Merge branch 'master' into play-storyboard-outro

osu.Android.props

@@ -51,7 +51,7 @@
     <Reference Include="Java.Interop" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Game.Resources" Version="2021.410.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.410.0" />
+    <PackageReference Include="ppy.osu.Game.Resources" Version="2021.412.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2021.415.0" />
   </ItemGroup>
 </Project>

osu.Android/OsuGameAndroid.cs

@@ -7,6 +7,8 @@ using Android.OS;
 using osu.Framework.Allocation;
 using osu.Game;
 using osu.Game.Updater;
+using osu.Game.Utils;
+using Xamarin.Essentials;
 
 namespace osu.Android
 {
@@ -72,5 +74,14 @@ namespace osu.Android
         }
 
         protected override UpdateManager CreateUpdateManager() => new SimpleUpdateManager();
+
+        protected override BatteryInfo CreateBatteryInfo() => new AndroidBatteryInfo();
+
+        private class AndroidBatteryInfo : BatteryInfo
+        {
+            public override double ChargeLevel => Battery.ChargeLevel;
+
+            public override bool IsCharging => Battery.PowerSource != BatteryPowerSource.Battery;
+        }
     }
 }

osu.Android/Properties/AndroidManifest.xml

@@ -6,5 +6,6 @@
 	<uses-permission android:name="android.permission.WAKE_LOCK" />
 	<uses-permission android:name="android.permission.READ_FRAME_BUFFER" />
 	<uses-permission android:name="android.permission.INTERNET" />
+	<uses-permission android:name="android.permission.BATTERY_STATS" />
 	<application android:allowBackup="true" android:supportsRtl="true" android:label="osu!" android:icon="@drawable/lazer" />
 </manifest>

osu.Android/osu.Android.csproj

@@ -63,5 +63,8 @@
       <Version>5.0.0</Version>
     </PackageReference>
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Xamarin.Essentials" Version="1.6.1" />
+  </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath)\Xamarin\Android\Xamarin.Android.CSharp.targets" />
 </Project>

osu.Desktop/Program.cs

@@ -69,7 +69,6 @@ namespace osu.Desktop
         /// Allow a maximum of one unhandled exception, per second of execution.
         /// </summary>
         /// <param name="arg"></param>
-        /// <returns></returns>
         private static bool handleException(Exception arg)
         {
             bool continueExecution = Interlocked.Decrement(ref allowableExceptions) >= 0;

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

@@ -482,7 +482,6 @@ namespace osu.Game.Rulesets.Mania.Beatmaps.Patterns.Legacy
         /// Retrieves the sample info list at a point in time.
         /// </summary>
         /// <param name="time">The time to retrieve the sample info list from.</param>
-        /// <returns></returns>
         private IList<HitSampleInfo> sampleInfoListAt(int time) => nodeSamplesAt(time)?.First() ?? HitObject.Samples;
 
         /// <summary>

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

@@ -15,6 +15,7 @@ namespace osu.Game.Rulesets.Mania.Mods
         public override string Name => "Mirror";
         public override string Acronym => "MR";
         public override ModType Type => ModType.Conversion;
+        public override string Description => "Notes are flipped horizontally.";
         public override double ScoreMultiplier => 1;
         public override bool Ranked => true;
 

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

@@ -0,0 +1,260 @@
+// 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.Game.Beatmaps;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Osu.Edit.Checks;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.UI;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Tests.Editor.Checks
+{
+    [TestFixture]
+    public class CheckOffscreenObjectsTest
+    {
+        private static readonly Vector2 playfield_centre = OsuPlayfield.BASE_SIZE * 0.5f;
+
+        private CheckOffscreenObjects check;
+
+        [SetUp]
+        public void Setup()
+        {
+            check = new CheckOffscreenObjects();
+        }
+
+        [Test]
+        public void TestCircleInCenter()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle
+                    {
+                        StartTime = 3000,
+                        Position = playfield_centre // Playfield is 640 x 480.
+                    }
+                }
+            };
+
+            Assert.That(check.Run(beatmap), Is.Empty);
+        }
+
+        [Test]
+        public void TestCircleNearEdge()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle
+                    {
+                        StartTime = 3000,
+                        Position = new Vector2(5, 5)
+                    }
+                }
+            };
+
+            Assert.That(check.Run(beatmap), Is.Empty);
+        }
+
+        [Test]
+        public void TestCircleNearEdgeStackedOffscreen()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle
+                    {
+                        StartTime = 3000,
+                        Position = new Vector2(5, 5),
+                        StackHeight = 5
+                    }
+                }
+            };
+
+            assertOffscreenCircle(beatmap);
+        }
+
+        [Test]
+        public void TestCircleOffscreen()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new HitCircle
+                    {
+                        StartTime = 3000,
+                        Position = new Vector2(0, 0)
+                    }
+                }
+            };
+
+            assertOffscreenCircle(beatmap);
+        }
+
+        [Test]
+        public void TestSliderInCenter()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = new Vector2(420, 240),
+                        Path = new SliderPath(new[]
+                        {
+                            new PathControlPoint(new Vector2(0, 0), PathType.Linear),
+                            new PathControlPoint(new Vector2(-100, 0))
+                        }),
+                    }
+                }
+            };
+
+            Assert.That(check.Run(beatmap), Is.Empty);
+        }
+
+        [Test]
+        public void TestSliderNearEdge()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = playfield_centre,
+                        Path = new SliderPath(new[]
+                        {
+                            new PathControlPoint(new Vector2(0, 0), PathType.Linear),
+                            new PathControlPoint(new Vector2(0, -playfield_centre.Y + 5))
+                        }),
+                    }
+                }
+            };
+
+            Assert.That(check.Run(beatmap), Is.Empty);
+        }
+
+        [Test]
+        public void TestSliderNearEdgeStackedOffscreen()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = playfield_centre,
+                        Path = new SliderPath(new[]
+                        {
+                            new PathControlPoint(new Vector2(0, 0), PathType.Linear),
+                            new PathControlPoint(new Vector2(0, -playfield_centre.Y + 5))
+                        }),
+                        StackHeight = 5
+                    }
+                }
+            };
+
+            assertOffscreenSlider(beatmap);
+        }
+
+        [Test]
+        public void TestSliderOffscreenStart()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = new Vector2(0, 0),
+                        Path = new SliderPath(new[]
+                        {
+                            new PathControlPoint(new Vector2(0, 0), PathType.Linear),
+                            new PathControlPoint(playfield_centre)
+                        }),
+                    }
+                }
+            };
+
+            assertOffscreenSlider(beatmap);
+        }
+
+        [Test]
+        public void TestSliderOffscreenEnd()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = playfield_centre,
+                        Path = new SliderPath(new[]
+                        {
+                            new PathControlPoint(new Vector2(0, 0), PathType.Linear),
+                            new PathControlPoint(-playfield_centre)
+                        }),
+                    }
+                }
+            };
+
+            assertOffscreenSlider(beatmap);
+        }
+
+        [Test]
+        public void TestSliderOffscreenPath()
+        {
+            var beatmap = new Beatmap<HitObject>
+            {
+                HitObjects = new List<HitObject>
+                {
+                    new Slider
+                    {
+                        StartTime = 3000,
+                        Position = playfield_centre,
+                        Path = new SliderPath(new[]
+                        {
+                            // Circular arc shoots over the top of the screen.
+                            new PathControlPoint(new Vector2(0, 0), PathType.PerfectCurve),
+                            new PathControlPoint(new Vector2(-100, -200)),
+                            new PathControlPoint(new Vector2(100, -200))
+                        }),
+                    }
+                }
+            };
+
+            assertOffscreenSlider(beatmap);
+        }
+
+        private void assertOffscreenCircle(IBeatmap beatmap)
+        {
+            var issues = check.Run(beatmap).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckOffscreenObjects.IssueTemplateOffscreenCircle);
+        }
+
+        private void assertOffscreenSlider(IBeatmap beatmap)
+        {
+            var issues = check.Run(beatmap).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckOffscreenObjects.IssueTemplateOffscreenSlider);
+        }
+    }
+}

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

@@ -0,0 +1,46 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Objects.Types;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Tests.Beatmaps;
+using osu.Game.Tests.Visual;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Tests.Editor
+{
+    public class TestSceneOsuEditorSelectInvalidPath : EditorTestScene
+    {
+        protected override Ruleset CreateEditorRuleset() => new OsuRuleset();
+
+        protected override IBeatmap CreateBeatmap(RulesetInfo ruleset) => new TestBeatmap(ruleset, false);
+
+        [Test]
+        public void TestSelectDoesNotModify()
+        {
+            Slider slider = new Slider { StartTime = 0, Position = new Vector2(320, 40) };
+
+            PathControlPoint[] points =
+            {
+                new PathControlPoint(new Vector2(0), PathType.PerfectCurve),
+                new PathControlPoint(new Vector2(-100, 0)),
+                new PathControlPoint(new Vector2(100, 20))
+            };
+
+            int preSelectVersion = -1;
+            AddStep("add slider", () =>
+            {
+                slider.Path = new SliderPath(points);
+                EditorBeatmap.Add(slider);
+                preSelectVersion = slider.Path.Version.Value;
+            });
+
+            AddStep("select added slider", () => EditorBeatmap.SelectedHitObjects.Add(slider));
+
+            AddAssert("slider same path", () => slider.Path.Version.Value == preSelectVersion);
+        }
+    }
+}

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

@@ -33,7 +33,7 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
 
         private void runSpmTest(Mod mod)
         {
-            SpinnerSpmCounter spmCounter = null;
+            SpinnerSpmCalculator spmCalculator = null;
 
             CreateModTest(new ModTestData
             {
@@ -53,13 +53,13 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
                 PassCondition = () => Player.ScoreProcessor.JudgedHits >= 1
             });
 
-            AddUntilStep("fetch SPM counter", () =>
+            AddUntilStep("fetch SPM calculator", () =>
             {
-                spmCounter = this.ChildrenOfType<SpinnerSpmCounter>().SingleOrDefault();
-                return spmCounter != null;
+                spmCalculator = this.ChildrenOfType<SpinnerSpmCalculator>().SingleOrDefault();
+                return spmCalculator != null;
             });
 
-            AddUntilStep("SPM is correct", () => Precision.AlmostEquals(spmCounter.SpinsPerMinute, 477, 5));
+            AddUntilStep("SPM is correct", () => Precision.AlmostEquals(spmCalculator.Result.Value, 477, 5));
         }
     }
 }

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

@@ -47,8 +47,8 @@ namespace osu.Game.Rulesets.Osu.Tests.Mods
                 Beatmap = singleSpinnerBeatmap,
                 PassCondition = () =>
                 {
-                    var counter = Player.ChildrenOfType<SpinnerSpmCounter>().SingleOrDefault();
-                    return counter != null && Precision.AlmostEquals(counter.SpinsPerMinute, 286, 1);
+                    var counter = Player.ChildrenOfType<SpinnerSpmCalculator>().SingleOrDefault();
+                    return counter != null && Precision.AlmostEquals(counter.Result.Value, 286, 1);
                 }
             });
         }

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

@@ -78,7 +78,7 @@ namespace osu.Game.Rulesets.Osu.Tests
                 RelativeSizeAxes = Axes.Both;
             }
 
-            public Drawable GetDrawableComponent(ISkinComponent component) => throw new NotImplementedException();
+            public Drawable GetDrawableComponent(ISkinComponent component) => null;
 
             public Texture GetTexture(string componentName, WrapMode wrapModeS, WrapMode wrapModeT)
             {
@@ -98,9 +98,9 @@ namespace osu.Game.Rulesets.Osu.Tests
                 return null;
             }
 
-            public ISample GetSample(ISampleInfo sampleInfo) => throw new NotImplementedException();
+            public ISample GetSample(ISampleInfo sampleInfo) => null;
 
-            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => throw new NotImplementedException();
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => null;
 
             public event Action SourceChanged
             {

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

@@ -4,13 +4,22 @@
 using System;
 using NUnit.Framework;
 using osu.Framework.Allocation;
+using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.OpenGL.Textures;
 using osu.Framework.Graphics.Shapes;
+using osu.Framework.Graphics.Textures;
+using osu.Framework.Input;
 using osu.Framework.Testing.Input;
 using osu.Framework.Utils;
+using osu.Game.Audio;
 using osu.Game.Configuration;
+using osu.Game.Rulesets.Osu.Skinning;
 using osu.Game.Rulesets.Osu.UI.Cursor;
 using osu.Game.Screens.Play;
+using osu.Game.Skinning;
 using osuTK;
 
 namespace osu.Game.Rulesets.Osu.Tests
@@ -21,7 +30,7 @@ namespace osu.Game.Rulesets.Osu.Tests
         [Cached]
         private GameplayBeatmap gameplayBeatmap;
 
-        private ClickingCursorContainer lastContainer;
+        private OsuCursorContainer lastContainer;
 
         [Resolved]
         private OsuConfigManager config { get; set; }
@@ -48,12 +57,10 @@ namespace osu.Game.Rulesets.Osu.Tests
             {
                 config.SetValue(OsuSetting.AutoCursorSize, true);
                 gameplayBeatmap.BeatmapInfo.BaseDifficulty.CircleSize = val;
-                Scheduler.AddOnce(recreate);
+                Scheduler.AddOnce(() => loadContent(false));
             });
 
-            AddStep("test cursor container", recreate);
-
-            void recreate() => SetContents(() => new OsuInputManager(new OsuRuleset().RulesetInfo) { Child = new OsuCursorContainer() });
+            AddStep("test cursor container", () => loadContent(false));
         }
 
         [TestCase(1, 1)]
@@ -68,7 +75,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             AddStep($"adjust cs to {circleSize}", () => gameplayBeatmap.BeatmapInfo.BaseDifficulty.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);
 
@@ -82,18 +89,46 @@ namespace osu.Game.Rulesets.Osu.Tests
             AddUntilStep("cursor size correct", () => lastContainer.ActiveCursor.Scale.X == userScale);
         }
 
-        private void loadContent()
+        [Test]
+        public void TestTopLeftOrigin()
         {
-            SetContents(() => new MovingCursorInputManager
+            AddStep("load content", () => loadContent(false, () => new SkinProvidingContainer(new TopLeftCursorSkin())));
+        }
+
+        private void loadContent(bool automated = true, Func<SkinProvidingContainer> skinProvider = null)
+        {
+            SetContents(() =>
             {
-                Child = lastContainer = new ClickingCursorContainer
-                {
-                    RelativeSizeAxes = Axes.Both,
-                    Masking = true,
-                }
+                var inputManager = automated ? (InputManager)new MovingCursorInputManager() : new OsuInputManager(new OsuRuleset().RulesetInfo);
+                var skinContainer = skinProvider?.Invoke() ?? new SkinProvidingContainer(null);
+
+                lastContainer = automated ? new ClickingCursorContainer() : new OsuCursorContainer();
+
+                return inputManager.WithChild(skinContainer.WithChild(lastContainer));
             });
         }
 
+        private class TopLeftCursorSkin : ISkin
+        {
+            public Drawable GetDrawableComponent(ISkinComponent component) => null;
+            public Texture GetTexture(string componentName, WrapMode wrapModeS, WrapMode wrapModeT) => null;
+            public ISample GetSample(ISampleInfo sampleInfo) => null;
+
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup)
+            {
+                switch (lookup)
+                {
+                    case OsuSkinConfiguration osuLookup:
+                        if (osuLookup == OsuSkinConfiguration.CursorCentre)
+                            return SkinUtils.As<TValue>(new BindableBool(false));
+
+                        break;
+                }
+
+                return null;
+            }
+        }
+
         private class ClickingCursorContainer : OsuCursorContainer
         {
             private bool pressed;

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

@@ -168,13 +168,13 @@ namespace osu.Game.Rulesets.Osu.Tests
             double estimatedSpm = 0;
 
             addSeekStep(1000);
-            AddStep("retrieve spm", () => estimatedSpm = drawableSpinner.SpmCounter.SpinsPerMinute);
+            AddStep("retrieve spm", () => estimatedSpm = drawableSpinner.SpinsPerMinute.Value);
 
             addSeekStep(2000);
-            AddAssert("spm still valid", () => Precision.AlmostEquals(drawableSpinner.SpmCounter.SpinsPerMinute, estimatedSpm, 1.0));
+            AddAssert("spm still valid", () => Precision.AlmostEquals(drawableSpinner.SpinsPerMinute.Value, estimatedSpm, 1.0));
 
             addSeekStep(1000);
-            AddAssert("spm still valid", () => Precision.AlmostEquals(drawableSpinner.SpmCounter.SpinsPerMinute, estimatedSpm, 1.0));
+            AddAssert("spm still valid", () => Precision.AlmostEquals(drawableSpinner.SpinsPerMinute.Value, estimatedSpm, 1.0));
         }
 
         [TestCase(0.5)]
@@ -188,7 +188,7 @@ namespace osu.Game.Rulesets.Osu.Tests
             AddStep("retrieve spinner state", () =>
             {
                 expectedProgress = drawableSpinner.Progress;
-                expectedSpm = drawableSpinner.SpmCounter.SpinsPerMinute;
+                expectedSpm = drawableSpinner.SpinsPerMinute.Value;
             });
 
             addSeekStep(0);
@@ -197,7 +197,7 @@ namespace osu.Game.Rulesets.Osu.Tests
 
             addSeekStep(1000);
             AddAssert("progress almost same", () => Precision.AlmostEquals(expectedProgress, drawableSpinner.Progress, 0.05));
-            AddAssert("spm almost same", () => Precision.AlmostEquals(expectedSpm, drawableSpinner.SpmCounter.SpinsPerMinute, 2.0));
+            AddAssert("spm almost same", () => Precision.AlmostEquals(expectedSpm, drawableSpinner.SpinsPerMinute.Value, 2.0));
         }
 
         private Replay applyRateAdjustment(Replay scoreReplay, double rate) => new Replay

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

@@ -59,11 +59,14 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
             this.slider = slider;
             ControlPoint = controlPoint;
 
+            // we don't want to run the path type update on construction as it may inadvertently change the slider.
+            cachePoints(slider);
+
             slider.Path.Version.BindValueChanged(_ =>
             {
-                PointsInSegment = slider.Path.PointsInSegment(ControlPoint);
+                cachePoints(slider);
                 updatePathType();
-            }, runOnceImmediately: true);
+            });
 
             controlPoint.Type.BindValueChanged(_ => updateMarkerDisplay());
 
@@ -205,6 +208,8 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
 
         protected override void OnDragEnd(DragEndEvent e) => changeHandler?.EndChange();
 
+        private void cachePoints(Slider slider) => PointsInSegment = slider.Path.PointsInSegment(ControlPoint);
+
         /// <summary>
         /// Handles correction of invalid path types.
         /// </summary>

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

@@ -0,0 +1,115 @@
+// 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 osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Checks.Components;
+using osu.Game.Rulesets.Osu.Objects;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Edit.Checks
+{
+    public class CheckOffscreenObjects : ICheck
+    {
+        // A close approximation for the bounding box of the screen in gameplay on 4:3 aspect ratio.
+        // Uses gameplay space coordinates (512 x 384 playfield / 640 x 480 screen area).
+        // See https://github.com/ppy/osu/pull/12361#discussion_r612199777 for reference.
+        private const int min_x = -67;
+        private const int min_y = -60;
+        private const int max_x = 579;
+        private const int max_y = 428;
+
+        // The amount of milliseconds to step through a slider path at a time
+        // (higher = more performant, but higher false-negative chance).
+        private const int path_step_size = 5;
+
+        public CheckMetadata Metadata { get; } = new CheckMetadata(CheckCategory.Compose, "Offscreen hitobjects");
+
+        public IEnumerable<IssueTemplate> PossibleTemplates => new IssueTemplate[]
+        {
+            new IssueTemplateOffscreenCircle(this),
+            new IssueTemplateOffscreenSlider(this)
+        };
+
+        public IEnumerable<Issue> Run(IBeatmap beatmap)
+        {
+            foreach (var hitobject in beatmap.HitObjects)
+            {
+                switch (hitobject)
+                {
+                    case Slider slider:
+                    {
+                        foreach (var issue in sliderIssues(slider))
+                            yield return issue;
+
+                        break;
+                    }
+
+                    case HitCircle circle:
+                    {
+                        if (isOffscreen(circle.StackedPosition, circle.Radius))
+                            yield return new IssueTemplateOffscreenCircle(this).Create(circle);
+
+                        break;
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Steps through points on the slider to ensure the entire path is on-screen.
+        /// Returns at most one issue.
+        /// </summary>
+        /// <param name="slider">The slider whose path to check.</param>
+        /// <returns></returns>
+        private IEnumerable<Issue> sliderIssues(Slider slider)
+        {
+            for (int i = 0; i < slider.Distance; i += path_step_size)
+            {
+                double progress = i / slider.Distance;
+                Vector2 position = slider.StackedPositionAt(progress);
+
+                if (!isOffscreen(position, slider.Radius))
+                    continue;
+
+                // `SpanDuration` ensures we don't include reverses.
+                double time = slider.StartTime + progress * slider.SpanDuration;
+                yield return new IssueTemplateOffscreenSlider(this).Create(slider, time);
+
+                yield break;
+            }
+
+            // Above loop may skip the last position in the slider due to step size.
+            if (!isOffscreen(slider.StackedEndPosition, slider.Radius))
+                yield break;
+
+            yield return new IssueTemplateOffscreenSlider(this).Create(slider, slider.EndTime);
+        }
+
+        private bool isOffscreen(Vector2 position, double radius)
+        {
+            return position.X - radius < min_x || position.X + radius > max_x ||
+                   position.Y - radius < min_y || position.Y + radius > max_y;
+        }
+
+        public class IssueTemplateOffscreenCircle : IssueTemplate
+        {
+            public IssueTemplateOffscreenCircle(ICheck check)
+                : base(check, IssueType.Problem, "This circle goes offscreen on a 4:3 aspect ratio.")
+            {
+            }
+
+            public Issue Create(HitCircle circle) => new Issue(circle, this);
+        }
+
+        public class IssueTemplateOffscreenSlider : IssueTemplate
+        {
+            public IssueTemplateOffscreenSlider(ICheck check)
+                : base(check, IssueType.Problem, "This slider goes offscreen here on a 4:3 aspect ratio.")
+            {
+            }
+
+            public Issue Create(Slider slider, double offscreenTime) => new Issue(slider, this) { Time = offscreenTime };
+        }
+    }
+}

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

@@ -0,0 +1,22 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit;
+using osu.Game.Rulesets.Edit.Checks.Components;
+using osu.Game.Rulesets.Osu.Edit.Checks;
+
+namespace osu.Game.Rulesets.Osu.Edit
+{
+    public class OsuBeatmapVerifier : IBeatmapVerifier
+    {
+        private readonly List<ICheck> checks = new List<ICheck>
+        {
+            new CheckOffscreenObjects()
+        };
+
+        public IEnumerable<Issue> Run(IBeatmap beatmap) => checks.SelectMany(check => check.Run(beatmap));
+    }
+}

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

@@ -0,0 +1,44 @@
+// 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.Bindables;
+using osu.Framework.Graphics;
+using osu.Game.Configuration;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.UI;
+using osu.Game.Rulesets.UI;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Mods
+{
+    public class OsuModBarrelRoll : Mod, IUpdatableByPlayfield, IApplicableToDrawableRuleset<OsuHitObject>
+    {
+        [SettingSource("Roll speed", "Rotations per minute")]
+        public BindableNumber<double> SpinSpeed { get; } = new BindableDouble(0.5)
+        {
+            MinValue = 0.02,
+            MaxValue = 4,
+            Precision = 0.01,
+        };
+
+        [SettingSource("Direction", "The direction of rotation")]
+        public Bindable<RotationDirection> Direction { get; } = new Bindable<RotationDirection>(RotationDirection.Clockwise);
+
+        public override string Name => "Barrel Roll";
+        public override string Acronym => "BR";
+        public override string Description => "The whole playfield is on a wheel!";
+        public override double ScoreMultiplier => 1;
+
+        public void Update(Playfield playfield)
+        {
+            playfield.Rotation = (Direction.Value == RotationDirection.CounterClockwise ? -1 : 1) * 360 * (float)(playfield.Time.Current / 60000 * SpinSpeed.Value);
+        }
+
+        public void ApplyToDrawableRuleset(DrawableRuleset<OsuHitObject> drawableRuleset)
+        {
+            // scale the playfield to allow all hitobjects to stay within the visible region.
+            drawableRuleset.Playfield.Scale = new Vector2(OsuPlayfield.BASE_SIZE.Y / OsuPlayfield.BASE_SIZE.X);
+        }
+    }
+}

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

@@ -9,6 +9,7 @@ namespace osu.Game.Rulesets.Osu.Mods
     {
         public override string Name => "Touch Device";
         public override string Acronym => "TD";
+        public override string Description => "Automatically applied to plays on devices with a touchscreen.";
         public override double ScoreMultiplier => 1;
 
         public override ModType Type => ModType.System;

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSpinner.cs

@@ -30,7 +30,8 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         public new OsuSpinnerJudgementResult Result => (OsuSpinnerJudgementResult)base.Result;
 
         public SpinnerRotationTracker RotationTracker { get; private set; }
-        public SpinnerSpmCounter SpmCounter { get; private set; }
+
+        private SpinnerSpmCalculator spmCalculator;
 
         private Container<DrawableSpinnerTick> ticks;
         private PausableSkinnableSound spinningSample;
@@ -43,7 +44,12 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         /// </summary>
         public IBindable<double> GainedBonus => gainedBonus;
 
-        private readonly Bindable<double> gainedBonus = new Bindable<double>();
+        private readonly Bindable<double> gainedBonus = new BindableDouble();
+
+        /// <summary>
+        /// The number of spins per minute this spinner is spinning at, for display purposes.
+        /// </summary>
+        public readonly IBindable<double> SpinsPerMinute = new BindableDouble();
 
         private const double fade_out_duration = 160;
 
@@ -63,8 +69,12 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
             Origin = Anchor.Centre;
             RelativeSizeAxes = Axes.Both;
 
-            InternalChildren = new Drawable[]
+            AddRangeInternal(new Drawable[]
             {
+                spmCalculator = new SpinnerSpmCalculator
+                {
+                    Result = { BindTarget = SpinsPerMinute },
+                },
                 ticks = new Container<DrawableSpinnerTick>(),
                 new AspectContainer
                 {
@@ -77,20 +87,13 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
                         RotationTracker = new SpinnerRotationTracker(this)
                     }
                 },
-                SpmCounter = new SpinnerSpmCounter
-                {
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
-                    Y = 120,
-                    Alpha = 0
-                },
                 spinningSample = new PausableSkinnableSound
                 {
                     Volume = { Value = 0 },
                     Looping = true,
                     Frequency = { Value = spinning_sample_initial_frequency }
                 }
-            };
+            });
 
             PositionBindable.BindValueChanged(pos => Position = pos.NewValue);
         }
@@ -161,17 +164,6 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
             }
         }
 
-        protected override void UpdateStartTimeStateTransforms()
-        {
-            base.UpdateStartTimeStateTransforms();
-
-            if (Result?.TimeStarted is double startTime)
-            {
-                using (BeginAbsoluteSequence(startTime))
-                    fadeInCounter();
-            }
-        }
-
         protected override void UpdateHitStateTransforms(ArmedState state)
         {
             base.UpdateHitStateTransforms(state);
@@ -282,22 +274,17 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables
         {
             base.UpdateAfterChildren();
 
-            if (!SpmCounter.IsPresent && RotationTracker.Tracking)
-            {
-                Result.TimeStarted ??= Time.Current;
-                fadeInCounter();
-            }
+            if (Result.TimeStarted == null && RotationTracker.Tracking)
+                Result.TimeStarted = Time.Current;
 
             // don't update after end time to avoid the rate display dropping during fade out.
             // this shouldn't be limited to StartTime as it causes weirdness with the underlying calculation, which is expecting updates during that period.
             if (Time.Current <= HitObject.EndTime)
-                SpmCounter.SetRotation(Result.RateAdjustedRotation);
+                spmCalculator.SetRotation(Result.RateAdjustedRotation);
 
             updateBonusScore();
         }
 
-        private void fadeInCounter() => SpmCounter.FadeIn(HitObject.TimeFadeIn);
-
         private static readonly int score_per_tick = new SpinnerBonusTick.OsuSpinnerBonusTickJudgement().MaxNumericResult;
 
         private int wholeSpins;

osu.Game.Rulesets.Osu/OsuRuleset.cs

@@ -185,6 +185,7 @@ namespace osu.Game.Rulesets.Osu
                         new MultiMod(new OsuModGrow(), new OsuModDeflate()),
                         new MultiMod(new ModWindUp(), new ModWindDown()),
                         new OsuModTraceable(),
+                        new OsuModBarrelRoll(),
                     };
 
                 case ModType.System:
@@ -206,6 +207,8 @@ namespace osu.Game.Rulesets.Osu
 
         public override HitObjectComposer CreateHitObjectComposer() => new OsuHitObjectComposer(this);
 
+        public override IBeatmapVerifier CreateBeatmapVerifier() => new OsuBeatmapVerifier();
+
         public override string Description => "osu!";
 
         public override string ShortName => SHORT_NAME;

osu.Game.Rulesets.Osu/Skinning/Default/DefaultSpinner.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
 using System.Globalization;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
@@ -19,6 +20,9 @@ namespace osu.Game.Rulesets.Osu.Skinning.Default
 
         private OsuSpriteText bonusCounter;
 
+        private Container spmContainer;
+        private OsuSpriteText spmCounter;
+
         public DefaultSpinner()
         {
             RelativeSizeAxes = Axes.Both;
@@ -46,11 +50,37 @@ namespace osu.Game.Rulesets.Osu.Skinning.Default
                     Origin = Anchor.Centre,
                     Font = OsuFont.Numeric.With(size: 24),
                     Y = -120,
+                },
+                spmContainer = new Container
+                {
+                    Alpha = 0f,
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Y = 120,
+                    Children = new[]
+                    {
+                        spmCounter = new OsuSpriteText
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.TopCentre,
+                            Text = @"0",
+                            Font = OsuFont.Numeric.With(size: 24)
+                        },
+                        new OsuSpriteText
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.TopCentre,
+                            Text = @"SPINS PER MINUTE",
+                            Font = OsuFont.Numeric.With(size: 12),
+                            Y = 30
+                        }
+                    }
                 }
             });
         }
 
         private IBindable<double> gainedBonus;
+        private IBindable<double> spinsPerMinute;
 
         protected override void LoadComplete()
         {
@@ -63,6 +93,40 @@ namespace osu.Game.Rulesets.Osu.Skinning.Default
                 bonusCounter.FadeOutFromOne(1500);
                 bonusCounter.ScaleTo(1.5f).Then().ScaleTo(1f, 1000, Easing.OutQuint);
             });
+
+            spinsPerMinute = drawableSpinner.SpinsPerMinute.GetBoundCopy();
+            spinsPerMinute.BindValueChanged(spm =>
+            {
+                spmCounter.Text = Math.Truncate(spm.NewValue).ToString(@"#0");
+            }, true);
+
+            drawableSpinner.ApplyCustomUpdateState += updateStateTransforms;
+            updateStateTransforms(drawableSpinner, drawableSpinner.State.Value);
+        }
+
+        protected override void Update()
+        {
+            base.Update();
+
+            if (!spmContainer.IsPresent && drawableSpinner.Result?.TimeStarted != null)
+                fadeCounterOnTimeStart();
+        }
+
+        private void updateStateTransforms(DrawableHitObject drawableHitObject, ArmedState state)
+        {
+            if (!(drawableHitObject is DrawableSpinner))
+                return;
+
+            fadeCounterOnTimeStart();
+        }
+
+        private void fadeCounterOnTimeStart()
+        {
+            if (drawableSpinner.Result?.TimeStarted is double startTime)
+            {
+                using (BeginAbsoluteSequence(startTime))
+                    spmContainer.FadeIn(drawableSpinner.HitObject.TimeFadeIn);
+            }
         }
     }
 }

osu.Game.Rulesets.Osu/Skinning/Default/SpinnerSpmCalculator.cs

@@ -1,77 +1,37 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
 using osu.Framework.Utils;
-using osu.Game.Graphics;
-using osu.Game.Graphics.Sprites;
 using osu.Game.Rulesets.Objects.Drawables;
 
 namespace osu.Game.Rulesets.Osu.Skinning.Default
 {
-    public class SpinnerSpmCounter : Container
+    public class SpinnerSpmCalculator : Component
     {
+        private readonly Queue<RotationRecord> records = new Queue<RotationRecord>();
+        private const double spm_count_duration = 595; // not using hundreds to avoid frame rounding issues
+
+        /// <summary>
+        /// The resultant spins per minute value, which is updated via <see cref="SetRotation"/>.
+        /// </summary>
+        public IBindable<double> Result => result;
+
+        private readonly Bindable<double> result = new BindableDouble();
+
         [Resolved]
         private DrawableHitObject drawableSpinner { get; set; }
 
-        private readonly OsuSpriteText spmText;
-
-        public SpinnerSpmCounter()
-        {
-            Children = new Drawable[]
-            {
-                spmText = new OsuSpriteText
-                {
-                    Anchor = Anchor.TopCentre,
-                    Origin = Anchor.TopCentre,
-                    Text = @"0",
-                    Font = OsuFont.Numeric.With(size: 24)
-                },
-                new OsuSpriteText
-                {
-                    Anchor = Anchor.TopCentre,
-                    Origin = Anchor.TopCentre,
-                    Text = @"SPINS PER MINUTE",
-                    Font = OsuFont.Numeric.With(size: 12),
-                    Y = 30
-                }
-            };
-        }
-
         protected override void LoadComplete()
         {
             base.LoadComplete();
             drawableSpinner.HitObjectApplied += resetState;
         }
 
-        private double spm;
-
-        public double SpinsPerMinute
-        {
-            get => spm;
-            private set
-            {
-                if (value == spm) return;
-
-                spm = value;
-                spmText.Text = Math.Truncate(value).ToString(@"#0");
-            }
-        }
-
-        private struct RotationRecord
-        {
-            public float Rotation;
-            public double Time;
-        }
-
-        private readonly Queue<RotationRecord> records = new Queue<RotationRecord>();
-        private const double spm_count_duration = 595; // not using hundreds to avoid frame rounding issues
-
         public void SetRotation(float currentRotation)
         {
             // Never calculate SPM by same time of record to avoid 0 / 0 = NaN or X / 0 = Infinity result.
@@ -88,7 +48,7 @@ namespace osu.Game.Rulesets.Osu.Skinning.Default
                 while (records.Count > 0 && Time.Current - records.Peek().Time > spm_count_duration)
                     record = records.Dequeue();
 
-                SpinsPerMinute = (currentRotation - record.Rotation) / (Time.Current - record.Time) * 1000 * 60 / 360;
+                result.Value = (currentRotation - record.Rotation) / (Time.Current - record.Time) * 1000 * 60 / 360;
             }
 
             records.Enqueue(new RotationRecord { Rotation = currentRotation, Time = Time.Current });
@@ -96,7 +56,7 @@ namespace osu.Game.Rulesets.Osu.Skinning.Default
 
         private void resetState(DrawableHitObject hitObject)
         {
-            SpinsPerMinute = 0;
+            result.Value = 0;
             records.Clear();
         }
 
@@ -107,5 +67,11 @@ namespace osu.Game.Rulesets.Osu.Skinning.Default
             if (drawableSpinner != null)
                 drawableSpinner.HitObjectApplied -= resetState;
         }
+
+        private struct RotationRecord
+        {
+            public float Rotation;
+            public double Time;
+        }
     }
 }

osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursor.cs

@@ -24,6 +24,7 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
         [BackgroundDependencyLoader]
         private void load(ISkinSource skin)
         {
+            bool centre = skin.GetConfig<OsuSkinConfiguration, bool>(OsuSkinConfiguration.CursorCentre)?.Value ?? true;
             spin = skin.GetConfig<OsuSkinConfiguration, bool>(OsuSkinConfiguration.CursorRotate)?.Value ?? true;
 
             InternalChildren = new[]
@@ -32,13 +33,13 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
                 {
                     Texture = skin.GetTexture("cursor"),
                     Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
+                    Origin = centre ? Anchor.Centre : Anchor.TopLeft,
                 },
                 new NonPlayfieldSprite
                 {
                     Texture = skin.GetTexture("cursormiddle"),
                     Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
+                    Origin = centre ? Anchor.Centre : Anchor.TopLeft,
                 },
             };
         }

osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursorTrail.cs

@@ -26,7 +26,17 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
             Texture = skin.GetTexture("cursortrail");
             disjointTrail = skin.GetTexture("cursormiddle") == null;
 
-            Blending = !disjointTrail ? BlendingParameters.Additive : BlendingParameters.Inherit;
+            if (disjointTrail)
+            {
+                bool centre = skin.GetConfig<OsuSkinConfiguration, bool>(OsuSkinConfiguration.CursorCentre)?.Value ?? true;
+
+                TrailOrigin = centre ? Anchor.Centre : Anchor.TopLeft;
+                Blending = BlendingParameters.Inherit;
+            }
+            else
+            {
+                Blending = BlendingParameters.Additive;
+            }
 
             if (Texture != null)
             {

osu.Game.Rulesets.Osu/Skinning/Legacy/LegacySpinner.cs

@@ -28,6 +28,8 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
 
         protected const float SPRITE_SCALE = 0.625f;
 
+        private const float spm_hide_offset = 50f;
+
         protected DrawableSpinner DrawableSpinner { get; private set; }
 
         private Sprite spin;
@@ -35,6 +37,9 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
 
         private LegacySpriteText bonusCounter;
 
+        private Sprite spmBackground;
+        private LegacySpriteText spmCounter;
+
         [BackgroundDependencyLoader]
         private void load(DrawableHitObject drawableHitObject, ISkinSource source)
         {
@@ -79,11 +84,27 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
                         Scale = new Vector2(SPRITE_SCALE),
                         Y = SPINNER_TOP_OFFSET + 299,
                     }.With(s => s.Font = s.Font.With(fixedWidth: false)),
+                    spmBackground = new Sprite
+                    {
+                        Anchor = Anchor.TopCentre,
+                        Origin = Anchor.TopLeft,
+                        Texture = source.GetTexture("spinner-rpm"),
+                        Scale = new Vector2(SPRITE_SCALE),
+                        Position = new Vector2(-87, 445 + spm_hide_offset),
+                    },
+                    spmCounter = new LegacySpriteText(source, LegacyFont.Score)
+                    {
+                        Anchor = Anchor.TopCentre,
+                        Origin = Anchor.TopRight,
+                        Scale = new Vector2(SPRITE_SCALE * 0.9f),
+                        Position = new Vector2(80, 448 + spm_hide_offset),
+                    }.With(s => s.Font = s.Font.With(fixedWidth: false)),
                 }
             });
         }
 
         private IBindable<double> gainedBonus;
+        private IBindable<double> spinsPerMinute;
 
         private readonly Bindable<bool> completed = new Bindable<bool>();
 
@@ -99,6 +120,12 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
                 bonusCounter.ScaleTo(SPRITE_SCALE * 2f).Then().ScaleTo(SPRITE_SCALE * 1.28f, 800, Easing.Out);
             });
 
+            spinsPerMinute = DrawableSpinner.SpinsPerMinute.GetBoundCopy();
+            spinsPerMinute.BindValueChanged(spm =>
+            {
+                spmCounter.Text = Math.Truncate(spm.NewValue).ToString(@"#0");
+            }, true);
+
             completed.BindValueChanged(onCompletedChanged, true);
 
             DrawableSpinner.ApplyCustomUpdateState += UpdateStateTransforms;
@@ -142,10 +169,16 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
             switch (drawableHitObject)
             {
                 case DrawableSpinner d:
-                    double fadeOutLength = Math.Min(400, d.HitObject.Duration);
+                    using (BeginAbsoluteSequence(d.HitObject.StartTime - d.HitObject.TimeFadeIn))
+                    {
+                        spmBackground.MoveToOffset(new Vector2(0, -spm_hide_offset), d.HitObject.TimeFadeIn, Easing.Out);
+                        spmCounter.MoveToOffset(new Vector2(0, -spm_hide_offset), d.HitObject.TimeFadeIn, Easing.Out);
+                    }
 
-                    using (BeginAbsoluteSequence(drawableHitObject.HitStateUpdateTime - fadeOutLength, true))
-                        spin.FadeOutFromOne(fadeOutLength);
+                    double spinFadeOutLength = Math.Min(400, d.HitObject.Duration);
+
+                    using (BeginAbsoluteSequence(drawableHitObject.HitStateUpdateTime - spinFadeOutLength, true))
+                        spin.FadeOutFromOne(spinFadeOutLength);
                     break;
 
                 case DrawableSpinnerTick d:

osu.Game.Rulesets.Osu/Skinning/OsuSkinConfiguration.cs

@@ -8,6 +8,7 @@ namespace osu.Game.Rulesets.Osu.Skinning
         SliderBorderSize,
         SliderPathRadius,
         AllowSliderBallTint,
+        CursorCentre,
         CursorExpand,
         CursorRotate,
         HitCircleOverlayAboveNumber,

osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs

@@ -5,6 +5,7 @@ using System;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
 using osu.Framework.Allocation;
+using osu.Framework.Extensions.EnumExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Batches;
 using osu.Framework.Graphics.OpenGL.Vertices;
@@ -31,6 +32,18 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
         private double timeOffset;
         private float time;
 
+        private Anchor trailOrigin = Anchor.Centre;
+
+        protected Anchor TrailOrigin
+        {
+            get => trailOrigin;
+            set
+            {
+                trailOrigin = value;
+                Invalidate(Invalidation.DrawNode);
+            }
+        }
+
         public CursorTrail()
         {
             // as we are currently very dependent on having a running clock, let's make our own clock for the time being.
@@ -197,6 +210,8 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             private readonly TrailPart[] parts = new TrailPart[max_sprites];
             private Vector2 size;
 
+            private Vector2 originPosition;
+
             private readonly QuadBatch<TexturedTrailVertex> vertexBatch = new QuadBatch<TexturedTrailVertex>(max_sprites, 1);
 
             public TrailDrawNode(CursorTrail source)
@@ -213,6 +228,18 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
                 size = Source.partSize;
                 time = Source.time;
 
+                originPosition = Vector2.Zero;
+
+                if (Source.TrailOrigin.HasFlagFast(Anchor.x1))
+                    originPosition.X = 0.5f;
+                else if (Source.TrailOrigin.HasFlagFast(Anchor.x2))
+                    originPosition.X = 1f;
+
+                if (Source.TrailOrigin.HasFlagFast(Anchor.y1))
+                    originPosition.Y = 0.5f;
+                else if (Source.TrailOrigin.HasFlagFast(Anchor.y2))
+                    originPosition.Y = 1f;
+
                 Source.parts.CopyTo(parts, 0);
             }
 
@@ -237,7 +264,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                     vertexBatch.Add(new TexturedTrailVertex
                     {
-                        Position = new Vector2(part.Position.X - size.X / 2, part.Position.Y + size.Y / 2),
+                        Position = new Vector2(part.Position.X - size.X * originPosition.X, part.Position.Y + size.Y * (1 - originPosition.Y)),
                         TexturePosition = textureRect.BottomLeft,
                         TextureRect = new Vector4(0, 0, 1, 1),
                         Colour = DrawColourInfo.Colour.BottomLeft.Linear,
@@ -246,7 +273,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                     vertexBatch.Add(new TexturedTrailVertex
                     {
-                        Position = new Vector2(part.Position.X + size.X / 2, part.Position.Y + size.Y / 2),
+                        Position = new Vector2(part.Position.X + size.X * (1 - originPosition.X), part.Position.Y + size.Y * (1 - originPosition.Y)),
                         TexturePosition = textureRect.BottomRight,
                         TextureRect = new Vector4(0, 0, 1, 1),
                         Colour = DrawColourInfo.Colour.BottomRight.Linear,
@@ -255,7 +282,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                     vertexBatch.Add(new TexturedTrailVertex
                     {
-                        Position = new Vector2(part.Position.X + size.X / 2, part.Position.Y - size.Y / 2),
+                        Position = new Vector2(part.Position.X + size.X * (1 - originPosition.X), part.Position.Y - size.Y * originPosition.Y),
                         TexturePosition = textureRect.TopRight,
                         TextureRect = new Vector4(0, 0, 1, 1),
                         Colour = DrawColourInfo.Colour.TopRight.Linear,
@@ -264,7 +291,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                     vertexBatch.Add(new TexturedTrailVertex
                     {
-                        Position = new Vector2(part.Position.X - size.X / 2, part.Position.Y - size.Y / 2),
+                        Position = new Vector2(part.Position.X - size.X * originPosition.X, part.Position.Y - size.Y * originPosition.Y),
                         TexturePosition = textureRect.TopLeft,
                         TextureRect = new Vector4(0, 0, 1, 1),
                         Colour = DrawColourInfo.Colour.TopLeft.Linear,

osu.Game.Rulesets.Osu/UI/OsuPlayfield.cs

@@ -42,6 +42,9 @@ namespace osu.Game.Rulesets.Osu.UI
 
         public OsuPlayfield()
         {
+            Anchor = Anchor.Centre;
+            Origin = Anchor.Centre;
+
             InternalChildren = new Drawable[]
             {
                 playfieldBorder = new PlayfieldBorder { RelativeSizeAxes = Axes.Both },

osu.Game.Rulesets.Osu/UI/OsuResumeOverlay.cs

@@ -33,7 +33,6 @@ namespace osu.Game.Rulesets.Osu.UI
         {
             Add(cursorScaleContainer = new Container
             {
-                RelativePositionAxes = Axes.Both,
                 Child = clickToResumeCursor = new OsuClickToResumeCursor { ResumeRequested = Resume }
             });
         }

osu.Game.Tests/Editing/Checks/CheckBackgroundTest.cs

@@ -0,0 +1,67 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using NUnit.Framework;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Checks;
+using osu.Game.Rulesets.Objects;
+
+namespace osu.Game.Tests.Editing.Checks
+{
+    [TestFixture]
+    public class CheckBackgroundTest
+    {
+        private CheckBackground check;
+        private IBeatmap beatmap;
+
+        [SetUp]
+        public void Setup()
+        {
+            check = new CheckBackground();
+            beatmap = new Beatmap<HitObject>
+            {
+                BeatmapInfo = new BeatmapInfo
+                {
+                    Metadata = new BeatmapMetadata { BackgroundFile = "abc123.jpg" },
+                    BeatmapSet = new BeatmapSetInfo
+                    {
+                        Files = new List<BeatmapSetFileInfo>(new[]
+                        {
+                            new BeatmapSetFileInfo { Filename = "abc123.jpg" }
+                        })
+                    }
+                }
+            };
+        }
+
+        [Test]
+        public void TestBackgroundSetAndInFiles()
+        {
+            Assert.That(check.Run(beatmap), Is.Empty);
+        }
+
+        [Test]
+        public void TestBackgroundSetAndNotInFiles()
+        {
+            beatmap.BeatmapInfo.BeatmapSet.Files.Clear();
+
+            var issues = check.Run(beatmap).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckBackground.IssueTemplateDoesNotExist);
+        }
+
+        [Test]
+        public void TestBackgroundNotSet()
+        {
+            beatmap.Metadata.BackgroundFile = null;
+
+            var issues = check.Run(beatmap).ToList();
+
+            Assert.That(issues, Has.Count.EqualTo(1));
+            Assert.That(issues.Single().Template is CheckBackground.IssueTemplateNoneSet);
+        }
+    }
+}

osu.Game.Tests/Mods/ModSettingsEqualityComparison.cs

@@ -0,0 +1,36 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using NUnit.Framework;
+using osu.Game.Online.API;
+using osu.Game.Rulesets.Osu.Mods;
+
+namespace osu.Game.Tests.Mods
+{
+    [TestFixture]
+    public class ModSettingsEqualityComparison
+    {
+        [Test]
+        public void Test()
+        {
+            var mod1 = new OsuModDoubleTime { SpeedChange = { Value = 1.25 } };
+            var mod2 = new OsuModDoubleTime { SpeedChange = { Value = 1.26 } };
+            var mod3 = new OsuModDoubleTime { SpeedChange = { Value = 1.26 } };
+            var apiMod1 = new APIMod(mod1);
+            var apiMod2 = new APIMod(mod2);
+            var apiMod3 = new APIMod(mod3);
+
+            Assert.That(mod1, Is.Not.EqualTo(mod2));
+            Assert.That(apiMod1, Is.Not.EqualTo(apiMod2));
+
+            Assert.That(mod2, Is.EqualTo(mod2));
+            Assert.That(apiMod2, Is.EqualTo(apiMod2));
+
+            Assert.That(mod2, Is.EqualTo(mod3));
+            Assert.That(apiMod2, Is.EqualTo(apiMod3));
+
+            Assert.That(mod3, Is.EqualTo(mod2));
+            Assert.That(apiMod3, Is.EqualTo(apiMod2));
+        }
+    }
+}

osu.Game.Tests/NonVisual/DifficultyAdjustmentModCombinationsTest.cs

@@ -144,6 +144,7 @@ namespace osu.Game.Tests.NonVisual
         {
             public override string Name => nameof(ModA);
             public override string Acronym => nameof(ModA);
+            public override string Description => string.Empty;
             public override double ScoreMultiplier => 1;
 
             public override Type[] IncompatibleMods => new[] { typeof(ModIncompatibleWithA), typeof(ModIncompatibleWithAAndB) };
@@ -152,6 +153,7 @@ namespace osu.Game.Tests.NonVisual
         private class ModB : Mod
         {
             public override string Name => nameof(ModB);
+            public override string Description => string.Empty;
             public override string Acronym => nameof(ModB);
             public override double ScoreMultiplier => 1;
 
@@ -162,6 +164,7 @@ namespace osu.Game.Tests.NonVisual
         {
             public override string Name => nameof(ModC);
             public override string Acronym => nameof(ModC);
+            public override string Description => string.Empty;
             public override double ScoreMultiplier => 1;
         }
 
@@ -169,6 +172,7 @@ namespace osu.Game.Tests.NonVisual
         {
             public override string Name => $"Incompatible With {nameof(ModA)}";
             public override string Acronym => $"Incompatible With {nameof(ModA)}";
+            public override string Description => string.Empty;
             public override double ScoreMultiplier => 1;
 
             public override Type[] IncompatibleMods => new[] { typeof(ModA) };
@@ -187,6 +191,7 @@ namespace osu.Game.Tests.NonVisual
         {
             public override string Name => $"Incompatible With {nameof(ModA)} and {nameof(ModB)}";
             public override string Acronym => $"Incompatible With {nameof(ModA)} and {nameof(ModB)}";
+            public override string Description => string.Empty;
             public override double ScoreMultiplier => 1;
 
             public override Type[] IncompatibleMods => new[] { typeof(ModA), typeof(ModB) };

osu.Game.Tests/NonVisual/FramedReplayInputHandlerTest.cs

@@ -20,27 +20,14 @@ namespace osu.Game.Tests.NonVisual
         {
             handler = new TestInputHandler(replay = new Replay
             {
-                Frames = new List<ReplayFrame>
-                {
-                    new TestReplayFrame(0),
-                    new TestReplayFrame(1000),
-                    new TestReplayFrame(2000),
-                    new TestReplayFrame(3000, true),
-                    new TestReplayFrame(4000, true),
-                    new TestReplayFrame(5000, true),
-                    new TestReplayFrame(7000, true),
-                    new TestReplayFrame(8000),
-                }
+                HasReceivedAllFrames = false
             });
         }
 
         [Test]
         public void TestNormalPlayback()
         {
-            Assert.IsNull(handler.CurrentFrame);
-
-            confirmCurrentFrame(null);
-            confirmNextFrame(0);
+            setReplayFrames();
 
             setTime(0, 0);
             confirmCurrentFrame(0);
@@ -107,6 +94,8 @@ namespace osu.Game.Tests.NonVisual
         [Test]
         public void TestIntroTime()
         {
+            setReplayFrames();
+
             setTime(-1000, -1000);
             confirmCurrentFrame(null);
             confirmNextFrame(0);
@@ -123,6 +112,8 @@ namespace osu.Game.Tests.NonVisual
         [Test]
         public void TestBasicRewind()
         {
+            setReplayFrames();
+
             setTime(2800, 0);
             setTime(2800, 1000);
             setTime(2800, 2000);
@@ -133,34 +124,35 @@ namespace osu.Game.Tests.NonVisual
             // pivot without crossing a frame boundary
             setTime(2700, 2700);
             confirmCurrentFrame(2);
-            confirmNextFrame(1);
+            confirmNextFrame(3);
 
-            // cross current frame boundary; should not yet update frame
-            setTime(1980, 1980);
+            // cross current frame boundary
+            setTime(1980, 2000);
             confirmCurrentFrame(2);
-            confirmNextFrame(1);
+            confirmNextFrame(3);
 
             setTime(1200, 1200);
-            confirmCurrentFrame(2);
-            confirmNextFrame(1);
+            confirmCurrentFrame(1);
+            confirmNextFrame(2);
 
             // ensure each frame plays out until start
             setTime(-500, 1000);
             confirmCurrentFrame(1);
-            confirmNextFrame(0);
+            confirmNextFrame(2);
 
             setTime(-500, 0);
             confirmCurrentFrame(0);
-            confirmNextFrame(null);
+            confirmNextFrame(1);
 
             setTime(-500, -500);
-            confirmCurrentFrame(0);
-            confirmNextFrame(null);
+            confirmCurrentFrame(null);
+            confirmNextFrame(0);
         }
 
         [Test]
         public void TestRewindInsideImportantSection()
         {
+            setReplayFrames();
             fastForwardToPoint(3000);
 
             setTime(4000, 4000);
@@ -168,12 +160,12 @@ namespace osu.Game.Tests.NonVisual
             confirmNextFrame(5);
 
             setTime(3500, null);
-            confirmCurrentFrame(4);
-            confirmNextFrame(3);
+            confirmCurrentFrame(3);
+            confirmNextFrame(4);
 
             setTime(3000, 3000);
             confirmCurrentFrame(3);
-            confirmNextFrame(2);
+            confirmNextFrame(4);
 
             setTime(3500, null);
             confirmCurrentFrame(3);
@@ -187,46 +179,127 @@ namespace osu.Game.Tests.NonVisual
             confirmCurrentFrame(4);
             confirmNextFrame(5);
 
-            setTime(4000, null);
+            setTime(4000, 4000);
             confirmCurrentFrame(4);
             confirmNextFrame(5);
 
             setTime(3500, null);
-            confirmCurrentFrame(4);
-            confirmNextFrame(3);
+            confirmCurrentFrame(3);
+            confirmNextFrame(4);
 
             setTime(3000, 3000);
             confirmCurrentFrame(3);
-            confirmNextFrame(2);
+            confirmNextFrame(4);
         }
 
         [Test]
         public void TestRewindOutOfImportantSection()
         {
+            setReplayFrames();
             fastForwardToPoint(3500);
 
             confirmCurrentFrame(3);
             confirmNextFrame(4);
 
             setTime(3200, null);
-            // next frame doesn't change even though direction reversed, because of important section.
             confirmCurrentFrame(3);
             confirmNextFrame(4);
 
-            setTime(3000, null);
+            setTime(3000, 3000);
             confirmCurrentFrame(3);
             confirmNextFrame(4);
 
             setTime(2800, 2800);
-            confirmCurrentFrame(3);
-            confirmNextFrame(2);
+            confirmCurrentFrame(2);
+            confirmNextFrame(3);
+        }
+
+        [Test]
+        public void TestReplayStreaming()
+        {
+            // no frames are arrived yet
+            setTime(0, null);
+            setTime(1000, null);
+            Assert.IsTrue(handler.WaitingForFrame, "Should be waiting for the first frame");
+
+            replay.Frames.Add(new TestReplayFrame(0));
+            replay.Frames.Add(new TestReplayFrame(1000));
+
+            // should always play from beginning
+            setTime(1000, 0);
+            confirmCurrentFrame(0);
+            Assert.IsFalse(handler.WaitingForFrame, "Should not be waiting yet");
+            setTime(1000, 1000);
+            confirmCurrentFrame(1);
+            confirmNextFrame(null);
+            Assert.IsTrue(handler.WaitingForFrame, "Should be waiting");
+
+            // cannot seek beyond the last frame
+            setTime(1500, null);
+            confirmCurrentFrame(1);
+
+            setTime(-100, 0);
+            confirmCurrentFrame(0);
+
+            // can seek to the point before the first frame, however
+            setTime(-100, -100);
+            confirmCurrentFrame(null);
+            confirmNextFrame(0);
+
+            fastForwardToPoint(1000);
+            setTime(3000, null);
+            replay.Frames.Add(new TestReplayFrame(2000));
+            confirmCurrentFrame(1);
+            setTime(1000, 1000);
+            setTime(3000, 2000);
+        }
+
+        [Test]
+        public void TestMultipleFramesSameTime()
+        {
+            replay.Frames.Add(new TestReplayFrame(0));
+            replay.Frames.Add(new TestReplayFrame(0));
+            replay.Frames.Add(new TestReplayFrame(1000));
+            replay.Frames.Add(new TestReplayFrame(1000));
+            replay.Frames.Add(new TestReplayFrame(2000));
+
+            // forward direction is prioritized when multiple frames have the same time.
+            setTime(0, 0);
+            setTime(0, 0);
+
+            setTime(2000, 1000);
+            setTime(2000, 1000);
+
+            setTime(1000, 1000);
+            setTime(1000, 1000);
+            setTime(-100, 1000);
+            setTime(-100, 0);
+            setTime(-100, 0);
+            setTime(-100, -100);
+        }
+
+        private void setReplayFrames()
+        {
+            replay.Frames = new List<ReplayFrame>
+            {
+                new TestReplayFrame(0),
+                new TestReplayFrame(1000),
+                new TestReplayFrame(2000),
+                new TestReplayFrame(3000, true),
+                new TestReplayFrame(4000, true),
+                new TestReplayFrame(5000, true),
+                new TestReplayFrame(7000, true),
+                new TestReplayFrame(8000),
+            };
+            replay.HasReceivedAllFrames = true;
         }
 
         private void fastForwardToPoint(double destination)
         {
             for (int i = 0; i < 1000; i++)
             {
-                if (handler.SetFrameFromTime(destination) == null)
+                var time = handler.SetFrameFromTime(destination);
+                if (time == null || time == destination)
                     return;
             }
 
@@ -235,33 +308,17 @@ namespace osu.Game.Tests.NonVisual
 
         private void setTime(double set, double? expect)
         {
-            Assert.AreEqual(expect, handler.SetFrameFromTime(set));
+            Assert.AreEqual(expect, handler.SetFrameFromTime(set), "Unexpected return value");
         }
 
         private void confirmCurrentFrame(int? frame)
         {
-            if (frame.HasValue)
-            {
-                Assert.IsNotNull(handler.CurrentFrame);
-                Assert.AreEqual(replay.Frames[frame.Value].Time, handler.CurrentFrame.Time);
-            }
-            else
-            {
-                Assert.IsNull(handler.CurrentFrame);
-            }
+            Assert.AreEqual(frame is int x ? replay.Frames[x].Time : (double?)null, handler.CurrentFrame?.Time, "Unexpected current frame");
         }
 
         private void confirmNextFrame(int? frame)
         {
-            if (frame.HasValue)
-            {
-                Assert.IsNotNull(handler.NextFrame);
-                Assert.AreEqual(replay.Frames[frame.Value].Time, handler.NextFrame.Time);
-            }
-            else
-            {
-                Assert.IsNull(handler.NextFrame);
-            }
+            Assert.AreEqual(frame is int x ? replay.Frames[x].Time : (double?)null, handler.NextFrame?.Time, "Unexpected next frame");
         }
 
         private class TestReplayFrame : ReplayFrame

osu.Game.Tests/NonVisual/StreamingFramedReplayInputHandlerTest.cs

@@ -1,296 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System;
-using System.Collections.Generic;
-using NUnit.Framework;
-using osu.Game.Replays;
-using osu.Game.Rulesets.Replays;
-
-namespace osu.Game.Tests.NonVisual
-{
-    [TestFixture]
-    public class StreamingFramedReplayInputHandlerTest
-    {
-        private Replay replay;
-        private TestInputHandler handler;
-
-        [SetUp]
-        public void SetUp()
-        {
-            handler = new TestInputHandler(replay = new Replay
-            {
-                HasReceivedAllFrames = false,
-                Frames = new List<ReplayFrame>
-                {
-                    new TestReplayFrame(0),
-                    new TestReplayFrame(1000),
-                    new TestReplayFrame(2000),
-                    new TestReplayFrame(3000, true),
-                    new TestReplayFrame(4000, true),
-                    new TestReplayFrame(5000, true),
-                    new TestReplayFrame(7000, true),
-                    new TestReplayFrame(8000),
-                }
-            });
-        }
-
-        [Test]
-        public void TestNormalPlayback()
-        {
-            Assert.IsNull(handler.CurrentFrame);
-
-            confirmCurrentFrame(null);
-            confirmNextFrame(0);
-
-            setTime(0, 0);
-            confirmCurrentFrame(0);
-            confirmNextFrame(1);
-
-            // if we hit the first frame perfectly, time should progress to it.
-            setTime(1000, 1000);
-            confirmCurrentFrame(1);
-            confirmNextFrame(2);
-
-            // in between non-important frames should progress based on input.
-            setTime(1200, 1200);
-            confirmCurrentFrame(1);
-
-            setTime(1400, 1400);
-            confirmCurrentFrame(1);
-
-            // progressing beyond the next frame should force time to that frame once.
-            setTime(2200, 2000);
-            confirmCurrentFrame(2);
-
-            // second attempt should progress to input time
-            setTime(2200, 2200);
-            confirmCurrentFrame(2);
-
-            // entering important section
-            setTime(3000, 3000);
-            confirmCurrentFrame(3);
-
-            // cannot progress within
-            setTime(3500, null);
-            confirmCurrentFrame(3);
-
-            setTime(4000, 4000);
-            confirmCurrentFrame(4);
-
-            // still cannot progress
-            setTime(4500, null);
-            confirmCurrentFrame(4);
-
-            setTime(5200, 5000);
-            confirmCurrentFrame(5);
-
-            // important section AllowedImportantTimeSpan allowance
-            setTime(5200, 5200);
-            confirmCurrentFrame(5);
-
-            setTime(7200, 7000);
-            confirmCurrentFrame(6);
-
-            setTime(7200, null);
-            confirmCurrentFrame(6);
-
-            // exited important section
-            setTime(8200, 8000);
-            confirmCurrentFrame(7);
-            confirmNextFrame(null);
-
-            setTime(8200, null);
-            confirmCurrentFrame(7);
-            confirmNextFrame(null);
-
-            setTime(8400, null);
-            confirmCurrentFrame(7);
-            confirmNextFrame(null);
-        }
-
-        [Test]
-        public void TestIntroTime()
-        {
-            setTime(-1000, -1000);
-            confirmCurrentFrame(null);
-            confirmNextFrame(0);
-
-            setTime(-500, -500);
-            confirmCurrentFrame(null);
-            confirmNextFrame(0);
-
-            setTime(0, 0);
-            confirmCurrentFrame(0);
-            confirmNextFrame(1);
-        }
-
-        [Test]
-        public void TestBasicRewind()
-        {
-            setTime(2800, 0);
-            setTime(2800, 1000);
-            setTime(2800, 2000);
-            setTime(2800, 2800);
-            confirmCurrentFrame(2);
-            confirmNextFrame(3);
-
-            // pivot without crossing a frame boundary
-            setTime(2700, 2700);
-            confirmCurrentFrame(2);
-            confirmNextFrame(1);
-
-            // cross current frame boundary; should not yet update frame
-            setTime(1980, 1980);
-            confirmCurrentFrame(2);
-            confirmNextFrame(1);
-
-            setTime(1200, 1200);
-            confirmCurrentFrame(2);
-            confirmNextFrame(1);
-
-            // ensure each frame plays out until start
-            setTime(-500, 1000);
-            confirmCurrentFrame(1);
-            confirmNextFrame(0);
-
-            setTime(-500, 0);
-            confirmCurrentFrame(0);
-            confirmNextFrame(null);
-
-            setTime(-500, -500);
-            confirmCurrentFrame(0);
-            confirmNextFrame(null);
-        }
-
-        [Test]
-        public void TestRewindInsideImportantSection()
-        {
-            fastForwardToPoint(3000);
-
-            setTime(4000, 4000);
-            confirmCurrentFrame(4);
-            confirmNextFrame(5);
-
-            setTime(3500, null);
-            confirmCurrentFrame(4);
-            confirmNextFrame(3);
-
-            setTime(3000, 3000);
-            confirmCurrentFrame(3);
-            confirmNextFrame(2);
-
-            setTime(3500, null);
-            confirmCurrentFrame(3);
-            confirmNextFrame(4);
-
-            setTime(4000, 4000);
-            confirmCurrentFrame(4);
-            confirmNextFrame(5);
-
-            setTime(4500, null);
-            confirmCurrentFrame(4);
-            confirmNextFrame(5);
-
-            setTime(4000, null);
-            confirmCurrentFrame(4);
-            confirmNextFrame(5);
-
-            setTime(3500, null);
-            confirmCurrentFrame(4);
-            confirmNextFrame(3);
-
-            setTime(3000, 3000);
-            confirmCurrentFrame(3);
-            confirmNextFrame(2);
-        }
-
-        [Test]
-        public void TestRewindOutOfImportantSection()
-        {
-            fastForwardToPoint(3500);
-
-            confirmCurrentFrame(3);
-            confirmNextFrame(4);
-
-            setTime(3200, null);
-            // next frame doesn't change even though direction reversed, because of important section.
-            confirmCurrentFrame(3);
-            confirmNextFrame(4);
-
-            setTime(3000, null);
-            confirmCurrentFrame(3);
-            confirmNextFrame(4);
-
-            setTime(2800, 2800);
-            confirmCurrentFrame(3);
-            confirmNextFrame(2);
-        }
-
-        private void fastForwardToPoint(double destination)
-        {
-            for (int i = 0; i < 1000; i++)
-            {
-                if (handler.SetFrameFromTime(destination) == null)
-                    return;
-            }
-
-            throw new TimeoutException("Seek was never fulfilled");
-        }
-
-        private void setTime(double set, double? expect)
-        {
-            Assert.AreEqual(expect, handler.SetFrameFromTime(set));
-        }
-
-        private void confirmCurrentFrame(int? frame)
-        {
-            if (frame.HasValue)
-            {
-                Assert.IsNotNull(handler.CurrentFrame);
-                Assert.AreEqual(replay.Frames[frame.Value].Time, handler.CurrentFrame.Time);
-            }
-            else
-            {
-                Assert.IsNull(handler.CurrentFrame);
-            }
-        }
-
-        private void confirmNextFrame(int? frame)
-        {
-            if (frame.HasValue)
-            {
-                Assert.IsNotNull(handler.NextFrame);
-                Assert.AreEqual(replay.Frames[frame.Value].Time, handler.NextFrame.Time);
-            }
-            else
-            {
-                Assert.IsNull(handler.NextFrame);
-            }
-        }
-
-        private class TestReplayFrame : ReplayFrame
-        {
-            public readonly bool IsImportant;
-
-            public TestReplayFrame(double time, bool isImportant = false)
-                : base(time)
-            {
-                IsImportant = isImportant;
-            }
-        }
-
-        private class TestInputHandler : FramedReplayInputHandler<TestReplayFrame>
-        {
-            public TestInputHandler(Replay replay)
-                : base(replay)
-            {
-                FrameAccuratePlayback = true;
-            }
-
-            protected override double AllowedImportantTimeSpan => 1000;
-
-            protected override bool IsImportant(TestReplayFrame frame) => frame.IsImportant;
-        }
-    }
-}

osu.Game.Tests/Online/TestAPIModJsonSerialization.cs

@@ -11,7 +11,10 @@ using osu.Game.Online.API;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Difficulty;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Osu;
+using osu.Game.Rulesets.Osu.Mods;
 using osu.Game.Rulesets.UI;
+using osu.Game.Scoring;
 
 namespace osu.Game.Tests.Online
 {
@@ -84,6 +87,36 @@ namespace osu.Game.Tests.Online
             Assert.That(converted?.OverallDifficulty.Value, Is.EqualTo(11));
         }
 
+        [Test]
+        public void TestDeserialiseScoreInfoWithEmptyMods()
+        {
+            var score = new ScoreInfo { Ruleset = new OsuRuleset().RulesetInfo };
+
+            var deserialised = JsonConvert.DeserializeObject<ScoreInfo>(JsonConvert.SerializeObject(score));
+
+            if (deserialised != null)
+                deserialised.Ruleset = new OsuRuleset().RulesetInfo;
+
+            Assert.That(deserialised?.Mods.Length, Is.Zero);
+        }
+
+        [Test]
+        public void TestDeserialiseScoreInfoWithCustomModSetting()
+        {
+            var score = new ScoreInfo
+            {
+                Ruleset = new OsuRuleset().RulesetInfo,
+                Mods = new Mod[] { new OsuModDoubleTime { SpeedChange = { Value = 2 } } }
+            };
+
+            var deserialised = JsonConvert.DeserializeObject<ScoreInfo>(JsonConvert.SerializeObject(score));
+
+            if (deserialised != null)
+                deserialised.Ruleset = new OsuRuleset().RulesetInfo;
+
+            Assert.That(((OsuModDoubleTime)deserialised?.Mods[0])?.SpeedChange.Value, Is.EqualTo(2));
+        }
+
         private class TestRuleset : Ruleset
         {
             public override IEnumerable<Mod> GetModsFor(ModType type) => new Mod[]
@@ -107,6 +140,7 @@ namespace osu.Game.Tests.Online
         {
             public override string Name => "Test Mod";
             public override string Acronym => "TM";
+            public override string Description => "This is a test mod.";
             public override double ScoreMultiplier => 1;
 
             [SettingSource("Test")]
@@ -123,6 +157,7 @@ namespace osu.Game.Tests.Online
         {
             public override string Name => "Test Mod";
             public override string Acronym => "TMTR";
+            public override string Description => "This is a test mod.";
             public override double ScoreMultiplier => 1;
 
             [SettingSource("Initial rate", "The starting speed of the track")]

osu.Game.Tests/Online/TestAPIModMessagePackSerialization.cs

@@ -100,6 +100,7 @@ namespace osu.Game.Tests.Online
         {
             public override string Name => "Test Mod";
             public override string Acronym => "TM";
+            public override string Description => "This is a test mod.";
             public override double ScoreMultiplier => 1;
 
             [SettingSource("Test")]
@@ -116,6 +117,7 @@ namespace osu.Game.Tests.Online
         {
             public override string Name => "Test Mod";
             public override string Acronym => "TMTR";
+            public override string Description => "This is a test mod.";
             public override double ScoreMultiplier => 1;
 
             [SettingSource("Initial rate", "The starting speed of the track")]
@@ -150,6 +152,7 @@ namespace osu.Game.Tests.Online
         {
             public override string Name => "Test Mod";
             public override string Acronym => "TM";
+            public override string Description => "This is a test mod.";
             public override double ScoreMultiplier => 1;
 
             [SettingSource("Test")]

osu.Game.Tests/Visual/Background/TestSceneUserDimBackgrounds.cs

@@ -65,6 +65,21 @@ namespace osu.Game.Tests.Visual.Background
             stack.Push(songSelect = new DummySongSelect());
         });
 
+        /// <summary>
+        /// User settings should always be ignored on song select screen.
+        /// </summary>
+        [Test]
+        public void TestUserSettingsIgnoredOnSongSelect()
+        {
+            setupUserSettings();
+            AddUntilStep("Screen is undimmed", () => songSelect.IsBackgroundUndimmed());
+            AddUntilStep("Screen using background blur", () => songSelect.IsBackgroundBlur());
+            performFullSetup();
+            AddStep("Exit to song select", () => player.Exit());
+            AddUntilStep("Screen is undimmed", () => songSelect.IsBackgroundUndimmed());
+            AddUntilStep("Screen using background blur", () => songSelect.IsBackgroundBlur());
+        }
+
         /// <summary>
         /// Check if <see cref="PlayerLoader"/> properly triggers the visual settings preview when a user hovers over the visual settings panel.
         /// </summary>
@@ -142,9 +157,9 @@ namespace osu.Game.Tests.Visual.Background
         {
             performFullSetup();
             AddUntilStep("Screen is dimmed and blur applied", () => songSelect.IsBackgroundDimmed() && songSelect.IsUserBlurApplied());
-            AddStep("Enable user dim", () => songSelect.DimEnabled.Value = false);
+            AddStep("Disable user dim", () => songSelect.IgnoreUserSettings.Value = true);
             AddUntilStep("Screen is undimmed and user blur removed", () => songSelect.IsBackgroundUndimmed() && songSelect.IsUserBlurDisabled());
-            AddStep("Disable user dim", () => songSelect.DimEnabled.Value = true);
+            AddStep("Enable user dim", () => songSelect.IgnoreUserSettings.Value = false);
             AddUntilStep("Screen is dimmed and blur applied", () => songSelect.IsBackgroundDimmed() && songSelect.IsUserBlurApplied());
         }
 
@@ -161,13 +176,36 @@ namespace osu.Game.Tests.Visual.Background
                 player.ReplacesBackground.Value = true;
                 player.StoryboardEnabled.Value = true;
             });
-            AddStep("Enable user dim", () => player.DimmableStoryboard.EnableUserDim.Value = true);
+            AddStep("Enable user dim", () => player.DimmableStoryboard.IgnoreUserSettings.Value = false);
             AddStep("Set dim level to 1", () => songSelect.DimLevel.Value = 1f);
             AddUntilStep("Storyboard is invisible", () => !player.IsStoryboardVisible);
-            AddStep("Disable user dim", () => player.DimmableStoryboard.EnableUserDim.Value = false);
+            AddStep("Disable user dim", () => player.DimmableStoryboard.IgnoreUserSettings.Value = true);
             AddUntilStep("Storyboard is visible", () => player.IsStoryboardVisible);
         }
 
+        [Test]
+        public void TestStoryboardIgnoreUserSettings()
+        {
+            performFullSetup();
+            createFakeStoryboard();
+            AddStep("Enable replacing background", () => player.ReplacesBackground.Value = true);
+
+            AddUntilStep("Storyboard is invisible", () => !player.IsStoryboardVisible);
+            AddUntilStep("Background is visible", () => songSelect.IsBackgroundVisible());
+
+            AddStep("Ignore user settings", () =>
+            {
+                player.ApplyToBackground(b => b.IgnoreUserSettings.Value = true);
+                player.DimmableStoryboard.IgnoreUserSettings.Value = true;
+            });
+            AddUntilStep("Storyboard is visible", () => player.IsStoryboardVisible);
+            AddUntilStep("Background is invisible", () => songSelect.IsBackgroundInvisible());
+
+            AddStep("Disable background replacement", () => player.ReplacesBackground.Value = false);
+            AddUntilStep("Storyboard is visible", () => player.IsStoryboardVisible);
+            AddUntilStep("Background is visible", () => songSelect.IsBackgroundVisible());
+        }
+
         /// <summary>
         /// Check if the visual settings container retains dim and blur when pausing
         /// </summary>
@@ -204,17 +242,6 @@ namespace osu.Game.Tests.Visual.Background
                 songSelect.IsBackgroundUndimmed() && songSelect.IsBackgroundCurrent() && songSelect.CheckBackgroundBlur(results.ExpectedBackgroundBlur));
         }
 
-        /// <summary>
-        /// Check if background gets undimmed and unblurred when leaving <see cref="Player"/>  for <see cref="PlaySongSelect"/>
-        /// </summary>
-        [Test]
-        public void TestTransitionOut()
-        {
-            performFullSetup();
-            AddStep("Exit to song select", () => player.Exit());
-            AddUntilStep("Screen is undimmed and user blur removed", () => songSelect.IsBackgroundUndimmed() && songSelect.IsBlurCorrect());
-        }
-
         /// <summary>
         /// Check if hovering on the visual settings dialogue after resuming from player still previews the background dim.
         /// </summary>
@@ -281,11 +308,11 @@ namespace osu.Game.Tests.Visual.Background
             protected override BackgroundScreen CreateBackground()
             {
                 background = new FadeAccessibleBackground(Beatmap.Value);
-                DimEnabled.BindTo(background.EnableUserDim);
+                IgnoreUserSettings.BindTo(background.IgnoreUserSettings);
                 return background;
             }
 
-            public readonly Bindable<bool> DimEnabled = new Bindable<bool>();
+            public readonly Bindable<bool> IgnoreUserSettings = new Bindable<bool>();
             public readonly Bindable<double> DimLevel = new BindableDouble();
             public readonly Bindable<double> BlurLevel = new BindableDouble();
 
@@ -310,7 +337,7 @@ namespace osu.Game.Tests.Visual.Background
 
             public bool IsBackgroundVisible() => background.CurrentAlpha == 1;
 
-            public bool IsBlurCorrect() => background.CurrentBlur == new Vector2(BACKGROUND_BLUR);
+            public bool IsBackgroundBlur() => background.CurrentBlur == new Vector2(BACKGROUND_BLUR);
 
             public bool CheckBackgroundBlur(Vector2 expected) => background.CurrentBlur == expected;
 

osu.Game.Tests/Visual/Editing/TestSceneEditorQuickDelete.cs

@@ -1,88 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System.Linq;
-using NUnit.Framework;
-using osu.Framework.Testing;
-using osu.Game.Beatmaps;
-using osu.Game.Rulesets;
-using osu.Game.Rulesets.Objects;
-using osu.Game.Rulesets.Osu;
-using osu.Game.Rulesets.Osu.Objects;
-using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles.Components;
-using osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components;
-using osu.Game.Tests.Beatmaps;
-using osu.Game.Screens.Edit.Compose.Components;
-using osuTK;
-using osuTK.Input;
-
-namespace osu.Game.Tests.Visual.Editing
-{
-    public class TestSceneEditorQuickDelete : EditorTestScene
-    {
-        protected override Ruleset CreateEditorRuleset() => new OsuRuleset();
-
-        protected override IBeatmap CreateBeatmap(RulesetInfo ruleset) => new TestBeatmap(ruleset, false);
-
-        private BlueprintContainer blueprintContainer
-            => Editor.ChildrenOfType<BlueprintContainer>().First();
-
-        [Test]
-        public void TestQuickDeleteRemovesObject()
-        {
-            var addedObject = new HitCircle { StartTime = 1000 };
-
-            AddStep("add hitobject", () => EditorBeatmap.Add(addedObject));
-
-            AddStep("select added object", () => EditorBeatmap.SelectedHitObjects.Add(addedObject));
-
-            AddStep("move mouse to object", () =>
-            {
-                var pos = blueprintContainer.ChildrenOfType<HitCirclePiece>().First().ScreenSpaceDrawQuad.Centre;
-                InputManager.MoveMouseTo(pos);
-            });
-            AddStep("hold shift", () => InputManager.PressKey(Key.ShiftLeft));
-            AddStep("right click", () => InputManager.Click(MouseButton.Right));
-            AddStep("release shift", () => InputManager.ReleaseKey(Key.ShiftLeft));
-
-            AddAssert("no hitobjects in beatmap", () => EditorBeatmap.HitObjects.Count == 0);
-        }
-
-        [Test]
-        public void TestQuickDeleteRemovesSliderControlPoint()
-        {
-            Slider slider = new Slider { StartTime = 1000 };
-
-            PathControlPoint[] points =
-            {
-                new PathControlPoint(),
-                new PathControlPoint(new Vector2(50, 0)),
-                new PathControlPoint(new Vector2(100, 0))
-            };
-
-            AddStep("add slider", () =>
-            {
-                slider.Path = new SliderPath(points);
-                EditorBeatmap.Add(slider);
-            });
-
-            AddStep("select added slider", () => EditorBeatmap.SelectedHitObjects.Add(slider));
-
-            AddStep("move mouse to controlpoint", () =>
-            {
-                var pos = blueprintContainer.ChildrenOfType<PathControlPointPiece>().ElementAt(1).ScreenSpaceDrawQuad.Centre;
-                InputManager.MoveMouseTo(pos);
-            });
-            AddStep("hold shift", () => InputManager.PressKey(Key.ShiftLeft));
-
-            AddStep("right click", () => InputManager.Click(MouseButton.Right));
-            AddAssert("slider has 2 points", () => slider.Path.ControlPoints.Count == 2);
-
-            // second click should nuke the object completely.
-            AddStep("right click", () => InputManager.Click(MouseButton.Right));
-            AddAssert("no hitobjects in beatmap", () => EditorBeatmap.HitObjects.Count == 0);
-
-            AddStep("release shift", () => InputManager.ReleaseKey(Key.ShiftLeft));
-        }
-    }
-}

osu.Game.Tests/Visual/Editing/TestSceneEditorSelection.cs

@@ -0,0 +1,219 @@
+// 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.Testing;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu;
+using osu.Game.Rulesets.Osu.Objects;
+using osu.Game.Rulesets.Osu.Edit.Blueprints.HitCircles.Components;
+using osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components;
+using osu.Game.Tests.Beatmaps;
+using osu.Game.Screens.Edit.Compose.Components;
+using osuTK;
+using osuTK.Input;
+
+namespace osu.Game.Tests.Visual.Editing
+{
+    public class TestSceneEditorSelection : EditorTestScene
+    {
+        protected override Ruleset CreateEditorRuleset() => new OsuRuleset();
+
+        protected override IBeatmap CreateBeatmap(RulesetInfo ruleset) => new TestBeatmap(ruleset, false);
+
+        private BlueprintContainer blueprintContainer
+            => Editor.ChildrenOfType<BlueprintContainer>().First();
+
+        private void moveMouseToObject(Func<HitObject> targetFunc)
+        {
+            AddStep("move mouse to object", () =>
+            {
+                var pos = blueprintContainer.SelectionBlueprints
+                                            .First(s => s.HitObject == targetFunc())
+                                            .ChildrenOfType<HitCirclePiece>()
+                                            .First().ScreenSpaceDrawQuad.Centre;
+
+                InputManager.MoveMouseTo(pos);
+            });
+        }
+
+        [Test]
+        public void TestBasicSelect()
+        {
+            var addedObject = new HitCircle { StartTime = 100 };
+            AddStep("add hitobject", () => EditorBeatmap.Add(addedObject));
+
+            moveMouseToObject(() => addedObject);
+            AddStep("left click", () => InputManager.Click(MouseButton.Left));
+
+            AddAssert("hitobject selected", () => EditorBeatmap.SelectedHitObjects.Single() == addedObject);
+
+            var addedObject2 = new HitCircle
+            {
+                StartTime = 100,
+                Position = new Vector2(100),
+            };
+
+            AddStep("add one more hitobject", () => EditorBeatmap.Add(addedObject2));
+            AddAssert("selection unchanged", () => EditorBeatmap.SelectedHitObjects.Single() == addedObject);
+
+            moveMouseToObject(() => addedObject2);
+            AddStep("left click", () => InputManager.Click(MouseButton.Left));
+            AddAssert("hitobject selected", () => EditorBeatmap.SelectedHitObjects.Single() == addedObject2);
+        }
+
+        [Test]
+        public void TestMultiSelect()
+        {
+            var addedObjects = new[]
+            {
+                new HitCircle { StartTime = 100 },
+                new HitCircle { StartTime = 200, Position = new Vector2(50) },
+                new HitCircle { StartTime = 300, Position = new Vector2(100) },
+                new HitCircle { StartTime = 400, Position = new Vector2(150) },
+            };
+
+            AddStep("add hitobjects", () => EditorBeatmap.AddRange(addedObjects));
+
+            moveMouseToObject(() => addedObjects[0]);
+            AddStep("click first", () => InputManager.Click(MouseButton.Left));
+
+            AddAssert("hitobject selected", () => EditorBeatmap.SelectedHitObjects.Single() == addedObjects[0]);
+
+            AddStep("hold control", () => InputManager.PressKey(Key.ControlLeft));
+
+            moveMouseToObject(() => addedObjects[1]);
+            AddStep("click second", () => InputManager.Click(MouseButton.Left));
+            AddAssert("2 hitobjects selected", () => EditorBeatmap.SelectedHitObjects.Count == 2 && EditorBeatmap.SelectedHitObjects.Contains(addedObjects[1]));
+
+            moveMouseToObject(() => addedObjects[2]);
+            AddStep("click third", () => InputManager.Click(MouseButton.Left));
+            AddAssert("3 hitobjects selected", () => EditorBeatmap.SelectedHitObjects.Count == 3 && EditorBeatmap.SelectedHitObjects.Contains(addedObjects[2]));
+
+            moveMouseToObject(() => addedObjects[1]);
+            AddStep("click second", () => InputManager.Click(MouseButton.Left));
+            AddAssert("2 hitobjects selected", () => EditorBeatmap.SelectedHitObjects.Count == 2 && !EditorBeatmap.SelectedHitObjects.Contains(addedObjects[1]));
+        }
+
+        [TestCase(false)]
+        [TestCase(true)]
+        public void TestMultiSelectFromDrag(bool alreadySelectedBeforeDrag)
+        {
+            HitCircle[] addedObjects = null;
+
+            AddStep("add hitobjects", () => EditorBeatmap.AddRange(addedObjects = new[]
+            {
+                new HitCircle { StartTime = 100 },
+                new HitCircle { StartTime = 200, Position = new Vector2(50) },
+                new HitCircle { StartTime = 300, Position = new Vector2(100) },
+                new HitCircle { StartTime = 400, Position = new Vector2(150) },
+            }));
+
+            moveMouseToObject(() => addedObjects[0]);
+            AddStep("click first", () => InputManager.Click(MouseButton.Left));
+
+            AddStep("hold control", () => InputManager.PressKey(Key.ControlLeft));
+
+            moveMouseToObject(() => addedObjects[1]);
+
+            if (alreadySelectedBeforeDrag)
+                AddStep("click second", () => InputManager.Click(MouseButton.Left));
+
+            AddStep("mouse down on second", () => InputManager.PressButton(MouseButton.Left));
+
+            AddAssert("2 hitobjects selected", () => EditorBeatmap.SelectedHitObjects.Count == 2 && EditorBeatmap.SelectedHitObjects.Contains(addedObjects[1]));
+
+            AddStep("drag to centre", () => InputManager.MoveMouseTo(blueprintContainer.ScreenSpaceDrawQuad.Centre));
+
+            AddAssert("positions changed", () => addedObjects[0].Position != Vector2.Zero && addedObjects[1].Position != new Vector2(50));
+
+            AddStep("release control", () => InputManager.ReleaseKey(Key.ControlLeft));
+            AddStep("mouse up", () => InputManager.ReleaseButton(MouseButton.Left));
+        }
+
+        [Test]
+        public void TestBasicDeselect()
+        {
+            var addedObject = new HitCircle { StartTime = 100 };
+            AddStep("add hitobject", () => EditorBeatmap.Add(addedObject));
+
+            moveMouseToObject(() => addedObject);
+            AddStep("left click", () => InputManager.Click(MouseButton.Left));
+
+            AddAssert("hitobject selected", () => EditorBeatmap.SelectedHitObjects.Single() == addedObject);
+
+            AddStep("click away", () =>
+            {
+                InputManager.MoveMouseTo(blueprintContainer.ScreenSpaceDrawQuad.Centre);
+                InputManager.Click(MouseButton.Left);
+            });
+
+            AddAssert("selection lost", () => EditorBeatmap.SelectedHitObjects.Count == 0);
+        }
+
+        [Test]
+        public void TestQuickDeleteRemovesObject()
+        {
+            var addedObject = new HitCircle { StartTime = 1000 };
+
+            AddStep("add hitobject", () => EditorBeatmap.Add(addedObject));
+
+            AddStep("select added object", () => EditorBeatmap.SelectedHitObjects.Add(addedObject));
+
+            moveMouseToObject(() => addedObject);
+
+            AddStep("hold shift", () => InputManager.PressKey(Key.ShiftLeft));
+            AddStep("right click", () => InputManager.Click(MouseButton.Right));
+            AddStep("release shift", () => InputManager.ReleaseKey(Key.ShiftLeft));
+
+            AddAssert("no hitobjects in beatmap", () => EditorBeatmap.HitObjects.Count == 0);
+        }
+
+        [Test]
+        public void TestQuickDeleteRemovesSliderControlPoint()
+        {
+            Slider slider = null;
+
+            PathControlPoint[] points =
+            {
+                new PathControlPoint(),
+                new PathControlPoint(new Vector2(50, 0)),
+                new PathControlPoint(new Vector2(100, 0))
+            };
+
+            AddStep("add slider", () =>
+            {
+                slider = new Slider
+                {
+                    StartTime = 1000,
+                    Path = new SliderPath(points)
+                };
+
+                EditorBeatmap.Add(slider);
+            });
+
+            AddStep("select added slider", () => EditorBeatmap.SelectedHitObjects.Add(slider));
+
+            AddStep("move mouse to controlpoint", () =>
+            {
+                var pos = blueprintContainer.ChildrenOfType<PathControlPointPiece>().ElementAt(1).ScreenSpaceDrawQuad.Centre;
+                InputManager.MoveMouseTo(pos);
+            });
+            AddStep("hold shift", () => InputManager.PressKey(Key.ShiftLeft));
+
+            AddStep("right click", () => InputManager.Click(MouseButton.Right));
+            AddAssert("slider has 2 points", () => slider.Path.ControlPoints.Count == 2);
+
+            AddStep("right click", () => InputManager.Click(MouseButton.Right));
+
+            // second click should nuke the object completely.
+            AddAssert("no hitobjects in beatmap", () => EditorBeatmap.HitObjects.Count == 0);
+
+            AddStep("release shift", () => InputManager.ReleaseKey(Key.ShiftLeft));
+        }
+    }
+}

osu.Game.Tests/Visual/Editing/TestSceneEditorSummaryTimeline.cs

@@ -5,7 +5,6 @@ using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Game.Rulesets.Osu;
-using osu.Game.Rulesets.Osu.Beatmaps;
 using osu.Game.Screens.Edit;
 using osu.Game.Screens.Edit.Components.Timelines.Summary;
 using osuTK;
@@ -16,18 +15,28 @@ namespace osu.Game.Tests.Visual.Editing
     public class TestSceneEditorSummaryTimeline : EditorClockTestScene
     {
         [Cached(typeof(EditorBeatmap))]
-        private readonly EditorBeatmap editorBeatmap = new EditorBeatmap(new OsuBeatmap());
+        private readonly EditorBeatmap editorBeatmap;
 
-        [BackgroundDependencyLoader]
-        private void load()
+        public TestSceneEditorSummaryTimeline()
         {
-            Beatmap.Value = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
+            editorBeatmap = new EditorBeatmap(CreateBeatmap(new OsuRuleset().RulesetInfo));
+        }
 
-            Add(new SummaryTimeline
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            AddStep("create timeline", () =>
             {
-                Anchor = Anchor.Centre,
-                Origin = Anchor.Centre,
-                Size = new Vector2(500, 50)
+                // required for track
+                Beatmap.Value = CreateWorkingBeatmap(editorBeatmap.PlayableBeatmap);
+
+                Add(new SummaryTimeline
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Size = new Vector2(500, 50)
+                });
             });
         }
     }

osu.Game.Tests/Visual/Editing/TestSceneTimelineHitObjectBlueprint.cs

@@ -21,7 +21,7 @@ namespace osu.Game.Tests.Visual.Editing
         [Test]
         public void TestDisallowZeroDurationObjects()
         {
-            DragBar dragBar;
+            DragArea dragArea;
 
             AddStep("add spinner", () =>
             {
@@ -29,7 +29,7 @@ namespace osu.Game.Tests.Visual.Editing
                 EditorBeatmap.Add(new Spinner
                 {
                     Position = new Vector2(256, 256),
-                    StartTime = 150,
+                    StartTime = 2700,
                     Duration = 500
                 });
             });
@@ -37,8 +37,8 @@ namespace osu.Game.Tests.Visual.Editing
             AddStep("hold down drag bar", () =>
             {
                 // distinguishes between the actual drag bar and its "underlay shadow".
-                dragBar = this.ChildrenOfType<DragBar>().Single(bar => bar.HandlePositionalInput);
-                InputManager.MoveMouseTo(dragBar);
+                dragArea = this.ChildrenOfType<DragArea>().Single(bar => bar.HandlePositionalInput);
+                InputManager.MoveMouseTo(dragArea);
                 InputManager.PressButton(MouseButton.Left);
             });
 

osu.Game.Tests/Visual/Editing/TimelineTestScene.cs

@@ -53,17 +53,21 @@ namespace osu.Game.Tests.Visual.Editing
                         new AudioVisualiser(),
                     }
                 },
-                TimelineArea = new TimelineArea
+                TimelineArea = new TimelineArea(CreateTestComponent())
                 {
-                    Child = CreateTestComponent(),
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
-                    RelativeSizeAxes = Axes.X,
-                    Size = new Vector2(0.8f, 100),
                 }
             });
         }
 
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            Clock.Seek(2500);
+        }
+
         public abstract Drawable CreateTestComponent();
 
         private class AudioVisualiser : CompositeDrawable

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

@@ -25,6 +25,7 @@ using osu.Game.Rulesets.Scoring;
 using osu.Game.Scoring;
 using osu.Game.Screens.Play;
 using osu.Game.Screens.Play.PlayerSettings;
+using osu.Game.Utils;
 using osuTK.Input;
 
 namespace osu.Game.Tests.Visual.Gameplay
@@ -48,6 +49,9 @@ namespace osu.Game.Tests.Visual.Gameplay
         [Cached]
         private readonly VolumeOverlay volumeOverlay;
 
+        [Cached(typeof(BatteryInfo))]
+        private readonly LocalBatteryInfo batteryInfo = new LocalBatteryInfo();
+
         private readonly ChangelogOverlay changelogOverlay;
 
         public TestScenePlayerLoader()
@@ -288,6 +292,33 @@ namespace osu.Game.Tests.Visual.Gameplay
             }
         }
 
+        [TestCase(false, 1.0, false)] // not charging, above cutoff --> no warning
+        [TestCase(true, 0.1, false)] // charging, below cutoff --> no warning
+        [TestCase(false, 0.25, true)] // not charging, at cutoff --> warning
+        public void TestLowBatteryNotification(bool isCharging, double chargeLevel, bool shouldWarn)
+        {
+            AddStep("reset notification lock", () => sessionStatics.GetBindable<bool>(Static.LowBatteryNotificationShownOnce).Value = false);
+
+            // set charge status and level
+            AddStep("load player", () => resetPlayer(false, () =>
+            {
+                batteryInfo.SetCharging(isCharging);
+                batteryInfo.SetChargeLevel(chargeLevel);
+            }));
+            AddUntilStep("wait for player", () => player?.LoadState == LoadState.Ready);
+            AddAssert($"notification {(shouldWarn ? "triggered" : "not triggered")}", () => notificationOverlay.UnreadCount.Value == (shouldWarn ? 1 : 0));
+            AddStep("click notification", () =>
+            {
+                var scrollContainer = (OsuScrollContainer)notificationOverlay.Children.Last();
+                var flowContainer = scrollContainer.Children.OfType<FillFlowContainer<NotificationSection>>().First();
+                var notification = flowContainer.First();
+
+                InputManager.MoveMouseTo(notification);
+                InputManager.Click(MouseButton.Left);
+            });
+            AddUntilStep("wait for player load", () => player.IsLoaded);
+        }
+
         [Test]
         public void TestEpilepsyWarningEarlyExit()
         {
@@ -321,6 +352,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             public override string Name => string.Empty;
             public override string Acronym => string.Empty;
             public override double ScoreMultiplier => 1;
+            public override string Description => string.Empty;
 
             public bool Applied { get; private set; }
 
@@ -348,5 +380,29 @@ namespace osu.Game.Tests.Visual.Gameplay
                     throw new TimeoutException();
             }
         }
+
+        /// <summary>
+        /// Mutable dummy BatteryInfo class for <see cref="TestScenePlayerLoader.TestLowBatteryNotification"/>
+        /// </summary>
+        /// <inheritdoc/>
+        private class LocalBatteryInfo : BatteryInfo
+        {
+            private bool isCharging = true;
+            private double chargeLevel = 1;
+
+            public override bool IsCharging => isCharging;
+
+            public override double ChargeLevel => chargeLevel;
+
+            public void SetCharging(bool value)
+            {
+                isCharging = value;
+            }
+
+            public void SetChargeLevel(double value)
+            {
+                chargeLevel = value;
+            }
+        }
     }
 }

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

@@ -83,7 +83,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             waitForPlayer();
             AddAssert("ensure frames arrived", () => replayHandler.HasFrames);
 
-            AddUntilStep("wait for frame starvation", () => replayHandler.NextFrame == null);
+            AddUntilStep("wait for frame starvation", () => replayHandler.WaitingForFrame);
             checkPaused(true);
 
             double? pausedTime = null;
@@ -92,7 +92,7 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             sendFrames();
 
-            AddUntilStep("wait for frame starvation", () => replayHandler.NextFrame == null);
+            AddUntilStep("wait for frame starvation", () => replayHandler.WaitingForFrame);
             checkPaused(true);
 
             AddAssert("time advanced", () => currentFrameStableTime > pausedTime);

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

@@ -204,27 +204,27 @@ namespace osu.Game.Tests.Visual.Gameplay
                 return;
             }
 
-            if (replayHandler.NextFrame != null)
-            {
-                var lastFrame = replay.Frames.LastOrDefault();
+            if (!replayHandler.HasFrames)
+                return;
 
-                // this isn't perfect as we basically can't be aware of the rate-of-send here (the streamer is not sending data when not being moved).
-                // in gameplay playback, the case where NextFrame is null would pause gameplay and handle this correctly; it's strictly a test limitation / best effort implementation.
-                if (lastFrame != null)
-                    latency = Math.Max(latency, Time.Current - lastFrame.Time);
+            var lastFrame = replay.Frames.LastOrDefault();
 
-                latencyDisplay.Text = $"latency: {latency:N1}";
+            // this isn't perfect as we basically can't be aware of the rate-of-send here (the streamer is not sending data when not being moved).
+            // in gameplay playback, the case where NextFrame is null would pause gameplay and handle this correctly; it's strictly a test limitation / best effort implementation.
+            if (lastFrame != null)
+                latency = Math.Max(latency, Time.Current - lastFrame.Time);
 
-                double proposedTime = Time.Current - latency + Time.Elapsed;
+            latencyDisplay.Text = $"latency: {latency:N1}";
 
-                // this will either advance by one or zero frames.
-                double? time = replayHandler.SetFrameFromTime(proposedTime);
+            double proposedTime = Time.Current - latency + Time.Elapsed;
 
-                if (time == null)
-                    return;
+            // this will either advance by one or zero frames.
+            double? time = replayHandler.SetFrameFromTime(proposedTime);
 
-                manualClock.CurrentTime = time.Value;
-            }
+            if (time == null)
+                return;
+
+            manualClock.CurrentTime = time.Value;
         }
 
         [TearDownSteps]

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

@@ -11,6 +11,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Testing;
 using osu.Framework.Utils;
+using osu.Game.Configuration;
 using osu.Game.Database;
 using osu.Game.Online;
 using osu.Game.Online.API;
@@ -38,6 +39,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
         protected override Container<Drawable> Content { get; } = new Container { RelativeSizeAxes = Axes.Both };
 
+        private OsuConfigManager config;
+
         public TestSceneMultiplayerGameplayLeaderboard()
         {
             base.Content.Children = new Drawable[]
@@ -48,6 +51,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
             };
         }
 
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Dependencies.Cache(config = new OsuConfigManager(LocalStorage));
+        }
+
         [SetUpSteps]
         public override void SetUpSteps()
         {
@@ -97,6 +106,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddRepeatStep("mark user quit", () => Client.CurrentMatchPlayingUserIds.RemoveAt(0), users);
         }
 
+        [Test]
+        public void TestChangeScoringMode()
+        {
+            AddRepeatStep("update state", () => streamingClient.RandomlyUpdateState(), 5);
+            AddStep("change to classic", () => config.SetValue(OsuSetting.ScoreDisplayMode, ScoringMode.Classic));
+            AddStep("change to standardised", () => config.SetValue(OsuSetting.ScoreDisplayMode, ScoringMode.Standardised));
+        }
+
         public class TestMultiplayerStreaming : SpectatorStreamingClient
         {
             public new BindableList<int> PlayingUsers => (BindableList<int>)base.PlayingUsers;
@@ -163,7 +180,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                             break;
                     }
 
-                    ((ISpectatorClient)this).UserSentFrames(userId, new FrameDataBundle(header, Array.Empty<LegacyReplayFrame>()));
+                    ((ISpectatorClient)this).UserSentFrames(userId, new FrameDataBundle(header, new[] { new LegacyReplayFrame(Time.Current, 0, 0, ReplayButtonState.None) }));
                 }
             }
         }

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

@@ -134,7 +134,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddAssert("match started", () => Client.Room?.State == MultiplayerRoomState.WaitingForLoad);
+            AddUntilStep("match started", () => Client.Room?.State == MultiplayerRoomState.WaitingForLoad);
         }
     }
 }

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

@@ -0,0 +1,229 @@
+// 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 System.Threading;
+using System.Threading.Tasks;
+using NUnit.Framework;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Testing;
+using osu.Framework.Timing;
+using osu.Framework.Utils;
+using osu.Game.Database;
+using osu.Game.Online;
+using osu.Game.Online.Spectator;
+using osu.Game.Replays.Legacy;
+using osu.Game.Rulesets.Osu.Scoring;
+using osu.Game.Scoring;
+using osu.Game.Screens.OnlinePlay.Multiplayer.Spectate;
+using osu.Game.Screens.Play.HUD;
+using osu.Game.Users;
+
+namespace osu.Game.Tests.Visual.Multiplayer
+{
+    public class TestSceneMultiplayerSpectatorLeaderboard : MultiplayerTestScene
+    {
+        [Cached(typeof(SpectatorStreamingClient))]
+        private TestSpectatorStreamingClient streamingClient = new TestSpectatorStreamingClient();
+
+        [Cached(typeof(UserLookupCache))]
+        private UserLookupCache lookupCache = new TestUserLookupCache();
+
+        protected override Container<Drawable> Content => content;
+        private readonly Container content;
+
+        private readonly Dictionary<int, ManualClock> clocks = new Dictionary<int, ManualClock>
+        {
+            { 55, new ManualClock() },
+            { 56, new ManualClock() }
+        };
+
+        public TestSceneMultiplayerSpectatorLeaderboard()
+        {
+            base.Content.AddRange(new Drawable[]
+            {
+                streamingClient,
+                lookupCache,
+                content = new Container { RelativeSizeAxes = Axes.Both }
+            });
+        }
+
+        [SetUpSteps]
+        public new void SetUpSteps()
+        {
+            MultiplayerSpectatorLeaderboard leaderboard = null;
+
+            AddStep("reset", () =>
+            {
+                Clear();
+
+                foreach (var (userId, clock) in clocks)
+                {
+                    streamingClient.EndPlay(userId, 0);
+                    clock.CurrentTime = 0;
+                }
+            });
+
+            AddStep("create leaderboard", () =>
+            {
+                foreach (var (userId, _) in clocks)
+                    streamingClient.StartPlay(userId, 0);
+
+                Beatmap.Value = CreateWorkingBeatmap(Ruleset.Value);
+
+                var playable = Beatmap.Value.GetPlayableBeatmap(Ruleset.Value);
+                var scoreProcessor = new OsuScoreProcessor();
+                scoreProcessor.ApplyBeatmap(playable);
+
+                LoadComponentAsync(leaderboard = new MultiplayerSpectatorLeaderboard(scoreProcessor, clocks.Keys.ToArray()) { Expanded = { Value = true } }, Add);
+            });
+
+            AddUntilStep("wait for load", () => leaderboard.IsLoaded);
+
+            AddStep("add clock sources", () =>
+            {
+                foreach (var (userId, clock) in clocks)
+                    leaderboard.AddClock(userId, clock);
+            });
+        }
+
+        [Test]
+        public void TestLeaderboardTracksCurrentTime()
+        {
+            AddStep("send frames", () =>
+            {
+                // For user 55, send frames in sets of 1.
+                // For user 56, send frames in sets of 10.
+                for (int i = 0; i < 100; i++)
+                {
+                    streamingClient.SendFrames(55, i, 1);
+
+                    if (i % 10 == 0)
+                        streamingClient.SendFrames(56, i, 10);
+                }
+            });
+
+            assertCombo(55, 1);
+            assertCombo(56, 10);
+
+            // Advance to a point where only user 55's frame changes.
+            setTime(500);
+            assertCombo(55, 5);
+            assertCombo(56, 10);
+
+            // Advance to a point where both user's frame changes.
+            setTime(1100);
+            assertCombo(55, 11);
+            assertCombo(56, 20);
+
+            // Advance user 56 only to a point where its frame changes.
+            setTime(56, 2100);
+            assertCombo(55, 11);
+            assertCombo(56, 30);
+
+            // Advance both users beyond their last frame
+            setTime(101 * 100);
+            assertCombo(55, 100);
+            assertCombo(56, 100);
+        }
+
+        [Test]
+        public void TestNoFrames()
+        {
+            assertCombo(55, 0);
+            assertCombo(56, 0);
+        }
+
+        private void setTime(double time) => AddStep($"set time {time}", () =>
+        {
+            foreach (var (_, clock) in clocks)
+                clock.CurrentTime = time;
+        });
+
+        private void setTime(int userId, double time)
+            => AddStep($"set user {userId} time {time}", () => clocks[userId].CurrentTime = time);
+
+        private void assertCombo(int userId, int expectedCombo)
+            => AddUntilStep($"player {userId} has {expectedCombo} combo", () => this.ChildrenOfType<GameplayLeaderboardScore>().Single(s => s.User?.Id == userId).Combo.Value == expectedCombo);
+
+        private class TestSpectatorStreamingClient : SpectatorStreamingClient
+        {
+            private readonly Dictionary<int, int> userBeatmapDictionary = new Dictionary<int, int>();
+            private readonly Dictionary<int, bool> userSentStateDictionary = new Dictionary<int, bool>();
+
+            public TestSpectatorStreamingClient()
+                : base(new DevelopmentEndpointConfiguration())
+            {
+            }
+
+            public void StartPlay(int userId, int beatmapId)
+            {
+                userBeatmapDictionary[userId] = beatmapId;
+                userSentStateDictionary[userId] = false;
+                sendState(userId, beatmapId);
+            }
+
+            public void EndPlay(int userId, int beatmapId)
+            {
+                ((ISpectatorClient)this).UserFinishedPlaying(userId, new SpectatorState
+                {
+                    BeatmapID = beatmapId,
+                    RulesetID = 0,
+                });
+                userSentStateDictionary[userId] = false;
+            }
+
+            public void SendFrames(int userId, int index, int count)
+            {
+                var frames = new List<LegacyReplayFrame>();
+
+                for (int i = index; i < index + count; i++)
+                {
+                    var buttonState = i == index + count - 1 ? ReplayButtonState.None : ReplayButtonState.Left1;
+                    frames.Add(new LegacyReplayFrame(i * 100, RNG.Next(0, 512), RNG.Next(0, 512), buttonState));
+                }
+
+                var bundle = new FrameDataBundle(new ScoreInfo { Combo = index + count }, frames);
+                ((ISpectatorClient)this).UserSentFrames(userId, bundle);
+                if (!userSentStateDictionary[userId])
+                    sendState(userId, userBeatmapDictionary[userId]);
+            }
+
+            public override void WatchUser(int userId)
+            {
+                if (userSentStateDictionary[userId])
+                {
+                    // usually the server would do this.
+                    sendState(userId, userBeatmapDictionary[userId]);
+                }
+
+                base.WatchUser(userId);
+            }
+
+            private void sendState(int userId, int beatmapId)
+            {
+                ((ISpectatorClient)this).UserBeganPlaying(userId, new SpectatorState
+                {
+                    BeatmapID = beatmapId,
+                    RulesetID = 0,
+                });
+                userSentStateDictionary[userId] = true;
+            }
+        }
+
+        private class TestUserLookupCache : UserLookupCache
+        {
+            protected override Task<User> ComputeValueAsync(int lookup, CancellationToken token = default)
+            {
+                return Task.FromResult(new User
+                {
+                    Id = lookup,
+                    Username = $"User {lookup}"
+                });
+            }
+        }
+    }
+}

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

@@ -0,0 +1,115 @@
+// 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.Graphics;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Utils;
+using osu.Game.Screens.OnlinePlay.Multiplayer.Spectate;
+using osuTK.Graphics;
+using osuTK.Input;
+
+namespace osu.Game.Tests.Visual.Multiplayer
+{
+    public class TestSceneMultiplayerSpectatorPlayerGrid : OsuManualInputManagerTestScene
+    {
+        private PlayerGrid grid;
+
+        [SetUp]
+        public void Setup() => Schedule(() =>
+        {
+            Child = grid = new PlayerGrid { RelativeSizeAxes = Axes.Both };
+        });
+
+        [Test]
+        public void TestMaximiseAndMinimise()
+        {
+            addCells(2);
+
+            assertMaximisation(0, false, true);
+            assertMaximisation(1, false, true);
+
+            clickCell(0);
+            assertMaximisation(0, true);
+            assertMaximisation(1, false, true);
+            clickCell(0);
+            assertMaximisation(0, false);
+            assertMaximisation(1, false, true);
+
+            clickCell(1);
+            assertMaximisation(1, true);
+            assertMaximisation(0, false, true);
+            clickCell(1);
+            assertMaximisation(1, false);
+            assertMaximisation(0, false, true);
+        }
+
+        [Test]
+        public void TestClickBothCellsSimultaneously()
+        {
+            addCells(2);
+
+            AddStep("click cell 0 then 1", () =>
+            {
+                InputManager.MoveMouseTo(grid.Content.ElementAt(0));
+                InputManager.Click(MouseButton.Left);
+
+                InputManager.MoveMouseTo(grid.Content.ElementAt(1));
+                InputManager.Click(MouseButton.Left);
+            });
+
+            assertMaximisation(1, true);
+            assertMaximisation(0, false);
+        }
+
+        [TestCase(1)]
+        [TestCase(2)]
+        [TestCase(3)]
+        [TestCase(4)]
+        [TestCase(5)]
+        [TestCase(9)]
+        [TestCase(11)]
+        [TestCase(12)]
+        [TestCase(15)]
+        [TestCase(16)]
+        public void TestCellCount(int count)
+        {
+            addCells(count);
+            AddWaitStep("wait for display", 2);
+        }
+
+        private void addCells(int count) => AddStep($"add {count} grid cells", () =>
+        {
+            for (int i = 0; i < count; i++)
+                grid.Add(new GridContent());
+        });
+
+        private void clickCell(int index) => AddStep($"click cell index {index}", () =>
+        {
+            InputManager.MoveMouseTo(grid.Content.ElementAt(index));
+            InputManager.Click(MouseButton.Left);
+        });
+
+        private void assertMaximisation(int index, bool shouldBeMaximised, bool instant = false)
+        {
+            string assertionText = $"cell index {index} {(shouldBeMaximised ? "is" : "is not")} maximised";
+
+            if (instant)
+                AddAssert(assertionText, checkAction);
+            else
+                AddUntilStep(assertionText, checkAction);
+
+            bool checkAction() => Precision.AlmostEquals(grid.MaximisedFacade.DrawSize, grid.Content.ElementAt(index).DrawSize, 10) == shouldBeMaximised;
+        }
+
+        private class GridContent : Box
+        {
+            public GridContent()
+            {
+                RelativeSizeAxes = Axes.Both;
+                Colour = new Color4(RNG.NextSingle(), RNG.NextSingle(), RNG.NextSingle(), 1f);
+            }
+        }
+    }
+}

osu.Game.Tests/Visual/Online/TestSceneUserHistoryGraph.cs

@@ -19,13 +19,12 @@ namespace osu.Game.Tests.Visual.Online
         {
             UserHistoryGraph graph;
 
-            Add(graph = new UserHistoryGraph
+            Add(graph = new UserHistoryGraph("Test")
             {
                 RelativeSizeAxes = Axes.X,
                 Height = 200,
                 Anchor = Anchor.Centre,
                 Origin = Anchor.Centre,
-                TooltipCounterName = "Test"
             });
 
             var values = new[]

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

@@ -57,6 +57,8 @@ namespace osu.Game.Tests.Visual.UserInterface
         private abstract class TestMod : Mod, IApplicableMod
         {
             public override double ScoreMultiplier => 1.0;
+
+            public override string Description => "This is a test mod.";
         }
     }
 }

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

@@ -226,6 +226,8 @@ namespace osu.Game.Tests.Visual.UserInterface
         {
             public override double ScoreMultiplier => 1.0;
 
+            public override string Description => "This is a customisable test mod.";
+
             public override ModType Type => ModType.Conversion;
 
             [SettingSource("Sample float", "Change something for a mod")]

osu.Game.Tests/osu.Game.Tests.csproj

@@ -22,4 +22,4 @@
     <ProjectReference Include="..\osu.Game.Rulesets.Mania\osu.Game.Rulesets.Mania.csproj" />
     <ProjectReference Include="..\osu.Game.Rulesets.Taiko\osu.Game.Rulesets.Taiko.csproj" />
   </ItemGroup>
-</Project>
+</Project>

osu.Game.Tournament/TournamentGameBase.cs

@@ -141,7 +141,6 @@ namespace osu.Game.Tournament
         /// <summary>
         /// Add missing player info based on user IDs.
         /// </summary>
-        /// <returns></returns>
         private bool addPlayers()
         {
             bool addedInfo = false;

osu.Game/Beatmaps/ControlPoints/DifficultyControlPoint.cs

@@ -25,7 +25,7 @@ namespace osu.Game.Beatmaps.ControlPoints
             MaxValue = 10
         };
 
-        public override Color4 GetRepresentingColour(OsuColour colours) => colours.GreenDark;
+        public override Color4 GetRepresentingColour(OsuColour colours) => colours.Lime1;
 
         /// <summary>
         /// The speed multiplier at this control point.

osu.Game/Beatmaps/ControlPoints/TimingControlPoint.cs

@@ -20,7 +20,7 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         private const double default_beat_length = 60000.0 / 60.0;
 
-        public override Color4 GetRepresentingColour(OsuColour colours) => colours.YellowDark;
+        public override Color4 GetRepresentingColour(OsuColour colours) => colours.Orange1;
 
         public static readonly TimingControlPoint DEFAULT = new TimingControlPoint
         {

osu.Game/Beatmaps/IBeatmap.cs

@@ -44,7 +44,6 @@ namespace osu.Game.Beatmaps
         /// <summary>
         /// Returns statistics for the <see cref="HitObjects"/> contained in this beatmap.
         /// </summary>
-        /// <returns></returns>
         IEnumerable<BeatmapStatistic> GetStatistics();
 
         /// <summary>

osu.Game/Configuration/OsuConfigManager.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Diagnostics;
-using osu.Framework.Bindables;
 using osu.Framework.Configuration;
 using osu.Framework.Configuration.Tracking;
 using osu.Framework.Extensions;
@@ -143,7 +142,7 @@ namespace osu.Game.Configuration
 
             SetDefault(OsuSetting.DiscordRichPresence, DiscordRichPresenceMode.Full);
 
-            SetDefault(OsuSetting.EditorWaveformOpacity, 1f);
+            SetDefault(OsuSetting.EditorWaveformOpacity, 0.25f);
         }
 
         public OsuConfigManager(Storage storage)
@@ -169,14 +168,9 @@ namespace osu.Game.Configuration
 
             int combined = (year * 10000) + monthDay;
 
-            if (combined < 20200305)
+            if (combined < 20210413)
             {
-                // the maximum value of this setting was changed.
-                // if we don't manually increase this, it causes song select to filter out beatmaps the user expects to see.
-                var maxStars = (BindableDouble)GetOriginalBindable<double>(OsuSetting.DisplayStarsMaximum);
-
-                if (maxStars.Value == 10)
-                    maxStars.Value = maxStars.MaxValue;
+                SetValue(OsuSetting.EditorWaveformOpacity, 0.25f);
             }
         }
 

osu.Game/Configuration/SessionStatics.cs

@@ -16,6 +16,7 @@ namespace osu.Game.Configuration
         {
             SetDefault(Static.LoginOverlayDisplayed, false);
             SetDefault(Static.MutedAudioNotificationShownOnce, false);
+            SetDefault(Static.LowBatteryNotificationShownOnce, false);
             SetDefault(Static.LastHoverSoundPlaybackTime, (double?)null);
             SetDefault<APISeasonalBackgrounds>(Static.SeasonalBackgrounds, null);
         }
@@ -25,6 +26,7 @@ namespace osu.Game.Configuration
     {
         LoginOverlayDisplayed,
         MutedAudioNotificationShownOnce,
+        LowBatteryNotificationShownOnce,
 
         /// <summary>
         /// Info about seasonal backgrounds available fetched from API - see <see cref="APISeasonalBackgrounds"/>.

osu.Game/Configuration/SettingsStore.cs

@@ -22,7 +22,6 @@ namespace osu.Game.Configuration
         /// </summary>
         /// <param name="rulesetId">The ruleset's internal ID.</param>
         /// <param name="variant">An optional variant.</param>
-        /// <returns></returns>
         public List<DatabasedSetting> Query(int? rulesetId = null, int? variant = null) =>
             ContextFactory.Get().DatabasedSetting.Where(b => b.RulesetID == rulesetId && b.Variant == variant).ToList();
 

osu.Game/Extensions/DrawableExtensions.cs

@@ -9,6 +9,9 @@ namespace osu.Game.Extensions
 {
     public static class DrawableExtensions
     {
+        public const double REPEAT_INTERVAL = 70;
+        public const double INITIAL_DELAY = 250;
+
         /// <summary>
         /// Helper method that is used while <see cref="IKeyBindingHandler"/> doesn't support repetitions of <see cref="IKeyBindingHandler{T}.OnPressed"/>.
         /// Simulates repetitions by continually invoking a delegate according to the default key repeat rate.
@@ -19,12 +22,13 @@ namespace osu.Game.Extensions
         /// <param name="handler">The <see cref="IKeyBindingHandler{T}"/> which is handling the repeat.</param>
         /// <param name="scheduler">The <see cref="Scheduler"/> to schedule repetitions on.</param>
         /// <param name="action">The <see cref="Action"/> to be invoked once immediately and with every repetition.</param>
+        /// <param name="initialRepeatDelay">The delay imposed on the first repeat. Defaults to <see cref="INITIAL_DELAY"/>.</param>
         /// <returns>A <see cref="ScheduledDelegate"/> which can be cancelled to stop the repeat events from firing.</returns>
-        public static ScheduledDelegate BeginKeyRepeat(this IKeyBindingHandler handler, Scheduler scheduler, Action action)
+        public static ScheduledDelegate BeginKeyRepeat(this IKeyBindingHandler handler, Scheduler scheduler, Action action, double initialRepeatDelay = INITIAL_DELAY)
         {
             action();
 
-            ScheduledDelegate repeatDelegate = new ScheduledDelegate(action, handler.Time.Current + 250, 70);
+            ScheduledDelegate repeatDelegate = new ScheduledDelegate(action, handler.Time.Current + initialRepeatDelay, REPEAT_INTERVAL);
             scheduler.Add(repeatDelegate);
             return repeatDelegate;
         }

osu.Game/Graphics/Backgrounds/Triangles.cs

@@ -346,7 +346,6 @@ namespace osu.Game.Graphics.Backgrounds
             /// such that the smaller triangles appear on top.
             /// </summary>
             /// <param name="other"></param>
-            /// <returns></returns>
             public int CompareTo(TriangleParticle other) => other.Scale.CompareTo(Scale);
         }
     }

osu.Game/Graphics/Containers/OsuFocusedOverlayContainer.cs

@@ -23,6 +23,8 @@ namespace osu.Game.Graphics.Containers
         protected virtual string PopInSampleName => "UI/overlay-pop-in";
         protected virtual string PopOutSampleName => "UI/overlay-pop-out";
 
+        protected override bool BlockScrollInput => false;
+
         protected override bool BlockNonPositionalInput => true;
 
         /// <summary>

osu.Game/Graphics/Containers/UserDimContainer.cs

@@ -23,11 +23,6 @@ namespace osu.Game.Graphics.Containers
 
         protected const double BACKGROUND_FADE_DURATION = 800;
 
-        /// <summary>
-        /// Whether or not user-configured dim levels should be applied to the container.
-        /// </summary>
-        public readonly Bindable<bool> EnableUserDim = new Bindable<bool>(true);
-
         /// <summary>
         /// Whether or not user-configured settings relating to brightness of elements should be ignored
         /// </summary>
@@ -57,7 +52,7 @@ namespace osu.Game.Graphics.Containers
 
         private float breakLightening => LightenDuringBreaks.Value && IsBreakTime.Value ? BREAK_LIGHTEN_AMOUNT : 0;
 
-        protected float DimLevel => Math.Max(EnableUserDim.Value && !IgnoreUserSettings.Value ? (float)UserDimLevel.Value - breakLightening : 0, 0);
+        protected float DimLevel => Math.Max(!IgnoreUserSettings.Value ? (float)UserDimLevel.Value - breakLightening : 0, 0);
 
         protected override Container<Drawable> Content => dimContent;
 
@@ -78,7 +73,6 @@ namespace osu.Game.Graphics.Containers
             LightenDuringBreaks = config.GetBindable<bool>(OsuSetting.LightenDuringBreaks);
             ShowStoryboard = config.GetBindable<bool>(OsuSetting.ShowStoryboard);
 
-            EnableUserDim.ValueChanged += _ => UpdateVisuals();
             UserDimLevel.ValueChanged += _ => UpdateVisuals();
             LightenDuringBreaks.ValueChanged += _ => UpdateVisuals();
             IsBreakTime.ValueChanged += _ => UpdateVisuals();

osu.Game/Graphics/OsuColour.cs

@@ -186,6 +186,13 @@ namespace osu.Game.Graphics
         public readonly Color4 GrayE = Color4Extensions.FromHex(@"eee");
         public readonly Color4 GrayF = Color4Extensions.FromHex(@"fff");
 
+        // in latest editor design logic, need to figure out where these sit...
+        public readonly Color4 Lime1 = Color4Extensions.FromHex(@"b2ff66");
+        public readonly Color4 Orange1 = Color4Extensions.FromHex(@"ffd966");
+
+        // Content Background
+        public readonly Color4 B5 = Color4Extensions.FromHex(@"222a28");
+
         public readonly Color4 RedLighter = Color4Extensions.FromHex(@"ffeded");
         public readonly Color4 RedLight = Color4Extensions.FromHex(@"ed7787");
         public readonly Color4 Red = Color4Extensions.FromHex(@"ed1121");

osu.Game/IO/Serialization/IJsonSerializable.cs

@@ -22,7 +22,6 @@ namespace osu.Game.IO.Serialization
         /// <summary>
         /// Creates the default <see cref="JsonSerializerSettings"/> that should be used for all <see cref="IJsonSerializable"/>s.
         /// </summary>
-        /// <returns></returns>
         public static JsonSerializerSettings CreateGlobalSettings() => new JsonSerializerSettings
         {
             ReferenceLoopHandling = ReferenceLoopHandling.Ignore,

osu.Game/Input/Bindings/GlobalActionContainer.cs

@@ -70,6 +70,7 @@ namespace osu.Game.Input.Bindings
             new KeyBinding(new[] { InputKey.F2 }, GlobalAction.EditorDesignMode),
             new KeyBinding(new[] { InputKey.F3 }, GlobalAction.EditorTimingMode),
             new KeyBinding(new[] { InputKey.F4 }, GlobalAction.EditorSetupMode),
+            new KeyBinding(new[] { InputKey.Control, InputKey.Shift, InputKey.A }, GlobalAction.EditorVerifyMode),
         };
 
         public IEnumerable<KeyBinding> InGameKeyBindings => new[]
@@ -97,9 +98,7 @@ namespace osu.Game.Input.Bindings
         public IEnumerable<KeyBinding> AudioControlKeyBindings => new[]
         {
             new KeyBinding(new[] { InputKey.Alt, InputKey.Up }, GlobalAction.IncreaseVolume),
-            new KeyBinding(new[] { InputKey.Alt, InputKey.MouseWheelUp }, GlobalAction.IncreaseVolume),
             new KeyBinding(new[] { InputKey.Alt, InputKey.Down }, GlobalAction.DecreaseVolume),
-            new KeyBinding(new[] { InputKey.Alt, InputKey.MouseWheelDown }, GlobalAction.DecreaseVolume),
 
             new KeyBinding(new[] { InputKey.Control, InputKey.F4 }, GlobalAction.ToggleMute),
 
@@ -249,5 +248,8 @@ namespace osu.Game.Input.Bindings
 
         [Description("Beatmap Options")]
         ToggleBeatmapOptions,
+
+        [Description("Verify mode")]
+        EditorVerifyMode,
     }
 }

osu.Game/Input/Handlers/ReplayInputHandler.cs

@@ -32,8 +32,6 @@ namespace osu.Game.Input.Handlers
 
         public override bool Initialize(GameHost host) => true;
 
-        public override bool IsActive => true;
-
         public class ReplayState<T> : IInput
             where T : struct
         {

osu.Game/Input/KeyBindingStore.cs

@@ -85,7 +85,6 @@ namespace osu.Game.Input
         /// </summary>
         /// <param name="rulesetId">The ruleset's internal ID.</param>
         /// <param name="variant">An optional variant.</param>
-        /// <returns></returns>
         public List<DatabasedKeyBinding> Query(int? rulesetId = null, int? variant = null) =>
             ContextFactory.Get().DatabasedKeyBinding.Where(b => b.RulesetID == rulesetId && b.Variant == variant).ToList();
 

osu.Game/Migrations/20210412045700_RefreshVolumeBindingsAgain.Designer.cs

@@ -0,0 +1,506 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using osu.Game.Database;
+
+namespace osu.Game.Migrations
+{
+    [DbContext(typeof(OsuDbContext))]
+    [Migration("20210412045700_RefreshVolumeBindingsAgain")]
+    partial class RefreshVolumeBindingsAgain
+    {
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "2.2.6-servicing-10079");
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapDifficulty", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<float>("ApproachRate");
+
+                    b.Property<float>("CircleSize");
+
+                    b.Property<float>("DrainRate");
+
+                    b.Property<float>("OverallDifficulty");
+
+                    b.Property<double>("SliderMultiplier");
+
+                    b.Property<double>("SliderTickRate");
+
+                    b.HasKey("ID");
+
+                    b.ToTable("BeatmapDifficulty");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<double>("AudioLeadIn");
+
+                    b.Property<double>("BPM");
+
+                    b.Property<int>("BaseDifficultyID");
+
+                    b.Property<int>("BeatDivisor");
+
+                    b.Property<int>("BeatmapSetInfoID");
+
+                    b.Property<bool>("Countdown");
+
+                    b.Property<double>("DistanceSpacing");
+
+                    b.Property<int>("GridSize");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<bool>("Hidden");
+
+                    b.Property<double>("Length");
+
+                    b.Property<bool>("LetterboxInBreaks");
+
+                    b.Property<string>("MD5Hash");
+
+                    b.Property<int?>("MetadataID");
+
+                    b.Property<int?>("OnlineBeatmapID");
+
+                    b.Property<string>("Path");
+
+                    b.Property<int>("RulesetID");
+
+                    b.Property<bool>("SpecialStyle");
+
+                    b.Property<float>("StackLeniency");
+
+                    b.Property<double>("StarDifficulty");
+
+                    b.Property<int>("Status");
+
+                    b.Property<string>("StoredBookmarks");
+
+                    b.Property<double>("TimelineZoom");
+
+                    b.Property<string>("Version");
+
+                    b.Property<bool>("WidescreenStoryboard");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("BaseDifficultyID");
+
+                    b.HasIndex("BeatmapSetInfoID");
+
+                    b.HasIndex("Hash");
+
+                    b.HasIndex("MD5Hash");
+
+                    b.HasIndex("MetadataID");
+
+                    b.HasIndex("OnlineBeatmapID")
+                        .IsUnique();
+
+                    b.HasIndex("RulesetID");
+
+                    b.ToTable("BeatmapInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapMetadata", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Artist");
+
+                    b.Property<string>("ArtistUnicode");
+
+                    b.Property<string>("AudioFile");
+
+                    b.Property<string>("AuthorString")
+                        .HasColumnName("Author");
+
+                    b.Property<string>("BackgroundFile");
+
+                    b.Property<int>("PreviewTime");
+
+                    b.Property<string>("Source");
+
+                    b.Property<string>("Tags");
+
+                    b.Property<string>("Title");
+
+                    b.Property<string>("TitleUnicode");
+
+                    b.Property<string>("VideoFile");
+
+                    b.HasKey("ID");
+
+                    b.ToTable("BeatmapMetadata");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetFileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("BeatmapSetInfoID");
+
+                    b.Property<int>("FileInfoID");
+
+                    b.Property<string>("Filename")
+                        .IsRequired();
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("BeatmapSetInfoID");
+
+                    b.HasIndex("FileInfoID");
+
+                    b.ToTable("BeatmapSetFileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<DateTimeOffset>("DateAdded");
+
+                    b.Property<bool>("DeletePending");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<int?>("MetadataID");
+
+                    b.Property<int?>("OnlineBeatmapSetID");
+
+                    b.Property<bool>("Protected");
+
+                    b.Property<int>("Status");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("DeletePending");
+
+                    b.HasIndex("Hash")
+                        .IsUnique();
+
+                    b.HasIndex("MetadataID");
+
+                    b.HasIndex("OnlineBeatmapSetID")
+                        .IsUnique();
+
+                    b.ToTable("BeatmapSetInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Configuration.DatabasedSetting", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Key")
+                        .HasColumnName("Key");
+
+                    b.Property<int?>("RulesetID");
+
+                    b.Property<int?>("SkinInfoID");
+
+                    b.Property<string>("StringValue")
+                        .HasColumnName("Value");
+
+                    b.Property<int?>("Variant");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("SkinInfoID");
+
+                    b.HasIndex("RulesetID", "Variant");
+
+                    b.ToTable("Settings");
+                });
+
+            modelBuilder.Entity("osu.Game.IO.FileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Hash");
+
+                    b.Property<int>("ReferenceCount");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("Hash")
+                        .IsUnique();
+
+                    b.HasIndex("ReferenceCount");
+
+                    b.ToTable("FileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Input.Bindings.DatabasedKeyBinding", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("IntAction")
+                        .HasColumnName("Action");
+
+                    b.Property<string>("KeysString")
+                        .HasColumnName("Keys");
+
+                    b.Property<int?>("RulesetID");
+
+                    b.Property<int?>("Variant");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("IntAction");
+
+                    b.HasIndex("RulesetID", "Variant");
+
+                    b.ToTable("KeyBinding");
+                });
+
+            modelBuilder.Entity("osu.Game.Rulesets.RulesetInfo", b =>
+                {
+                    b.Property<int?>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<bool>("Available");
+
+                    b.Property<string>("InstantiationInfo");
+
+                    b.Property<string>("Name");
+
+                    b.Property<string>("ShortName");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("Available");
+
+                    b.HasIndex("ShortName")
+                        .IsUnique();
+
+                    b.ToTable("RulesetInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreFileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("FileInfoID");
+
+                    b.Property<string>("Filename")
+                        .IsRequired();
+
+                    b.Property<int?>("ScoreInfoID");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("FileInfoID");
+
+                    b.HasIndex("ScoreInfoID");
+
+                    b.ToTable("ScoreFileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<double>("Accuracy")
+                        .HasColumnType("DECIMAL(1,4)");
+
+                    b.Property<int>("BeatmapInfoID");
+
+                    b.Property<int>("Combo");
+
+                    b.Property<DateTimeOffset>("Date");
+
+                    b.Property<bool>("DeletePending");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<int>("MaxCombo");
+
+                    b.Property<string>("ModsJson")
+                        .HasColumnName("Mods");
+
+                    b.Property<long?>("OnlineScoreID");
+
+                    b.Property<double?>("PP");
+
+                    b.Property<int>("Rank");
+
+                    b.Property<int>("RulesetID");
+
+                    b.Property<string>("StatisticsJson")
+                        .HasColumnName("Statistics");
+
+                    b.Property<long>("TotalScore");
+
+                    b.Property<long?>("UserID")
+                        .HasColumnName("UserID");
+
+                    b.Property<string>("UserString")
+                        .HasColumnName("User");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("BeatmapInfoID");
+
+                    b.HasIndex("OnlineScoreID")
+                        .IsUnique();
+
+                    b.HasIndex("RulesetID");
+
+                    b.ToTable("ScoreInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Skinning.SkinFileInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<int>("FileInfoID");
+
+                    b.Property<string>("Filename")
+                        .IsRequired();
+
+                    b.Property<int>("SkinInfoID");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("FileInfoID");
+
+                    b.HasIndex("SkinInfoID");
+
+                    b.ToTable("SkinFileInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Skinning.SkinInfo", b =>
+                {
+                    b.Property<int>("ID")
+                        .ValueGeneratedOnAdd();
+
+                    b.Property<string>("Creator");
+
+                    b.Property<bool>("DeletePending");
+
+                    b.Property<string>("Hash");
+
+                    b.Property<string>("Name");
+
+                    b.HasKey("ID");
+
+                    b.HasIndex("DeletePending");
+
+                    b.HasIndex("Hash")
+                        .IsUnique();
+
+                    b.ToTable("SkinInfo");
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapDifficulty", "BaseDifficulty")
+                        .WithMany()
+                        .HasForeignKey("BaseDifficultyID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Beatmaps.BeatmapSetInfo", "BeatmapSet")
+                        .WithMany("Beatmaps")
+                        .HasForeignKey("BeatmapSetInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Beatmaps.BeatmapMetadata", "Metadata")
+                        .WithMany("Beatmaps")
+                        .HasForeignKey("MetadataID");
+
+                    b.HasOne("osu.Game.Rulesets.RulesetInfo", "Ruleset")
+                        .WithMany()
+                        .HasForeignKey("RulesetID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetFileInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapSetInfo")
+                        .WithMany("Files")
+                        .HasForeignKey("BeatmapSetInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.IO.FileInfo", "FileInfo")
+                        .WithMany()
+                        .HasForeignKey("FileInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("osu.Game.Beatmaps.BeatmapSetInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapMetadata", "Metadata")
+                        .WithMany("BeatmapSets")
+                        .HasForeignKey("MetadataID");
+                });
+
+            modelBuilder.Entity("osu.Game.Configuration.DatabasedSetting", b =>
+                {
+                    b.HasOne("osu.Game.Skinning.SkinInfo")
+                        .WithMany("Settings")
+                        .HasForeignKey("SkinInfoID");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreFileInfo", b =>
+                {
+                    b.HasOne("osu.Game.IO.FileInfo", "FileInfo")
+                        .WithMany()
+                        .HasForeignKey("FileInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Scoring.ScoreInfo")
+                        .WithMany("Files")
+                        .HasForeignKey("ScoreInfoID");
+                });
+
+            modelBuilder.Entity("osu.Game.Scoring.ScoreInfo", b =>
+                {
+                    b.HasOne("osu.Game.Beatmaps.BeatmapInfo", "Beatmap")
+                        .WithMany("Scores")
+                        .HasForeignKey("BeatmapInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Rulesets.RulesetInfo", "Ruleset")
+                        .WithMany()
+                        .HasForeignKey("RulesetID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+
+            modelBuilder.Entity("osu.Game.Skinning.SkinFileInfo", b =>
+                {
+                    b.HasOne("osu.Game.IO.FileInfo", "FileInfo")
+                        .WithMany()
+                        .HasForeignKey("FileInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+
+                    b.HasOne("osu.Game.Skinning.SkinInfo")
+                        .WithMany("Files")
+                        .HasForeignKey("SkinInfoID")
+                        .OnDelete(DeleteBehavior.Cascade);
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

osu.Game/Migrations/20210412045700_RefreshVolumeBindingsAgain.cs

@@ -0,0 +1,16 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace osu.Game.Migrations
+{
+    public partial class RefreshVolumeBindingsAgain : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql("DELETE FROM KeyBinding WHERE action in (6,7)");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+        }
+    }
+}

osu.Game/Online/API/APIMod.cs

@@ -11,11 +11,12 @@ using osu.Framework.Bindables;
 using osu.Game.Configuration;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
+using osu.Game.Utils;
 
 namespace osu.Game.Online.API
 {
     [MessagePackObject]
-    public class APIMod : IMod
+    public class APIMod : IMod, IEquatable<APIMod>
     {
         [JsonProperty("acronym")]
         [Key(0)]
@@ -63,7 +64,16 @@ namespace osu.Game.Online.API
             return resultMod;
         }
 
-        public bool Equals(IMod other) => Acronym == other?.Acronym;
+        public bool Equals(IMod other) => other is APIMod them && Equals(them);
+
+        public bool Equals(APIMod other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return Acronym == other.Acronym &&
+                   Settings.SequenceEqual(other.Settings, ModSettingsEqualityComparer.Default);
+        }
 
         public override string ToString()
         {
@@ -72,5 +82,20 @@ namespace osu.Game.Online.API
 
             return $"{Acronym}";
         }
+
+        private class ModSettingsEqualityComparer : IEqualityComparer<KeyValuePair<string, object>>
+        {
+            public static ModSettingsEqualityComparer Default { get; } = new ModSettingsEqualityComparer();
+
+            public bool Equals(KeyValuePair<string, object> x, KeyValuePair<string, object> y)
+            {
+                object xValue = ModUtils.GetSettingUnderlyingValue(x.Value);
+                object yValue = ModUtils.GetSettingUnderlyingValue(y.Value);
+
+                return x.Key == y.Key && EqualityComparer<object>.Default.Equals(xValue, yValue);
+            }
+
+            public int GetHashCode(KeyValuePair<string, object> obj) => HashCode.Combine(obj.Key, ModUtils.GetSettingUnderlyingValue(obj.Value));
+        }
     }
 }

osu.Game/Online/API/ModSettingsDictionaryFormatter.cs

@@ -3,11 +3,10 @@
 
 using System.Buffers;
 using System.Collections.Generic;
-using System.Diagnostics;
 using System.Text;
 using MessagePack;
 using MessagePack.Formatters;
-using osu.Framework.Bindables;
+using osu.Game.Utils;
 
 namespace osu.Game.Online.API
 {
@@ -24,36 +23,7 @@ namespace osu.Game.Online.API
                 var stringBytes = new ReadOnlySequence<byte>(Encoding.UTF8.GetBytes(kvp.Key));
                 writer.WriteString(in stringBytes);
 
-                switch (kvp.Value)
-                {
-                    case Bindable<double> d:
-                        primitiveFormatter.Serialize(ref writer, d.Value, options);
-                        break;
-
-                    case Bindable<int> i:
-                        primitiveFormatter.Serialize(ref writer, i.Value, options);
-                        break;
-
-                    case Bindable<float> f:
-                        primitiveFormatter.Serialize(ref writer, f.Value, options);
-                        break;
-
-                    case Bindable<bool> b:
-                        primitiveFormatter.Serialize(ref writer, b.Value, options);
-                        break;
-
-                    case IBindable u:
-                        // A mod with unknown (e.g. enum) generic type.
-                        var valueMethod = u.GetType().GetProperty(nameof(IBindable<int>.Value));
-                        Debug.Assert(valueMethod != null);
-                        primitiveFormatter.Serialize(ref writer, valueMethod.GetValue(u), options);
-                        break;
-
-                    default:
-                        // fall back for non-bindable cases.
-                        primitiveFormatter.Serialize(ref writer, kvp.Value, options);
-                        break;
-                }
+                primitiveFormatter.Serialize(ref writer, ModUtils.GetSettingUnderlyingValue(kvp.Value), options);
             }
         }
 

osu.Game/OsuGameBase.cs

@@ -40,6 +40,7 @@ using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Scoring;
 using osu.Game.Skinning;
+using osu.Game.Utils;
 using osuTK.Input;
 using RuntimeInfo = osu.Framework.RuntimeInfo;
 
@@ -156,6 +157,8 @@ namespace osu.Game
 
         protected override UserInputManager CreateUserInputManager() => new OsuUserInputManager();
 
+        protected virtual BatteryInfo CreateBatteryInfo() => null;
+
         /// <summary>
         /// The maximum volume at which audio tracks should playback. This can be set lower than 1 to create some head-room for sound effects.
         /// </summary>
@@ -281,6 +284,11 @@ namespace osu.Game
             dependencies.Cache(KeyBindingStore = new KeyBindingStore(contextFactory, RulesetStore));
             dependencies.Cache(SettingsStore = new SettingsStore(contextFactory));
             dependencies.Cache(RulesetConfigCache = new RulesetConfigCache(SettingsStore));
+
+            var powerStatus = CreateBatteryInfo();
+            if (powerStatus != null)
+                dependencies.CacheAs(powerStatus);
+
             dependencies.Cache(new SessionStatics());
             dependencies.Cache(new OsuColour());
 
@@ -433,12 +441,15 @@ namespace osu.Game
             if (paths.Length == 0)
                 return;
 
-            var extension = Path.GetExtension(paths.First())?.ToLowerInvariant();
+            var filesPerExtension = paths.GroupBy(p => Path.GetExtension(p).ToLowerInvariant());
 
-            foreach (var importer in fileImporters)
+            foreach (var groups in filesPerExtension)
             {
-                if (importer.HandledExtensions.Contains(extension))
-                    await importer.Import(paths).ConfigureAwait(false);
+                foreach (var importer in fileImporters)
+                {
+                    if (importer.HandledExtensions.Contains(groups.Key))
+                        await importer.Import(groups.ToArray()).ConfigureAwait(false);
+                }
             }
         }
 

osu.Game/Overlays/Profile/Sections/Historical/ChartProfileSubsection.cs

@@ -15,6 +15,11 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
     {
         private ProfileLineChart chart;
 
+        /// <summary>
+        /// Text describing the value being plotted on the graph, which will be displayed as a prefix to the value in the history graph tooltip.
+        /// </summary>
+        protected abstract string GraphCounterName { get; }
+
         protected ChartProfileSubsection(Bindable<User> user, string headerText)
             : base(user, headerText)
         {
@@ -30,7 +35,7 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
                 Left = 20,
                 Right = 40
             },
-            Child = chart = new ProfileLineChart()
+            Child = chart = new ProfileLineChart(GraphCounterName)
         };
 
         protected override void LoadComplete()

osu.Game/Overlays/Profile/Sections/Historical/PlayHistorySubsection.cs

@@ -9,6 +9,8 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
 {
     public class PlayHistorySubsection : ChartProfileSubsection
     {
+        protected override string GraphCounterName => "Plays";
+
         public PlayHistorySubsection(Bindable<User> user)
             : base(user, "Play History")
         {

osu.Game/Overlays/Profile/Sections/Historical/ProfileLineChart.cs

@@ -42,7 +42,7 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
         private readonly Container<TickLine> rowLinesContainer;
         private readonly Container<TickLine> columnLinesContainer;
 
-        public ProfileLineChart()
+        public ProfileLineChart(string graphCounterName)
         {
             RelativeSizeAxes = Axes.X;
             Height = 250;
@@ -88,7 +88,7 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
                                         }
                                     }
                                 },
-                                graph = new UserHistoryGraph
+                                graph = new UserHistoryGraph(graphCounterName)
                                 {
                                     RelativeSizeAxes = Axes.Both
                                 }

osu.Game/Overlays/Profile/Sections/Historical/ReplaysSubsection.cs

@@ -9,6 +9,8 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
 {
     public class ReplaysSubsection : ChartProfileSubsection
     {
+        protected override string GraphCounterName => "Replays Watched";
+
         public ReplaysSubsection(Bindable<User> user)
             : base(user, "Replays Watched History")
         {

osu.Game/Overlays/Profile/Sections/Historical/UserHistoryGraph.cs

@@ -11,25 +11,28 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
 {
     public class UserHistoryGraph : UserGraph<DateTime, long>
     {
+        private readonly string tooltipCounterName;
+
         [CanBeNull]
         public UserHistoryCount[] Values
         {
             set => Data = value?.Select(v => new KeyValuePair<DateTime, long>(v.Date, v.Count)).ToArray();
         }
 
-        /// <summary>
-        /// Text describing the value being plotted on the graph, which will be displayed as a prefix to the value in the <see cref="HistoryGraphTooltip"/>.
-        /// </summary>
-        public string TooltipCounterName { get; set; } = "Plays";
+        public UserHistoryGraph(string tooltipCounterName)
+        {
+            this.tooltipCounterName = tooltipCounterName;
+        }
 
         protected override float GetDataPointHeight(long playCount) => playCount;
 
-        protected override UserGraphTooltip GetTooltip() => new HistoryGraphTooltip(TooltipCounterName);
+        protected override UserGraphTooltip GetTooltip() => new HistoryGraphTooltip(tooltipCounterName);
 
         protected override object GetTooltipContent(DateTime date, long playCount)
         {
             return new TooltipDisplayContent
             {
+                Name = tooltipCounterName,
                 Count = playCount.ToString("N0"),
                 Date = date.ToString("MMMM yyyy")
             };
@@ -37,14 +40,17 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
 
         protected class HistoryGraphTooltip : UserGraphTooltip
         {
+            private readonly string tooltipCounterName;
+
             public HistoryGraphTooltip(string tooltipCounterName)
                 : base(tooltipCounterName)
             {
+                this.tooltipCounterName = tooltipCounterName;
             }
 
             public override bool SetContent(object content)
             {
-                if (!(content is TooltipDisplayContent info))
+                if (!(content is TooltipDisplayContent info) || info.Name != tooltipCounterName)
                     return false;
 
                 Counter.Text = info.Count;
@@ -55,6 +61,7 @@ namespace osu.Game.Overlays.Profile.Sections.Historical
 
         private class TooltipDisplayContent
         {
+            public string Name;
             public string Count;
             public string Date;
         }

osu.Game/Overlays/Volume/VolumeControlReceptor.cs

@@ -6,6 +6,8 @@ using osu.Framework.Graphics.Containers;
 using osu.Framework.Input;
 using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Events;
+using osu.Framework.Threading;
+using osu.Game.Extensions;
 using osu.Game.Input.Bindings;
 
 namespace osu.Game.Overlays.Volume
@@ -15,8 +17,30 @@ namespace osu.Game.Overlays.Volume
         public Func<GlobalAction, bool> ActionRequested;
         public Func<GlobalAction, float, bool, bool> ScrollActionRequested;
 
-        public bool OnPressed(GlobalAction action) =>
-            ActionRequested?.Invoke(action) ?? false;
+        private ScheduledDelegate keyRepeat;
+
+        public bool OnPressed(GlobalAction action)
+        {
+            switch (action)
+            {
+                case GlobalAction.DecreaseVolume:
+                case GlobalAction.IncreaseVolume:
+                    keyRepeat?.Cancel();
+                    keyRepeat = this.BeginKeyRepeat(Scheduler, () => ActionRequested?.Invoke(action), 150);
+                    return true;
+
+                case GlobalAction.ToggleMute:
+                    ActionRequested?.Invoke(action);
+                    return true;
+            }
+
+            return false;
+        }
+
+        public void OnReleased(GlobalAction action)
+        {
+            keyRepeat?.Cancel();
+        }
 
         protected override bool OnScroll(ScrollEvent e)
         {
@@ -27,9 +51,5 @@ namespace osu.Game.Overlays.Volume
 
         public bool OnScroll(GlobalAction action, float amount, bool isPrecise) =>
             ScrollActionRequested?.Invoke(action, amount, isPrecise) ?? false;
-
-        public void OnReleased(GlobalAction action)
-        {
-        }
     }
 }

osu.Game/Overlays/Volume/VolumeMeter.cs

@@ -13,6 +13,7 @@ using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Input.Bindings;
 using osu.Framework.Input.Events;
+using osu.Framework.Threading;
 using osu.Framework.Utils;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
@@ -225,7 +226,7 @@ namespace osu.Game.Overlays.Volume
             private set => Bindable.Value = value;
         }
 
-        private const double adjust_step = 0.05;
+        private const double adjust_step = 0.01;
 
         public void Increase(double amount = 1, bool isPrecise = false) => adjust(amount, isPrecise);
         public void Decrease(double amount = 1, bool isPrecise = false) => adjust(-amount, isPrecise);
@@ -233,16 +234,40 @@ namespace osu.Game.Overlays.Volume
         // because volume precision is set to 0.01, this local is required to keep track of more precise adjustments and only apply when possible.
         private double scrollAccumulation;
 
+        private double accelerationModifier = 1;
+
+        private const double max_acceleration = 5;
+        private const double acceleration_multiplier = 1.8;
+
+        private ScheduledDelegate accelerationDebounce;
+
+        private void resetAcceleration() => accelerationModifier = 1;
+
         private void adjust(double delta, bool isPrecise)
         {
-            scrollAccumulation += delta * adjust_step * (isPrecise ? 0.1 : 1);
+            // every adjust increment increases the rate at which adjustments happen up to a cutoff.
+            // this debounce will reset on inactivity.
+            accelerationDebounce?.Cancel();
+            accelerationDebounce = Scheduler.AddDelayed(resetAcceleration, 150);
+
+            delta *= accelerationModifier;
+            accelerationModifier = Math.Min(max_acceleration, accelerationModifier * acceleration_multiplier);
 
             var precision = Bindable.Precision;
 
-            while (Precision.AlmostBigger(Math.Abs(scrollAccumulation), precision))
+            if (isPrecise)
             {
-                Volume += Math.Sign(scrollAccumulation) * precision;
-                scrollAccumulation = scrollAccumulation < 0 ? Math.Min(0, scrollAccumulation + precision) : Math.Max(0, scrollAccumulation - precision);
+                scrollAccumulation += delta * adjust_step * 0.1;
+
+                while (Precision.AlmostBigger(Math.Abs(scrollAccumulation), precision))
+                {
+                    Volume += Math.Sign(scrollAccumulation) * precision;
+                    scrollAccumulation = scrollAccumulation < 0 ? Math.Min(0, scrollAccumulation + precision) : Math.Max(0, scrollAccumulation - precision);
+                }
+            }
+            else
+            {
+                Volume += Math.Sign(delta) * Math.Max(precision, Math.Abs(delta * adjust_step));
             }
         }
 

osu.Game/Rulesets/Edit/BeatmapVerifier.cs

@@ -0,0 +1,24 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Checks;
+using osu.Game.Rulesets.Edit.Checks.Components;
+
+namespace osu.Game.Rulesets.Edit
+{
+    /// <summary>
+    /// A ruleset-agnostic beatmap verifier that identifies issues in common metadata or mapping standards.
+    /// </summary>
+    public class BeatmapVerifier : IBeatmapVerifier
+    {
+        private readonly List<ICheck> checks = new List<ICheck>
+        {
+            new CheckBackground(),
+        };
+
+        public IEnumerable<Issue> Run(IBeatmap beatmap) => checks.SelectMany(check => check.Run(beatmap));
+    }
+}

osu.Game/Rulesets/Edit/Checks/CheckBackground.cs

@@ -0,0 +1,61 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Checks.Components;
+
+namespace osu.Game.Rulesets.Edit.Checks
+{
+    public class CheckBackground : ICheck
+    {
+        public CheckMetadata Metadata { get; } = new CheckMetadata(CheckCategory.Resources, "Missing background");
+
+        public IEnumerable<IssueTemplate> PossibleTemplates => new IssueTemplate[]
+        {
+            new IssueTemplateNoneSet(this),
+            new IssueTemplateDoesNotExist(this)
+        };
+
+        public IEnumerable<Issue> Run(IBeatmap beatmap)
+        {
+            if (beatmap.Metadata.BackgroundFile == null)
+            {
+                yield return new IssueTemplateNoneSet(this).Create();
+
+                yield break;
+            }
+
+            // If the background is set, also make sure it still exists.
+
+            var set = beatmap.BeatmapInfo.BeatmapSet;
+            var file = set.Files.FirstOrDefault(f => f.Filename == beatmap.Metadata.BackgroundFile);
+
+            if (file != null)
+                yield break;
+
+            yield return new IssueTemplateDoesNotExist(this).Create(beatmap.Metadata.BackgroundFile);
+        }
+
+        public class IssueTemplateNoneSet : IssueTemplate
+        {
+            public IssueTemplateNoneSet(ICheck check)
+                : base(check, IssueType.Problem, "No background has been set.")
+            {
+            }
+
+            public Issue Create() => new Issue(this);
+        }
+
+        public class IssueTemplateDoesNotExist : IssueTemplate
+        {
+            public IssueTemplateDoesNotExist(ICheck check)
+                : base(check, IssueType.Problem, "The background file \"{0}\" does not exist.")
+            {
+            }
+
+            public Issue Create(string filename) => new Issue(this, filename);
+        }
+    }
+}

osu.Game/Rulesets/Edit/Checks/Components/CheckCategory.cs

@@ -0,0 +1,61 @@
+// 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.
+
+namespace osu.Game.Rulesets.Edit.Checks.Components
+{
+    /// <summary>
+    /// The category of an issue.
+    /// </summary>
+    public enum CheckCategory
+    {
+        /// <summary>
+        /// Anything to do with control points.
+        /// </summary>
+        Timing,
+
+        /// <summary>
+        /// Anything to do with artist, title, creator, etc.
+        /// </summary>
+        Metadata,
+
+        /// <summary>
+        /// Anything to do with non-audio files, e.g. background, skin, sprites, and video.
+        /// </summary>
+        Resources,
+
+        /// <summary>
+        /// Anything to do with audio files, e.g. song and hitsounds.
+        /// </summary>
+        Audio,
+
+        /// <summary>
+        /// Anything to do with files that don't fit into the above, e.g. unused, osu, or osb.
+        /// </summary>
+        Files,
+
+        /// <summary>
+        /// Anything to do with hitobjects unrelated to spread.
+        /// </summary>
+        Compose,
+
+        /// <summary>
+        /// Anything to do with difficulty levels or their progression.
+        /// </summary>
+        Spread,
+
+        /// <summary>
+        /// Anything to do with variables like CS, OD, AR, HP, and global SV.
+        /// </summary>
+        Settings,
+
+        /// <summary>
+        /// Anything to do with hitobject feedback.
+        /// </summary>
+        HitObjects,
+
+        /// <summary>
+        /// Anything to do with storyboarding, breaks, video offset, etc.
+        /// </summary>
+        Events
+    }
+}

osu.Game/Rulesets/Edit/Checks/Components/CheckMetadata.cs

@@ -0,0 +1,24 @@
+// 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.
+
+namespace osu.Game.Rulesets.Edit.Checks.Components
+{
+    public class CheckMetadata
+    {
+        /// <summary>
+        /// The category this check belongs to. E.g. <see cref="CheckCategory.Metadata"/>, <see cref="CheckCategory.Timing"/>, or <see cref="CheckCategory.Compose"/>.
+        /// </summary>
+        public readonly CheckCategory Category;
+
+        /// <summary>
+        /// Describes the issue(s) that this check looks for. Keep this brief, such that it fits into "No {description}". E.g. "Offscreen objects" / "Too short sliders".
+        /// </summary>
+        public readonly string Description;
+
+        public CheckMetadata(CheckCategory category, string description)
+        {
+            Category = category;
+            Description = description;
+        }
+    }
+}

osu.Game/Rulesets/Edit/Checks/Components/ICheck.cs

@@ -0,0 +1,30 @@
+// 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 osu.Game.Beatmaps;
+
+namespace osu.Game.Rulesets.Edit.Checks.Components
+{
+    /// <summary>
+    /// A specific check that can be run on a beatmap to verify or find issues.
+    /// </summary>
+    public interface ICheck
+    {
+        /// <summary>
+        /// The metadata for this check.
+        /// </summary>
+        public CheckMetadata Metadata { get; }
+
+        /// <summary>
+        /// All possible templates for issues that this check may return.
+        /// </summary>
+        public IEnumerable<IssueTemplate> PossibleTemplates { get; }
+
+        /// <summary>
+        /// Runs this check and returns any issues detected for the provided beatmap.
+        /// </summary>
+        /// <param name="beatmap">The beatmap to run the check on.</param>
+        public IEnumerable<Issue> Run(IBeatmap beatmap);
+    }
+}

osu.Game/Rulesets/Edit/Checks/Components/Issue.cs

@@ -0,0 +1,77 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using osu.Game.Extensions;
+using osu.Game.Rulesets.Objects;
+
+namespace osu.Game.Rulesets.Edit.Checks.Components
+{
+    public class Issue
+    {
+        /// <summary>
+        /// The time which this issue is associated with, if any, otherwise null.
+        /// </summary>
+        public double? Time;
+
+        /// <summary>
+        /// The hitobjects which this issue is associated with. Empty by default.
+        /// </summary>
+        public IReadOnlyList<HitObject> HitObjects;
+
+        /// <summary>
+        /// The template which this issue is using. This provides properties such as the <see cref="IssueType"/>, and the <see cref="IssueTemplate.UnformattedMessage"/>.
+        /// </summary>
+        public IssueTemplate Template;
+
+        /// <summary>
+        /// The check that this issue originates from.
+        /// </summary>
+        public ICheck Check => Template.Check;
+
+        /// <summary>
+        /// The arguments that give this issue its context, based on the <see cref="IssueTemplate"/>. These are then substituted into the <see cref="IssueTemplate.UnformattedMessage"/>.
+        /// This could for instance include timestamps, which diff is being compared to, what some volume is, etc.
+        /// </summary>
+        public object[] Arguments;
+
+        public Issue(IssueTemplate template, params object[] args)
+        {
+            Time = null;
+            HitObjects = Array.Empty<HitObject>();
+            Template = template;
+            Arguments = args;
+        }
+
+        public Issue(double? time, IssueTemplate template, params object[] args)
+            : this(template, args)
+        {
+            Time = time;
+        }
+
+        public Issue(HitObject hitObject, IssueTemplate template, params object[] args)
+            : this(template, args)
+        {
+            Time = hitObject.StartTime;
+            HitObjects = new[] { hitObject };
+        }
+
+        public Issue(IEnumerable<HitObject> hitObjects, IssueTemplate template, params object[] args)
+            : this(template, args)
+        {
+            var hitObjectList = hitObjects.ToList();
+
+            Time = hitObjectList.FirstOrDefault()?.StartTime;
+            HitObjects = hitObjectList;
+        }
+
+        public override string ToString() => Template.GetMessage(Arguments);
+
+        public string GetEditorTimestamp()
+        {
+            return Time == null ? string.Empty : Time.Value.ToEditorFormattedString();
+        }
+    }
+}

osu.Game/Rulesets/Edit/Checks/Components/IssueTemplate.cs

@@ -0,0 +1,74 @@
+// 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 Humanizer;
+using osu.Framework.Graphics;
+using osuTK.Graphics;
+
+namespace osu.Game.Rulesets.Edit.Checks.Components
+{
+    public class IssueTemplate
+    {
+        private static readonly Color4 problem_red = new Colour4(1.0f, 0.4f, 0.4f, 1.0f);
+        private static readonly Color4 warning_yellow = new Colour4(1.0f, 0.8f, 0.2f, 1.0f);
+        private static readonly Color4 negligible_green = new Colour4(0.33f, 0.8f, 0.5f, 1.0f);
+        private static readonly Color4 error_gray = new Colour4(0.5f, 0.5f, 0.5f, 1.0f);
+
+        /// <summary>
+        /// The check that this template originates from.
+        /// </summary>
+        public readonly ICheck Check;
+
+        /// <summary>
+        /// The type of the issue.
+        /// </summary>
+        public readonly IssueType Type;
+
+        /// <summary>
+        /// The unformatted message given when this issue is detected.
+        /// This gets populated later when an issue is constructed with this template.
+        /// E.g. "Inconsistent snapping (1/{0}) with [{1}] (1/{2})."
+        /// </summary>
+        public readonly string UnformattedMessage;
+
+        public IssueTemplate(ICheck check, IssueType type, string unformattedMessage)
+        {
+            Check = check;
+            Type = type;
+            UnformattedMessage = unformattedMessage;
+        }
+
+        /// <summary>
+        /// Returns the formatted message given the arguments used to format it.
+        /// </summary>
+        /// <param name="args">The arguments used to format the message.</param>
+        public string GetMessage(params object[] args) => UnformattedMessage.FormatWith(args);
+
+        /// <summary>
+        /// Returns the colour corresponding to the type of this issue.
+        /// </summary>
+        public Colour4 Colour
+        {
+            get
+            {
+                switch (Type)
+                {
+                    case IssueType.Problem:
+                        return problem_red;
+
+                    case IssueType.Warning:
+                        return warning_yellow;
+
+                    case IssueType.Negligible:
+                        return negligible_green;
+
+                    case IssueType.Error:
+                        return error_gray;
+
+                    default:
+                        return Color4.White;
+                }
+            }
+        }
+    }
+}

osu.Game/Rulesets/Edit/Checks/Components/IssueType.cs

@@ -0,0 +1,25 @@
+// 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.
+
+namespace osu.Game.Rulesets.Edit.Checks.Components
+{
+    /// <summary>
+    /// The type, or severity, of an issue.
+    /// </summary>
+    public enum IssueType
+    {
+        /// <summary> A must-fix in the vast majority of cases. </summary>
+        Problem,
+
+        /// <summary> A possible mistake. Often requires critical thinking.  </summary>
+        Warning,
+
+        // TODO: Try/catch all checks run and return error templates if exceptions occur.
+        /// <summary> An error occurred and a complete check could not be made. </summary>
+        Error,
+
+        // TODO: Negligible issues should be hidden by default.
+        /// <summary> A possible mistake so minor/unlikely that it can often be safely ignored. </summary>
+        Negligible,
+    }
+}

osu.Game/Rulesets/Edit/IBeatmapVerifier.cs

@@ -0,0 +1,17 @@
+// 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 osu.Game.Beatmaps;
+using osu.Game.Rulesets.Edit.Checks.Components;
+
+namespace osu.Game.Rulesets.Edit
+{
+    /// <summary>
+    /// A class which can run against a beatmap and surface issues to the user which could go against known criteria or hinder gameplay.
+    /// </summary>
+    public interface IBeatmapVerifier
+    {
+        public IEnumerable<Issue> Run(IBeatmap beatmap);
+    }
+}

osu.Game/Rulesets/Mods/Mod.cs

@@ -12,6 +12,7 @@ using osu.Framework.Testing;
 using osu.Game.Configuration;
 using osu.Game.IO.Serialization;
 using osu.Game.Rulesets.UI;
+using osu.Game.Utils;
 
 namespace osu.Game.Rulesets.Mods
 {
@@ -19,7 +20,7 @@ namespace osu.Game.Rulesets.Mods
     /// The base class for gameplay modifiers.
     /// </summary>
     [ExcludeFromDynamicCompile]
-    public abstract class Mod : IMod, IJsonSerializable
+    public abstract class Mod : IMod, IEquatable<Mod>, IJsonSerializable
     {
         /// <summary>
         /// The name of this mod.
@@ -48,7 +49,7 @@ namespace osu.Game.Rulesets.Mods
         /// The user readable description of this mod.
         /// </summary>
         [JsonIgnore]
-        public virtual string Description => string.Empty;
+        public abstract string Description { get; }
 
         /// <summary>
         /// The tooltip to display for this mod when used in a <see cref="ModIcon"/>.
@@ -172,7 +173,19 @@ namespace osu.Game.Rulesets.Mods
                 target.Parse(source);
         }
 
-        public bool Equals(IMod other) => GetType() == other?.GetType();
+        public bool Equals(IMod other) => other is Mod them && Equals(them);
+
+        public bool Equals(Mod other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return GetType() == other.GetType() &&
+                   this.GetSettingsSourceProperties().All(pair =>
+                       EqualityComparer<object>.Default.Equals(
+                           ModUtils.GetSettingUnderlyingValue(pair.Item2.GetValue(this)),
+                           ModUtils.GetSettingUnderlyingValue(pair.Item2.GetValue(other))));
+        }
 
         /// <summary>
         /// Reset all custom settings for this mod back to their defaults.

osu.Game/Rulesets/Mods/ModCinema.cs

@@ -37,8 +37,7 @@ namespace osu.Game.Rulesets.Mods
 
         public void ApplyToPlayer(Player player)
         {
-            player.ApplyToBackground(b => b.EnableUserDim.Value = false);
-
+            player.ApplyToBackground(b => b.IgnoreUserSettings.Value = true);
             player.DimmableStoryboard.IgnoreUserSettings.Value = true;
 
             player.BreakOverlay.Hide();

osu.Game/Rulesets/Mods/ModNoMod.cs

@@ -12,6 +12,7 @@ namespace osu.Game.Rulesets.Mods
     {
         public override string Name => "No Mod";
         public override string Acronym => "NM";
+        public override string Description => "No mods applied.";
         public override double ScoreMultiplier => 1;
         public override IconUsage? Icon => FontAwesome.Solid.Ban;
         public override ModType Type => ModType.System;

osu.Game/Rulesets/Objects/Drawables/DrawableHitObject.cs

@@ -56,8 +56,8 @@ namespace osu.Game.Rulesets.Objects.Drawables
 
         public virtual IEnumerable<HitSampleInfo> GetSamples() => HitObject.Samples;
 
-        private readonly Lazy<List<DrawableHitObject>> nestedHitObjects = new Lazy<List<DrawableHitObject>>();
-        public IReadOnlyList<DrawableHitObject> NestedHitObjects => nestedHitObjects.IsValueCreated ? nestedHitObjects.Value : (IReadOnlyList<DrawableHitObject>)Array.Empty<DrawableHitObject>();
+        private readonly List<DrawableHitObject> nestedHitObjects = new List<DrawableHitObject>();
+        public IReadOnlyList<DrawableHitObject> NestedHitObjects => nestedHitObjects;
 
         /// <summary>
         /// Whether this object should handle any user input events.
@@ -249,7 +249,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
                 // Must be done before the nested DHO is added to occur before the nested Apply()!
                 drawableNested.ParentHitObject = this;
 
-                nestedHitObjects.Value.Add(drawableNested);
+                nestedHitObjects.Add(drawableNested);
                 AddNestedHitObject(drawableNested);
             }
 
@@ -305,19 +305,16 @@ namespace osu.Game.Rulesets.Objects.Drawables
             if (Samples != null)
                 Samples.Samples = null;
 
-            if (nestedHitObjects.IsValueCreated)
+            foreach (var obj in nestedHitObjects)
             {
-                foreach (var obj in nestedHitObjects.Value)
-                {
-                    obj.OnNewResult -= onNewResult;
-                    obj.OnRevertResult -= onRevertResult;
-                    obj.ApplyCustomUpdateState -= onApplyCustomUpdateState;
-                }
-
-                nestedHitObjects.Value.Clear();
-                ClearNestedHitObjects();
+                obj.OnNewResult -= onNewResult;
+                obj.OnRevertResult -= onRevertResult;
+                obj.ApplyCustomUpdateState -= onApplyCustomUpdateState;
             }
 
+            nestedHitObjects.Clear();
+            ClearNestedHitObjects();
+
             HitObject.DefaultsApplied -= onDefaultsApplied;
 
             OnFree();
@@ -574,7 +571,6 @@ namespace osu.Game.Rulesets.Objects.Drawables
         /// Calculate the position to be used for sample playback at a specified X position (0..1).
         /// </summary>
         /// <param name="position">The lookup X position. Generally should be <see cref="SamplePlaybackPosition"/>.</param>
-        /// <returns></returns>
         protected double CalculateSamplePlaybackBalance(double position)
         {
             const float balance_adjust_amount = 0.4f;

osu.Game/Rulesets/Objects/SliderPath.cs

@@ -147,7 +147,6 @@ namespace osu.Game.Rulesets.Objects
         /// to 1 (end of the path).
         /// </summary>
         /// <param name="progress">Ranges from 0 (beginning of the path) to 1 (end of the path).</param>
-        /// <returns></returns>
         public Vector2 PositionAt(double progress)
         {
             ensureValid();
@@ -161,7 +160,6 @@ namespace osu.Game.Rulesets.Objects
         /// The first point has a PathType which all other points inherit.
         /// </summary>
         /// <param name="controlPoint">One of the control points in the segment.</param>
-        /// <returns></returns>
         public List<PathControlPoint> PointsInSegment(PathControlPoint controlPoint)
         {
             bool found = false;

osu.Game/Rulesets/Replays/FramedReplayInputHandler.cs

@@ -3,7 +3,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Diagnostics;
 using JetBrains.Annotations;
 using osu.Game.Input.Handlers;
 using osu.Game.Replays;
@@ -17,80 +16,92 @@ namespace osu.Game.Rulesets.Replays
     public abstract class FramedReplayInputHandler<TFrame> : ReplayInputHandler
         where TFrame : ReplayFrame
     {
-        private readonly Replay replay;
+        /// <summary>
+        /// Whether we have at least one replay frame.
+        /// </summary>
+        public bool HasFrames => Frames.Count != 0;
 
-        protected List<ReplayFrame> Frames => replay.Frames;
+        /// <summary>
+        /// Whether we are waiting for new frames to be received.
+        /// </summary>
+        public bool WaitingForFrame => !replay.HasReceivedAllFrames && currentFrameIndex == Frames.Count - 1;
 
+        /// <summary>
+        /// The current frame of the replay.
+        /// The current time is always between the start and the end time of the current frame.
+        /// </summary>
+        /// <remarks>Returns null if the current time is strictly before the first frame.</remarks>
+        /// <exception cref="InvalidOperationException">The replay is empty.</exception>
         public TFrame CurrentFrame
         {
             get
             {
-                if (!HasFrames || !currentFrameIndex.HasValue)
-                    return null;
+                if (!HasFrames)
+                    throw new InvalidOperationException($"Attempted to get {nameof(CurrentFrame)} of an empty replay");
 
-                return (TFrame)Frames[currentFrameIndex.Value];
+                return currentFrameIndex == -1 ? null : (TFrame)Frames[currentFrameIndex];
             }
         }
 
+        /// <summary>
+        /// The next frame of the replay.
+        /// The start time is always greater or equal to the start time of <see cref="CurrentFrame"/> regardless of the seeking direction.
+        /// </summary>
+        /// <remarks>Returns null if the current frame is the last frame.</remarks>
+        /// <exception cref="InvalidOperationException">The replay is empty.</exception>
         public TFrame NextFrame
         {
             get
             {
                 if (!HasFrames)
-                    return null;
+                    throw new InvalidOperationException($"Attempted to get {nameof(NextFrame)} of an empty replay");
 
-                if (!currentFrameIndex.HasValue)
-                    return currentDirection > 0 ? (TFrame)Frames[0] : null;
-
-                int nextFrame = clampedNextFrameIndex;
-
-                if (nextFrame == currentFrameIndex.Value)
-                    return null;
-
-                return (TFrame)Frames[clampedNextFrameIndex];
+                return currentFrameIndex == Frames.Count - 1 ? null : (TFrame)Frames[currentFrameIndex + 1];
             }
         }
 
-        private int? currentFrameIndex;
-
-        private int clampedNextFrameIndex =>
-            currentFrameIndex.HasValue ? Math.Clamp(currentFrameIndex.Value + currentDirection, 0, Frames.Count - 1) : 0;
-
-        protected FramedReplayInputHandler(Replay replay)
-        {
-            this.replay = replay;
-        }
-
-        private const double sixty_frame_time = 1000.0 / 60;
-
-        protected virtual double AllowedImportantTimeSpan => sixty_frame_time * 1.2;
-
-        protected double? CurrentTime { get; private set; }
-
-        private int currentDirection = 1;
-
         /// <summary>
         /// When set, we will ensure frames executed by nested drawables are frame-accurate to replay data.
         /// Disabling this can make replay playback smoother (useful for autoplay, currently).
         /// </summary>
         public bool FrameAccuratePlayback;
 
-        public bool HasFrames => Frames.Count > 0;
+        // This input handler should be enabled only if there is at least one replay frame.
+        public override bool IsActive => HasFrames;
+
+        // Can make it non-null but that is a breaking change.
+        protected double? CurrentTime { get; private set; }
+
+        protected virtual double AllowedImportantTimeSpan => sixty_frame_time * 1.2;
+
+        protected List<ReplayFrame> Frames => replay.Frames;
+
+        private readonly Replay replay;
+
+        private int currentFrameIndex;
+
+        private const double sixty_frame_time = 1000.0 / 60;
+
+        protected FramedReplayInputHandler(Replay replay)
+        {
+            // TODO: This replay frame ordering should be enforced on the Replay type.
+            // Currently, the ordering can be broken if the frames are added after this construction.
+            replay.Frames.Sort((x, y) => x.Time.CompareTo(y.Time));
+
+            this.replay = replay;
+            currentFrameIndex = -1;
+            CurrentTime = double.NegativeInfinity;
+        }
 
         private bool inImportantSection
         {
             get
             {
-                if (!HasFrames || !FrameAccuratePlayback)
+                if (!HasFrames || !FrameAccuratePlayback || CurrentFrame == null)
                     return false;
 
-                var frame = currentDirection > 0 ? CurrentFrame : NextFrame;
-
-                if (frame == null)
-                    return false;
-
-                return IsImportant(frame) && // a button is in a pressed state
-                       Math.Abs(CurrentTime - NextFrame?.Time ?? 0) <= AllowedImportantTimeSpan; // the next frame is within an allowable time span
+                return IsImportant(CurrentFrame) && // a button is in a pressed state
+                       Math.Abs(CurrentTime - NextFrame.Time ?? 0) <= AllowedImportantTimeSpan; // the next frame is within an allowable time span
             }
         }
 
@@ -105,71 +116,52 @@ namespace osu.Game.Rulesets.Replays
         /// <returns>The usable time value. If null, we should not advance time as we do not have enough data.</returns>
         public override double? SetFrameFromTime(double time)
         {
-            updateDirection(time);
-
-            Debug.Assert(currentDirection != 0);
-
             if (!HasFrames)
             {
-                // in the case all frames are received, allow time to progress regardless.
+                // In the case all frames are received, allow time to progress regardless.
                 if (replay.HasReceivedAllFrames)
                     return CurrentTime = time;
 
                 return null;
             }
 
-            TFrame next = NextFrame;
+            double frameStart = getFrameTime(currentFrameIndex);
+            double frameEnd = getFrameTime(currentFrameIndex + 1);
 
-            // if we have a next frame, check if it is before or at the current time in playback, and advance time to it if so.
-            if (next != null)
+            // If the proposed time is after the current frame end time, we progress forwards to precisely the new frame's time (regardless of incoming time).
+            if (frameEnd <= time)
             {
-                int compare = time.CompareTo(next.Time);
-
-                if (compare == 0 || compare == currentDirection)
-                {
-                    currentFrameIndex = clampedNextFrameIndex;
-                    return CurrentTime = CurrentFrame.Time;
-                }
+                time = frameEnd;
+                currentFrameIndex++;
             }
+            // If the proposed time is before the current frame start time, and we are at the frame boundary, we progress backwards.
+            else if (time < frameStart && CurrentTime == frameStart)
+                currentFrameIndex--;
 
-            // at this point, the frame index can't be advanced.
-            // even so, we may be able to propose the clock progresses forward due to being at an extent of the replay,
-            // or moving towards the next valid frame (ie. interpolating in a non-important section).
+            frameStart = getFrameTime(currentFrameIndex);
+            frameEnd = getFrameTime(currentFrameIndex + 1);
 
-            // the exception is if currently in an important section, which is respected above all.
-            if (inImportantSection)
+            // Pause until more frames are arrived.
+            if (WaitingForFrame && frameStart < time)
             {
-                Debug.Assert(next != null || !replay.HasReceivedAllFrames);
+                CurrentTime = frameStart;
                 return null;
             }
 
-            // if a next frame does exist, allow interpolation.
-            if (next != null)
-                return CurrentTime = time;
+            CurrentTime = Math.Clamp(time, frameStart, frameEnd);
 
-            // if all frames have been received, allow playing beyond extents.
-            if (replay.HasReceivedAllFrames)
-                return CurrentTime = time;
-
-            // if not all frames are received but we are before the first frame, allow playing.
-            if (time < Frames[0].Time)
-                return CurrentTime = time;
-
-            // in the case we have no next frames and haven't received enough frame data, block.
-            return null;
+            // In an important section, a mid-frame time cannot be used and a null is returned instead.
+            return inImportantSection && frameStart < time && time < frameEnd ? null : CurrentTime;
         }
 
-        private void updateDirection(double time)
+        private double getFrameTime(int index)
         {
-            if (!CurrentTime.HasValue)
-            {
-                currentDirection = 1;
-            }
-            else
-            {
-                currentDirection = time.CompareTo(CurrentTime);
-                if (currentDirection == 0) currentDirection = 1;
-            }
+            if (index < 0)
+                return double.NegativeInfinity;
+            if (index >= Frames.Count)
+                return double.PositiveInfinity;
+
+            return Frames[index].Time;
         }
     }
 }