feat: cache modified material

Close #94

Scripts/ModifiedMaterial.cs

@@ -0,0 +1,74 @@
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace Coffee.UIParticleExtensions
+{
+    internal class ModifiedMaterial
+    {
+        private static readonly List<MatEntry> s_Entries = new List<MatEntry>();
+
+        public static Material Add(Material baseMat, Texture texture, int id)
+        {
+            MatEntry e;
+            for (var i = 0; i < s_Entries.Count; ++i)
+            {
+                e = s_Entries[i];
+                if (e.baseMat != baseMat || e.texture != texture || e.id != id) continue;
+                ++e.count;
+                return e.customMat;
+            }
+
+            e = new MatEntry();
+            e.count = 1;
+            e.baseMat = baseMat;
+            e.texture = texture;
+            e.id = id;
+            e.customMat = new Material(baseMat);
+            e.customMat.hideFlags = HideFlags.HideAndDontSave;
+            if (texture)
+                e.customMat.mainTexture = texture;
+            s_Entries.Add(e);
+            // Debug.LogFormat(">>>> ModifiedMaterial.Add -> count = {0} {1} {2} {3}", s_Entries.Count, baseMat, texture, id);
+            return e.customMat;
+        }
+
+        public static void Remove(Material customMat)
+        {
+            if (!customMat) return;
+
+            for (var i = 0; i < s_Entries.Count; ++i)
+            {
+                var e = s_Entries[i];
+                if (e.customMat != customMat) continue;
+                if (--e.count == 0)
+                {
+                    // Debug.LogFormat(">>>> ModifiedMaterial.Add -> count = {0} {1} {2} {3}", s_Entries.Count - 1, e.customMat, e.texture, e.id);
+                    DestroyImmediate(e.customMat);
+                    e.baseMat = null;
+                    e.texture = null;
+                    s_Entries.RemoveAt(i);
+                }
+
+                break;
+            }
+        }
+
+        private static void DestroyImmediate(Object obj)
+        {
+            if (!obj) return;
+            if (Application.isEditor)
+                Object.DestroyImmediate(obj);
+            else
+                Object.Destroy(obj);
+        }
+
+        private class MatEntry
+        {
+            public Material baseMat;
+            public Material customMat;
+            public int count;
+            public Texture texture;
+            public int id;
+        }
+    }
+}

Scripts/UIParticle.cs

@@ -48,6 +48,8 @@ public class UIParticle : MaskableGraphic
         private Vector3 _cachedPosition;
         private static readonly List<Material> s_TempMaterials = new List<Material>(2);
         private static MaterialPropertyBlock s_Mpb;
+        private static readonly List<Material> s_PrevMaskMaterials = new List<Material>();
+        private static readonly List<Material> s_PrevModifiedMaterials = new List<Material>();
 
 
         /// <summary>
@@ -210,21 +212,11 @@ public void RefreshParticles(GameObject root)
         protected override void UpdateMaterial()
         {
             // Clear mask materials.
-            for (var i = 0; i < _maskMaterials.Count; i++)
-            {
-                StencilMaterial.Remove(_maskMaterials[i]);
-                _maskMaterials[i] = null;
-            }
-
+            s_PrevMaskMaterials.AddRange(_maskMaterials);
             _maskMaterials.Clear();
 
             // Clear modified materials.
-            for (var i = 0; i < _modifiedMaterials.Count; i++)
-            {
-                DestroyImmediate(_modifiedMaterials[i]);
-                _modifiedMaterials[i] = null;
-            }
-
+            s_PrevModifiedMaterials.AddRange(_modifiedMaterials);
             _modifiedMaterials.Clear();
 
             // Recalculate stencil value.
@@ -240,6 +232,12 @@ protected override void UpdateMaterial()
             {
                 _activeMeshIndices = 0;
                 canvasRenderer.Clear();
+
+                foreach (var m in s_PrevMaskMaterials)
+                    StencilMaterial.Remove(m);
+
+                foreach (var m in s_PrevModifiedMaterials)
+                    ModifiedMaterial.Remove(m);
                 return;
             }
 
@@ -275,6 +273,12 @@ protected override void UpdateMaterial()
                     canvasRenderer.SetMaterial(mat, j++);
                 }
             }
+
+            foreach (var m in s_PrevMaskMaterials)
+                StencilMaterial.Remove(m);
+
+            foreach (var m in s_PrevModifiedMaterials)
+                ModifiedMaterial.Remove(m);
         }
 
         private Material GetModifiedMaterial(Material baseMaterial, Texture2D texture)
@@ -287,10 +291,9 @@ private Material GetModifiedMaterial(Material baseMaterial, Texture2D texture)
 
             if (texture == null && m_AnimatableProperties.Length == 0) return baseMaterial;
 
-            baseMaterial = new Material(baseMaterial);
+            var id = m_AnimatableProperties.Length == 0 ? 0 : GetInstanceID();
+            baseMaterial = ModifiedMaterial.Add(baseMaterial, texture, id);
             _modifiedMaterials.Add(baseMaterial);
-            if (texture)
-                baseMaterial.mainTexture = texture;
 
             return baseMaterial;
         }