From b0415dc30abb7aec345c535988097be14446271b Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Tue, 16 Jul 2019 17:33:14 +0900
Subject: [PATCH 1/2] Remove cursortrail drawnode allocs

---
 .../UI/Cursor/CursorTrail.cs                  | 33 ++++++++++++++-----
 1 file changed, 24 insertions(+), 9 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs b/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
index b986076593..6a70728c50 100644
--- a/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
+++ b/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
@@ -162,7 +162,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             private readonly TrailPart[] parts = new TrailPart[max_sprites];
             private Vector2 size;
 
-            private readonly VertexBatch<TexturedTrailVertex> vertexBatch = new QuadBatch<TexturedTrailVertex>(max_sprites, 1);
+            private readonly CustomBatch vertexBatch = new CustomBatch(max_sprites, 1);
 
             public TrailDrawNode(CursorTrail source)
                 : base(source)
@@ -197,20 +197,14 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
                 for (int i = 0; i < parts.Length; ++i)
                 {
                     Vector2 pos = parts[i].Position;
-                    float localTime = parts[i].Time;
+                    vertexBatch.DrawTime = parts[i].Time;
 
                     DrawQuad(
                         texture,
                         new Quad(pos.X - size.X / 2, pos.Y - size.Y / 2, size.X, size.Y),
                         DrawColourInfo.Colour,
                         null,
-                        v => vertexBatch.Add(new TexturedTrailVertex
-                        {
-                            Position = v.Position,
-                            TexturePosition = v.TexturePosition,
-                            Time = localTime + 1,
-                            Colour = v.Colour,
-                        }));
+                        vertexBatch.AddAction);
                 }
 
                 shader.Unbind();
@@ -222,6 +216,27 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                 vertexBatch.Dispose();
             }
+
+            private class CustomBatch : QuadBatch<TexturedTrailVertex>
+            {
+                public new readonly Action<TexturedVertex2D> AddAction;
+
+                public float DrawTime;
+
+                public CustomBatch(int size, int maxBuffers)
+                    : base(size, maxBuffers)
+                {
+                    AddAction = add;
+                }
+
+                private void add(TexturedVertex2D vertex) => Add(new TexturedTrailVertex
+                {
+                    Position = vertex.Position,
+                    TexturePosition = vertex.TexturePosition,
+                    Time = DrawTime + 1,
+                    Colour = vertex.Colour,
+                });
+            }
         }
 
         [StructLayout(LayoutKind.Sequential)]

From 62b867018d555d6c034ce00991768bb35bcc2338 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Tue, 16 Jul 2019 17:50:03 +0900
Subject: [PATCH 2/2] Refactor a bit

---
 .../UI/Cursor/CursorTrail.cs                  | 27 +++++++++----------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs b/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
index 6a70728c50..05eb0ffdbf 100644
--- a/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
+++ b/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
@@ -162,7 +162,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             private readonly TrailPart[] parts = new TrailPart[max_sprites];
             private Vector2 size;
 
-            private readonly CustomBatch vertexBatch = new CustomBatch(max_sprites, 1);
+            private readonly TrailBatch vertexBatch = new TrailBatch(max_sprites, 1);
 
             public TrailDrawNode(CursorTrail source)
                 : base(source)
@@ -196,9 +196,10 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                 for (int i = 0; i < parts.Length; ++i)
                 {
-                    Vector2 pos = parts[i].Position;
                     vertexBatch.DrawTime = parts[i].Time;
 
+                    Vector2 pos = parts[i].Position;
+
                     DrawQuad(
                         texture,
                         new Quad(pos.X - size.X / 2, pos.Y - size.Y / 2, size.X, size.Y),
@@ -217,25 +218,23 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
                 vertexBatch.Dispose();
             }
 
-            private class CustomBatch : QuadBatch<TexturedTrailVertex>
+            // Todo: This shouldn't exist, but is currently used to reduce allocations by caching variable-capturing closures.
+            private class TrailBatch : QuadBatch<TexturedTrailVertex>
             {
                 public new readonly Action<TexturedVertex2D> AddAction;
-
                 public float DrawTime;
 
-                public CustomBatch(int size, int maxBuffers)
+                public TrailBatch(int size, int maxBuffers)
                     : base(size, maxBuffers)
                 {
-                    AddAction = add;
+                    AddAction = v => Add(new TexturedTrailVertex
+                    {
+                        Position = v.Position,
+                        TexturePosition = v.TexturePosition,
+                        Time = DrawTime + 1,
+                        Colour = v.Colour,
+                    });
                 }
-
-                private void add(TexturedVertex2D vertex) => Add(new TexturedTrailVertex
-                {
-                    Position = vertex.Position,
-                    TexturePosition = vertex.TexturePosition,
-                    Time = DrawTime + 1,
-                    Colour = vertex.Colour,
-                });
             }
         }