]Fixed CustomPassUtils scaling issues when used with RTHandles allocated from a RenderTexture. (#4140)

* Fixed custom pass scaling issues when using RTHandles allocated from a RenderTexture

* Updated changelog

Co-authored-by: sebastienlagarde <sebastien@unity3d.com>

Author: alelievr

com.unity.render-pipelines.core/Runtime/Textures/RTHandle.cs

@@ -155,6 +155,9 @@ public void Release()
         /// <returns>Input size scaled by the RTHandle scale factor.</returns>
         public Vector2Int GetScaledSize(Vector2Int refSize)
         {
+            if (!useScaling)
+                return refSize;
+
             if (scaleFunc != null)
             {
                 return scaleFunc(refSize);

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -154,6 +154,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed GBuffer clear option in FrameSettings not working
 - Fixed usage of Panini Projection with floating point HDRP and Post Processing color buffers.
 - Fixed a NaN generating in Area light code.
+- Fixed CustomPassUtils scaling issues when used with RTHandles allocated from a RenderTexture.
 
 ### Changed
 - Changed Window/Render Pipeline/HD Render Pipeline Wizard to Window/Rendering/HDRP Wizard

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/RenderPass/CustomPass/CustomPassUtils.cs

@@ -569,7 +569,11 @@ internal static void SetRenderTargetWithScaleBias(in CustomPassContext ctx, Mate
         {
             // viewport with RT handle scale and scale factor:
             Rect viewport = new Rect();
-            Vector2 destSize = viewport.size = destination.GetScaledSize(destination.rtHandleProperties.currentViewportSize);
+            if (destination.useScaling)
+                viewport.size = destination.GetScaledSize(destination.rtHandleProperties.currentViewportSize);
+            else
+                viewport.size = new Vector2Int(destination.rt.width, destination.rt.height);
+            Vector2 destSize = viewport.size;
             viewport.position = new Vector2(viewport.size.x * destScaleBias.z, viewport.size.y * destScaleBias.w);
             viewport.size *= new Vector2(destScaleBias.x, destScaleBias.y);