Simplified prepare inputs shader and added a comment about the depth RT

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Runtime/Effects/Upscaling/PSSRUpscaler.cs

@@ -39,7 +39,7 @@ namespace UnityEngine.Rendering.PostProcessing
 			initParams.maxRenderHeight = (uint)config.MaxRenderSize.y;
 
 			CreateRenderTexture(ref _inputColor, "PSSR Input Color", config.MaxRenderSize, context.sourceFormat, true);
-			CreateRenderTexture(ref _inputDepth, "PSSR Input Depth", config.MaxRenderSize, GraphicsFormat.R32_SFloat, true);
+			CreateRenderTexture(ref _inputDepth, "PSSR Input Depth", config.MaxRenderSize, GraphicsFormat.R32_SFloat, true);	// TODO: this texture won't have tile mode kDepth, meaning PSSR doesn't detect it correctly. Is this a problem?
 			CreateRenderTexture(ref _inputMotionVectors, "PSSR Input Motion Vectors", config.MaxRenderSize, GraphicsFormat.R16G16_SFloat, true);
 			CreateRenderTexture(ref _outputColor, "PSSR Output Color", config.UpscaleSize, RenderTextureFormat.RGB111110Float);
 

Packages/com.unity.postprocessing@3.2.2/PostProcessing/Shaders/Builtins/PrepareInputs.compute

@@ -17,9 +17,9 @@ cbuffer Params: register(b0)
 };
 
 [numthreads(8, 8, 1)]
-void CS(uint2 GroupId: SV_GroupID, uint2 GroupThreadId: SV_GroupThreadID)
+void CS(uint3 dtid : SV_DispatchThreadID)
 {
-    uint2 InputPos = GroupId * uint2(8, 8) + GroupThreadId;
+    uint2 InputPos = dtid.xy;
 
     if (prepareColor) OutColor[InputPos] = InColor[InputPos];
     if (prepareDepth) OutDepth[InputPos] = InDepth[InputPos];