Merge branch 'master' into improve-dho-time-offsets

osu.Android.props

@@ -52,6 +52,6 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="ppy.osu.Game.Resources" Version="2020.1030.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2020.1120.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2020.1127.0" />
   </ItemGroup>
 </Project>

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

@@ -1,9 +1,10 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using NUnit.Framework;
 using osu.Framework.Graphics;
+using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.ControlPoints;
 using osu.Game.Rulesets.Catch.Objects;
 using osu.Game.Rulesets.Catch.Objects.Drawables;
 using osuTK;
@@ -17,34 +18,49 @@ namespace osu.Game.Rulesets.Catch.Tests
         {
             base.LoadComplete();
 
-            foreach (FruitVisualRepresentation rep in Enum.GetValues(typeof(FruitVisualRepresentation)))
+            AddStep("show pear", () => SetContents(() => createDrawableFruit(0)));
-                AddStep($"show {rep}", () => SetContents(() => createDrawableFruit(rep)));
+            AddStep("show grape", () => SetContents(() => createDrawableFruit(1)));
+            AddStep("show pineapple / apple", () => SetContents(() => createDrawableFruit(2)));
+            AddStep("show raspberry / orange", () => SetContents(() => createDrawableFruit(3)));
+
+            AddStep("show banana", () => SetContents(createDrawableBanana));
 
             AddStep("show droplet", () => SetContents(() => createDrawableDroplet()));
             AddStep("show tiny droplet", () => SetContents(createDrawableTinyDroplet));
 
-            foreach (FruitVisualRepresentation rep in Enum.GetValues(typeof(FruitVisualRepresentation)))
+            AddStep("show hyperdash pear", () => SetContents(() => createDrawableFruit(0, true)));
-                AddStep($"show hyperdash {rep}", () => SetContents(() => createDrawableFruit(rep, true)));
+            AddStep("show hyperdash grape", () => SetContents(() => createDrawableFruit(1, true)));
+            AddStep("show hyperdash pineapple / apple", () => SetContents(() => createDrawableFruit(2, true)));
+            AddStep("show hyperdash raspberry / orange", () => SetContents(() => createDrawableFruit(3, true)));
 
             AddStep("show hyperdash droplet", () => SetContents(() => createDrawableDroplet(true)));
         }
 
-        private Drawable createDrawableFruit(FruitVisualRepresentation rep, bool hyperdash = false) =>
+        private Drawable createDrawableFruit(int indexInBeatmap, bool hyperdash = false) =>
-            setProperties(new DrawableFruit(new TestCatchFruit(rep)), hyperdash);
+            SetProperties(new DrawableFruit(new Fruit
+            {
+                IndexInBeatmap = indexInBeatmap,
+                HyperDashBindable = { Value = hyperdash }
+            }));
 
-        private Drawable createDrawableDroplet(bool hyperdash = false) => setProperties(new DrawableDroplet(new Droplet()), hyperdash);
+        private Drawable createDrawableBanana() =>
+            SetProperties(new DrawableBanana(new Banana()));
 
-        private Drawable createDrawableTinyDroplet() => setProperties(new DrawableTinyDroplet(new TinyDroplet()));
+        private Drawable createDrawableDroplet(bool hyperdash = false) =>
+            SetProperties(new DrawableDroplet(new Droplet
+            {
+                HyperDashBindable = { Value = hyperdash }
+            }));
 
-        private DrawableCatchHitObject setProperties(DrawableCatchHitObject d, bool hyperdash = false)
+        private Drawable createDrawableTinyDroplet() => SetProperties(new DrawableTinyDroplet(new TinyDroplet()));
+
+        protected virtual DrawableCatchHitObject SetProperties(DrawableCatchHitObject d)
         {
             var hitObject = d.HitObject;
+            hitObject.ApplyDefaults(new ControlPointInfo(), new BeatmapDifficulty { CircleSize = 0 });
             hitObject.StartTime = 1000000000000;
             hitObject.Scale = 1.5f;
 
-            if (hyperdash)
-                ((PalpableCatchHitObject)hitObject).HyperDashTarget = new Banana();
-
             d.Anchor = Anchor.Centre;
             d.RelativePositionAxes = Axes.None;
             d.Position = Vector2.Zero;
@@ -55,15 +71,5 @@ namespace osu.Game.Rulesets.Catch.Tests
             };
             return d;
         }
-
-        public class TestCatchFruit : Fruit
-        {
-            public TestCatchFruit(FruitVisualRepresentation rep)
-            {
-                VisualRepresentation = rep;
-            }
-
-            public override FruitVisualRepresentation VisualRepresentation { get; }
-        }
     }
 }

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

@@ -0,0 +1,32 @@
+// 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.Game.Rulesets.Catch.Objects;
+using osu.Game.Rulesets.Catch.Objects.Drawables;
+
+namespace osu.Game.Rulesets.Catch.Tests
+{
+    public class TestSceneFruitVisualChange : TestSceneFruitObjects
+    {
+        private readonly Bindable<int> indexInBeatmap = new Bindable<int>();
+        private readonly Bindable<bool> hyperDash = new Bindable<bool>();
+
+        protected override void LoadComplete()
+        {
+            AddStep("fruit changes visual and hyper", () => SetContents(() => SetProperties(new DrawableFruit(new Fruit
+            {
+                IndexInBeatmapBindable = { BindTarget = indexInBeatmap },
+                HyperDashBindable = { BindTarget = hyperDash },
+            }))));
+
+            AddStep("droplet changes hyper", () => SetContents(() => SetProperties(new DrawableDroplet(new Droplet
+            {
+                HyperDashBindable = { BindTarget = hyperDash },
+            }))));
+
+            Scheduler.AddDelayed(() => indexInBeatmap.Value++, 250, true);
+            Scheduler.AddDelayed(() => hyperDash.Value = !hyperDash.Value, 1000, true);
+        }
+    }
+}

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

@@ -18,8 +18,6 @@ namespace osu.Game.Rulesets.Catch.Objects
         /// </summary>
         public int BananaIndex;
 
-        public override FruitVisualRepresentation VisualRepresentation => FruitVisualRepresentation.Banana;
-
         public override Judgement CreateJudgement() => new CatchBananaJudgement();
 
         private static readonly List<HitSampleInfo> samples = new List<HitSampleInfo> { new BananaHitSampleInfo() };

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

@@ -9,8 +9,6 @@ namespace osu.Game.Rulesets.Catch.Objects
 {
     public class BananaShower : CatchHitObject, IHasDuration
     {
-        public override FruitVisualRepresentation VisualRepresentation => FruitVisualRepresentation.Banana;
-
         public override bool LastInCombo => true;
 
         public override Judgement CreateJudgement() => new IgnoreJudgement();

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

@@ -16,27 +16,47 @@ namespace osu.Game.Rulesets.Catch.Objects
     {
         public const float OBJECT_RADIUS = 64;
 
-        private float x;
+        // This value is after XOffset applied.
+        public readonly Bindable<float> XBindable = new Bindable<float>();
+
+        // This value is before XOffset applied.
+        private float originalX;
 
         /// <summary>
         /// The horizontal position of the fruit between 0 and <see cref="CatchPlayfield.WIDTH"/>.
         /// </summary>
         public float X
         {
-            get => x + XOffset;
+            // TODO: I don't like this asymmetry.
-            set => x = value;
+            get => XBindable.Value;
+            // originalX is set by `XBindable.BindValueChanged`
+            set => XBindable.Value = value + xOffset;
         }
 
+        private float xOffset;
+
         /// <summary>
         /// A random offset applied to <see cref="X"/>, set by the <see cref="CatchBeatmapProcessor"/>.
         /// </summary>
-        internal float XOffset { get; set; }
+        internal float XOffset
+        {
+            get => xOffset;
+            set
+            {
+                xOffset = value;
+                XBindable.Value = originalX + xOffset;
+            }
+        }
 
         public double TimePreempt = 1000;
 
-        public int IndexInBeatmap { get; set; }
+        public readonly Bindable<int> IndexInBeatmapBindable = new Bindable<int>();
 
-        public virtual FruitVisualRepresentation VisualRepresentation => (FruitVisualRepresentation)(IndexInBeatmap % 4);
+        public int IndexInBeatmap
+        {
+            get => IndexInBeatmapBindable.Value;
+            set => IndexInBeatmapBindable.Value = value;
+        }
 
         public virtual bool NewCombo { get; set; }
 
@@ -69,7 +89,13 @@ namespace osu.Game.Rulesets.Catch.Objects
             set => LastInComboBindable.Value = value;
         }
 
-        public float Scale { get; set; } = 1;
+        public readonly Bindable<float> ScaleBindable = new Bindable<float>(1);
+
+        public float Scale
+        {
+            get => ScaleBindable.Value;
+            set => ScaleBindable.Value = value;
+        }
 
         protected override void ApplyDefaultsToSelf(ControlPointInfo controlPointInfo, BeatmapDifficulty difficulty)
         {
@@ -81,14 +107,10 @@ namespace osu.Game.Rulesets.Catch.Objects
         }
 
         protected override HitWindows CreateHitWindows() => HitWindows.Empty;
-    }
 
-    public enum FruitVisualRepresentation
+        protected CatchHitObject()
-    {
+        {
-        Pear,
+            XBindable.BindValueChanged(x => originalX = x.NewValue - xOffset);
-        Grape,
+        }
-        Pineapple,
-        Raspberry,
-        Banana // banananananannaanana
     }
 }

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableBanana.cs

@@ -8,6 +8,8 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
 {
     public class DrawableBanana : DrawableFruit
     {
+        protected override FruitVisualRepresentation GetVisualRepresentation(int indexInBeatmap) => FruitVisualRepresentation.Banana;
+
         public DrawableBanana(Banana h)
             : base(h)
         {

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableCatchHitObject.cs

@@ -2,6 +2,8 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using JetBrains.Annotations;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Game.Rulesets.Catch.UI;
 using osu.Game.Rulesets.Objects.Drawables;
@@ -10,19 +12,34 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
 {
     public abstract class DrawableCatchHitObject : DrawableHitObject<CatchHitObject>
     {
+        public readonly Bindable<float> XBindable = new Bindable<float>();
+
         protected override double InitialLifetimeOffset => HitObject.TimePreempt;
 
         public float DisplayRadius => DrawSize.X / 2 * Scale.X * HitObject.Scale;
 
         protected override float SamplePlaybackPosition => HitObject.X / CatchPlayfield.WIDTH;
 
-        protected DrawableCatchHitObject(CatchHitObject hitObject)
+        protected DrawableCatchHitObject([CanBeNull] CatchHitObject hitObject)
             : base(hitObject)
         {
-            X = hitObject.X;
             Anchor = Anchor.BottomLeft;
         }
 
+        protected override void OnApply()
+        {
+            base.OnApply();
+
+            XBindable.BindTo(HitObject.XBindable);
+        }
+
+        protected override void OnFree()
+        {
+            base.OnFree();
+
+            XBindable.UnbindFrom(HitObject.XBindable);
+        }
+
         public Func<CatchHitObject, bool> CheckPosition;
 
         public bool IsOnPlate;

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableDroplet.cs

@@ -21,7 +21,17 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
         [BackgroundDependencyLoader]
         private void load()
         {
-            ScaleContainer.Child = new SkinnableDrawable(new CatchSkinComponent(CatchSkinComponents.Droplet), _ => new DropletPiece());
+            HyperDash.BindValueChanged(_ => updatePiece(), true);
+        }
+
+        private void updatePiece()
+        {
+            ScaleContainer.Child = new SkinnableDrawable(
+                new CatchSkinComponent(CatchSkinComponents.Droplet),
+                _ => new DropletPiece
+                {
+                    HyperDash = { BindTarget = HyperDash }
+                });
         }
 
         protected override void UpdateInitialTransforms()

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableFruit.cs

@@ -3,6 +3,7 @@
 
 using System;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Utils;
 using osu.Game.Rulesets.Catch.Objects.Drawables.Pieces;
 using osu.Game.Skinning;
@@ -11,6 +12,10 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
 {
     public class DrawableFruit : DrawablePalpableCatchHitObject
     {
+        public readonly Bindable<FruitVisualRepresentation> VisualRepresentation = new Bindable<FruitVisualRepresentation>();
+
+        protected virtual FruitVisualRepresentation GetVisualRepresentation(int indexInBeatmap) => (FruitVisualRepresentation)(indexInBeatmap % 4);
+
         public DrawableFruit(CatchHitObject h)
             : base(h)
         {
@@ -19,10 +24,26 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
         [BackgroundDependencyLoader]
         private void load()
         {
-            ScaleContainer.Child = new SkinnableDrawable(
-                new CatchSkinComponent(getComponent(HitObject.VisualRepresentation)), _ => new FruitPiece());
-
             ScaleContainer.Rotation = (float)(RNG.NextDouble() - 0.5f) * 40;
+
+            IndexInBeatmap.BindValueChanged(change =>
+            {
+                VisualRepresentation.Value = GetVisualRepresentation(change.NewValue);
+            }, true);
+
+            VisualRepresentation.BindValueChanged(_ => updatePiece());
+            HyperDash.BindValueChanged(_ => updatePiece(), true);
+        }
+
+        private void updatePiece()
+        {
+            ScaleContainer.Child = new SkinnableDrawable(
+                new CatchSkinComponent(getComponent(VisualRepresentation.Value)),
+                _ => new FruitPiece
+                {
+                    VisualRepresentation = { BindTarget = VisualRepresentation },
+                    HyperDash = { BindTarget = HyperDash },
+                });
         }
 
         private CatchSkinComponents getComponent(FruitVisualRepresentation hitObjectVisualRepresentation)
@@ -49,4 +70,13 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
             }
         }
     }
+
+    public enum FruitVisualRepresentation
+    {
+        Pear,
+        Grape,
+        Pineapple,
+        Raspberry,
+        Banana // banananananannaanana
+    }
 }

osu.Game.Rulesets.Catch/Objects/Drawables/DrawablePalpableCatchHitObject.cs

@@ -1,7 +1,9 @@
 // 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 JetBrains.Annotations;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osuTK;
@@ -12,6 +14,17 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
     {
         public new PalpableCatchHitObject HitObject => (PalpableCatchHitObject)base.HitObject;
 
+        public readonly Bindable<bool> HyperDash = new Bindable<bool>();
+
+        public readonly Bindable<float> ScaleBindable = new Bindable<float>(1);
+
+        public readonly Bindable<int> IndexInBeatmap = new Bindable<int>();
+
+        /// <summary>
+        /// The multiplicative factor applied to <see cref="ScaleContainer"/> scale relative to <see cref="HitObject"/> scale.
+        /// </summary>
+        protected virtual float ScaleFactor => 1;
+
         /// <summary>
         /// Whether this hit object should stay on the catcher plate when the object is caught by the catcher.
         /// </summary>
@@ -19,7 +32,7 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
 
         protected readonly Container ScaleContainer;
 
-        protected DrawablePalpableCatchHitObject(CatchHitObject h)
+        protected DrawablePalpableCatchHitObject([CanBeNull] CatchHitObject h)
             : base(h)
         {
             Origin = Anchor.Centre;
@@ -36,7 +49,35 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables
         [BackgroundDependencyLoader]
         private void load()
         {
-            ScaleContainer.Scale = new Vector2(HitObject.Scale);
+            XBindable.BindValueChanged(x =>
+            {
+                if (!IsOnPlate) X = x.NewValue;
+            }, true);
+
+            ScaleBindable.BindValueChanged(scale =>
+            {
+                ScaleContainer.Scale = new Vector2(scale.NewValue * ScaleFactor);
+            }, true);
+
+            IndexInBeatmap.BindValueChanged(_ => UpdateComboColour());
+        }
+
+        protected override void OnApply()
+        {
+            base.OnApply();
+
+            HyperDash.BindTo(HitObject.HyperDashBindable);
+            ScaleBindable.BindTo(HitObject.ScaleBindable);
+            IndexInBeatmap.BindTo(HitObject.IndexInBeatmapBindable);
+        }
+
+        protected override void OnFree()
+        {
+            HyperDash.UnbindFrom(HitObject.HyperDashBindable);
+            ScaleBindable.UnbindFrom(HitObject.ScaleBindable);
+            IndexInBeatmap.UnbindFrom(HitObject.IndexInBeatmapBindable);
+
+            base.OnFree();
         }
     }
 }

osu.Game.Rulesets.Catch/Objects/Drawables/DrawableTinyDroplet.cs

@@ -1,21 +1,15 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Allocation;
-
 namespace osu.Game.Rulesets.Catch.Objects.Drawables
 {
     public class DrawableTinyDroplet : DrawableDroplet
     {
+        protected override float ScaleFactor => base.ScaleFactor / 2;
+
         public DrawableTinyDroplet(TinyDroplet h)
             : base(h)
         {
         }
-
-        [BackgroundDependencyLoader]
-        private void load()
-        {
-            ScaleContainer.Scale /= 2;
-        }
     }
 }

osu.Game.Rulesets.Catch/Objects/Drawables/Pieces/DropletPiece.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Rulesets.Objects.Drawables;
@@ -11,6 +12,8 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables.Pieces
 {
     public class DropletPiece : CompositeDrawable
     {
+        public readonly Bindable<bool> HyperDash = new Bindable<bool>();
+
         public DropletPiece()
         {
             Size = new Vector2(CatchHitObject.OBJECT_RADIUS / 2);
@@ -19,15 +22,13 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables.Pieces
         [BackgroundDependencyLoader]
         private void load(DrawableHitObject drawableObject)
         {
-            var drawableCatchObject = (DrawablePalpableCatchHitObject)drawableObject;
-
             InternalChild = new Pulp
             {
                 RelativeSizeAxes = Axes.Both,
                 AccentColour = { BindTarget = drawableObject.AccentColour }
             };
 
-            if (drawableCatchObject.HitObject.HyperDash)
+            if (HyperDash.Value)
             {
                 AddInternal(new HyperDropletBorderPiece());
             }

osu.Game.Rulesets.Catch/Objects/Drawables/Pieces/FruitPiece.cs

@@ -2,7 +2,9 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using JetBrains.Annotations;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Rulesets.Objects.Drawables;
@@ -16,36 +18,39 @@ namespace osu.Game.Rulesets.Catch.Objects.Drawables.Pieces
         /// </summary>
         public const float RADIUS_ADJUST = 1.1f;
 
-        private BorderPiece border;
+        public readonly Bindable<FruitVisualRepresentation> VisualRepresentation = new Bindable<FruitVisualRepresentation>();
-        private PalpableCatchHitObject hitObject;
+        public readonly Bindable<bool> HyperDash = new Bindable<bool>();
+
+        [CanBeNull]
+        private DrawableCatchHitObject drawableHitObject;
+
+        [CanBeNull]
+        private BorderPiece borderPiece;
 
         public FruitPiece()
         {
             RelativeSizeAxes = Axes.Both;
         }
 
-        [BackgroundDependencyLoader]
+        [BackgroundDependencyLoader(permitNulls: true)]
-        private void load(DrawableHitObject drawableObject)
+        private void load([CanBeNull] DrawableHitObject drawable)
         {
-            var drawableCatchObject = (DrawablePalpableCatchHitObject)drawableObject;
+            drawableHitObject = (DrawableCatchHitObject)drawable;
-            hitObject = drawableCatchObject.HitObject;
 
-            AddRangeInternal(new[]
+            AddInternal(getFruitFor(VisualRepresentation.Value));
-            {
-                getFruitFor(hitObject.VisualRepresentation),
-                border = new BorderPiece(),
-            });
 
-            if (hitObject.HyperDash)
+            // if it is not part of a DHO, the border is always invisible.
-            {
+            if (drawableHitObject != null)
+                AddInternal(borderPiece = new BorderPiece());
+
+            if (HyperDash.Value)
                 AddInternal(new HyperBorderPiece());
-            }
         }
 
         protected override void Update()
         {
-            base.Update();
+            if (borderPiece != null && drawableHitObject?.HitObject != null)
-            border.Alpha = (float)Math.Clamp((hitObject.StartTime - Time.Current) / 500, 0, 1);
+                borderPiece.Alpha = (float)Math.Clamp((drawableHitObject.HitObject.StartTime - Time.Current) / 500, 0, 1);
         }
 
         private Drawable getFruitFor(FruitVisualRepresentation representation)

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

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using osu.Framework.Bindables;
 using osu.Game.Rulesets.Objects.Types;
 using osuTK.Graphics;
 
@@ -20,15 +21,27 @@ namespace osu.Game.Rulesets.Catch.Objects
         /// </summary>
         public float DistanceToHyperDash { get; set; }
 
+        public readonly Bindable<bool> HyperDashBindable = new Bindable<bool>();
+
         /// <summary>
         /// Whether this fruit can initiate a hyperdash.
         /// </summary>
-        public bool HyperDash => HyperDashTarget != null;
+        public bool HyperDash => HyperDashBindable.Value;
+
+        private CatchHitObject hyperDashTarget;
 
         /// <summary>
         /// The target fruit if we are to initiate a hyperdash.
         /// </summary>
-        public CatchHitObject HyperDashTarget;
+        public CatchHitObject HyperDashTarget
+        {
+            get => hyperDashTarget;
+            set
+            {
+                hyperDashTarget = value;
+                HyperDashBindable.Value = value != null;
+            }
+        }
 
         Color4 IHasComboInformation.GetComboColour(IReadOnlyList<Color4> comboColours) => comboColours[(IndexInBeatmap + 1) % comboColours.Count];
     }

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

@@ -55,7 +55,13 @@ namespace osu.Game.Rulesets.Catch.UI
                 HitObjectContainer,
                 CatcherArea,
             };
+        }
 
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            // these subscriptions need to be done post constructor to ensure externally bound components have a chance to populate required fields (ScoreProcessor / ComboAtJudgement in this case).
             NewResult += onNewResult;
             RevertResult += onRevertResult;
         }

osu.Game.Rulesets.Osu/Objects/Drawables/Pieces/SliderBall.cs

@@ -248,7 +248,7 @@ namespace osu.Game.Rulesets.Osu.Objects.Drawables.Pieces
             }
 
             private void trackingChanged(ValueChangedEvent<bool> tracking) =>
-                box.FadeTo(tracking.NewValue ? 0.6f : 0.05f, 200, Easing.OutQuint);
+                box.FadeTo(tracking.NewValue ? 0.3f : 0.05f, 200, Easing.OutQuint);
         }
     }
 }

osu.Game.Rulesets.Taiko/UI/TaikoPlayfield.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.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -37,7 +38,7 @@ namespace osu.Game.Rulesets.Taiko.UI
         private SkinnableDrawable mascot;
 
         private ProxyContainer topLevelHitContainer;
-        private ProxyContainer barlineContainer;
+        private ScrollingHitObjectContainer barlineContainer;
         private Container rightArea;
         private Container leftArea;
 
@@ -83,10 +84,7 @@ namespace osu.Game.Rulesets.Taiko.UI
                             RelativeSizeAxes = Axes.Both,
                             Children = new Drawable[]
                             {
-                                barlineContainer = new ProxyContainer
+                                barlineContainer = new ScrollingHitObjectContainer(),
-                                {
-                                    RelativeSizeAxes = Axes.Both,
-                                },
                                 new Container
                                 {
                                     Name = "Hit objects",
@@ -159,18 +157,37 @@ namespace osu.Game.Rulesets.Taiko.UI
 
         public override void Add(DrawableHitObject h)
         {
-            h.OnNewResult += OnNewResult;
-            base.Add(h);
-
             switch (h)
             {
                 case DrawableBarLine barline:
-                    barlineContainer.Add(barline.CreateProxy());
+                    barlineContainer.Add(barline);
                     break;
 
                 case DrawableTaikoHitObject taikoObject:
+                    h.OnNewResult += OnNewResult;
                     topLevelHitContainer.Add(taikoObject.CreateProxiedContent());
+                    base.Add(h);
                     break;
+
+                default:
+                    throw new ArgumentException($"Unsupported {nameof(DrawableHitObject)} type");
+            }
+        }
+
+        public override bool Remove(DrawableHitObject h)
+        {
+            switch (h)
+            {
+                case DrawableBarLine barline:
+                    return barlineContainer.Remove(barline);
+
+                case DrawableTaikoHitObject _:
+                    h.OnNewResult -= OnNewResult;
+                    // todo: consider tidying of proxied content if required.
+                    return base.Remove(h);
+
+                default:
+                    throw new ArgumentException($"Unsupported {nameof(DrawableHitObject)} type");
             }
         }
 

osu.Game.Tests/Editing/EditorChangeHandlerTest.cs

@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using NUnit.Framework;
-using osu.Framework.Utils;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Screens.Edit;
@@ -44,6 +43,36 @@ namespace osu.Game.Tests.Editing
             Assert.That(stateChangedFired, Is.EqualTo(2));
         }
 
+        [Test]
+        public void TestApplyThenUndoThenApplySameChange()
+        {
+            var (handler, beatmap) = createChangeHandler();
+
+            Assert.That(handler.CanUndo.Value, Is.False);
+            Assert.That(handler.CanRedo.Value, Is.False);
+
+            string originalHash = handler.CurrentStateHash;
+
+            addArbitraryChange(beatmap);
+            handler.SaveState();
+
+            Assert.That(handler.CanUndo.Value, Is.True);
+            Assert.That(handler.CanRedo.Value, Is.False);
+            Assert.That(stateChangedFired, Is.EqualTo(1));
+
+            string hash = handler.CurrentStateHash;
+
+            // undo a change without saving
+            handler.RestoreState(-1);
+
+            Assert.That(originalHash, Is.EqualTo(handler.CurrentStateHash));
+            Assert.That(stateChangedFired, Is.EqualTo(2));
+
+            addArbitraryChange(beatmap);
+            handler.SaveState();
+            Assert.That(hash, Is.EqualTo(handler.CurrentStateHash));
+        }
+
         [Test]
         public void TestSaveSameStateDoesNotSave()
         {
@@ -139,7 +168,7 @@ namespace osu.Game.Tests.Editing
 
         private void addArbitraryChange(EditorBeatmap beatmap)
         {
-            beatmap.Add(new HitCircle { StartTime = RNG.Next(0, 100000) });
+            beatmap.Add(new HitCircle { StartTime = 2760 });
         }
     }
 }

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

@@ -3,7 +3,6 @@
 
 using NUnit.Framework;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Sprites;
 using osu.Framework.Utils;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
@@ -14,44 +13,41 @@ namespace osu.Game.Tests.Visual.Gameplay
     [TestFixture]
     public class TestSceneStarCounter : OsuTestScene
     {
+        private readonly StarCounter starCounter;
+        private readonly OsuSpriteText starsLabel;
+
         public TestSceneStarCounter()
         {
-            StarCounter stars = new StarCounter
+            starCounter = new StarCounter
             {
                 Origin = Anchor.Centre,
                 Anchor = Anchor.Centre,
-                Current = 5,
             };
 
-            Add(stars);
+            Add(starCounter);
 
-            SpriteText starsLabel = new OsuSpriteText
+            starsLabel = new OsuSpriteText
             {
                 Origin = Anchor.Centre,
                 Anchor = Anchor.Centre,
                 Scale = new Vector2(2),
                 Y = 50,
-                Text = stars.Current.ToString("0.00"),
             };
 
             Add(starsLabel);
 
-            AddRepeatStep(@"random value", delegate
+            setStars(5);
-            {
-                stars.Current = RNG.NextSingle() * (stars.StarCount + 1);
-                starsLabel.Text = stars.Current.ToString("0.00");
-            }, 10);
 
-            AddStep(@"Stop animation", delegate
+            AddRepeatStep("random value", () => setStars(RNG.NextSingle() * (starCounter.StarCount + 1)), 10);
-            {
+            AddSliderStep("exact value", 0f, 10f, 5f, setStars);
-                stars.StopAnimation();
+            AddStep("stop animation", () => starCounter.StopAnimation());
-            });
+            AddStep("reset", () => setStars(0));
+        }
 
-            AddStep(@"Reset", delegate
+        private void setStars(float stars)
-            {
+        {
-                stars.Current = 0;
+            starCounter.Current = stars;
-                starsLabel.Text = stars.Current.ToString("0.00");
+            starsLabel.Text = starCounter.Current.ToString("0.00");
-            });
         }
     }
 }

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

@@ -917,7 +917,7 @@ namespace osu.Game.Tests.Visual.SongSelect
             {
                 get
                 {
-                    foreach (var item in ScrollableContent)
+                    foreach (var item in Scroll.Children)
                     {
                         yield return item;
 

osu.Game/Graphics/Containers/OsuScrollContainer.cs

@@ -12,7 +12,19 @@ using osuTK.Input;
 
 namespace osu.Game.Graphics.Containers
 {
-    public class OsuScrollContainer : ScrollContainer<Drawable>
+    public class OsuScrollContainer : OsuScrollContainer<Drawable>
+    {
+        public OsuScrollContainer()
+        {
+        }
+
+        public OsuScrollContainer(Direction direction)
+            : base(direction)
+        {
+        }
+    }
+
+    public class OsuScrollContainer<T> : ScrollContainer<T> where T : Drawable
     {
         public const float SCROLL_BAR_HEIGHT = 10;
         public const float SCROLL_BAR_PADDING = 3;

osu.Game/Graphics/UserInterface/StarCounter.cs

@@ -147,7 +147,7 @@ namespace osu.Game.Graphics.UserInterface
 
             public override void DisplayAt(float scale)
             {
-                scale = Math.Clamp(scale, min_star_scale, 1);
+                scale = (float)Interpolation.Lerp(min_star_scale, 1, Math.Clamp(scale, 0, 1));
 
                 this.FadeTo(scale, fading_duration);
                 Icon.ScaleTo(scale, scaling_duration, scaling_easing);

osu.Game/Overlays/Settings/Sections/AudioSection.cs

@@ -27,7 +27,6 @@ namespace osu.Game.Overlays.Settings.Sections
                 new AudioDevicesSettings(),
                 new VolumeSettings(),
                 new OffsetSettings(),
-                new MainMenuSettings()
             };
         }
     }

osu.Game/Overlays/Settings/Sections/GameplaySection.cs

@@ -26,7 +26,6 @@ namespace osu.Game.Overlays.Settings.Sections
             Children = new Drawable[]
             {
                 new GeneralSettings(),
-                new SongSelectSettings(),
                 new ModsSettings(),
             };
         }

osu.Game/Overlays/Settings/Sections/GraphicsSection.cs

@@ -23,7 +23,6 @@ namespace osu.Game.Overlays.Settings.Sections
                 new RendererSettings(),
                 new LayoutSettings(),
                 new DetailSettings(),
-                new UserInterfaceSettings(),
             };
         }
     }

osu.Game/Overlays/Settings/Sections/SizeSlider.cs

@@ -0,0 +1,15 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Game.Graphics.UserInterface;
+
+namespace osu.Game.Overlays.Settings.Sections
+{
+    /// <summary>
+    /// A slider intended to show a "size" multiplier number, where 1x is 1.0.
+    /// </summary>
+    internal class SizeSlider : OsuSliderBar<float>
+    {
+        public override string TooltipText => Current.Value.ToString(@"0.##x");
+    }
+}

osu.Game/Overlays/Settings/Sections/SkinSection.cs

@@ -54,12 +54,6 @@ namespace osu.Game.Overlays.Settings.Sections
                 skinDropdown = new SkinSettingsDropdown(),
                 new ExportSkinButton(),
                 new SettingsSlider<float, SizeSlider>
-                {
-                    LabelText = "Menu cursor size",
-                    Current = config.GetBindable<float>(OsuSetting.MenuCursorSize),
-                    KeyboardStep = 0.01f
-                },
-                new SettingsSlider<float, SizeSlider>
                 {
                     LabelText = "Gameplay cursor size",
                     Current = config.GetBindable<float>(OsuSetting.GameplayCursorSize),
@@ -136,11 +130,6 @@ namespace osu.Game.Overlays.Settings.Sections
                 Schedule(() => skinDropdown.Items = skinDropdown.Items.Where(i => i.ID != item.ID).ToArray());
         }
 
-        private class SizeSlider : OsuSliderBar<float>
-        {
-            public override string TooltipText => Current.Value.ToString(@"0.##x");
-        }
-
         private class SkinSettingsDropdown : SettingsDropdown<SkinInfo>
         {
             protected override OsuDropdown<SkinInfo> CreateDropdown() => new SkinDropdownControl();

osu.Game/Overlays/Settings/Sections/UserInterface/GeneralSettings.cs

@@ -6,11 +6,11 @@ using osu.Framework.Graphics;
 using osu.Game.Configuration;
 using osu.Game.Graphics.UserInterface;
 
-namespace osu.Game.Overlays.Settings.Sections.Graphics
+namespace osu.Game.Overlays.Settings.Sections.UserInterface
 {
-    public class UserInterfaceSettings : SettingsSubsection
+    public class GeneralSettings : SettingsSubsection
     {
-        protected override string Header => "User Interface";
+        protected override string Header => "General";
 
         [BackgroundDependencyLoader]
         private void load(OsuConfigManager config)
@@ -22,6 +22,12 @@ namespace osu.Game.Overlays.Settings.Sections.Graphics
                     LabelText = "Rotate cursor when dragging",
                     Current = config.GetBindable<bool>(OsuSetting.CursorRotation)
                 },
+                new SettingsSlider<float, SizeSlider>
+                {
+                    LabelText = "Menu cursor size",
+                    Current = config.GetBindable<float>(OsuSetting.MenuCursorSize),
+                    KeyboardStep = 0.01f
+                },
                 new SettingsCheckbox
                 {
                     LabelText = "Parallax",

osu.Game/Overlays/Settings/Sections/UserInterface/MainMenuSettings.cs

@@ -7,7 +7,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Game.Configuration;
 
-namespace osu.Game.Overlays.Settings.Sections.Audio
+namespace osu.Game.Overlays.Settings.Sections.UserInterface
 {
     public class MainMenuSettings : SettingsSubsection
     {

osu.Game/Overlays/Settings/Sections/UserInterface/SongSelectSettings.cs

@@ -8,7 +8,7 @@ using osu.Framework.Graphics;
 using osu.Game.Configuration;
 using osu.Game.Graphics.UserInterface;
 
-namespace osu.Game.Overlays.Settings.Sections.Gameplay
+namespace osu.Game.Overlays.Settings.Sections.UserInterface
 {
     public class SongSelectSettings : SettingsSubsection
     {

osu.Game/Overlays/Settings/Sections/UserInterfaceSection.cs

@@ -0,0 +1,29 @@
+// 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.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Overlays.Settings.Sections.UserInterface;
+
+namespace osu.Game.Overlays.Settings.Sections
+{
+    public class UserInterfaceSection : SettingsSection
+    {
+        public override string Header => "User Interface";
+
+        public override Drawable CreateIcon() => new SpriteIcon
+        {
+            Icon = FontAwesome.Solid.LayerGroup
+        };
+
+        public UserInterfaceSection()
+        {
+            Children = new Drawable[]
+            {
+                new GeneralSettings(),
+                new MainMenuSettings(),
+                new SongSelectSettings()
+            };
+        }
+    }
+}

osu.Game/Overlays/SettingsOverlay.cs

@@ -23,10 +23,11 @@ namespace osu.Game.Overlays
         {
             new GeneralSection(),
             new GraphicsSection(),
-            new GameplaySection(),
             new AudioSection(),
-            new SkinSection(),
             new InputSection(createSubPanel(new KeyBindingPanel())),
+            new UserInterfaceSection(),
+            new GameplaySection(),
+            new SkinSection(),
             new OnlineSection(),
             new MaintenanceSection(),
             new DebugSection(),

osu.Game/Rulesets/Judgements/DrawableJudgement.cs

@@ -32,9 +32,6 @@ namespace osu.Game.Rulesets.Judgements
 
         private readonly Container aboveHitObjectsContent;
 
-        [Resolved]
-        private ISkinSource skinSource { get; set; }
-
         /// <summary>
         /// Duration of initial fade in.
         /// </summary>
@@ -78,29 +75,6 @@ namespace osu.Game.Rulesets.Judgements
 
         public Drawable GetProxyAboveHitObjectsContent() => aboveHitObjectsContent.CreateProxy();
 
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-            skinSource.SourceChanged += onSkinChanged;
-        }
-
-        private void onSkinChanged()
-        {
-            // on a skin change, the child component will update but not get correctly triggered to play its animation.
-            // we need to trigger a reinitialisation to make things right.
-            currentDrawableType = null;
-
-            PrepareForUse();
-        }
-
-        protected override void Dispose(bool isDisposing)
-        {
-            base.Dispose(isDisposing);
-
-            if (skinSource != null)
-                skinSource.SourceChanged -= onSkinChanged;
-        }
-
         /// <summary>
         /// Apply top-level animations to the current judgement when successfully hit.
         /// If displaying components which require lifetime extensions, manually adjusting <see cref="Drawable.LifetimeEnd"/> is required.
@@ -142,13 +116,14 @@ namespace osu.Game.Rulesets.Judgements
 
             Debug.Assert(Result != null);
 
-            prepareDrawables();
-
             runAnimation();
         }
 
         private void runAnimation()
         {
+            // is a no-op if the drawables are already in a correct state.
+            prepareDrawables();
+
             // undo any transforms applies in ApplyMissAnimations/ApplyHitAnimations to get a sane initial state.
             ApplyTransformsAt(double.MinValue, true);
             ClearTransforms(true);
@@ -203,7 +178,6 @@ namespace osu.Game.Rulesets.Judgements
             if (JudgementBody != null)
                 RemoveInternal(JudgementBody);
 
-            aboveHitObjectsContent.Clear();
             AddInternal(JudgementBody = new SkinnableDrawable(new GameplaySkinComponent<HitResult>(type), _ =>
                 CreateDefaultJudgement(type), confineMode: ConfineMode.NoScaling)
             {
@@ -211,14 +185,29 @@ namespace osu.Game.Rulesets.Judgements
                 Origin = Anchor.Centre,
             });
 
-            if (JudgementBody.Drawable is IAnimatableJudgement animatable)
+            JudgementBody.OnSkinChanged += () =>
             {
-                var proxiedContent = animatable.GetAboveHitObjectsProxiedContent();
+                // on a skin change, the child component will update but not get correctly triggered to play its animation (or proxy the newly created content).
-                if (proxiedContent != null)
+                // we need to trigger a reinitialisation to make things right.
-                    aboveHitObjectsContent.Add(proxiedContent);
+                proxyContent();
-            }
+                runAnimation();
+            };
+
+            proxyContent();
 
             currentDrawableType = type;
+
+            void proxyContent()
+            {
+                aboveHitObjectsContent.Clear();
+
+                if (JudgementBody.Drawable is IAnimatableJudgement animatable)
+                {
+                    var proxiedContent = animatable.GetAboveHitObjectsProxiedContent();
+                    if (proxiedContent != null)
+                        aboveHitObjectsContent.Add(proxiedContent);
+                }
+            }
         }
 
         protected virtual Drawable CreateDefaultJudgement(HitResult result) => new DefaultJudgementPiece(result);

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

@@ -190,7 +190,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
         {
             base.LoadComplete();
 
-            comboIndexBindable.BindValueChanged(_ => updateComboColour(), true);
+            comboIndexBindable.BindValueChanged(_ => UpdateComboColour(), true);
 
             updateState(ArmedState.Idle, true);
         }
@@ -263,18 +263,15 @@ namespace osu.Game.Rulesets.Objects.Drawables
             OnApply();
             HitObjectApplied?.Invoke(this);
 
-            // If not loaded, the state update happens in LoadComplete(). Otherwise, the update is scheduled to allow for lifetime updates.
+            // If not loaded, the state update happens in LoadComplete().
             if (IsLoaded)
             {
-                Scheduler.Add(() =>
+                if (Result.IsHit)
-                {
+                    updateState(ArmedState.Hit, true);
-                    if (Result.IsHit)
+                else if (Result.HasResult)
-                        updateState(ArmedState.Hit, true);
+                    updateState(ArmedState.Miss, true);
-                    else if (Result.HasResult)
+                else
-                        updateState(ArmedState.Miss, true);
+                    updateState(ArmedState.Idle, true);
-                    else
-                        updateState(ArmedState.Idle, true);
-                });
             }
 
             hasHitObjectApplied = true;
@@ -533,7 +530,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
         {
             base.SkinChanged(skin, allowFallback);
 
-            updateComboColour();
+            UpdateComboColour();
 
             ApplySkin(skin, allowFallback);
 
@@ -541,7 +538,7 @@ namespace osu.Game.Rulesets.Objects.Drawables
                 updateState(State.Value, true);
         }
 
-        private void updateComboColour()
+        protected void UpdateComboColour()
         {
             if (!(HitObject is IHasComboInformation combo)) return;
 

osu.Game/Screens/Edit/Compose/Components/BlueprintContainer.cs

@@ -496,10 +496,7 @@ namespace osu.Game.Screens.Edit.Compose.Components
                 double offset = result.Time.Value - movementBlueprints.First().HitObject.StartTime;
 
                 foreach (HitObject obj in Beatmap.SelectedHitObjects)
-                {
                     obj.StartTime += offset;
-                    Beatmap.Update(obj);
-                }
             }
 
             return true;

osu.Game/Screens/Edit/EditorChangeHandler.cs

@@ -76,7 +76,7 @@ namespace osu.Game.Screens.Edit
                 var newState = stream.ToArray();
 
                 // if the previous state is binary equal we don't need to push a new one, unless this is the initial state.
-                if (savedStates.Count > 0 && newState.SequenceEqual(savedStates.Last())) return;
+                if (savedStates.Count > 0 && newState.SequenceEqual(savedStates[currentState])) return;
 
                 if (currentState < savedStates.Count - 1)
                     savedStates.RemoveRange(currentState + 1, savedStates.Count - currentState - 1);

osu.Game/Screens/Select/BeatmapCarousel.cs

@@ -91,7 +91,7 @@ namespace osu.Game.Screens.Select
         /// </summary>
         public bool BeatmapSetsLoaded { get; private set; }
 
-        private readonly CarouselScrollContainer scroll;
+        protected readonly CarouselScrollContainer Scroll;
 
         private IEnumerable<CarouselBeatmapSet> beatmapSets => root.Children.OfType<CarouselBeatmapSet>();
 
@@ -112,9 +112,9 @@ namespace osu.Game.Screens.Select
             if (selectedBeatmapSet != null && !beatmapSets.Contains(selectedBeatmapSet.BeatmapSet))
                 selectedBeatmapSet = null;
 
-            ScrollableContent.Clear(false);
+            Scroll.Clear(false);
             itemsCache.Invalidate();
-            scrollPositionCache.Invalidate();
+            ScrollToSelected();
 
             // apply any pending filter operation that may have been delayed (see applyActiveCriteria's scheduling behaviour when BeatmapSetsLoaded is false).
             FlushPendingFilterOperations();
@@ -130,9 +130,7 @@ namespace osu.Game.Screens.Select
         private readonly List<CarouselItem> visibleItems = new List<CarouselItem>();
 
         private readonly Cached itemsCache = new Cached();
-        private readonly Cached scrollPositionCache = new Cached();
+        private PendingScrollOperation pendingScrollOperation = PendingScrollOperation.None;
-
-        protected readonly Container<DrawableCarouselItem> ScrollableContent;
 
         public Bindable<bool> RightClickScrollingEnabled = new Bindable<bool>();
 
@@ -155,17 +153,12 @@ namespace osu.Game.Screens.Select
             InternalChild = new OsuContextMenuContainer
             {
                 RelativeSizeAxes = Axes.Both,
-                Child = scroll = new CarouselScrollContainer
+                Children = new Drawable[]
                 {
-                    Masking = false,
+                    setPool,
-                    RelativeSizeAxes = Axes.Both,
+                    Scroll = new CarouselScrollContainer
-                    Children = new Drawable[]
                     {
-                        setPool,
+                        RelativeSizeAxes = Axes.Both,
-                        ScrollableContent = new Container<DrawableCarouselItem>
-                        {
-                            RelativeSizeAxes = Axes.X,
-                        }
                     }
                 }
             };
@@ -180,7 +173,7 @@ namespace osu.Game.Screens.Select
             config.BindWith(OsuSetting.RandomSelectAlgorithm, RandomAlgorithm);
             config.BindWith(OsuSetting.SongSelectRightMouseScroll, RightClickScrollingEnabled);
 
-            RightClickScrollingEnabled.ValueChanged += enabled => scroll.RightMouseScrollbar = enabled.NewValue;
+            RightClickScrollingEnabled.ValueChanged += enabled => Scroll.RightMouseScrollbar = enabled.NewValue;
             RightClickScrollingEnabled.TriggerChange();
 
             itemUpdated = beatmaps.ItemUpdated.GetBoundCopy();
@@ -421,12 +414,12 @@ namespace osu.Game.Screens.Select
         /// <summary>
         /// The position of the lower visible bound with respect to the current scroll position.
         /// </summary>
-        private float visibleBottomBound => scroll.Current + DrawHeight + BleedBottom;
+        private float visibleBottomBound => Scroll.Current + DrawHeight + BleedBottom;
 
         /// <summary>
         /// The position of the upper visible bound with respect to the current scroll position.
         /// </summary>
-        private float visibleUpperBound => scroll.Current - BleedTop;
+        private float visibleUpperBound => Scroll.Current - BleedTop;
 
         public void FlushPendingFilterOperations()
         {
@@ -468,8 +461,8 @@ namespace osu.Game.Screens.Select
                 root.Filter(activeCriteria);
                 itemsCache.Invalidate();
 
-                if (alwaysResetScrollPosition || !scroll.UserScrolling)
+                if (alwaysResetScrollPosition || !Scroll.UserScrolling)
-                    ScrollToSelected();
+                    ScrollToSelected(true);
             }
         }
 
@@ -478,7 +471,12 @@ namespace osu.Game.Screens.Select
         /// <summary>
         /// Scroll to the current <see cref="SelectedBeatmap"/>.
         /// </summary>
-        public void ScrollToSelected() => scrollPositionCache.Invalidate();
+        /// <param name="immediate">
+        /// Whether the scroll position should immediately be shifted to the target, delegating animation to visible panels.
+        /// This should be true for operations like filtering - where panels are changing visibility state - to avoid large jumps in animation.
+        /// </param>
+        public void ScrollToSelected(bool immediate = false) =>
+            pendingScrollOperation = immediate ? PendingScrollOperation.Immediate : PendingScrollOperation.Standard;
 
         #region Key / button selection logic
 
@@ -488,12 +486,12 @@ namespace osu.Game.Screens.Select
             {
                 case Key.Left:
                     if (!e.Repeat)
-                        beginRepeatSelection(() => SelectNext(-1, true), e.Key);
+                        beginRepeatSelection(() => SelectNext(-1), e.Key);
                     return true;
 
                 case Key.Right:
                     if (!e.Repeat)
-                        beginRepeatSelection(() => SelectNext(1, true), e.Key);
+                        beginRepeatSelection(() => SelectNext(), e.Key);
                     return true;
             }
 
@@ -580,6 +578,11 @@ namespace osu.Game.Screens.Select
             if (revalidateItems)
                 updateYPositions();
 
+            // if there is a pending scroll action we apply it without animation and transfer the difference in position to the panels.
+            // this is intentionally applied before updating the visible range below, to avoid animating new items (sourced from pool) from locations off-screen, as it looks bad.
+            if (pendingScrollOperation != PendingScrollOperation.None)
+                updateScrollPosition();
+
             // This data is consumed to find the currently displayable range.
             // This is the range we want to keep drawables for, and should exceed the visible range slightly to avoid drawable churn.
             var newDisplayRange = getDisplayRange();
@@ -594,7 +597,7 @@ namespace osu.Game.Screens.Select
                 {
                     var toDisplay = visibleItems.GetRange(displayedRange.first, displayedRange.last - displayedRange.first + 1);
 
-                    foreach (var panel in ScrollableContent.Children)
+                    foreach (var panel in Scroll.Children)
                     {
                         if (toDisplay.Remove(panel.Item))
                         {
@@ -620,24 +623,14 @@ namespace osu.Game.Screens.Select
                         panel.Depth = item.CarouselYPosition;
                         panel.Y = item.CarouselYPosition;
 
-                        ScrollableContent.Add(panel);
+                        Scroll.Add(panel);
                     }
                 }
             }
 
-            // Finally, if the filtered items have changed, animate drawables to their new locations.
-            // This is common if a selected/collapsed state has changed.
-            if (revalidateItems)
-            {
-                foreach (DrawableCarouselItem panel in ScrollableContent.Children)
-                {
-                    panel.MoveToY(panel.Item.CarouselYPosition, 800, Easing.OutQuint);
-                }
-            }
-
             // Update externally controlled state of currently visible items (e.g. x-offset and opacity).
             // This is a per-frame update on all drawable panels.
-            foreach (DrawableCarouselItem item in ScrollableContent.Children)
+            foreach (DrawableCarouselItem item in Scroll.Children)
             {
                 updateItem(item);
 
@@ -670,14 +663,6 @@ namespace osu.Game.Screens.Select
             return (firstIndex, lastIndex);
         }
 
-        protected override void UpdateAfterChildren()
-        {
-            base.UpdateAfterChildren();
-
-            if (!scrollPositionCache.IsValid)
-                updateScrollPosition();
-        }
-
         private void beatmapRemoved(ValueChangedEvent<WeakReference<BeatmapSetInfo>> weakItem)
         {
             if (weakItem.NewValue.TryGetTarget(out var item))
@@ -789,7 +774,8 @@ namespace osu.Game.Screens.Select
             }
 
             currentY += visibleHalfHeight;
-            ScrollableContent.Height = currentY;
+
+            Scroll.ScrollContent.Height = currentY;
 
             if (BeatmapSetsLoaded && (selectedBeatmapSet == null || selectedBeatmap == null || selectedBeatmapSet.State.Value != CarouselItemState.Selected))
             {
@@ -809,12 +795,31 @@ namespace osu.Game.Screens.Select
                 if (firstScroll)
                 {
                     // reduce movement when first displaying the carousel.
-                    scroll.ScrollTo(scrollTarget.Value - 200, false);
+                    Scroll.ScrollTo(scrollTarget.Value - 200, false);
                     firstScroll = false;
                 }
 
-                scroll.ScrollTo(scrollTarget.Value);
+                switch (pendingScrollOperation)
-                scrollPositionCache.Validate();
+                {
+                    case PendingScrollOperation.Standard:
+                        Scroll.ScrollTo(scrollTarget.Value);
+                        break;
+
+                    case PendingScrollOperation.Immediate:
+                        // in order to simplify animation logic, rather than using the animated version of ScrollTo,
+                        // we take the difference in scroll height and apply to all visible panels.
+                        // this avoids edge cases like when the visible panels is reduced suddenly, causing ScrollContainer
+                        // to enter clamp-special-case mode where it animates completely differently to normal.
+                        float scrollChange = scrollTarget.Value - Scroll.Current;
+
+                        Scroll.ScrollTo(scrollTarget.Value, false);
+
+                        foreach (var i in Scroll.Children)
+                            i.Y += scrollChange;
+                        break;
+                }
+
+                pendingScrollOperation = PendingScrollOperation.None;
             }
         }
 
@@ -844,7 +849,7 @@ namespace osu.Game.Screens.Select
         /// <param name="parent">For nested items, the parent of the item to be updated.</param>
         private void updateItem(DrawableCarouselItem item, DrawableCarouselItem parent = null)
         {
-            Vector2 posInScroll = ScrollableContent.ToLocalSpace(item.Header.ScreenSpaceDrawQuad.Centre);
+            Vector2 posInScroll = Scroll.ScrollContent.ToLocalSpace(item.Header.ScreenSpaceDrawQuad.Centre);
             float itemDrawY = posInScroll.Y - visibleUpperBound;
             float dist = Math.Abs(1f - itemDrawY / visibleHalfHeight);
 
@@ -858,6 +863,13 @@ namespace osu.Game.Screens.Select
             item.SetMultiplicativeAlpha(Math.Clamp(1.75f - 1.5f * dist, 0, 1));
         }
 
+        private enum PendingScrollOperation
+        {
+            None,
+            Standard,
+            Immediate,
+        }
+
         /// <summary>
         /// A carousel item strictly used for binary search purposes.
         /// </summary>
@@ -889,7 +901,7 @@ namespace osu.Game.Screens.Select
             }
         }
 
-        private class CarouselScrollContainer : OsuScrollContainer
+        protected class CarouselScrollContainer : OsuScrollContainer<DrawableCarouselItem>
         {
             private bool rightMouseScrollBlocked;
 
@@ -898,6 +910,12 @@ namespace osu.Game.Screens.Select
             /// </summary>
             public bool UserScrolling { get; private set; }
 
+            public CarouselScrollContainer()
+            {
+                // size is determined by the carousel itself, due to not all content necessarily being loaded.
+                ScrollContent.AutoSizeAxes = Axes.None;
+            }
+
             // ReSharper disable once OptionalParameterHierarchyMismatch 2020.3 EAP4 bug. (https://youtrack.jetbrains.com/issue/RSRP-481535?p=RIDER-51910)
             protected override void OnUserScroll(float value, bool animated = true, double? distanceDecay = default)
             {

osu.Game/Screens/Select/Carousel/DrawableCarouselBeatmapSet.cs

@@ -10,6 +10,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Cursor;
 using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Utils;
 using osu.Game.Beatmaps;
 using osu.Game.Collections;
 using osu.Game.Graphics.UserInterface;
@@ -60,6 +61,25 @@ namespace osu.Game.Screens.Select.Carousel
                 viewDetails = beatmapOverlay.FetchAndShowBeatmapSet;
         }
 
+        protected override void Update()
+        {
+            base.Update();
+
+            // position updates should not occur if the item is filtered away.
+            // this avoids panels flying across the screen only to be eventually off-screen or faded out.
+            if (!Item.Visible)
+                return;
+
+            float targetY = Item.CarouselYPosition;
+
+            if (Precision.AlmostEquals(targetY, Y))
+                Y = targetY;
+            else
+                // algorithm for this is taken from ScrollContainer.
+                // while it doesn't necessarily need to match 1:1, as we are emulating scroll in some cases this feels most correct.
+                Y = (float)Interpolation.Lerp(targetY, Y, Math.Exp(-0.01 * Time.Elapsed));
+        }
+
         protected override void UpdateItem()
         {
             base.UpdateItem();

osu.Game/osu.Game.csproj

@@ -26,7 +26,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.2.6" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite.Core" Version="2.2.6" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
-    <PackageReference Include="ppy.osu.Framework" Version="2020.1120.0" />
+    <PackageReference Include="ppy.osu.Framework" Version="2020.1127.0" />
     <PackageReference Include="ppy.osu.Game.Resources" Version="2020.1030.0" />
     <PackageReference Include="Sentry" Version="2.1.6" />
     <PackageReference Include="SharpCompress" Version="0.26.0" />

osu.iOS.props

@@ -70,7 +70,7 @@
     <Reference Include="System.Net.Http" />
   </ItemGroup>
   <ItemGroup Label="Package References">
-    <PackageReference Include="ppy.osu.Framework.iOS" Version="2020.1120.0" />
+    <PackageReference Include="ppy.osu.Framework.iOS" Version="2020.1127.0" />
     <PackageReference Include="ppy.osu.Game.Resources" Version="2020.1030.0" />
   </ItemGroup>
   <!-- See https://github.com/dotnet/runtime/issues/35988 (can be removed after Xamarin uses net5.0 / net6.0) -->
@@ -88,7 +88,7 @@
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="2.2.6" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite.Core" Version="2.2.6" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
-    <PackageReference Include="ppy.osu.Framework" Version="2020.1120.0" />
+    <PackageReference Include="ppy.osu.Framework" Version="2020.1127.0" />
     <PackageReference Include="SharpCompress" Version="0.26.0" />
     <PackageReference Include="NUnit" Version="3.12.0" />
     <PackageReference Include="SharpRaven" Version="2.4.0" />