Introduce concept of falling back textures to black in rendergraph + ReadWrite tag

com.unity.render-pipelines.core/Runtime/RenderGraph/RenderGraphBuilder.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using UnityEngine.Rendering;
 
 namespace UnityEngine.Experimental.Rendering.RenderGraphModule
 {
@@ -24,6 +25,7 @@ public struct RenderGraphBuilder : IDisposable
         public TextureHandle UseColorBuffer(in TextureHandle input, int index)
         {
             CheckResource(input.handle);
+            m_Resources.IncrementWriteCount(input.handle);
             m_RenderPass.SetColorBuffer(input, index);
             return input;
         }
@@ -37,6 +39,7 @@ public TextureHandle UseColorBuffer(in TextureHandle input, int index)
         public TextureHandle UseDepthBuffer(in TextureHandle input, DepthAccess flags)
         {
             CheckResource(input.handle);
+            m_Resources.IncrementWriteCount(input.handle);
             m_RenderPass.SetDepthBuffer(input, flags);
             return input;
         }
@@ -49,6 +52,20 @@ public TextureHandle UseDepthBuffer(in TextureHandle input, DepthAccess flags)
         public TextureHandle ReadTexture(in TextureHandle input)
         {
             CheckResource(input.handle);
+
+            if (!m_Resources.IsResourceImported(input.handle) && m_Resources.TextureNeedsFallback(input))
+            {
+                var texDimension = m_Resources.GetTextureResourceDesc(input.handle).dimension;
+                if (texDimension == TextureXR.dimension)
+                {
+                    return m_RenderGraph.defaultResources.blackTextureXR;
+                }
+                else if (texDimension == TextureDimension.Tex3D)
+                {
+                    return m_RenderGraph.defaultResources.blackTexture3DXR;
+                }
+            }
+
             m_RenderPass.AddResourceRead(input.handle);
             return input;
         }
@@ -61,11 +78,25 @@ public TextureHandle ReadTexture(in TextureHandle input)
         public TextureHandle WriteTexture(in TextureHandle input)
         {
             CheckResource(input.handle);
+            m_Resources.IncrementWriteCount(input.handle);
             // TODO RENDERGRAPH: Manage resource "version" for debugging purpose
             m_RenderPass.AddResourceWrite(input.handle);
             return input;
         }
 
+        /// <summary>
+        /// Specify a Texture resource to read and write to during the pass.
+        /// </summary>
+        /// <param name="input">The Texture resource to read and write to during the pass.</param>
+        /// <returns>An updated resource handle to the input resource.</returns>
+        public TextureHandle ReadWriteTexture(in TextureHandle input)
+        {
+            CheckResource(input.handle);
+            m_RenderPass.AddResourceWrite(input.handle);
+            m_RenderPass.AddResourceRead(input.handle);
+            return input;
+        }
+
         /// <summary>
         /// Create a new Render Graph Texture resource.
         /// This texture will only be available for the current pass and will be assumed to be both written and read so users don't need to add explicit read/write declarations.
@@ -125,6 +156,7 @@ public ComputeBufferHandle WriteComputeBuffer(in ComputeBufferHandle input)
         {
             CheckResource(input.handle);
             m_RenderPass.AddResourceWrite(input.handle);
+            m_Resources.IncrementWriteCount(input.handle);
             return input;
         }
 

com.unity.render-pipelines.core/Runtime/RenderGraph/RenderGraphResourceRegistry.cs

@@ -32,16 +32,20 @@ internal static RenderGraphResourceRegistry current
         class IRenderGraphResource
         {
             public bool imported;
-            public int  cachedHash;
-            public int  transientPassIndex;
+            public int cachedHash;
+            public int transientPassIndex;
+            public uint writeCount;
             public bool wasReleased;
+            public bool requestFallBack;
 
             public virtual void Reset()
             {
                 imported = false;
                 cachedHash = -1;
                 transientPassIndex = -1;
                 wasReleased = false;
+                requestFallBack = false;
+                writeCount = 0;
             }
 
             public virtual string GetName()
@@ -53,6 +57,16 @@ public virtual bool IsCreated()
             {
                 return false;
             }
+
+            public void IncrementWriteCount()
+            {
+                writeCount++;
+            }
+
+            public bool NeedsFallBack()
+            {
+                return requestFallBack && writeCount == 0;
+            }
         }
 
         #region Resources
@@ -63,7 +77,7 @@ class RenderGraphResource<DescType, ResType>
             where ResType : class
         {
             public DescType desc;
-            public ResType  resource;
+            public ResType resource;
 
             protected RenderGraphResource()
             {
@@ -108,7 +122,7 @@ public override string GetName()
         internal struct RendererListResource
         {
             public RendererListDesc desc;
-            public RendererList     rendererList;
+            public RendererList rendererList;
 
             internal RendererListResource(in RendererListDesc desc)
             {
@@ -121,15 +135,15 @@ internal RendererListResource(in RendererListDesc desc)
 
         DynamicArray<IRenderGraphResource>[] m_Resources = new DynamicArray<IRenderGraphResource>[(int)RenderGraphResourceType.Count];
 
-        TexturePool                         m_TexturePool = new TexturePool();
-        int                                 m_TextureCreationIndex;
-        ComputeBufferPool                   m_ComputeBufferPool = new ComputeBufferPool();
-        DynamicArray<RendererListResource>  m_RendererListResources = new DynamicArray<RendererListResource>();
-        RenderGraphDebugParams              m_RenderGraphDebug;
-        RenderGraphLogger                   m_Logger;
-        int                                 m_CurrentFrameIndex;
+        TexturePool m_TexturePool = new TexturePool();
+        int m_TextureCreationIndex;
+        ComputeBufferPool m_ComputeBufferPool = new ComputeBufferPool();
+        DynamicArray<RendererListResource> m_RendererListResources = new DynamicArray<RendererListResource>();
+        RenderGraphDebugParams m_RenderGraphDebug;
+        RenderGraphLogger m_Logger;
+        int m_CurrentFrameIndex;
 
-        RTHandle                            m_CurrentBackbuffer;
+        RTHandle m_CurrentBackbuffer;
 
         internal RTHandle GetTexture(in TextureHandle handle)
         {
@@ -139,6 +153,14 @@ internal RTHandle GetTexture(in TextureHandle handle)
             return GetTextureResource(handle.handle).resource;
         }
 
+        internal bool TextureNeedsFallback(in TextureHandle handle)
+        {
+            if (!handle.IsValid())
+                return false;
+
+            return GetTextureResource(handle.handle).NeedsFallBack();
+        }
+
         internal RendererList GetRendererList(in RendererListHandle handle)
         {
             if (!handle.IsValid() || handle >= m_RendererListResources.size)
@@ -192,6 +214,11 @@ void CheckHandleValidity(RenderGraphResourceType type, int index)
             if (index >= resources.size)
                 throw new ArgumentException($"Trying to access resource of type {type} with an invalid resource index {index}");
         }
+        internal void IncrementWriteCount(in ResourceHandle res)
+        {
+            CheckHandleValidity(res);
+            m_Resources[res.iType][res.index].IncrementWriteCount();
+        }
 
         internal string GetResourceName(in ResourceHandle res)
         {
@@ -276,6 +303,7 @@ internal TextureHandle CreateTexture(in TextureDesc desc, int transientPassIndex
             ValidateTextureDesc(desc);
 
             int newHandle = AddNewResource(m_Resources[(int)RenderGraphResourceType.Texture], out TextureResource texResource);
+            texResource.requestFallBack = desc.fallBackToBlackTexture;
             texResource.desc = desc;
             texResource.transientPassIndex = transientPassIndex;
             return new TextureHandle(newHandle);

com.unity.render-pipelines.core/Runtime/RenderGraph/RenderGraphResources.cs

@@ -249,6 +249,8 @@ public struct TextureDesc
         ///<summary>Descriptor to determine how the texture will be in fast memory on platform that supports it.</summary>
         public FastMemoryDesc fastMemoryDesc;
 #endif
+        ///<summary>Determines whether the texture will fallback to a black texture if it is read without ever writing to it.</summary>
+        public bool fallBackToBlackTexture;
 
         // Initial state. Those should not be used in the hash
         ///<summary>Texture needs to be cleared on first use.</summary>

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

@@ -43,6 +43,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed the clear coat not being handled properly for SSR and RTR (case 1291654).
 - Fixed ghosting in RTGI and RTAO when denoising is enabled and the RTHandle size is not equal to the Viewport size (case 1291654).
 - Fixed alpha output when atmospheric scattering is enabled.
+- Fixed issue with normal buffer being read without ever being written to.
 
 ### Changed
 - Volume Manager now always tests scene culling masks. This was required to fix hybrid workflow.

com.unity.render-pipelines.high-definition/Runtime/Lighting/ScreenSpaceLighting/SSGIDenoiser.cs

@@ -320,17 +320,17 @@ public struct SSGIDenoiserOutput
                 // History buffer
                 bool historyRequireClear = false;
                 RTHandle indirectDiffuseHistory0 = RequestIndirectDiffuseHistory0(hdCamera, out historyRequireClear);
-                passData.indirectDiffuseHistory0 = builder.ReadTexture(builder.WriteTexture(renderGraph.ImportTexture(indirectDiffuseHistory0)));
+                passData.indirectDiffuseHistory0 = builder.ReadWriteTexture(renderGraph.ImportTexture(indirectDiffuseHistory0));
                 RTHandle indirectDiffuseHistory1 = RequestIndirectDiffuseHistory1(hdCamera, out historyRequireClear);
-                passData.indirectDiffuseHistory1 = builder.ReadTexture(builder.WriteTexture(renderGraph.ImportTexture(indirectDiffuseHistory1)));
+                passData.indirectDiffuseHistory1 = builder.ReadWriteTexture(renderGraph.ImportTexture(indirectDiffuseHistory1));
                 var historyDepthBuffer = halfResolution ? hdCamera.GetCurrentFrameRT((int)HDCameraFrameHistoryType.Depth1) : hdCamera.GetCurrentFrameRT((int)HDCameraFrameHistoryType.Depth);
                 passData.historyDepthBuffer = historyDepthBuffer != null ? builder.ReadTexture(renderGraph.ImportTexture(historyDepthBuffer)) : renderGraph.defaultResources.blackTextureXR;
                 passData.intermediateBuffer0 = builder.CreateTransientTexture(new TextureDesc(Vector2.one, true, true)
                     { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "SSGI Denoiser Intermediate0" });
                 passData.intermediateBuffer1 = builder.CreateTransientTexture(new TextureDesc(Vector2.one, true, true)
                     { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "SSGI Denoiser Intermediate1" });
-                passData.inputOutputBuffer0 = builder.WriteTexture(builder.ReadTexture(inputOutputBuffer0));
-                passData.inputOutputBuffer1 = builder.WriteTexture(builder.ReadTexture(inputOutputBuffer1));
+                passData.inputOutputBuffer0 = builder.ReadWriteTexture(inputOutputBuffer0);
+                passData.inputOutputBuffer1 = builder.ReadWriteTexture(inputOutputBuffer1);
 
                 passData.parameters = PrepareSSGIDenoiserParameters(hdCamera, halfResolution, historyValidity, historyRequireClear, depthMipInfo);
 

com.unity.render-pipelines.high-definition/Runtime/Lighting/ScreenSpaceLighting/ScreenSpaceGlobalIllumination.RenderGraph.cs

@@ -129,8 +129,8 @@ TextureHandle ConvertSSGI(RenderGraph renderGraph, HDCamera hdCamera, bool halfR
                 passData.depthTexture = builder.ReadTexture(depthPyramid);
                 passData.stencilBuffer = builder.ReadTexture(stencilBuffer);
                 passData.normalBuffer = builder.ReadTexture(normalBuffer);
-                passData.inoutputBuffer0 = builder.WriteTexture(builder.ReadTexture(inoutputBuffer0));
-                passData.inoutputBuffer1 = builder.WriteTexture(builder.ReadTexture(inoutputBuffer1));
+                passData.inoutputBuffer0 = builder.ReadWriteTexture(inoutputBuffer0);
+                passData.inoutputBuffer1 = builder.ReadWriteTexture(inoutputBuffer1);
 
                 builder.SetRenderFunc(
                     (ConvertSSGIPassData data, RenderGraphContext ctx) =>

com.unity.render-pipelines.high-definition/Runtime/Lighting/Shadow/ScreenSpaceShadowManager.RenderGraph.cs

@@ -68,7 +68,7 @@ void WriteScreenSpaceShadow(RenderGraph renderGraph, HDCamera hdCamera, TextureH
             {
                 passData.parameters = PrepareWriteScreenSpaceShadowParameters(hdCamera, shadowIndex, shadowType);
                 passData.inputShadowBuffer = builder.ReadTexture(shadowTexture);
-                passData.outputShadowArrayBuffer = builder.WriteTexture(builder.ReadTexture(screenSpaceShadowArray));
+                passData.outputShadowArrayBuffer = builder.ReadWriteTexture(screenSpaceShadowArray);
 
                 builder.SetRenderFunc(
                     (WriteScreenSpaceShadowPassData data, RenderGraphContext context) =>

com.unity.render-pipelines.high-definition/Runtime/Lighting/Shadow/ScreenSpaceShadowManagerArea.cs

@@ -438,8 +438,8 @@ class RTShadowAreaPassData
                     passData.gbuffer3 = builder.ReadTexture(renderGraph.defaultResources.blackTextureXR);
                 }
 
-                passData.shadowHistoryArray = builder.ReadTexture(builder.WriteTexture(renderGraph.ImportTexture(shadowHistoryArray)));
-                passData.analyticHistoryArray = builder.ReadTexture(builder.WriteTexture(renderGraph.ImportTexture(analyticHistoryArray)));
+                passData.shadowHistoryArray = builder.ReadWriteTexture(renderGraph.ImportTexture(shadowHistoryArray));
+                passData.analyticHistoryArray = builder.ReadWriteTexture(renderGraph.ImportTexture(analyticHistoryArray));
 
                 // Intermediate buffers
                 passData.directionBuffer = builder.CreateTransientTexture(new TextureDesc(Vector2.one, true, true) { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "Direction Buffer" });
@@ -448,10 +448,10 @@ class RTShadowAreaPassData
                 passData.intermediateBufferRG0 = builder.CreateTransientTexture(new TextureDesc(Vector2.one, true, true) { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "Intermediate Buffer RG0" });
 
                 // Debug textures
-                passData.rayCountTexture = builder.ReadTexture(builder.WriteTexture(rayCountTexture));
+                passData.rayCountTexture = builder.ReadWriteTexture(rayCountTexture);
 
                 // Output buffers
-                passData.outputShadowTexture = builder.ReadTexture(builder.WriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true) { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "Shadow Buffer" })));
+                passData.outputShadowTexture = builder.ReadWriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true) { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "Shadow Buffer" }));
                 builder.SetRenderFunc(
                     (RTShadowAreaPassData data, RenderGraphContext context) =>
                     {

com.unity.render-pipelines.high-definition/Runtime/Lighting/Shadow/ScreenSpaceShadowManagerDirectional.RenderGraph.cs

@@ -75,15 +75,15 @@ void RenderRayTracedDirectionalScreenSpaceShadow(RenderGraph renderGraph, HDCame
                 passData.directionBuffer = builder.CreateTransientTexture(new TextureDesc(Vector2.one, true, true) { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, name = "Direction Buffer" });
 
                 // Debug buffers
-                passData.rayCountTexture = builder.ReadTexture(builder.WriteTexture(rayCountTexture));
+                passData.rayCountTexture = builder.ReadWriteTexture(rayCountTexture);
 
                 // Output Buffers
-                passData.velocityBuffer = builder.ReadTexture(builder.WriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true)
-                    { colorFormat = GraphicsFormat.R8_SNorm, enableRandomWrite = true, clearBuffer = true, name = "Velocity Buffer" })));
-                passData.distanceBuffer = builder.ReadTexture(builder.WriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true)
-                    { colorFormat = GraphicsFormat.R32_SFloat, enableRandomWrite = true, clearBuffer = true, name = "Distance Buffer" })));
-                passData.outputShadowBuffer = builder.ReadTexture(builder.WriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true)
-                    { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, clearBuffer = true, name = "RT Directional Shadow" })));
+                passData.velocityBuffer = builder.ReadWriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true)
+                    { colorFormat = GraphicsFormat.R8_SNorm, enableRandomWrite = true, clearBuffer = true, name = "Velocity Buffer" }));
+                passData.distanceBuffer = builder.ReadWriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true)
+                    { colorFormat = GraphicsFormat.R32_SFloat, enableRandomWrite = true, clearBuffer = true, name = "Distance Buffer" }));
+                passData.outputShadowBuffer = builder.ReadWriteTexture(renderGraph.CreateTexture(new TextureDesc(Vector2.one, true, true)
+                    { colorFormat = GraphicsFormat.R16G16B16A16_SFloat, enableRandomWrite = true, clearBuffer = true, name = "RT Directional Shadow" }));
 
                 builder.SetRenderFunc(
                     (RTSDirectionalTracePassData data, RenderGraphContext context) =>
@@ -143,7 +143,7 @@ void RenderDirectionalLightScreenSpaceShadow(RenderGraph renderGraph, HDCamera h
                     {
                         passData.parameters = PrepareSSShadowDirectionalParameters();
                         passData.normalBuffer = builder.ReadTexture(normalBuffer);
-                        passData.screenSpaceShadowArray = builder.ReadTexture(builder.WriteTexture(screenSpaceShadowArray));
+                        passData.screenSpaceShadowArray = builder.ReadWriteTexture(screenSpaceShadowArray);
 
                         builder.SetRenderFunc(
                             (SSSDirectionalTracePassData data, RenderGraphContext context) =>