Merge pull request #750 from Unity-Technologies/load-rt-when-viewport-used

Update RuntimeUtilities.cs

Author: Chman

PostProcessing/Runtime/Utils/RuntimeUtilities.cs

@@ -14,6 +14,8 @@ namespace UnityEngine.Rendering.PostProcessing
 {
     using SceneManagement;
     using UnityObject = UnityEngine.Object;
+    using LoadAction = RenderBufferLoadAction;
+    using StoreAction = RenderBufferStoreAction;
 
     /// <summary>
     /// A set of runtime utilities used by the post-processing stack.
@@ -200,7 +202,7 @@ public static Texture2D GetLutStrip(int size)
                 var format = TextureFormat.RGBAHalf;
                 if (!format.IsSupported())
                     format = TextureFormat.ARGB32;
-                    
+
                 texture = new Texture2D(size * size, size, format, false, true)
                 {
                     name = "Strip Lut" + size,
@@ -431,7 +433,7 @@ public static void SetRenderTargetWithLoadStoreAction(this CommandBuffer cmd,
         public static void BlitFullscreenTriangle(this CommandBuffer cmd, RenderTargetIdentifier source, RenderTargetIdentifier destination, bool clear = false, Rect? viewport = null)
         {
             cmd.SetGlobalTexture(ShaderIDs.MainTex, source);
-            cmd.SetRenderTargetWithLoadStoreAction(destination, RenderBufferLoadAction.DontCare, RenderBufferStoreAction.Store);
+            cmd.SetRenderTargetWithLoadStoreAction(destination, viewport == null ? LoadAction.DontCare : LoadAction.Load, StoreAction.Store);
 
             if (viewport != null)
                 cmd.SetViewport(viewport.Value);
@@ -456,11 +458,13 @@ public static void BlitFullscreenTriangle(this CommandBuffer cmd, RenderTargetId
         {
             cmd.SetGlobalTexture(ShaderIDs.MainTex, source);
             #if UNITY_2018_2_OR_NEWER
-            bool clear = (loadAction == RenderBufferLoadAction.Clear);
+            bool clear = (loadAction == LoadAction.Clear);
+            if(clear)
+                loadAction = LoadAction.DontCare;
             #else
             bool clear = false;
             #endif
-            cmd.SetRenderTargetWithLoadStoreAction(destination, clear ? RenderBufferLoadAction.DontCare : loadAction, RenderBufferStoreAction.Store);
+            cmd.SetRenderTargetWithLoadStoreAction(destination, viewport == null ? loadAction : LoadAction.Load, StoreAction.Store);
 
             if (viewport != null)
                 cmd.SetViewport(viewport.Value);
@@ -484,10 +488,10 @@ public static void BlitFullscreenTriangle(this CommandBuffer cmd, RenderTargetId
         public static void BlitFullscreenTriangle(this CommandBuffer cmd, RenderTargetIdentifier source, RenderTargetIdentifier destination, PropertySheet propertySheet, int pass, bool clear = false, Rect? viewport = null)
         {
             #if UNITY_2018_2_OR_NEWER
-            cmd.BlitFullscreenTriangle(source, destination, propertySheet, pass, clear ? RenderBufferLoadAction.Clear : RenderBufferLoadAction.DontCare, viewport);
+            cmd.BlitFullscreenTriangle(source, destination, propertySheet, pass, clear ? LoadAction.Clear : LoadAction.DontCare, viewport);
             #else
             cmd.SetGlobalTexture(ShaderIDs.MainTex, source);
-            cmd.SetRenderTargetWithLoadStoreAction(destination, RenderBufferLoadAction.DontCare, RenderBufferStoreAction.Store);
+            cmd.SetRenderTargetWithLoadStoreAction(destination, viewport == null ? LoadAction.DontCare : LoadAction.Load, StoreAction.Store);
 
             if (viewport != null)
                 cmd.SetViewport(viewport.Value);
@@ -597,17 +601,16 @@ public static void BlitFullscreenTriangleToTexArray(this CommandBuffer cmd, Rend
         public static void BlitFullscreenTriangle(this CommandBuffer cmd, RenderTargetIdentifier source, RenderTargetIdentifier destination, RenderTargetIdentifier depth, PropertySheet propertySheet, int pass, bool clear = false, Rect? viewport = null)
         {
             cmd.SetGlobalTexture(ShaderIDs.MainTex, source);
-            
+
+            LoadAction loadAction = viewport == null ? LoadAction.DontCare : LoadAction.Load;
             if (clear)
             {
-                cmd.SetRenderTargetWithLoadStoreAction(destination, RenderBufferLoadAction.DontCare, RenderBufferStoreAction.Store,
-                                                       depth, RenderBufferLoadAction.DontCare, RenderBufferStoreAction.Store);
+                cmd.SetRenderTargetWithLoadStoreAction(destination, loadAction, StoreAction.Store, depth, loadAction, StoreAction.Store);
                 cmd.ClearRenderTarget(true, true, Color.clear);
             }
             else
             {
-                cmd.SetRenderTargetWithLoadStoreAction(destination, RenderBufferLoadAction.DontCare, RenderBufferStoreAction.Store,
-                                                       depth, RenderBufferLoadAction.Load, RenderBufferStoreAction.Store);
+                cmd.SetRenderTargetWithLoadStoreAction(destination, loadAction, StoreAction.Store, depth, LoadAction.Load, StoreAction.Store);
             }
 
             if (viewport != null)