Fix accumulation on DX11 (#1987)

* Fix accumulation on DX11

* Remove left-over line of code

* minor bugfix

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

Author: pmavridis

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

@@ -120,6 +120,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed the Ray-Tracing related Debug Display not working in render graph mode.
 - Fix nan in pbr sky
 - Fixed Light skin not properly applied on the LookDev when switching from Dark Skin (case 1278802)
+- Fixed accumulation on DX11
 
 ### Changed
 - Preparation pass for RTSSShadows to be supported by render graph.

com.unity.render-pipelines.high-definition/Documentation~/Accumulation.md

@@ -69,7 +69,7 @@ public class FrameManager : MonoBehaviour
     {
         RenderPipelineManager.beginFrameRendering -= PrepareSubFrameCallBack;
         HDRenderPipeline renderPipeline = RenderPipelineManager.currentPipeline as HDRenderPipeline;
-        renderPipeline.EndRecording();
+        renderPipeline?.EndRecording();
         m_Recording = false;
     }
 

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/Accumulation/Shaders/Accumulation.compute

@@ -4,8 +4,13 @@
 
 #pragma kernel KMain
 
+#pragma multi_compile _ INPUT_FROM_RADIANCE_TEXTURE
+
 // Inputs
+#ifdef INPUT_FROM_RADIANCE_TEXTURE
 TEXTURE2D_X(_RadianceTexture);
+#endif
+
 float4      _AccumulationWeights;
 int         _AccumulationNeedsExposure;
 uint        _AccumulationFrameIndex;
@@ -55,8 +60,12 @@ void KMain(uint3 dispatchThreadId : SV_DispatchThreadID)
         _CameraColorTextureRW[COORD_TEXTURE2D_X(currentPixelCoord)] = float4(_AccumulatedFrameTexture[COORD_TEXTURE2D_X(currentPixelCoord)].xyz * exposureMultiplier, 1.0);
     }
     else
-    {    
+    {
+#ifdef INPUT_FROM_RADIANCE_TEXTURE
         float4 color = _RadianceTexture[COORD_TEXTURE2D_X(dispatchThreadId.xy)];
+#else
+        float4 color = _CameraColorTextureRW[COORD_TEXTURE2D_X(dispatchThreadId.xy)];
+#endif
 
         if (sampleCount++)
             color.xyz = (_AccumulatedFrameTexture[COORD_TEXTURE2D_X(currentPixelCoord)].xyz * _AccumulationWeights.y + _AccumulationWeights.x * color.xyz) * _AccumulationWeights.z;

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/Accumulation/SubFrameManager.cs

@@ -291,7 +291,7 @@ struct RenderAccumulationParameters
             public HDCamera         hdCamera;
         }
 
-        RenderAccumulationParameters PrepareRenderAccumulationParameters(HDCamera hdCamera, bool needExposure)
+        RenderAccumulationParameters PrepareRenderAccumulationParameters(HDCamera hdCamera, bool needExposure, bool inputFromRadianceTexture)
         {
             var parameters = new RenderAccumulationParameters();
 
@@ -301,6 +301,11 @@ RenderAccumulationParameters PrepareRenderAccumulationParameters(HDCamera hdCame
             parameters.needExposure = needExposure;
             parameters.hdCamera = hdCamera;
 
+            parameters.accumulationCS.shaderKeywords = null;
+            if (inputFromRadianceTexture)
+            {
+                parameters.accumulationCS.EnableKeyword("INPUT_FROM_RADIANCE_TEXTURE");
+            }
             return parameters;
         }
 
@@ -310,7 +315,8 @@ void RenderAccumulation(HDCamera hdCamera, RTHandle inputTexture, RTHandle outpu
             RTHandle history = hdCamera.GetCurrentFrameRT((int)HDCameraFrameHistoryType.PathTracing)
                 ?? hdCamera.AllocHistoryFrameRT((int)HDCameraFrameHistoryType.PathTracing, PathTracingHistoryBufferAllocatorFunction, 1);
 
-            var parameters = PrepareRenderAccumulationParameters(hdCamera, needExposure);
+            bool inputFromRadianceTexture = !inputTexture.Equals(outputTexture);
+            var parameters = PrepareRenderAccumulationParameters(hdCamera, needExposure, inputFromRadianceTexture);
             RenderAccumulation(parameters, inputTexture, outputTexture, history, cmd);
         }
 
@@ -332,7 +338,10 @@ static void RenderAccumulation(in RenderAccumulationParameters parameters, RTHan
             cmd.SetComputeIntParam(accumulationShader, HDShaderIDs._AccumulationNumSamples, (int)parameters.subFrameManager.subFrameCount);
             cmd.SetComputeTextureParam(accumulationShader, parameters.accumulationKernel, HDShaderIDs._AccumulatedFrameTexture, historyTexture);
             cmd.SetComputeTextureParam(accumulationShader, parameters.accumulationKernel, HDShaderIDs._CameraColorTextureRW, outputTexture);
-            cmd.SetComputeTextureParam(accumulationShader, parameters.accumulationKernel, HDShaderIDs._RadianceTexture, inputTexture);
+            if (!inputTexture.Equals(outputTexture))
+            {
+                cmd.SetComputeTextureParam(accumulationShader, parameters.accumulationKernel, HDShaderIDs._RadianceTexture, inputTexture);
+            }
             cmd.SetComputeVectorParam(accumulationShader, HDShaderIDs._AccumulationWeights, frameWeights);
             cmd.SetComputeIntParam(accumulationShader, HDShaderIDs._AccumulationNeedsExposure, parameters.needExposure ? 1 : 0);
             cmd.DispatchCompute(accumulationShader, parameters.accumulationKernel, (parameters.hdCamera.actualWidth + 7) / 8, (parameters.hdCamera.actualHeight + 7) / 8, parameters.hdCamera.viewCount);

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/HDRenderPipeline.RenderGraph.cs

@@ -1383,7 +1383,8 @@ void RenderAccumulation(RenderGraph renderGraph, HDCamera hdCamera, TextureHandl
                 TextureHandle history = renderGraph.ImportTexture(hdCamera.GetCurrentFrameRT((int)HDCameraFrameHistoryType.PathTracing)
                     ?? hdCamera.AllocHistoryFrameRT((int)HDCameraFrameHistoryType.PathTracing, PathTracingHistoryBufferAllocatorFunction, 1));
 
-                passData.parameters = PrepareRenderAccumulationParameters(hdCamera, needExposure);
+                bool inputFromRadianceTexture = !inputTexture.Equals(outputTexture);
+                passData.parameters = PrepareRenderAccumulationParameters(hdCamera, needExposure, inputFromRadianceTexture);
                 passData.input = builder.ReadTexture(inputTexture);
                 passData.output = builder.WriteTexture(outputTexture);
                 passData.history = builder.WriteTexture(history);