From 47c9807f2fd069c09a4f4e65bdc8054391dcca78 Mon Sep 17 00:00:00 2001
From: SolidAlloy <perepelartem@gmail.com>
Date: Sun, 21 Feb 2021 18:30:54 +0200
Subject: [PATCH] Started caching materials and moved texture-changing methods
 to TextureHelper

This shaved off 10-20 more ms.
---
 Editor/Icons/HierarchyFolderIcon.cs | 49 ++--------------------
 Editor/Icons/TextureHelper.cs       | 65 ++++++++++++++++++++++++++++-
 2 files changed, 67 insertions(+), 47 deletions(-)

diff --git a/Editor/Icons/HierarchyFolderIcon.cs b/Editor/Icons/HierarchyFolderIcon.cs
index 3f161bd..6286677 100644
--- a/Editor/Icons/HierarchyFolderIcon.cs
+++ b/Editor/Icons/HierarchyFolderIcon.cs
@@ -7,7 +7,6 @@
 using UnityEditor;
 using UnityEditor.IMGUI.Controls;
 using UnityEngine;
-using UnityEngine.Experimental.Rendering;
 using UnityHierarchyFolders.Runtime;
 using Object = UnityEngine.Object;
 
@@ -74,46 +73,6 @@ private static void Startup()
             EditorApplication.hierarchyWindowItemOnGUI += RefreshFolderIcons;
         }
 
-        private static Texture2D GetTintedTexture(Texture2D original, Color tint, string name)
-        {
-            var material = new Material(Shader.Find("UI/Default")) { color = tint };
-            return GetTextureWithMaterial(original, material, name);
-        }
-
-        private static Texture2D GetWhiteTexture(Texture2D original, string name)
-        {
-            var material = new Material(Shader.Find("UI/Replace color")) { color = Color.white };
-            return GetTextureWithMaterial(original, material, name);
-        }
-
-        private static Texture2D GetTextureWithMaterial(Texture2D original, Material material, string name)
-        {
-            Texture2D newTexture;
-
-            using (new TextureHelper.SRGBWriteScope(true))
-            {
-                using (var temporary = new TextureHelper.TemporaryActiveTexture(original.width, original.height, 0))
-                {
-                    GL.Clear(false, true, new Color(1f, 1f, 1f, 0f));
-
-                    Graphics.Blit(original, temporary, material);
-
-                    newTexture = new Texture2D(original.width, original.width, TextureFormat.ARGB32, false, true)
-                    {
-                        name = name,
-                        filterMode = FilterMode.Bilinear,
-                        hideFlags = HideFlags.DontSave
-                    };
-
-                    newTexture.ReadPixels(new Rect(0.0f, 0.0f, original.width, original.width), 0, 0);
-                    newTexture.alphaIsTransparency = true;
-                    newTexture.Apply();
-                }
-            }
-
-            return newTexture;
-        }
-
         private static void InitIfNeeded()
         {
             if (_isInitialized) { return; }
@@ -124,8 +83,8 @@ private static void InitIfNeeded()
             // We could use the actual white folder icons but I prefer the look of the tinted white folder icon
             // To use the actual white version:
             // texture = (Texture2D) EditorGUIUtility.IconContent($"{OpenedFolderPrefix | ClosedFolderPrefix} On Icon").image;
-            _openFolderSelectedTexture = GetWhiteTexture(_openFolderTexture, $"{_openedFolderPrefix} Icon White");
-            _closedFolderSelectedTexture = GetWhiteTexture(_closedFolderTexture, $"{_closedFolderPrefix} Icon White");
+            _openFolderSelectedTexture = TextureHelper.GetWhiteTexture(_openFolderTexture, $"{_openedFolderPrefix} Icon White");
+            _closedFolderSelectedTexture = TextureHelper.GetWhiteTexture(_closedFolderTexture, $"{_closedFolderPrefix} Icon White");
 
             _coloredFolderIcons = new (Texture2D, Texture2D)[] { (_openFolderTexture, _closedFolderTexture) };
 
@@ -136,9 +95,9 @@ private static void InitIfNeeded()
                     int index = 1 + column + row * IconColumnCount;
                     var color = IconColors[column, row];
 
-                    var openFolderIcon = GetTintedTexture(_openFolderSelectedTexture,
+                    var openFolderIcon = TextureHelper.GetTintedTexture(_openFolderSelectedTexture,
                         color, $"{_openFolderSelectedTexture.name} {index}");
-                    var closedFolderIcon = GetTintedTexture(_closedFolderSelectedTexture,
+                    var closedFolderIcon = TextureHelper.GetTintedTexture(_closedFolderSelectedTexture,
                         color, $"{_closedFolderSelectedTexture.name} {index}");
 
                     ArrayUtility.Add(ref _coloredFolderIcons, (openFolderIcon, closedFolderIcon));
diff --git a/Editor/Icons/TextureHelper.cs b/Editor/Icons/TextureHelper.cs
index a38bbea..5ca3ad7 100644
--- a/Editor/Icons/TextureHelper.cs
+++ b/Editor/Icons/TextureHelper.cs
@@ -12,8 +12,69 @@ namespace UnityHierarchyFolders.Editor
     using UnityEngine;
 
     /// <summary>Helps to create new textures.</summary>
-    public static class TextureHelper
+    internal static class TextureHelper
     {
+        private static readonly Color _fullyTransparent = new Color(1f, 1f, 1f, 0f);
+
+        private static Material _tintMaterial;
+        private static Material _colorReplaceMaterial;
+
+        public static Texture2D GetTintedTexture(Texture2D original, Color tint, string name)
+        {
+            return GetTextureWithMaterial(original, GetTintMaterial(tint), name);
+        }
+
+        public static Texture2D GetWhiteTexture(Texture2D original, string name)
+        {
+            return GetTextureWithMaterial(original, GetColorReplaceMaterial(Color.white), name);
+        }
+
+        private static Material GetTintMaterial(Color tint)
+        {
+            if (_tintMaterial == null)
+                _tintMaterial = new Material(Shader.Find("UI/Default"));
+
+            _tintMaterial.color = tint;
+            return _tintMaterial;
+        }
+
+        private static Material GetColorReplaceMaterial(Color color)
+        {
+            if (_colorReplaceMaterial == null)
+                _colorReplaceMaterial = new Material(Shader.Find("UI/Replace color"));
+
+            _colorReplaceMaterial.color = color;
+            return _colorReplaceMaterial;
+        }
+
+        private static Texture2D GetTextureWithMaterial(Texture2D original, Material material, string name)
+        {
+            Texture2D newTexture;
+
+            using (new SRGBWriteScope(true))
+            {
+                using (var temporary = new TemporaryActiveTexture(original.width, original.height, 0))
+                {
+                    GL.Clear(false, true, _fullyTransparent);
+
+                    Graphics.Blit(original, temporary, material);
+
+                    newTexture = new Texture2D(original.width, original.width, TextureFormat.ARGB32, false, true)
+                    {
+                        name = name,
+                        filterMode = FilterMode.Bilinear,
+                        hideFlags = HideFlags.DontSave
+                    };
+
+                    newTexture.ReadPixels(new Rect(0f, 0f, original.width, original.width), 0, 0);
+                    newTexture.alphaIsTransparency = true;
+                    newTexture.Apply();
+                }
+            }
+
+            return newTexture;
+        }
+
         /// <summary>
         /// Temporarily sets <see cref="GL.sRGBWrite"/> to the passed value, then returns it back.
         /// </summary>
@@ -22,7 +83,7 @@ public static class TextureHelper
         {
             private readonly bool _previousValue;
 
-            /// <summary>Temporarily sets <see cref="GL.sRGBWrite"/> to <paramref name=""/>, then executes the action.</summary>
+            /// <summary>Temporarily sets <see cref="GL.sRGBWrite"/> to <c>true</c>, then executes the action.</summary>
             /// <param name="enableWrite"> Temporary value of <see cref="GL.sRGBWrite"/>. </param>
             /// <example><code>
             /// using (new SRGBWriteScope(true))