[HDRP][Compositor] Fix camera stacking for AOVs in the graphics compositor

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

@@ -132,6 +132,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed an inconsistency in the LOD group UI where LOD bias was not the right one.
 - Fixed outlines in transitions between post-processed and plain regions in the graphics compositor (case 1278775).
 - Fix decal being applied twice with LOD Crossfade.
+- Fixed camera stacking for AOVs in the graphics compositor (case 1273223).
 
 ### Changed
 - Preparation pass for RTSSShadows to be supported by render graph.

com.unity.render-pipelines.high-definition/Editor/Compositor/CompositorWindow.cs

@@ -190,12 +190,17 @@ private void OnDestroy()
             GraphData.onSaveGraph -= MarkShaderAsDirty;
 
             Undo.undoRedoPerformed -= UndoCallback;
-            s_SelectionIndex = m_Editor.selectionIndex;
+            s_SelectionIndex = m_Editor ? m_Editor.selectionIndex : -1;
         }
 
         void UndoCallback()
         {
             // Undo-redo might change the layer order, so we need to redraw the compositor UI and also refresh the layer setup
+            if (!m_Editor)
+            {
+                return;
+            }
+
             m_Editor.CacheSerializedObjects();
             m_RequiresRedraw = true;
             s_SelectionIndex = m_Editor.selectionIndex;

com.unity.render-pipelines.high-definition/Runtime/Compositor/AdditionalCompositorData.cs

@@ -14,6 +14,7 @@ internal enum BackgroundFitMode
     internal class AdditionalCompositorData : MonoBehaviour
     {
         public Texture clearColorTexture = null;
+        public RenderTexture clearDepthTexture = null;
         public bool clearAlpha = true;    // Clearing the alpha allows the post process to run only on the pixels covered by a stacked camera (and not the previous ones).
         public BackgroundFitMode imageFitMode = BackgroundFitMode.Stretch;
         public List<CompositionFilter> layerFilters;
@@ -29,6 +30,7 @@ public void Init(List<CompositionFilter> layerFilters, bool clearAlpha)
         public void ResetData()
         {
             clearColorTexture = null;
+            clearDepthTexture = null;
             clearAlpha = true;
             imageFitMode = BackgroundFitMode.Stretch;
 

com.unity.render-pipelines.high-definition/Runtime/Compositor/CompositionLayer.cs

@@ -612,7 +612,7 @@ public void SetupLayerCamera(CompositorLayer targetLayer, int layerPositionInSta
             var cameraData = m_LayerCamera.GetComponent<HDAdditionalCameraData>();
             m_LayerCamera.targetTexture = targetLayer.GetRenderTarget(false);
 
-            if (targetLayer.m_AOVBitmask == 0)
+            // Setup the custom clear pass for camera stacking
             {
                 if (layerPositionInStack != 0)
                 {
@@ -625,7 +625,8 @@ public void SetupLayerCamera(CompositorLayer targetLayer, int layerPositionInSta
                     }
                     if (m_Type != LayerType.Image)
                     {
-                        compositorData.clearColorTexture = targetLayer.GetRenderTarget(false);
+                        compositorData.clearColorTexture = targetLayer.GetRenderTarget();
+                        compositorData.clearDepthTexture = targetLayer.m_RTHandle;
                     }
                     cameraData.volumeLayerMask |= 1 << 31;
                 }
@@ -638,7 +639,7 @@ public void SetupLayerCamera(CompositorLayer targetLayer, int layerPositionInSta
 
             // The target layer expects AOVs, so this stacked layer should also generate AOVs
             int aovMask = (1 << (int)targetLayer.m_AOVBitmask);
-            if (aovMask > 1)
+            if (m_Show && aovMask > 1)
             {
                 var aovRequestBuilder = new AOVRequestBuilder();
 

com.unity.render-pipelines.high-definition/Runtime/Compositor/CompositionManager.cs

@@ -861,5 +861,39 @@ static public Vector4 GetAlphaScaleAndBiasForCamera(HDCamera hdCamera)
             return new Vector4(1.0f, 0.0f, 0.0f, 0.0f);
         }
 
+        /// <summary>
+        /// For stacked cameras, returns the color buffer that will be used to draw on top
+        /// </summary>
+        /// <param name="hdCamera">The input camera</param>
+        /// <returns> The color buffer that will be used to draw on top, or null if not a stacked camera </returns>
+        static internal Texture GetClearTextureForStackedCamera(HDCamera hdCamera)
+        {
+            AdditionalCompositorData compositorData = null;
+            hdCamera.camera.TryGetComponent<AdditionalCompositorData>(out compositorData);
+
+            if (compositorData)
+            {
+                return compositorData.clearColorTexture;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// For stacked cameras, returns the depth buffer that will be used to draw on top
+        /// </summary>
+        /// <param name="hdCamera">The input camera</param>
+        /// <returns> The depth buffer that will be used to draw on top, or null if not a stacked camera </returns>
+        static internal RenderTexture GetClearDepthForStackedCamera(HDCamera hdCamera)
+        {
+            AdditionalCompositorData compositorData = null;
+            hdCamera.camera.TryGetComponent<AdditionalCompositorData>(out compositorData);
+
+            if (compositorData)
+            {
+                return compositorData.clearDepthTexture;
+            }
+            return null;
+        }
+
     }
 }

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

@@ -507,11 +507,15 @@ class DebugViewMaterialData
             public RendererListHandle transparentRendererList;
             public Material debugGBufferMaterial;
             public FrameSettings frameSettings;
+
+            public Texture clearColorTexture;
+            public RenderTexture clearDepthTexture;
         }
 
         TextureHandle RenderDebugViewMaterial(RenderGraph renderGraph, CullingResults cull, HDCamera hdCamera)
         {
             bool msaa = hdCamera.frameSettings.IsEnabled(FrameSettingsField.MSAA);
+
             var output = renderGraph.CreateTexture(
                 new TextureDesc(Vector2.one, true, true)
                 {
@@ -557,9 +561,19 @@ TextureHandle RenderDebugViewMaterial(RenderGraph renderGraph, CullingResults cu
                             rendererConfiguration: m_CurrentRendererConfigurationBakedLighting,
                             stateBlock: m_DepthStateOpaque)));
 
+                    passData.clearColorTexture = Compositor.CompositionManager.GetClearTextureForStackedCamera(hdCamera);   // returns null if is not a stacked camera
+                    passData.clearDepthTexture = Compositor.CompositionManager.GetClearDepthForStackedCamera(hdCamera);     // returns null if is not a stacked camera
+
                     builder.SetRenderFunc(
                     (DebugViewMaterialData data, RenderGraphContext context) =>
                     {
+                        // If we are doing camera stacking, then we want to clear the debug color and depth buffer using the data from the previous camera on the stack
+                        // Note: Ideally here we would like to draw directly on the same buffers as the previous camera, but currently the compositor is not using 
+                        // Texture Arrays so this would not work. We might need to revise this in the future. 
+                        if (data.clearColorTexture != null)
+                        {
+                            HDUtils.BlitColorAndDepth(context.cmd, data.clearColorTexture, data.clearDepthTexture, new Vector4(1, 1, 0, 0), 0, !hdCamera.clearDepth);
+                        }
                         DrawOpaqueRendererList(context, data.frameSettings, data.opaqueRendererList);
                         DrawTransparentRendererList(context, data.frameSettings, data.transparentRendererList);
                     });

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

@@ -175,6 +175,7 @@ internal static Volume GetOrCreateDefaultVolume()
         Material m_Blit;
         Material m_BlitTexArray;
         Material m_BlitTexArraySingleSlice;
+        Material m_BlitColorAndDepth;
         MaterialPropertyBlock m_BlitPropertyBlock = new MaterialPropertyBlock();
 
         RenderTargetIdentifier[] m_MRTCache2 = new RenderTargetIdentifier[2];
@@ -327,6 +328,7 @@ internal int GetMaxScreenSpaceShadows()
         string m_ForwardPassProfileName;
 
         internal Material GetBlitMaterial(bool useTexArray, bool singleSlice) { return useTexArray ? (singleSlice ? m_BlitTexArraySingleSlice : m_BlitTexArray) : m_Blit; }
+        internal Material GetBlitColorAndDepthMaterial() { return m_BlitColorAndDepth; }
 
         ComputeBuffer m_DepthPyramidMipLevelOffsetsBuffer = null;
 
@@ -1088,6 +1090,7 @@ void InitializeDebugMaterials()
             m_DebugColorPicker = CoreUtils.CreateEngineMaterial(defaultResources.shaders.debugColorPickerPS);
             m_DebugExposure = CoreUtils.CreateEngineMaterial(defaultResources.shaders.debugExposurePS);
             m_Blit = CoreUtils.CreateEngineMaterial(defaultResources.shaders.blitPS);
+            m_BlitColorAndDepth = CoreUtils.CreateEngineMaterial(defaultResources.shaders.blitColorAndDepthPS);
             m_ErrorMaterial = CoreUtils.CreateEngineMaterial("Hidden/InternalErrorShader");
 
             // With texture array enabled, we still need the normal blit version for other systems like atlas
@@ -4080,8 +4083,16 @@ void RenderDebugViewMaterial(CullingResults cull, HDCamera hdCamera, ScriptableR
                 {
                     // When rendering debug material we shouldn't rely on a depth prepass for optimizing the alpha clip test. As it is control on the material inspector side
                     // we must override the state here.
-
                     CoreUtils.SetRenderTarget(cmd, m_CameraColorBuffer, m_SharedRTManager.GetDepthStencilBuffer(), ClearFlag.All, Color.clear);
+
+                    // [case 1273223] When the camera is stacked on top of another one, we need to clear the debug view RT using the data from the previous camera in the stack
+                    var clearColorTexture = Compositor.CompositionManager.GetClearTextureForStackedCamera(hdCamera);   // returns null if is not a stacked camera
+                    var clearDepthTexture = Compositor.CompositionManager.GetClearDepthForStackedCamera(hdCamera);     // returns null if is not a stacked camera
+                    if (clearColorTexture)
+                    {
+                        HDUtils.BlitColorAndDepth(cmd, clearColorTexture, clearDepthTexture, new Vector4(1, 1, 0, 0), 0, !hdCamera.clearDepth);
+                    }
+
                     // Render Opaque forward
                     var rendererListOpaque = RendererList.Create(CreateOpaqueRendererListDesc(cull, hdCamera.camera, m_AllForwardOpaquePassNames, m_CurrentRendererConfigurationBakedLighting, stateBlock: m_DepthStateOpaque));
                     DrawOpaqueRendererList(renderContext, cmd, hdCamera.frameSettings, rendererListOpaque);

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

@@ -110,6 +110,8 @@ public sealed class ShaderResources
             public Shader copyDepthBufferPS;
             [Reload("Runtime/ShaderLibrary/Blit.shader")]
             public Shader blitPS;
+            [Reload("Runtime/ShaderLibrary/BlitColorAndDepth.shader")]
+            public Shader blitColorAndDepthPS;
 
             [Reload("Runtime/ShaderLibrary/DownsampleDepth.shader")]
             public Shader downsampleDepthPS;

com.unity.render-pipelines.high-definition/Runtime/RenderPipeline/Utility/HDUtils.cs

@@ -307,6 +307,32 @@ public static void BlitTexture(CommandBuffer cmd, RTHandle source, Vector4 scale
             s_PropertyBlock.SetFloat(HDShaderIDs._BlitMipLevel, mipLevel);
             BlitTexture(cmd, source, scaleBias, GetBlitMaterial(TextureXR.dimension), bilinear ? 1 : 0);
         }
+
+        /// <summary>
+        /// Blit a 2D texture and depth buffer.
+        /// </summary>
+        /// <param name="cmd">Command Buffer used for rendering.</param>
+        /// <param name="sourceColor">Source Texture for color.</param>
+        /// <param name="sourceDepth">Source RenderTexture for depth.</param>
+        /// <param name="scaleBias">Scale and bias for sampling the input texture.</param>
+        /// <param name="mipLevel">Mip level to blit.</param>
+        /// <param name="bilinear">Enable bilinear filtering.</param>
+        internal static void BlitColorAndDepth(CommandBuffer cmd, Texture sourceColor, RenderTexture sourceDepth, Vector4 scaleBias, float mipLevel, bool blitDepth)
+        {
+            HDRenderPipeline hdPipeline = RenderPipelineManager.currentPipeline as HDRenderPipeline;
+            if (hdPipeline != null)
+            {
+                Material mat = hdPipeline.GetBlitColorAndDepthMaterial();
+
+                s_PropertyBlock.SetFloat(HDShaderIDs._BlitMipLevel, mipLevel);
+                s_PropertyBlock.SetVector(HDShaderIDs._BlitScaleBias, scaleBias);
+                s_PropertyBlock.SetTexture(HDShaderIDs._BlitTexture, sourceColor);
+                if (blitDepth)
+                    s_PropertyBlock.SetTexture(HDShaderIDs._InputDepth, sourceDepth, RenderTextureSubElement.Depth);
+                cmd.DrawProcedural(Matrix4x4.identity, mat, blitDepth ? 1 : 0, MeshTopology.Triangles, 3, 1, s_PropertyBlock);
+            }
+        }
+
         /// <summary>
         /// Blit a RTHandle texture
         /// </summary>

com.unity.render-pipelines.high-definition/Runtime/RenderPipelineResources/HDRenderPipelineResources.asset

@@ -85,6 +85,8 @@ MonoBehaviour:
       type: 3}
     copyDepthBufferPS: {fileID: 4800000, guid: 42dfcc8fe803ece4096c58630689982f, type: 3}
     blitPS: {fileID: 4800000, guid: 370f7a9cc4e362d488af024d371091e8, type: 3}
+    blitColorAndDepthPS: {fileID: 4800000, guid: c6e57f5bdbd2a284a86a3097c03884c8,
+      type: 3}
     downsampleDepthPS: {fileID: 4800000, guid: 67d6171b0acc6554aad48c845ec7e67f, type: 3}
     upsampleTransparentPS: {fileID: 4800000, guid: 2ad7ce40f0dbaf64dadef1f58d8524d3,
       type: 3}

com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/BlitColorAndDepth.shader

@@ -0,0 +1,97 @@
+Shader "Hidden/HDRP/BlitColorAndDepth"
+{
+    HLSLINCLUDE
+
+        #pragma target 4.5
+        #pragma editor_sync_compilation
+        #pragma only_renderers d3d11 playstation xboxone vulkan metal switch
+        #pragma multi_compile _ DISABLE_TEXTURE2D_X_ARRAY
+        #pragma multi_compile _ BLIT_SINGLE_SLICE
+        #include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
+        #include "Packages/com.unity.render-pipelines.high-definition/Runtime/ShaderLibrary/ShaderVariables.hlsl"
+
+        TEXTURE2D (_BlitTexture);
+        TEXTURE2D (_InputDepthTexture);
+        SamplerState sampler_PointClamp;
+        SamplerState sampler_LinearClamp;
+        uniform float4 _BlitScaleBias;
+        uniform float _BlitMipLevel;
+
+        struct Attributes
+        {
+            uint vertexID : SV_VertexID;
+            UNITY_VERTEX_INPUT_INSTANCE_ID
+        };
+
+        struct Varyings
+        {
+            float4 positionCS : SV_POSITION;
+            float2 texcoord   : TEXCOORD0;
+            UNITY_VERTEX_OUTPUT_STEREO
+        };
+
+        Varyings Vert(Attributes input)
+        {
+            Varyings output;
+            UNITY_SETUP_INSTANCE_ID(input);
+            UNITY_INITIALIZE_VERTEX_OUTPUT_STEREO(output);
+            output.positionCS = GetFullScreenTriangleVertexPosition(input.vertexID);
+            output.texcoord   = GetFullScreenTriangleTexCoord(input.vertexID) * _BlitScaleBias.xy + _BlitScaleBias.zw;
+            return output;
+        }
+
+        float4 FragColorOnly(Varyings input) : SV_Target
+        {
+            UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
+
+            return SAMPLE_TEXTURE2D_LOD(_BlitTexture, sampler_LinearClamp, input.texcoord.xy, _BlitMipLevel);
+        }
+
+        struct PixelData
+        {
+            float4 color : SV_Target;
+            float  depth : SV_Depth;
+        };
+
+        PixelData FragColorAndDepth(Varyings input)
+        {
+            UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
+
+            PixelData pd;
+            pd.color = SAMPLE_TEXTURE2D_LOD(_BlitTexture, sampler_LinearClamp, input.texcoord.xy, _BlitMipLevel);
+            pd.depth = SAMPLE_TEXTURE2D_LOD(_InputDepthTexture, sampler_PointClamp, input.texcoord.xy, _BlitMipLevel).x;
+            return pd;
+        }
+
+    ENDHLSL
+
+    SubShader
+    {
+        Tags{ "RenderPipeline" = "HDRenderPipeline" }
+
+        // 0: Color Only
+        Pass
+        {
+            ZWrite Off ZTest Always Blend Off Cull Off
+
+            HLSLPROGRAM
+                #pragma vertex Vert
+                #pragma fragment FragColorOnly
+            ENDHLSL
+        }
+
+        // 1:  Color Only and Depth
+        Pass
+        {
+            ZWrite On ZTest Always Blend Off Cull Off
+
+            HLSLPROGRAM
+                #pragma vertex Vert
+                #pragma fragment FragColorAndDepth
+            ENDHLSL
+        }
+
+    }
+
+    Fallback Off
+}