Implement disjoint (old style) cursor trail (#6046)

Implement disjoint (old style) cursor trail

Co-authored-by: Dean Herbert <pe@ppy.sh>

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

@@ -0,0 +1,128 @@
+// 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.Allocation;
+using osu.Framework.Audio.Sample;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Textures;
+using osu.Framework.Testing.Input;
+using osu.Game.Audio;
+using osu.Game.Rulesets.Osu.Skinning;
+using osu.Game.Rulesets.Osu.UI.Cursor;
+using osu.Game.Skinning;
+using osu.Game.Tests.Visual;
+using osuTK;
+
+namespace osu.Game.Rulesets.Osu.Tests
+{
+    public class TestSceneCursorTrail : OsuTestScene
+    {
+        [Test]
+        public void TestSmoothCursorTrail()
+        {
+            Container scalingContainer = null;
+
+            createTest(() => scalingContainer = new Container
+            {
+                RelativeSizeAxes = Axes.Both,
+                Child = new CursorTrail()
+            });
+
+            AddStep("set large scale", () => scalingContainer.Scale = new Vector2(10));
+        }
+
+        [Test]
+        public void TestLegacySmoothCursorTrail()
+        {
+            createTest(() => new LegacySkinContainer(false)
+            {
+                Child = new LegacyCursorTrail()
+            });
+        }
+
+        [Test]
+        public void TestLegacyDisjointCursorTrail()
+        {
+            createTest(() => new LegacySkinContainer(true)
+            {
+                Child = new LegacyCursorTrail()
+            });
+        }
+
+        private void createTest(Func<Drawable> createContent) => AddStep("create trail", () =>
+        {
+            Clear();
+
+            Add(new Container
+            {
+                RelativeSizeAxes = Axes.Both,
+                Size = new Vector2(0.8f),
+                Child = new MovingCursorInputManager { Child = createContent?.Invoke() }
+            });
+        });
+
+        [Cached(typeof(ISkinSource))]
+        private class LegacySkinContainer : Container, ISkinSource
+        {
+            private readonly bool disjoint;
+
+            public LegacySkinContainer(bool disjoint)
+            {
+                this.disjoint = disjoint;
+
+                RelativeSizeAxes = Axes.Both;
+            }
+
+            public Drawable GetDrawableComponent(ISkinComponent component) => throw new NotImplementedException();
+
+            public Texture GetTexture(string componentName)
+            {
+                switch (componentName)
+                {
+                    case "cursortrail":
+                        var tex = new Texture(Texture.WhitePixel.TextureGL);
+
+                        if (disjoint)
+                            tex.ScaleAdjust = 1 / 25f;
+                        return tex;
+
+                    case "cursormiddle":
+                        return disjoint ? null : Texture.WhitePixel;
+                }
+
+                return null;
+            }
+
+            public SampleChannel GetSample(ISampleInfo sampleInfo) => throw new NotImplementedException();
+
+            public IBindable<TValue> GetConfig<TLookup, TValue>(TLookup lookup) => throw new NotImplementedException();
+
+            public event Action SourceChanged;
+        }
+
+        private class MovingCursorInputManager : ManualInputManager
+        {
+            public MovingCursorInputManager()
+            {
+                UseParentInput = false;
+            }
+
+            protected override void Update()
+            {
+                base.Update();
+
+                const double spin_duration = 1000;
+                double currentTime = Time.Current;
+
+                double angle = (currentTime % spin_duration) / spin_duration * 2 * Math.PI;
+                Vector2 rPos = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle));
+
+                MoveMouseTo(ToScreenSpace(DrawSize / 2 + DrawSize / 3 * rPos));
+            }
+        }
+    }
+}

osu.Game.Rulesets.Osu/OsuSkinComponents.cs

@@ -8,6 +8,7 @@ namespace osu.Game.Rulesets.Osu
         HitCircle,
         FollowPoint,
         Cursor,
+        CursorTrail,
         SliderScorePoint,
         ApproachCircle,
         ReverseArrow,

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

@@ -0,0 +1,55 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Input.Events;
+using osu.Game.Rulesets.Osu.UI.Cursor;
+using osu.Game.Skinning;
+
+namespace osu.Game.Rulesets.Osu.Skinning
+{
+    public class LegacyCursorTrail : CursorTrail
+    {
+        private const double disjoint_trail_time_separation = 1000 / 60.0;
+
+        private bool disjointTrail;
+        private double lastTrailTime;
+
+        public LegacyCursorTrail()
+        {
+            Blending = BlendingParameters.Additive;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(ISkinSource skin)
+        {
+            Texture = skin.GetTexture("cursortrail");
+            disjointTrail = skin.GetTexture("cursormiddle") == null;
+
+            if (Texture != null)
+            {
+                // stable "magic ratio". see OsuPlayfieldAdjustmentContainer for full explanation.
+                Texture.ScaleAdjust *= 1.6f;
+            }
+        }
+
+        protected override double FadeDuration => disjointTrail ? 150 : 500;
+
+        protected override bool InterpolateMovements => !disjointTrail;
+
+        protected override bool OnMouseMove(MouseMoveEvent e)
+        {
+            if (!disjointTrail)
+                return base.OnMouseMove(e);
+
+            if (Time.Current - lastTrailTime >= disjoint_trail_time_separation)
+            {
+                lastTrailTime = Time.Current;
+                return base.OnMouseMove(e);
+            }
+
+            return false;
+        }
+    }
+}

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

@@ -78,6 +78,12 @@ namespace osu.Game.Rulesets.Osu.Skinning
 
                     return null;
 
+                case OsuSkinComponents.CursorTrail:
+                    if (source.GetTexture("cursortrail") != null)
+                        return new LegacyCursorTrail();
+
+                    return null;
+
                 case OsuSkinComponents.HitCircleText:
                     var font = GetConfig<OsuSkinConfiguration, string>(OsuSkinConfiguration.HitCirclePrefix)?.Value ?? "default";
                     var overlap = GetConfig<OsuSkinConfiguration, float>(OsuSkinConfiguration.HitCircleOverlap)?.Value ?? 0;

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.Caching;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Batches;
 using osu.Framework.Graphics.OpenGL.Vertices;
@@ -20,14 +21,13 @@ using osuTK.Graphics.ES30;
 
 namespace osu.Game.Rulesets.Osu.UI.Cursor
 {
-    internal class CursorTrail : Drawable, IRequireHighFrequencyMousePosition
+    public class CursorTrail : Drawable, IRequireHighFrequencyMousePosition
     {
         private const int max_sprites = 2048;
 
         private readonly TrailPart[] parts = new TrailPart[max_sprites];
         private int currentIndex;
         private IShader shader;
-        private Texture texture;
         private double timeOffset;
         private float time;
 
@@ -47,11 +47,9 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
         }
 
         [BackgroundDependencyLoader]
-        private void load(ShaderManager shaders, TextureStore textures)
+        private void load(ShaderManager shaders)
         {
             shader = shaders.Load(@"CursorTrail", FragmentShaderDescriptor.TEXTURE);
-            texture = textures.Get(@"Cursor/cursortrail");
-            Scale = new Vector2(1 / texture.ScaleAdjust);
         }
 
         protected override void LoadComplete()
@@ -60,6 +58,40 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             resetTime();
         }
 
+        private Texture texture = Texture.WhitePixel;
+
+        public Texture Texture
+        {
+            get => texture;
+            set
+            {
+                if (texture == value)
+                    return;
+
+                texture = value;
+                Invalidate(Invalidation.DrawNode);
+            }
+        }
+
+        private readonly Cached<Vector2> partSizeCache = new Cached<Vector2>();
+
+        private Vector2 partSize => partSizeCache.IsValid
+            ? partSizeCache.Value
+            : (partSizeCache.Value = new Vector2(Texture.DisplayWidth, Texture.DisplayHeight) * DrawInfo.Matrix.ExtractScale().Xy);
+
+        public override bool Invalidate(Invalidation invalidation = Invalidation.All, Drawable source = null, bool shallPropagate = true)
+        {
+            if ((invalidation & (Invalidation.DrawInfo | Invalidation.RequiredParentSizeToFit | Invalidation.Presence)) > 0)
+                partSizeCache.Invalidate();
+
+            return base.Invalidate(invalidation, source, shallPropagate);
+        }
+
+        /// <summary>
+        /// The amount of time to fade the cursor trail pieces.
+        /// </summary>
+        protected virtual double FadeDuration => 300;
+
         public override bool IsPresent => true;
 
         protected override void Update()
@@ -70,7 +102,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
             const int fade_clock_reset_threshold = 1000000;
 
-            time = (float)(Time.Current - timeOffset) / 300f;
+            time = (float)((Time.Current - timeOffset) / FadeDuration);
             if (time > fade_clock_reset_threshold)
                 resetTime();
         }
@@ -87,7 +119,10 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             timeOffset = Time.Current;
         }
 
-        private Vector2 size => texture.Size * Scale;
+        /// <summary>
+        /// Whether to interpolate mouse movements and add trail pieces at intermediate points.
+        /// </summary>
+        protected virtual bool InterpolateMovements => true;
 
         private Vector2? lastPosition;
         private readonly InputResampler resampler = new InputResampler();
@@ -109,29 +144,41 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             {
                 Trace.Assert(lastPosition.HasValue);
 
-                // ReSharper disable once PossibleInvalidOperationException
+                if (InterpolateMovements)
-                Vector2 pos1 = lastPosition.Value;
-                Vector2 diff = pos2 - pos1;
-                float distance = diff.Length;
-                Vector2 direction = diff / distance;
-
-                float interval = size.X / 2 * 0.9f;
-
-                for (float d = interval; d < distance; d += interval)
                 {
-                    lastPosition = pos1 + direction * d;
+                    // ReSharper disable once PossibleInvalidOperationException
+                    Vector2 pos1 = lastPosition.Value;
+                    Vector2 diff = pos2 - pos1;
+                    float distance = diff.Length;
+                    Vector2 direction = diff / distance;
 
-                    parts[currentIndex].Position = lastPosition.Value;
+                    float interval = partSize.X / 2.5f;
-                    parts[currentIndex].Time = time;
-                    ++parts[currentIndex].InvalidationID;
 
-                    currentIndex = (currentIndex + 1) % max_sprites;
+                    for (float d = interval; d < distance; d += interval)
+                    {
+                        lastPosition = pos1 + direction * d;
+                        addPart(lastPosition.Value);
+                    }
+                }
+                else
+                {
+                    lastPosition = pos2;
+                    addPart(lastPosition.Value);
                 }
             }
 
             return base.OnMouseMove(e);
         }
 
+        private void addPart(Vector2 screenSpacePosition)
+        {
+            parts[currentIndex].Position = screenSpacePosition;
+            parts[currentIndex].Time = time;
+            ++parts[currentIndex].InvalidationID;
+
+            currentIndex = (currentIndex + 1) % max_sprites;
+        }
+
         protected override DrawNode CreateDrawNode() => new TrailDrawNode(this);
 
         private struct TrailPart
@@ -168,7 +215,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                 shader = Source.shader;
                 texture = Source.texture;
-                size = Source.size;
+                size = Source.partSize;
                 time = Source.time;
 
                 for (int i = 0; i < Source.parts.Length; ++i)

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

@@ -6,9 +6,12 @@ using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Textures;
 using osu.Framework.Input.Bindings;
 using osu.Game.Rulesets.Osu.Configuration;
 using osu.Game.Rulesets.UI;
+using osu.Game.Skinning;
+using osuTK;
 
 namespace osu.Game.Rulesets.Osu.UI.Cursor
 {
@@ -22,17 +25,14 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
         private readonly Bindable<bool> showTrail = new Bindable<bool>(true);
 
-        private readonly CursorTrail cursorTrail;
+        private readonly Drawable cursorTrail;
 
         public OsuCursorContainer()
         {
             InternalChild = fadeContainer = new Container
             {
                 RelativeSizeAxes = Axes.Both,
-                Children = new Drawable[]
+                Child = cursorTrail = new SkinnableDrawable(new OsuSkinComponent(OsuSkinComponents.CursorTrail), _ => new DefaultCursorTrail(), confineMode: ConfineMode.NoScaling)
-                {
-                    cursorTrail = new CursorTrail { Depth = 1 }
-                }
             };
         }
 
@@ -98,5 +98,15 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             fadeContainer.FadeTo(0.05f, 450, Easing.OutQuint);
             ActiveCursor.ScaleTo(0.8f, 450, Easing.OutQuint);
         }
+
+        private class DefaultCursorTrail : CursorTrail
+        {
+            [BackgroundDependencyLoader]
+            private void load(TextureStore textures)
+            {
+                Texture = textures.Get(@"Cursor/cursortrail");
+                Scale = new Vector2(1 / Texture.ScaleAdjust);
+            }
+        }
     }
 }