From 524102951348592f84312bb946e1eb85b40298c7 Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 13 Aug 2021 10:27:26 +0900
Subject: [PATCH] Use new FadeExponent shader uniform

---
 .../Skinning/Legacy/LegacyCursorTrail.cs        |  6 ++----
 osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs  | 17 +++++++++++------
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursorTrail.cs b/osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursorTrail.cs
index f98d936b48..9493dc2ef1 100644
--- a/osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursorTrail.cs
+++ b/osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyCursorTrail.cs
@@ -5,7 +5,6 @@ using System;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Shaders;
 using osu.Framework.Input.Events;
 using osu.Game.Configuration;
 using osu.Game.Rulesets.Osu.UI.Cursor;
@@ -31,10 +30,8 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
         }
 
         [BackgroundDependencyLoader]
-        private void load(ShaderManager shaders, OsuConfigManager config)
+        private void load(OsuConfigManager config)
         {
-            Shader = shaders.Load(@"LegacyCursorTrail", FragmentShaderDescriptor.TEXTURE);
-
             Texture = skin.GetTexture("cursortrail");
             disjointTrail = skin.GetTexture("cursormiddle") == null;
 
@@ -60,6 +57,7 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
         }
 
         protected override double FadeDuration => disjointTrail ? 150 : 500;
+        protected override float FadeExponent => 1;
 
         protected override bool InterpolateMovements => !disjointTrail;
 
diff --git a/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs b/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
index 66a9302f5f..b05bf5c93e 100644
--- a/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
+++ b/osu.Game.Rulesets.Osu/UI/Cursor/CursorTrail.cs
@@ -26,11 +26,14 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
     {
         private const int max_sprites = 2048;
 
+        /// <summary>
+        /// An exponentiating factor to ease the trail fade.
+        /// </summary>
+        protected virtual float FadeExponent => 1.7f;
+
         private readonly TrailPart[] parts = new TrailPart[max_sprites];
         private int currentIndex;
-
-        protected IShader Shader;
-
+        private IShader shader;
         private double timeOffset;
         private float time;
 
@@ -65,7 +68,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
         [BackgroundDependencyLoader]
         private void load(ShaderManager shaders)
         {
-            Shader = shaders.Load(@"CursorTrail", FragmentShaderDescriptor.TEXTURE);
+            shader = shaders.Load(@"CursorTrail", FragmentShaderDescriptor.TEXTURE);
         }
 
         protected override void LoadComplete()
@@ -217,10 +220,10 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             private Texture texture;
 
             private float time;
+            private float fadeExponent;
 
             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);
@@ -234,10 +237,11 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
             {
                 base.ApplyState();
 
-                shader = Source.Shader;
+                shader = Source.shader;
                 texture = Source.texture;
                 size = Source.partSize;
                 time = Source.time;
+                fadeExponent = Source.FadeExponent;
 
                 originPosition = Vector2.Zero;
 
@@ -260,6 +264,7 @@ namespace osu.Game.Rulesets.Osu.UI.Cursor
 
                 shader.Bind();
                 shader.GetUniform<float>("g_FadeClock").UpdateValue(ref time);
+                shader.GetUniform<float>("g_FadeExponent").UpdateValue(ref fadeExponent);
 
                 texture.TextureGL.Bind();