Grid Snap", () => new SpriteIcon { Icon = FontAwesome.Solid.Th })
         });
 
         private BindableList<HitObject> selectedHitObjects;
@@ -63,6 +65,10 @@ namespace osu.Game.Rulesets.Osu.Edit
                     PlayfieldBorderStyle = { Value = PlayfieldBorderStyle.Corners }
                 },
                 distanceSnapGridContainer = new Container
+                {
+                    RelativeSizeAxes = Axes.Both
+                },
+                rectangularPositionSnapGrid = new OsuRectangularPositionSnapGrid
                 {
                     RelativeSizeAxes = Axes.Both
                 }
@@ -73,7 +79,19 @@ namespace osu.Game.Rulesets.Osu.Edit
 
             placementObject = EditorBeatmap.PlacementObject.GetBoundCopy();
             placementObject.ValueChanged += _ => updateDistanceSnapGrid();
-            distanceSnapToggle.ValueChanged += _ => updateDistanceSnapGrid();
+            distanceSnapToggle.ValueChanged += _ =>
+            {
+                updateDistanceSnapGrid();
+
+                if (distanceSnapToggle.Value == TernaryState.True)
+                    rectangularGridSnapToggle.Value = TernaryState.False;
+            };
+
+            rectangularGridSnapToggle.ValueChanged += _ =>
+            {
+                if (rectangularGridSnapToggle.Value == TernaryState.True)
+                    distanceSnapToggle.Value = TernaryState.False;
+            };
 
             // we may be entering the screen with a selection already active
             updateDistanceSnapGrid();
@@ -91,6 +109,8 @@ namespace osu.Game.Rulesets.Osu.Edit
         private readonly Cached distanceSnapGridCache = new Cached();
         private double? lastDistanceSnapGridTime;
 
+        private RectangularPositionSnapGrid rectangularPositionSnapGrid;
+
         protected override void Update()
         {
             base.Update();
@@ -122,13 +142,19 @@ namespace osu.Game.Rulesets.Osu.Edit
             if (positionSnap.ScreenSpacePosition != screenSpacePosition)
                 return positionSnap;
 
-            // will be null if distance snap is disabled or not feasible for the current time value.
-            if (distanceSnapGrid == null)
-                return base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
+            if (distanceSnapToggle.Value == TernaryState.True && distanceSnapGrid != null)
+            {
+                (Vector2 pos, double time) = distanceSnapGrid.GetSnappedPosition(distanceSnapGrid.ToLocalSpace(screenSpacePosition));
+                return new SnapResult(distanceSnapGrid.ToScreenSpace(pos), time, PlayfieldAtScreenSpacePosition(screenSpacePosition));
+            }
 
-            (Vector2 pos, double time) = distanceSnapGrid.GetSnappedPosition(distanceSnapGrid.ToLocalSpace(screenSpacePosition));
+            if (rectangularGridSnapToggle.Value == TernaryState.True)
+            {
+                Vector2 pos = rectangularPositionSnapGrid.GetSnappedPosition(rectangularPositionSnapGrid.ToLocalSpace(screenSpacePosition));
+                return new SnapResult(rectangularPositionSnapGrid.ToScreenSpace(pos), null, PlayfieldAtScreenSpacePosition(screenSpacePosition));
+            }
 
-            return new SnapResult(distanceSnapGrid.ToScreenSpace(pos), time, PlayfieldAtScreenSpacePosition(screenSpacePosition));
+            return base.SnapScreenSpacePositionToValidTime(screenSpacePosition);
         }
 
         private bool snapToVisibleBlueprints(Vector2 screenSpacePosition, out SnapResult snapResult)

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

@@ -0,0 +1,69 @@
+// 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.Allocation;
+using osu.Framework.Input.Bindings;
+using osu.Framework.Input.Events;
+using osu.Game.Input.Bindings;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Screens.Edit;
+using osu.Game.Screens.Edit.Compose.Components;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuRectangularPositionSnapGrid : RectangularPositionSnapGrid, IKeyBindingHandler<GlobalAction>
+    {
+        private static readonly int[] grid_sizes = { 4, 8, 16, 32 };
+
+        private int currentGridSizeIndex = grid_sizes.Length - 1;
+
+        [Resolved]
+        private EditorBeatmap editorBeatmap { get; set; }
+
+        public OsuRectangularPositionSnapGrid()
+            : base(OsuPlayfield.BASE_SIZE / 2)
+        {
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            int gridSizeIndex = Array.IndexOf(grid_sizes, editorBeatmap.BeatmapInfo.GridSize);
+            if (gridSizeIndex >= 0)
+                currentGridSizeIndex = gridSizeIndex;
+            updateSpacing();
+        }
+
+        private void nextGridSize()
+        {
+            currentGridSizeIndex = (currentGridSizeIndex + 1) % grid_sizes.Length;
+            updateSpacing();
+        }
+
+        private void updateSpacing()
+        {
+            int gridSize = grid_sizes[currentGridSizeIndex];
+
+            editorBeatmap.BeatmapInfo.GridSize = gridSize;
+            Spacing = new Vector2(gridSize);
+        }
+
+        public bool OnPressed(KeyBindingPressEvent<GlobalAction> e)
+        {
+            switch (e.Action)
+            {
+                case GlobalAction.EditorCycleGridDisplayMode:
+                    nextGridSize();
+                    return true;
+            }
+
+            return false;
+        }
+
+        public void OnReleased(KeyBindingReleaseEvent<GlobalAction> e)
+        {
+        }
+    }
+}