Merge pull request #128 from EvgeniiG/master

Add the initial implementation of SSS

Assets/ScriptableRenderLoop/HDRenderPipeline/Debug/Resources/DebugViewMaterialGBuffer.shader

 
             HLSLPROGRAM
             #pragma target 4.5
-            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
+            #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/Debug/Resources/DebugViewTiles.shader

 
             HLSLPROGRAM
             #pragma target 4.5
-            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
+            #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/DefaultCommonSettings.asset

     m_ShadowCascadeSplit0: 0.05
     m_ShadowCascadeSplit1: 0.2
     m_ShadowCascadeSplit2: 0.3
+    m_SssProfileStdDev1: {r: 0.3, g: 0.3, b: 0.3, a: 0}
+    m_SssProfileStdDev2: {r: 1, g: 1, b: 1, a: 0}
+    m_SssProfileLerpWeight: 0.5
+    m_SssBilateralScale: 0.1

Assets/ScriptableRenderLoop/HDRenderPipeline/HDRenderPipeline.asset

     m_ShadowCascadeSplit0: 0.05
     m_ShadowCascadeSplit1: 0.2
     m_ShadowCascadeSplit2: 0.3
+    m_SssProfileStdDev1: {r: 0.3, g: 0.3, b: 0.3, a: 0}
+    m_SssProfileStdDev2: {r: 1, g: 1, b: 1, a: 0}
+    m_SssProfileLerpWeight: 0.5
+    m_SssBilateralScale: 0.1
   m_SkyParameters: {fileID: 0}
   m_LightLoopProducer: {fileID: 11400000, guid: bf8cd9ae03ff7d54c89603e67be0bfc5,
     type: 2}
     maxShadowDistance: 1000
     directionalLightCascadeCount: 4
     directionalLightCascades: {x: 0.05, y: 0.2, z: 0.3}
+  m_SssParameters:
+    profiles: []
+    bilateralScale: 0.1
   m_TextureSettings:
     spotCookieSize: 128
     pointCookieSize: 512

Assets/ScriptableRenderLoop/HDRenderPipeline/HDRenderPipeline.asset.meta

 fileFormatVersion: 2
 guid: e185fecca3c73cd47a09f1092663ef32
-timeCreated: 1485857876
+timeCreated: 1485874614
 licenseType: Pro
 NativeFormatImporter:
   mainObjectFileID: 11400000

Assets/ScriptableRenderLoop/HDRenderPipeline/HDRenderPipeline.cs

                     return SkyParametersSingleton.overrideSettings;
 
                 return m_SkyParameters;
-        }
+            }
         }
 
 
         public ShadowSettings shadowSettings
         {
             get { return m_ShadowSettings; }
+        }
+
+        [SerializeField]
+        SubsurfaceScatteringParameters m_SssParameters = SubsurfaceScatteringParameters.Default;
+
+        public SubsurfaceScatteringParameters sssParameters
+        {
+            get { return m_SssParameters; } 
         }
 
         [SerializeField]
         public void UpdateCommonSettings()
         {
             var commonSettings = commonSettingsToUse;
+
+
+            // TODO: how can we avoid dynamic memory allocation each frame?
+            m_SssParameters.profiles    = new SubsurfaceScatteringProfile[SubsurfaceScatteringParameters.numProfiles];
+            m_SssParameters.profiles[0] = new SubsurfaceScatteringProfile();
+
+            m_SssParameters.profiles[0].stdDev1    = commonSettings.sssProfileStdDev1;
+            m_SssParameters.profiles[0].stdDev2    = commonSettings.sssProfileStdDev2;
+            m_SssParameters.profiles[0].lerpWeight = commonSettings.sssProfileLerpWeight;
+            m_SssParameters.bilateralScale         = commonSettings.sssBilateralScale;	
         }
     }
 
 
         // Various set of material use in render loop
         readonly Material m_DebugViewMaterialGBuffer;
+        readonly Material m_CombineSubsurfaceScattering;
-        readonly int m_CameraDepthBuffer;
+        readonly int m_CameraSubsurfaceBuffer;
+        readonly int m_CameraFilteringBuffer;
+        readonly int m_CameraDepthStencilBuffer;
+        readonly int m_CameraStencilBuffer;
+        // 'm_CameraColorBuffer' does not contain diffuse lighting of SSS materials until the SSS pass.
+        // It is stored within 'm_CameraSubsurfaceBufferRT'.
-        readonly RenderTargetIdentifier m_CameraDepthBufferRT;
+        readonly RenderTargetIdentifier m_CameraSubsurfaceBufferRT;
+        readonly RenderTargetIdentifier m_CameraFilteringBufferRT;
+        readonly RenderTargetIdentifier m_CameraDepthStencilBufferRT;
+        // 'm_CameraStencilBufferRT' is a temporary copy of the stencil buffer and should be removed
+        // once we are able to read from the depth buffer and perform the stencil test simultaneously.
+        readonly RenderTargetIdentifier m_CameraStencilBufferRT;
         readonly RenderTargetIdentifier m_VelocityBufferRT;
         readonly RenderTargetIdentifier m_DistortionBufferRT;
 
         {
             m_Owner = owner;
 
-            m_CameraColorBuffer = Shader.PropertyToID("_CameraColorTexture");
-            m_CameraDepthBuffer  = Shader.PropertyToID("_CameraDepthTexture");
+            m_CameraColorBuffer          = Shader.PropertyToID("_CameraColorTexture");
+            m_CameraSubsurfaceBuffer     = Shader.PropertyToID("_CameraSubsurfaceTexture");
+            m_CameraFilteringBuffer      = Shader.PropertyToID("_CameraFilteringBuffer");
+            m_CameraDepthStencilBuffer   = Shader.PropertyToID("_CameraDepthTexture");
+            m_CameraStencilBuffer        = Shader.PropertyToID("_CameraStencilTexture");
-            m_CameraColorBufferRT = new RenderTargetIdentifier(m_CameraColorBuffer);
-            m_CameraDepthBufferRT = new RenderTargetIdentifier(m_CameraDepthBuffer);
+            m_CameraColorBufferRT        = new RenderTargetIdentifier(m_CameraColorBuffer);
+            m_CameraSubsurfaceBufferRT   = new RenderTargetIdentifier(m_CameraSubsurfaceBuffer);
+            m_CameraFilteringBufferRT    = new RenderTargetIdentifier(m_CameraFilteringBuffer);
+            m_CameraDepthStencilBufferRT = new RenderTargetIdentifier(m_CameraDepthStencilBuffer);
+            m_CameraStencilBufferRT      = new RenderTargetIdentifier(m_CameraStencilBuffer);
+            m_CombineSubsurfaceScattering = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/CombineSubsurfaceScattering");
+
-
             m_gbufferManager.gbufferCount = m_LitRenderLoop.GetMaterialGBufferCount();
             RenderTextureFormat[] RTFormat;
             RenderTextureReadWrite[] RTReadWrite;
             RenderForwardOnlyOpaqueDepthPrepass(cullResults, camera, renderContext);
             RenderGBuffer(cullResults, camera, renderContext);
 
+            // 'm_CameraStencilBufferRT' is a temporary copy of the stencil buffer and should be removed
+            // once we are able to read from the depth buffer and perform the stencil test simultaneously.
+            using (new Utilities.ProfilingSample("Copy depth-stencil buffer", renderContext))
+            {
+                var cmd = new CommandBuffer();
+                cmd.CopyTexture(m_CameraDepthStencilBufferRT, m_CameraStencilBufferRT);
+                renderContext.ExecuteCommandBuffer(cmd);
+                cmd.Dispose();
+            }
+
             if (debugParameters.debugViewMaterial != 0)
             {
                 RenderDebugViewMaterial(cullResults, hdCamera, renderContext);
             ShadowOutput shadows;
             using (new Utilities.ProfilingSample("Shadow Pass", renderContext))
-                {
+            {
-                }
+            }
-                {
+            {
-                    {
+                {
-                    m_LightLoop.BuildGPULightLists(camera, renderContext, m_CameraDepthBufferRT); // TODO: Use async compute here to run light culling during shadow
-                    }
+                    m_LightLoop.BuildGPULightLists(camera, renderContext, m_CameraDepthStencilBufferRT); // TODO: Use async compute here to run light culling during shadow
+            }
 
             PushGlobalParams(hdCamera, renderContext);
 
 
             RenderDeferredLighting(hdCamera, renderContext);
 
+            // We compute subsurface scattering here. Therefore, no objects rendered afterwards will exhibit SSS.
+            // Currently, there is no efficient way to switch between SRT and MRT for the forward pass;
+            // therefore, forward-rendered objects do not output split lighting required for the SSS pass.
+            CombineSubsurfaceScattering(hdCamera, renderContext, m_Owner.sssParameters);
+
             // For opaque forward we have split rendering in two categories
             // Material that are always forward and material that can be deferred or forward depends on render pipeline options (like switch to rendering forward only mode)
             // Material that are always forward are unlit and complex (Like Hair) and don't require sorting, so it is ok to split them.
 
             FinalPass(camera, renderContext);
 
-
-                cmd.SetRenderTarget(BuiltinRenderTextureType.CameraTarget, m_CameraDepthBufferRT);
+                cmd.SetRenderTarget(BuiltinRenderTextureType.CameraTarget, m_CameraDepthStencilBufferRT);
                 renderContext.ExecuteCommandBuffer(cmd);
                 cmd.Dispose();
             }
             {
                 // TODO: Must do opaque then alpha masked for performance!
                 // TODO: front to back for opaque and by materal for opaque tested when we split in two
-                Utilities.SetRenderTarget(renderContext, m_CameraDepthBufferRT);
+                Utilities.SetRenderTarget(renderContext, m_CameraDepthStencilBufferRT);
                 RenderOpaqueRenderList(cull, camera, renderContext, "DepthOnly");
             }
         }
             using (new Utilities.ProfilingSample("GBuffer Pass", renderContext))
             {
                 // setup GBuffer for rendering
-                Utilities.SetRenderTarget(renderContext, m_gbufferManager.GetGBuffers(), m_CameraDepthBufferRT);
+                Utilities.SetRenderTarget(renderContext, m_gbufferManager.GetGBuffers(), m_CameraDepthStencilBufferRT);
                 // render opaque objects into GBuffer
                 RenderOpaqueRenderList(cull, camera, renderContext, "GBuffer", Utilities.kRendererConfigurationBakedLighting);
             }
 
             using (new Utilities.ProfilingSample("Forward opaque depth", renderContext))
             {
-                Utilities.SetRenderTarget(renderContext, m_CameraDepthBufferRT);
+                Utilities.SetRenderTarget(renderContext, m_CameraDepthStencilBufferRT);
                 RenderOpaqueRenderList(cull, camera, renderContext, "ForwardOnlyOpaqueDepthOnly");
             }
         }
             using (new Utilities.ProfilingSample("DebugView Material Mode Pass", renderContext))
             // Render Opaque forward
             {
-                Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthBufferRT, Utilities.kClearAll, Color.black);
+                Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthStencilBufferRT, Utilities.kClearAll, Color.black);
 
                 Shader.SetGlobalInt("_DebugViewMaterial", (int)debugParameters.debugViewMaterial);
 
 
         void RenderDeferredLighting(HDCamera hdCamera, ScriptableRenderContext renderContext)
         {
-            if (debugParameters.ShouldUseForwardRenderingOnly())
+            if (debugParameters.ShouldUseForwardRenderingOnly() || m_LightLoop == null)
-            if (m_LightLoop != null)
-                m_LightLoop.RenderDeferredLighting(hdCamera, renderContext, m_CameraColorBuffer);
+
+            RenderTargetIdentifier[] colorRTs = { m_CameraColorBufferRT, m_CameraSubsurfaceBufferRT };
+
+            // Output split lighting for materials tagged with the SSS stencil bit.
+            m_LightLoop.RenderDeferredLighting(hdCamera, renderContext, colorRTs, m_CameraStencilBufferRT, true);
+
+            // Output combined lighting for all the other materials.
+            m_LightLoop.RenderDeferredLighting(hdCamera, renderContext, colorRTs, m_CameraStencilBufferRT, false);
+        }
+
+        // Combines specular lighting and diffuse lighting with subsurface scattering.
+        void CombineSubsurfaceScattering(HDCamera hdCamera, ScriptableRenderContext context, SubsurfaceScatteringParameters sssParameters)
+        {
+            // Currently, forward-rendered objects do not output split lighting required for the SSS pass.
+            if (debugParameters.ShouldUseForwardRenderingOnly()) return;
+
+            // Assume that the height of the projection window is 2 meters.
+            float distanceToProjectionWindow = 1.0f / Mathf.Tan(0.5f * Mathf.Deg2Rad * hdCamera.camera.fieldOfView);
+            m_CombineSubsurfaceScattering.SetFloat("_DistToProjWindow", distanceToProjectionWindow);
+            m_CombineSubsurfaceScattering.SetFloat("_BilateralScale", 0.05f * sssParameters.bilateralScale);
+            // TODO: use user-defined values for '_ProfileID' and '_FilterRadius.'
+            m_CombineSubsurfaceScattering.SetVectorArray("_FilterKernel", sssParameters.profiles[0].filterKernel);
+            m_CombineSubsurfaceScattering.SetFloat("_FilterRadius", 3.0f);
+
+            MaterialPropertyBlock properties = new MaterialPropertyBlock();
+
+            var cmd = new CommandBuffer() { name = "Combine Subsurface Scattering" };
+
+            // Perform the vertical SSS filtering pass.
+            properties.SetFloat("_DstBlend", (float)BlendMode.Zero); // TODO: this doesn't work for some reason...
+            properties.SetFloat("_FilterHorizontal", 0);
+            cmd.SetGlobalTexture("_IrradianceSource", m_CameraSubsurfaceBufferRT);
+            Utilities.DrawFullscreen(cmd, m_CombineSubsurfaceScattering, hdCamera,
+                                     m_CameraFilteringBufferRT, m_CameraStencilBufferRT, properties);
+
+            // Perform the horizontal SSS filtering pass, and combine diffuse and specular lighting.
+            properties.SetFloat("_DstBlend", (float)BlendMode.One);  // TODO: this doesn't work for some reason...
+            properties.SetFloat("_FilterHorizontal", 1);
+            cmd.SetGlobalTexture("_IrradianceSource", m_CameraFilteringBufferRT);
+            Utilities.DrawFullscreen(cmd, m_CombineSubsurfaceScattering, hdCamera,
+                                     m_CameraColorBufferRT, m_CameraStencilBufferRT, properties);
+
+            context.ExecuteCommandBuffer(cmd);
+            cmd.Dispose();
         }
 
         void UpdateSkyEnvironment(HDCamera hdCamera, ScriptableRenderContext renderContext)
 
         void RenderSky(HDCamera hdCamera, ScriptableRenderContext renderContext)
         {
-            m_SkyManager.RenderSky(hdCamera, m_LightLoop == null ? null : m_LightLoop.GetCurrentSunLight(), m_CameraColorBufferRT, m_CameraDepthBufferRT, renderContext);
+            m_SkyManager.RenderSky(hdCamera, m_LightLoop == null ? null : m_LightLoop.GetCurrentSunLight(), m_CameraColorBufferRT, m_CameraDepthStencilBufferRT, renderContext);
-        
+
         void RenderForward(CullResults cullResults, Camera camera, ScriptableRenderContext renderContext, bool renderOpaque)
         {
             // TODO: Currently we can't render opaque object forward when deferred is enabled
 
             using (new Utilities.ProfilingSample("Forward Pass", renderContext))
             {
-                Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthBufferRT);
+                Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthStencilBufferRT);
 
                 if (m_LightLoop != null)
                     m_LightLoop.RenderForward(camera, renderContext, renderOpaque);
         {
             using (new Utilities.ProfilingSample("Forward Only Pass", renderContext))
             {
-                Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthBufferRT);
+                Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthStencilBufferRT);
 
                 if (m_LightLoop != null)
                     m_LightLoop.RenderForward(camera, renderContext, true);
 
                 var cmd = new CommandBuffer { name = "" };
                 cmd.GetTemporaryRT(m_VelocityBuffer, w, h, 0, FilterMode.Point, Builtin.RenderLoop.GetVelocityBufferFormat(), Builtin.RenderLoop.GetVelocityBufferReadWrite());
-                cmd.SetRenderTarget(m_VelocityBufferRT, m_CameraDepthBufferRT);
+                cmd.SetRenderTarget(m_VelocityBufferRT, m_CameraDepthStencilBufferRT);
                 renderContext.ExecuteCommandBuffer(cmd);
                 cmd.Dispose();
 
 
                 var cmd = new CommandBuffer { name = "" };
                 cmd.GetTemporaryRT(m_DistortionBuffer, w, h, 0, FilterMode.Point, Builtin.RenderLoop.GetDistortionBufferFormat(), Builtin.RenderLoop.GetDistortionBufferReadWrite());
-                cmd.SetRenderTarget(m_DistortionBufferRT, m_CameraDepthBufferRT);
+                cmd.SetRenderTarget(m_DistortionBufferRT, m_CameraDepthStencilBufferRT);
                 cmd.ClearRenderTarget(false, true, Color.black); // TODO: can we avoid this clear for performance ?
                 renderContext.ExecuteCommandBuffer(cmd);
                 cmd.Dispose();
                     int w = camera.pixelWidth;
                     int h = camera.pixelHeight;
 
-                    cmd.GetTemporaryRT(m_CameraColorBuffer, w, h, 0, FilterMode.Point, RenderTextureFormat.ARGBHalf, RenderTextureReadWrite.Linear, 1, true); // Enable UAV
-                    cmd.GetTemporaryRT(m_CameraDepthBuffer, w, h, 24, FilterMode.Point, RenderTextureFormat.Depth);
+                    cmd.GetTemporaryRT(m_CameraColorBuffer,        w, h,  0, FilterMode.Point, RenderTextureFormat.ARGBHalf,       RenderTextureReadWrite.Linear, 1, true); // Enable UAV
+                    cmd.GetTemporaryRT(m_CameraSubsurfaceBuffer,   w, h,  0, FilterMode.Point, RenderTextureFormat.RGB111110Float, RenderTextureReadWrite.Linear, 1, true); // Enable UAV
+                    cmd.GetTemporaryRT(m_CameraFilteringBuffer,    w, h,  0, FilterMode.Point, RenderTextureFormat.RGB111110Float, RenderTextureReadWrite.Linear, 1, true); // Enable UAV
+                    cmd.GetTemporaryRT(m_CameraDepthStencilBuffer, w, h, 24, FilterMode.Point, RenderTextureFormat.Depth);
+                    cmd.GetTemporaryRT(m_CameraStencilBuffer,      w, h, 24, FilterMode.Point, RenderTextureFormat.Depth);
+
-        {
+                    {
-            }
-            renderContext.ExecuteCommandBuffer(cmd);
-            cmd.Dispose();
+                    }
+
+                    renderContext.ExecuteCommandBuffer(cmd);
+                    cmd.Dispose();
+
+                    Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthStencilBufferRT, ClearFlag.ClearDepth);
+                }
+
+                // Clear the diffuse SSS lighting target
+                using (new Utilities.ProfilingSample("Clear SSS diffuse target", renderContext))
+                {
+                    Utilities.SetRenderTarget(renderContext, m_CameraSubsurfaceBufferRT, m_CameraDepthStencilBufferRT, ClearFlag.ClearColor, Color.black);
+                }
-                    Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthBufferRT, ClearFlag.ClearDepth);
-        }
+                // Clear the SSS filtering target
+                using (new Utilities.ProfilingSample("Clear SSS filtering target", renderContext))
+                {
+                    Utilities.SetRenderTarget(renderContext, m_CameraFilteringBuffer, m_CameraDepthStencilBufferRT, ClearFlag.ClearColor, Color.black);
+                }
-                // Clear HDR target
+                // Clear the HDR target
-        {
-                    Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthBufferRT, ClearFlag.ClearColor, Color.black);
-            }
+                {
+                    Utilities.SetRenderTarget(renderContext, m_CameraColorBufferRT, m_CameraDepthStencilBufferRT, ClearFlag.ClearColor, Color.black);
+                }
-            {
-                    using (new Utilities.ProfilingSample("Clear GBuffer", renderContext))
-                        Utilities.SetRenderTarget(renderContext, m_gbufferManager.GetGBuffers(), m_CameraDepthBufferRT, ClearFlag.ClearColor, Color.black);
-                }
+                    using (new Utilities.ProfilingSample("Clear GBuffer", renderContext))
+                    {
+                        Utilities.SetRenderTarget(renderContext, m_gbufferManager.GetGBuffers(), m_CameraDepthStencilBufferRT, ClearFlag.ClearColor, Color.black);
+                }
                 // END TEMP
             }
         }

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/LightLoop.cs

+using UnityEngine;
 using UnityEngine.Rendering;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 
         public virtual void PushGlobalParams(Camera camera, ScriptableRenderContext loop) {}
 
-        public virtual void RenderDeferredLighting(HDCamera hdCamera, ScriptableRenderContext renderContext, RenderTargetIdentifier cameraColorBufferRT) {}
+        public virtual void RenderDeferredLighting(HDCamera hdCamera, ScriptableRenderContext renderContext,
+                                                   RenderTargetIdentifier[] colorBuffers, RenderTargetIdentifier stencilBuffer,
+                                                   bool outputSplitLighting) {}
 
         public virtual void RenderForward(Camera camera, ScriptableRenderContext renderContext, bool renderOpaque) {}
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/Resources/Deferred.shader

         // We need to be able to control the blend mode for deferred shader in case we do multiple pass
         _SrcBlend("", Float) = 1
         _DstBlend("", Float) = 1
+
+        _StencilRef("_StencilRef", Int) = 0
-
+            Stencil
+            {
+                Ref  [_StencilRef]
+                Comp Equal
+                Pass Keep
+            }
+
-            Blend Off
-            Blend[_SrcBlend][_DstBlend]
+            ZTest  Always
+            Blend [_SrcBlend][_DstBlend]
-            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
+            #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
 
             #pragma vertex Vert
             #pragma fragment Frag
             #pragma multi_compile LIGHTLOOP_TILE_DIRECT LIGHTLOOP_TILE_INDIRECT LIGHTLOOP_TILE_ALL
             #pragma multi_compile USE_FPTL_LIGHTLIST USE_CLUSTERED_LIGHTLIST
 
+            // Split lighting is utilized during the SSS pass.
+            #pragma multi_compile _ OUTPUT_SPLIT_LIGHTING
+
             //-------------------------------------------------------------------------------------
             // Include
             //-------------------------------------------------------------------------------------
             // Note: We have fix as guidelines that we have only one deferred material (with control of GBuffer enabled). Mean a users that add a new
-            // deferred material must replace the old one here. If in the future we want to support multiple layout (cause a lot of consistency problem), 
+            // deferred material must replace the old one here. If in the future we want to support multiple layout (cause a lot of consistency problem),
- 
+
- 
+
-                float3 positionOS : POSITION;
+                uint vertexID : SV_VertexID;
             };
 
             struct Varyings
 
+            struct Outputs
+            {
+            #ifdef OUTPUT_SPLIT_LIGHTING
+            	float4 specularLighting : SV_Target0;
+            	float3 diffuseLighting  : SV_Target1;
+            #else
+                float4 combinedLighting : SV_Target0;
+            #endif
+            };
+
-                // TODO: implement SV_vertexID full screen quad
-                // Lights are draw as one fullscreen quad
-                float3 positionWS = TransformObjectToWorld(input.positionOS);
-                output.positionCS = TransformWorldToHClip(positionWS);
-
+			    output.positionCS = GetFullscreenTriangleVertexPosition(input.vertexID);
-            float4 Frag(Varyings input) : SV_Target
+            Outputs Frag(Varyings input)
             {
                 // input.positionCS is SV_Position
                 PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw);
                 float3 specularLighting;
                 LightLoop(V, posInput, preLightData, bsdfData, bakeDiffuseLighting, diffuseLighting, specularLighting);
 
-                return float4(diffuseLighting + specularLighting, 1.0);
+                Outputs outputs;
+            #ifdef OUTPUT_SPLIT_LIGHTING
+                outputs.specularLighting = float4(specularLighting, 1.0);
+                outputs.diffuseLighting  = diffuseLighting;
+            #else
+                outputs.combinedLighting = float4(diffuseLighting + specularLighting, 1.0);
+            #endif
+                return outputs;
             }
 
         ENDHLSL

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/TilePass/Resources/shadeopaque.compute

 #pragma kernel ShadeOpaque_Fptl				SHADE_OPAQUE_ENTRY=ShadeOpaque_Fptl				USE_FPTL_LIGHTLIST=1
 #pragma kernel ShadeOpaque_Clustered		SHADE_OPAQUE_ENTRY=ShadeOpaque_Clustered		USE_CLUSTERED_LIGHTLIST=1
 
+// Split lighting is required for the SSS pass.
+// Not currently possible since we need to access the stencil buffer from the compute shader.
+// #pragma multi_compile _ OUTPUT_SPLIT_LIGHTING
 
 #define LIGHTLOOP_TILE_PASS 1
 #define LIGHTLOOP_TILE_DIRECT 1
-
 
 //-------------------------------------------------------------------------------------
 // Include
 TEXTURE2D(_CameraDepthTexture);
 SAMPLER2D(sampler_CameraDepthTexture);
 
-RWTexture2D<float4> uavOutput;
+#ifdef OUTPUT_SPLIT_LIGHTING
+    RWTexture2D<float4> specularLightingUAV;
+    RWTexture2D<float3> diffuseLightingUAV;
+#else
+    RWTexture2D<float4> combinedLightingUAV;
+#endif
 
 [numthreads(TILE_SIZE, TILE_SIZE, 1)]
 void SHADE_OPAQUE_ENTRY(uint2 dispatchThreadId : SV_DispatchThreadID, uint2 groupId : SV_GroupID)
     float3 specularLighting;
     LightLoop(V, posInput, preLightData, bsdfData, bakeDiffuseLighting, diffuseLighting, specularLighting);
 
-    uavOutput[pixelCoord] = float4(diffuseLighting + specularLighting, 1.0);
+#ifdef OUTPUT_SPLIT_LIGHTING
+    specularLightingUAV[pixelCoord] = float4(specularLighting, 1.0);
+    diffuseLightingUAV[pixelCoord]  = diffuseLighting;
+#else
+    combinedLightingUAV[pixelCoord] = float4(diffuseLighting + specularLighting, 1.0);
+#endif
 }
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Lighting/TilePass/TilePass.cs

                 }
             }
 
+            Material m_DeferredDirectMaterialSRT   = null;
+            Material m_DeferredDirectMaterialMRT   = null;
+            Material m_DeferredIndirectMaterialSRT = null;
+            Material m_DeferredIndirectMaterialMRT = null;
+            Material m_DeferredAllMaterialSRT      = null;
+            Material m_DeferredAllMaterialMRT      = null;
-            Material m_DeferredDirectMaterial = null;
-            Material m_DeferredIndirectMaterial = null;
-            Material m_DeferredAllMaterial = null;
-            Material m_DebugViewTilesMaterial = null;
+            Material m_DebugViewTilesMaterial      = null;
-            Material m_SingleDeferredMaterial = null;
+            Material m_SingleDeferredMaterialSRT   = null;
+            Material m_SingleDeferredMaterialMRT   = null;
-
 
             int GetNumTileX(Camera camera)
             {
 
                 s_LightList = null;
 
-                m_DeferredDirectMaterial = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
-                m_DeferredDirectMaterial.EnableKeyword("LIGHTLOOP_TILE_PASS");
-                m_DeferredDirectMaterial.EnableKeyword("LIGHTLOOP_TILE_DIRECT");
-                m_DeferredDirectMaterial.DisableKeyword("LIGHTLOOP_TILE_INDIRECT");
-                m_DeferredDirectMaterial.DisableKeyword("LIGHTLOOP_TILE_ALL");
+                string[] tileKeywords = {"LIGHTLOOP_TILE_DIRECT", "LIGHTLOOP_TILE_INDIRECT", "LIGHTLOOP_TILE_ALL"};
+
+                m_DeferredDirectMaterialSRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                Utilities.SelectKeyword(m_DeferredDirectMaterialSRT, tileKeywords, 0);
+                m_DeferredDirectMaterialSRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
+                m_DeferredDirectMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_DeferredDirectMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_DeferredDirectMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_DeferredDirectMaterialSRT.SetInt("_DstBlend", (int)BlendMode.Zero);
+
+                m_DeferredDirectMaterialMRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                Utilities.SelectKeyword(m_DeferredDirectMaterialMRT, tileKeywords, 0);
+                m_DeferredDirectMaterialMRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
+                m_DeferredDirectMaterialMRT.EnableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_DeferredDirectMaterialMRT.SetInt("_StencilRef", (int)StencilBits.SSS);
+                m_DeferredDirectMaterialMRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_DeferredDirectMaterialMRT.SetInt("_DstBlend", (int)BlendMode.Zero);
+
+                m_DeferredIndirectMaterialSRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                Utilities.SelectKeyword(m_DeferredIndirectMaterialSRT, tileKeywords, 1);
+                m_DeferredIndirectMaterialSRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
+                m_DeferredIndirectMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_DeferredIndirectMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_DeferredIndirectMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_DeferredIndirectMaterialSRT.SetInt("_DstBlend", (int)BlendMode.One); // Additive
+
+                m_DeferredIndirectMaterialMRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                Utilities.SelectKeyword(m_DeferredIndirectMaterialMRT, tileKeywords, 1);
+                m_DeferredIndirectMaterialMRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
+                m_DeferredIndirectMaterialMRT.EnableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_DeferredIndirectMaterialMRT.SetInt("_StencilRef", (int)StencilBits.SSS);
+                m_DeferredIndirectMaterialMRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_DeferredIndirectMaterialMRT.SetInt("_DstBlend", (int)BlendMode.One); // Additive
-                m_DeferredIndirectMaterial = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
-                m_DeferredIndirectMaterial.EnableKeyword("LIGHTLOOP_TILE_PASS");
-                m_DeferredIndirectMaterial.DisableKeyword("LIGHTLOOP_TILE_DIRECT");
-                m_DeferredIndirectMaterial.EnableKeyword("LIGHTLOOP_TILE_INDIRECT");
-                m_DeferredIndirectMaterial.DisableKeyword("LIGHTLOOP_TILE_ALL");
+                m_DeferredAllMaterialSRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                Utilities.SelectKeyword(m_DeferredAllMaterialSRT, tileKeywords, 2);
+                m_DeferredAllMaterialSRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
+                m_DeferredAllMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_DeferredAllMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_DeferredAllMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_DeferredAllMaterialSRT.SetInt("_DstBlend", (int)BlendMode.Zero);
-                m_DeferredAllMaterial = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
-                m_DeferredAllMaterial.EnableKeyword("LIGHTLOOP_TILE_PASS");
-                m_DeferredAllMaterial.DisableKeyword("LIGHTLOOP_TILE_DIRECT");
-                m_DeferredAllMaterial.DisableKeyword("LIGHTLOOP_TILE_INDIRECT");
-                m_DeferredAllMaterial.EnableKeyword("LIGHTLOOP_TILE_ALL");
+                m_DeferredAllMaterialMRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                Utilities.SelectKeyword(m_DeferredAllMaterialMRT, tileKeywords, 2);
+                m_DeferredAllMaterialMRT.EnableKeyword("LIGHTLOOP_TILE_PASS");
+                m_DeferredAllMaterialMRT.EnableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_DeferredAllMaterialMRT.SetInt("_StencilRef", (int)StencilBits.SSS);
+                m_DeferredAllMaterialMRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_DeferredAllMaterialMRT.SetInt("_DstBlend", (int)BlendMode.Zero);
-                m_SingleDeferredMaterial = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
-                m_SingleDeferredMaterial.EnableKeyword("LIGHTLOOP_SINGLE_PASS");
+                m_SingleDeferredMaterialSRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                m_SingleDeferredMaterialSRT.EnableKeyword("LIGHTLOOP_SINGLE_PASS");
+                m_SingleDeferredMaterialSRT.DisableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_SingleDeferredMaterialSRT.SetInt("_StencilRef", (int)StencilBits.None);
+                m_SingleDeferredMaterialSRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_SingleDeferredMaterialSRT.SetInt("_DstBlend", (int)BlendMode.Zero);
+
+                m_SingleDeferredMaterialMRT = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/Deferred");
+                m_SingleDeferredMaterialMRT.EnableKeyword("LIGHTLOOP_SINGLE_PASS");
+                m_SingleDeferredMaterialMRT.EnableKeyword("OUTPUT_SPLIT_LIGHTING");
+                m_SingleDeferredMaterialMRT.SetInt("_StencilRef", (int)StencilBits.SSS);
+                m_SingleDeferredMaterialMRT.SetInt("_SrcBlend", (int)BlendMode.One);
+                m_SingleDeferredMaterialMRT.SetInt("_DstBlend", (int)BlendMode.Zero);
 
                 m_DefaultTexture2DArray = new Texture2DArray(1, 1, 1, TextureFormat.ARGB32, false);
                 m_DefaultTexture2DArray.SetPixels32(new Color32[1] { new Color32(128, 128, 128, 128) }, 0);
                 // enableClustered
                 Utilities.SafeRelease(s_GlobalLightListAtomic);
 
-                Utilities.Destroy(m_DeferredDirectMaterial);
-                Utilities.Destroy(m_DeferredIndirectMaterial);
-                Utilities.Destroy(m_DeferredAllMaterial);
+                Utilities.Destroy(m_DeferredDirectMaterialSRT);
+                Utilities.Destroy(m_DeferredDirectMaterialMRT);
+                Utilities.Destroy(m_DeferredIndirectMaterialSRT);
+                Utilities.Destroy(m_DeferredIndirectMaterialMRT);
+                Utilities.Destroy(m_DeferredAllMaterialSRT);
+                Utilities.Destroy(m_DeferredAllMaterialMRT);
+
-                Utilities.Destroy(m_SingleDeferredMaterial);
+                Utilities.Destroy(m_SingleDeferredMaterialSRT);
+                Utilities.Destroy(m_SingleDeferredMaterialMRT);
 
                 Utilities.Destroy(s_DefaultAdditionalLightDataGameObject);
                 s_DefaultAdditionalLightDataGameObject = null;
             }
 #endif
 
-            public override void RenderDeferredLighting(HDCamera hdCamera, ScriptableRenderContext renderContext, RenderTargetIdentifier cameraColorBufferRT)
+            public override void RenderDeferredLighting(HDCamera hdCamera, ScriptableRenderContext renderContext,
+                                                        RenderTargetIdentifier[] colorBuffers, RenderTargetIdentifier stencilBuffer,
+                                                        bool outputSplitLighting)
             {
                 var bUseClusteredForDeferred = !usingFptl;
 
                     if (m_PassSettings.disableTileAndCluster)
                     {
                         // This is a debug brute force renderer to debug tile/cluster which render all the lights
-                        Utilities.SetupMaterialHDCamera(hdCamera, m_SingleDeferredMaterial);
-                        m_SingleDeferredMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
-                        m_SingleDeferredMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
-
-                        cmd.Blit(null, cameraColorBufferRT, m_SingleDeferredMaterial, 0);
+                        if (outputSplitLighting)
+                        {
+                            Utilities.DrawFullscreen(cmd, m_SingleDeferredMaterialMRT, hdCamera, colorBuffers, stencilBuffer);
+                        }
+                        else
+                        {
+                            Utilities.DrawFullscreen(cmd, m_SingleDeferredMaterialSRT, hdCamera, colorBuffers[0], stencilBuffer);
+                        }
                     }
                     else
                     {
                             cmd.SetComputeTextureParam(shadeOpaqueShader, kernel, "_IESArray", IESArrayTexture ? IESArrayTexture : m_DefaultTexture2DArray);
                             cmd.SetComputeTextureParam(shadeOpaqueShader, kernel, "_SkyTexture", skyTexture ? skyTexture : m_DefaultTexture2DArray);
 
-                            cmd.SetComputeTextureParam(shadeOpaqueShader, kernel, "uavOutput", cameraColorBufferRT);
+                            // Since we need the stencil test, the compute path does not currently support SSS.
+                            cmd.SetComputeTextureParam(shadeOpaqueShader, kernel, "combinedLightingUAV", colorBuffers[0]);
                             cmd.DispatchCompute(shadeOpaqueShader, kernel, numTilesX, numTilesY, 1);
                         }
                         else
                             {
-                                Utilities.SetupMaterialHDCamera(hdCamera, m_DeferredDirectMaterial);
-                                m_DeferredDirectMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
-                                m_DeferredDirectMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
-                                m_DeferredDirectMaterial.EnableKeyword(bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
-                                m_DeferredDirectMaterial.DisableKeyword(!bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
+                                if (outputSplitLighting)
+                                {
+                                    Utilities.SelectKeyword(m_DeferredDirectMaterialMRT, "USE_CLUSTERED_LIGHTLIST", "USE_FPTL_LIGHTLIST", bUseClusteredForDeferred);
+                                    Utilities.DrawFullscreen(cmd, m_DeferredDirectMaterialMRT, hdCamera, colorBuffers, stencilBuffer);
-                                Utilities.SetupMaterialHDCamera(hdCamera, m_DeferredIndirectMaterial);
-                                m_DeferredIndirectMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
-                                m_DeferredIndirectMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.One); // Additive
-                                m_DeferredIndirectMaterial.EnableKeyword(bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
-                                m_DeferredIndirectMaterial.DisableKeyword(!bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
+                                    Utilities.SelectKeyword(m_DeferredIndirectMaterialMRT, "USE_CLUSTERED_LIGHTLIST", "USE_FPTL_LIGHTLIST", bUseClusteredForDeferred);
+                                    Utilities.DrawFullscreen(cmd, m_DeferredIndirectMaterialMRT, hdCamera, colorBuffers, stencilBuffer);
+                                }
+                                else
+                                {
+                                    Utilities.SelectKeyword(m_DeferredDirectMaterialSRT, "USE_CLUSTERED_LIGHTLIST", "USE_FPTL_LIGHTLIST", bUseClusteredForDeferred);
+                                    Utilities.DrawFullscreen(cmd, m_DeferredDirectMaterialSRT, hdCamera, colorBuffers[0], stencilBuffer);
-                                cmd.Blit(null, cameraColorBufferRT, m_DeferredDirectMaterial, 0);
-                                cmd.Blit(null, cameraColorBufferRT, m_DeferredIndirectMaterial, 0);
+                                    Utilities.SelectKeyword(m_DeferredIndirectMaterialSRT, "USE_CLUSTERED_LIGHTLIST", "USE_FPTL_LIGHTLIST", bUseClusteredForDeferred);
+                                    Utilities.DrawFullscreen(cmd, m_DeferredIndirectMaterialSRT, hdCamera, colorBuffers[0], stencilBuffer);
+                                }
-                                Utilities.SetupMaterialHDCamera(hdCamera, m_DeferredAllMaterial);
-                                m_DeferredAllMaterial.SetInt("_SrcBlend", (int)UnityEngine.Rendering.BlendMode.One);
-                                m_DeferredAllMaterial.SetInt("_DstBlend", (int)UnityEngine.Rendering.BlendMode.Zero);
-                                m_DeferredAllMaterial.EnableKeyword(bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
-                                m_DeferredAllMaterial.DisableKeyword(!bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
-
-                                cmd.Blit(null, cameraColorBufferRT, m_DeferredAllMaterial, 0);
+                                if (outputSplitLighting)
+                                {
+                                    Utilities.SelectKeyword(m_DeferredAllMaterialMRT, "USE_CLUSTERED_LIGHTLIST", "USE_FPTL_LIGHTLIST", bUseClusteredForDeferred);
+                                    Utilities.DrawFullscreen(cmd, m_DeferredAllMaterialMRT, hdCamera, colorBuffers, stencilBuffer);
+                                }
+                                else
+                                {
+                                    Utilities.SelectKeyword(m_DeferredAllMaterialSRT, "USE_CLUSTERED_LIGHTLIST", "USE_FPTL_LIGHTLIST", bUseClusteredForDeferred);
+                                    Utilities.DrawFullscreen(cmd, m_DeferredAllMaterialSRT, hdCamera, colorBuffers[0], stencilBuffer);
+                                }
                             }
                         }
 
                             m_DebugViewTilesMaterial.EnableKeyword(bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
                             m_DebugViewTilesMaterial.DisableKeyword(!bUseClusteredForDeferred ? "USE_CLUSTERED_LIGHTLIST" : "USE_FPTL_LIGHTLIST");
 
-                            cmd.Blit(null, cameraColorBufferRT, m_DebugViewTilesMaterial, 0);
+                            cmd.Blit(null, colorBuffers[0], m_DebugViewTilesMaterial, 0);
                         }
                     }
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/LayeredLit/LayeredLit.shader

     HLSLINCLUDE
 
     #pragma target 4.5
-    #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
+    #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
 
     #pragma shader_feature _ALPHATEST_ON
     #pragma shader_feature _DISTORTION_ON

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/LayeredLit/LayeredLitTessellation.shader

     HLSLINCLUDE
 
     #pragma target 5.0
-    #pragma only_renderers d3d11 ps4 // TEMP: unitl we go futher in dev
+    #pragma only_renderers d3d11 ps4 // TEMP: until we go further in dev
 
     #pragma shader_feature _ALPHATEST_ON
     #pragma shader_feature _DISTORTION_ON

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Editor/BaseLitUI.cs

             
             public static GUIContent detailMapModeText = new GUIContent("Detail Map with Normal", "Detail Map with AO / Height");
             public static GUIContent UVDetailMappingText = new GUIContent("UV set for Detail", "");
+            public static GUIContent materialIDText = new GUIContent("Material Class", "Subsurface Scattering: enable for translucent materials such as skin, vegetation, fruit, marble, wax and milk.");
             public static GUIContent emissiveColorModeText = new GUIContent("Emissive Color Usage", "Use emissive color or emissive mask");
 
             public static string InputsText = "Inputs";

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Editor/LitUI.cs

 using System;
 using UnityEngine;
 using UnityEngine.Rendering;
+using UnityEngine.Experimental.Rendering.HDPipeline;
 
 namespace UnityEditor.Experimental.Rendering.HDPipeline
 {
         protected const string kUVDetail = "_UVDetail";
         protected MaterialProperty UVDetailsMappingMask = null;
         protected const string kUVDetailsMappingMask = "_UVDetailsMappingMask";
+        protected MaterialProperty materialID = null;
+        protected const string kMaterialID = "_MaterialID";
         protected MaterialProperty emissiveColorMode = null;
         protected const string kEmissiveColorMode = "_EmissiveColorMode";
 
         // These are options that are shared with the LayeredLit shader. Don't put anything that can't be shared here:
         // For instance, properties like BaseColor and such don't exist in the LayeredLit so don't put them here.
         protected void FindMaterialOptionProperties(MaterialProperty[] props)
-        {   
+        {
             smoothnessMapChannel = FindProperty(kSmoothnessTextureChannel, props);
             normalMapSpace = FindProperty(kNormalMapSpace, props);
             enablePerPixelDisplacement = FindProperty(kEnablePerPixelDisplacement, props);
+            materialID = FindProperty(kMaterialID, props);
             emissiveColorMode = FindProperty(kEmissiveColorMode, props);
         }
 
 
             EditorGUI.indentLevel++;
             GUILayout.Label(Styles.InputsOptionsText, EditorStyles.boldLabel);
-            m_MaterialEditor.ShaderProperty(smoothnessMapChannel, Styles.smoothnessMapChannelText.text);
-            m_MaterialEditor.ShaderProperty(UVBase, enableUVDetail ? Styles.UVBaseDetailMappingText.text : Styles.UVBaseMappingText.text);
+            m_MaterialEditor.ShaderProperty(smoothnessMapChannel, Styles.smoothnessMapChannelText);
+            m_MaterialEditor.ShaderProperty(UVBase, enableUVDetail ? Styles.UVBaseDetailMappingText : Styles.UVBaseMappingText);
 
             float X, Y, Z, W;
             X = ((UVBaseMapping)UVBase.floatValue == UVBaseMapping.UV0) ? 1.0f : 0.0f;
             {
                 EditorGUI.indentLevel++;
-                m_MaterialEditor.ShaderProperty(TexWorldScale, Styles.texWorldScaleText.text);
+                m_MaterialEditor.ShaderProperty(TexWorldScale, Styles.texWorldScaleText);
-                m_MaterialEditor.ShaderProperty(UVDetail, Styles.UVDetailMappingText.text);
+                m_MaterialEditor.ShaderProperty(UVDetail, Styles.UVDetailMappingText);
             }
 
             X = ((UVDetailMapping)UVDetail.floatValue == UVDetailMapping.UV0) ? 1.0f : 0.0f;
             UVDetailsMappingMask.colorValue = new Color(X, Y, Z, W);
 
-            //m_MaterialEditor.ShaderProperty(detailMapMode, Styles.detailMapModeText.text);
-            m_MaterialEditor.ShaderProperty(normalMapSpace, Styles.normalMapSpaceText.text);            
-            m_MaterialEditor.ShaderProperty(emissiveColorMode, Styles.emissiveColorModeText.text);
-            m_MaterialEditor.ShaderProperty(enablePerPixelDisplacement, Styles.enablePerPixelDisplacementText.text);
-            m_MaterialEditor.ShaderProperty(ppdMinSamples, Styles.ppdMinSamplesText.text);
-            m_MaterialEditor.ShaderProperty(ppdMaxSamples, Styles.ppdMaxSamplesText.text);
+            //m_MaterialEditor.ShaderProperty(detailMapMode, Styles.detailMapModeText);
+            m_MaterialEditor.ShaderProperty(normalMapSpace, Styles.normalMapSpaceText);
+            m_MaterialEditor.ShaderProperty(emissiveColorMode, Styles.emissiveColorModeText);
+            m_MaterialEditor.ShaderProperty(enablePerPixelDisplacement, Styles.enablePerPixelDisplacementText);
+            m_MaterialEditor.ShaderProperty(ppdMinSamples, Styles.ppdMinSamplesText);
+            m_MaterialEditor.ShaderProperty(ppdMaxSamples, Styles.ppdMaxSamplesText);
+            m_MaterialEditor.ShaderProperty(materialID, Styles.materialIDText);
             EditorGUI.indentLevel--;
         }
 
-            bool smoothnessInAlbedoAlpha = (SmoothnessMapChannel)smoothnessMapChannel.floatValue == SmoothnessMapChannel.AlbedoAlpha;            
+            bool smoothnessInAlbedoAlpha = (SmoothnessMapChannel)smoothnessMapChannel.floatValue == SmoothnessMapChannel.AlbedoAlpha;
             bool useDetailMapWithNormal = (DetailMapMode)detailMapMode.floatValue == DetailMapMode.DetailWithNormal;
             bool useEmissiveMask = (EmissiveColorMode)emissiveColorMode.floatValue == EmissiveColorMode.UseEmissiveMask;
 
                 material.DisableKeyword("_REQUIRE_UV2");
                 material.DisableKeyword("_REQUIRE_UV3");
             }
+
+            material.SetInt("_StencilRef", (int)material.GetFloat(kMaterialID)); // See 'StencilBits'.
          }
     }
 } // namespace UnityEditor

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Lit.shader

         _DetailNormalScale("_DetailNormalScale", Range(0.0, 2.0)) = 1
         _DetailSmoothnessScale("_DetailSmoothnessScale", Range(-2.0, 2.0)) = 1
         _DetailHeightScale("_DetailHeightScale", Range(-2.0, 2.0)) = 1
-        _DetailAOScale("_DetailAOScale", Range(-2.0, 2.0)) = 1        
+        _DetailAOScale("_DetailAOScale", Range(-2.0, 2.0)) = 1
+        [Enum(Standard, 0, Subsurface Scattering, 1, Clear Coat, 2)] _MaterialID("Material Class", Int) = 0
         _SubSurfaceRadius("SubSurfaceRadius", Range(0.0, 1.0)) = 0
         _SubSurfaceRadiusMap("SubSurfaceRadiusMap", 2D) = "white" {}
         //_Thickness("Thickness", Range(0.0, 1.0)) = 0
         [ToggleOff]  _AlphaCutoffEnable("Alpha Cutoff Enable", Float) = 0.0
         _AlphaCutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
 
+
+
+        // Stencil state
+        [HideInInspector] _StencilRef("_StencilRef", Int) = 0
 
         // Blending state
         [HideInInspector] _SurfaceType("__surfacetype", Float) = 0.0
             Tags { "LightMode" = "GBuffer" } // This will be only for opaque object based on the RenderQueue index
 
             Cull  [_CullMode]
+
+            Stencil
+            {
+                Ref  [_StencilRef]
+                Comp Always
+                Pass Replace
+            }
 
             HLSLPROGRAM
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/LitDataInternal.hlsl

     // This part of the code is not used in case of layered shader but we keep the same macro system for simplicity
 #if !defined(LAYERED_LIT_SHADER)
 
-    surfaceData.materialId = 0; // TODO
+    surfaceData.materialId = _MaterialID;
 
     // TODO: think about using BC5
 #ifdef _TANGENTMAP

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/LitProperties.hlsl

 TEXTURE2D(_AnisotropyMap);
 SAMPLER2D(sampler_AnisotropyMap);
 
+float _MaterialID;
+
 //float _SubSurfaceRadius;
 //TEXTURE2D(_SubSurfaceRadiusMap);
 //SAMPLER2D(sampler_SubSurfaceRadiusMap);

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/LitTessellation.shader

         _DetailNormalScale("_DetailNormalScale", Range(0.0, 2.0)) = 1
         _DetailSmoothnessScale("_DetailSmoothnessScale", Range(-2.0, 2.0)) = 1
         _DetailHeightScale("_DetailHeightScale", Range(-2.0, 2.0)) = 1
-        _DetailAOScale("_DetailAOScale", Range(-2.0, 2.0)) = 1        
+        _DetailAOScale("_DetailAOScale", Range(-2.0, 2.0)) = 1
+        [Enum(Standard, 0, Subsurface Scattering, 1, Clear Coat, 2)] _MaterialID("Material Class", Int) = 0
         _SubSurfaceRadius("SubSurfaceRadius", Range(0.0, 1.0)) = 0
         _SubSurfaceRadiusMap("SubSurfaceRadiusMap", 2D) = "white" {}
         //_Thickness("Thickness", Range(0.0, 1.0)) = 0
         _AlphaCutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5
 
         _HorizonFade("Horizon fade", Range(0.0, 5.0)) = 1.0
+
+        // Stencil state
+        [HideInInspector] _StencilRef("_StencilRef", Int) = 0
 
         // Blending state
         [HideInInspector] _SurfaceType("__surfacetype", Float) = 0.0
         _TessellationFactor("Tessellation Factor", Range(0.0, 15.0)) = 4.0
         _TessellationFactorMinDistance("Tessellation start fading distance", Float) = 20.0
         _TessellationFactorMaxDistance("Tessellation end fading distance", Float) = 50.0
-        _TessellationFactorTriangleSize("Tessellation triangle size", Float) = 100.0      
+        _TessellationFactorTriangleSize("Tessellation triangle size", Float) = 100.0
         _TessellationShapeFactor("Tessellation shape factor", Range(0.0, 1.0)) = 0.75 // Only use with Phong
         _TessellationBackFaceCullEpsilon("Tessellation back face epsilon", Range(-1.0, 0.0)) = -0.25
         [ToggleOff] _TessellationObjectScale("Tessellation object scale", Float) = 0.0
     #pragma shader_feature _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
     #pragma shader_feature _MAPPING_TRIPLANAR
     #pragma shader_feature _DETAIL_MAP_WITH_NORMAL
-    #pragma shader_feature _NORMALMAP_TANGENT_SPACE   
+    #pragma shader_feature _NORMALMAP_TANGENT_SPACE
-    #pragma shader_feature _NORMALMAP  
+    #pragma shader_feature _NORMALMAP
     #pragma shader_feature _MASKMAP
     #pragma shader_feature _SPECULAROCCLUSIONMAP
     #pragma shader_feature _EMISSIVE_COLOR_MAP
-    #pragma shader_feature _DETAIL_MAP  
+    #pragma shader_feature _DETAIL_MAP
-    //#pragma multi_compile VELOCITYOUTPUT_OFF VELOCITYOUTPUT_ON 
+    //#pragma multi_compile VELOCITYOUTPUT_OFF VELOCITYOUTPUT_ON
 
     //-------------------------------------------------------------------------------------
     // Define
     //-------------------------------------------------------------------------------------
     // Include
     //-------------------------------------------------------------------------------------
-    
+
     #include "common.hlsl"
     #include "tessellation.hlsl"
     #include "Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderConfig.cs.hlsl"
 
             Cull  [_CullMode]
 
+            Stencil
+            {
+                Ref  [_StencilRef]
+                Comp Always
+                Pass Replace
+            }
+
             HLSLPROGRAM
 
             #pragma hull Hull
             HLSLPROGRAM
 
             // Lightmap memo
-            // DYNAMICLIGHTMAP_ON is used when we have an "enlighten lightmap" ie a lightmap updated at runtime by enlighten.This lightmap contain indirect lighting from realtime lights and realtime emissive material.Offline baked lighting(from baked material / light, 
+            // DYNAMICLIGHTMAP_ON is used when we have an "enlighten lightmap" ie a lightmap updated at runtime by enlighten.This lightmap contain indirect lighting from realtime lights and realtime emissive material.Offline baked lighting(from baked material / light,
-			// No tessellation for Meta pass
+            // No tessellation for Meta pass
-            #include "../../Material/Material.hlsl"            
+            #include "../../Material/Material.hlsl"
             #include "ShaderPass/LitMetaPass.hlsl"
             #include "LitData.hlsl"
             #include "../../ShaderPass/ShaderPassLightTransport.hlsl"
 
             Cull[_CullMode]
 
-            ZWrite On 
+            ZWrite On
             ZTest LEqual
 
             HLSLPROGRAM
 
             #define SHADERPASS SHADERPASS_DEPTH_ONLY
-            #include "../../Material/Material.hlsl"            
+            #include "../../Material/Material.hlsl"
             #include "ShaderPass/LitDepthPass.hlsl"
             #include "LitData.hlsl"
             #include "../../ShaderPass/ShaderPassDepthOnly.hlsl"
 
             Cull[_CullMode]
 
-            ZWrite On 
- 
+            ZWrite On
+
             HLSLPROGRAM
 
             #pragma hull Hull
-            #include "../../Material/Material.hlsl"            
+            #include "../../Material/Material.hlsl"
             #include "ShaderPass/LitDepthPass.hlsl"
             #include "LitData.hlsl"
             #include "../../ShaderPass/ShaderPassDepthOnly.hlsl"
 
             HLSLPROGRAM
 
-			// TODO: Tesselation can't work with velocity for now...
+            // TODO: Tesselation can't work with velocity for now...
-            #include "../../Material/Material.hlsl"         
+            #include "../../Material/Material.hlsl"
             #include "ShaderPass/LitVelocityPass.hlsl"
             #include "LitData.hlsl"
             #include "../../ShaderPass/ShaderPassVelocity.hlsl"
             #pragma hull Hull
             #pragma domain Domain
 
-            #define SHADERPASS SHADERPASS_FORWARD            
+            #define SHADERPASS SHADERPASS_FORWARD
             #include "../../Lighting/Forward.hlsl"
             // TEMP until pragma work in include
             #pragma multi_compile LIGHTLOOP_SINGLE_PASS LIGHTLOOP_TILE_PASS

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Resources/PreIntegratedFGD.shader

             #pragma vertex Vert
             #pragma fragment Frag
             #pragma target 4.5
-            #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
+            #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
 
             #include "Common.hlsl"
             #include "ImageBasedLighting.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Unlit/Unlit.shader

     HLSLINCLUDE
 
     #pragma target 4.5
-    #pragma only_renderers d3d11 ps4 metal  // TEMP: unitl we go futher in dev
+    #pragma only_renderers d3d11 ps4 metal  // TEMP: until we go further in dev
 
     //-------------------------------------------------------------------------------------
     // Variant

Assets/ScriptableRenderLoop/HDRenderPipeline/SceneSettings/CommonSettings.cs

     {
         [Serializable]
         public struct Settings
-        { 
+        {
+            // Shadows
-
-            int m_ShadowCascadeCount;
-
+            int   m_ShadowCascadeCount;
-
-
-            public float shadowMaxDistance { set { m_ShadowMaxDistance = value; OnValidate(); } get { return m_ShadowMaxDistance; } }
-            public int shadowCascadeCount { set { m_ShadowCascadeCount = value; OnValidate(); } get { return m_ShadowCascadeCount; } }
+            public float shadowMaxDistance   { set { m_ShadowMaxDistance   = value; OnValidate(); } get { return m_ShadowMaxDistance; } }
+            public int   shadowCascadeCount  { set { m_ShadowCascadeCount  = value; OnValidate(); } get { return m_ShadowCascadeCount; } }
-            public void OnValidate()
+            // Subsurface scattering
+            [SerializeField] [ColorUsage(false, true, 0.05f, 2.0f, 1.0f, 1.0f)]
+            Color m_SssProfileStdDev1;
+            [SerializeField] [ColorUsage(false, true, 0.05f, 2.0f, 1.0f, 1.0f)]
+            Color m_SssProfileStdDev2;
+            [SerializeField]
+            float m_SssProfileLerpWeight;
+            [SerializeField]
+            float m_SssBilateralScale;
+
+            public Color sssProfileStdDev1    { set { m_SssProfileStdDev1    = value; OnValidate(); } get { return m_SssProfileStdDev1; } }
+            public Color sssProfileStdDev2    { set { m_SssProfileStdDev2    = value; OnValidate(); } get { return m_SssProfileStdDev2; } }
+            public float sssProfileLerpWeight { set { m_SssProfileLerpWeight = value; OnValidate(); } get { return m_SssProfileLerpWeight; } }
+            public float sssBilateralScale    { set { m_SssBilateralScale    = value; OnValidate(); } get { return m_SssBilateralScale; } }
+
+            void OnValidate()
-                m_ShadowMaxDistance = Mathf.Max(0.0f, m_ShadowMaxDistance);
-                m_ShadowCascadeCount = Math.Min(4, Math.Max(1, m_ShadowCascadeCount));
-                m_ShadowCascadeSplit0 = Mathf.Min(1.0f, Mathf.Max(0.0f, m_ShadowCascadeSplit0));
-                m_ShadowCascadeSplit1 = Mathf.Min(1.0f, Mathf.Max(0.0f, m_ShadowCascadeSplit1));
-                m_ShadowCascadeSplit2 = Mathf.Min(1.0f, Mathf.Max(0.0f, m_ShadowCascadeSplit2));
+                m_ShadowMaxDistance    = Mathf.Max(0.0f, m_ShadowMaxDistance);
+                m_ShadowCascadeCount   = Math.Min(4, Math.Max(1, m_ShadowCascadeCount));
+                m_ShadowCascadeSplit0  = Mathf.Clamp01(m_ShadowCascadeSplit0);
+                m_ShadowCascadeSplit1  = Mathf.Clamp01(m_ShadowCascadeSplit1);
+                m_ShadowCascadeSplit2  = Mathf.Clamp01(m_ShadowCascadeSplit2);
+
+                m_SssProfileStdDev1.r  = Mathf.Max(0.05f, m_SssProfileStdDev1.r);
+                m_SssProfileStdDev1.g  = Mathf.Max(0.05f, m_SssProfileStdDev1.g);
+                m_SssProfileStdDev1.b  = Mathf.Max(0.05f, m_SssProfileStdDev1.b);
+                m_SssProfileStdDev1.a  = 0.0f;
+                m_SssProfileStdDev2.r  = Mathf.Max(0.05f, m_SssProfileStdDev2.r);
+                m_SssProfileStdDev2.g  = Mathf.Max(0.05f, m_SssProfileStdDev2.g);
+                m_SssProfileStdDev2.b  = Mathf.Max(0.05f, m_SssProfileStdDev2.b);
+                m_SssProfileStdDev2.a  = 0.0f;
+                m_SssProfileLerpWeight = Mathf.Clamp01(m_SssProfileLerpWeight);
+                m_SssBilateralScale    = Mathf.Clamp01(m_SssBilateralScale);
+                m_ShadowMaxDistance    = ShadowSettings.Default.maxShadowDistance,
+                m_ShadowCascadeCount   = ShadowSettings.Default.directionalLightCascadeCount,
+                m_ShadowCascadeSplit0  = ShadowSettings.Default.directionalLightCascades.x,
+                m_ShadowCascadeSplit1  = ShadowSettings.Default.directionalLightCascades.y,
+                m_ShadowCascadeSplit2  = ShadowSettings.Default.directionalLightCascades.z,
-                m_ShadowCascadeCount = ShadowSettings.Default.directionalLightCascadeCount,
-                m_ShadowCascadeSplit0 = ShadowSettings.Default.directionalLightCascades.x,
-                m_ShadowMaxDistance = ShadowSettings.Default.maxShadowDistance,
-                m_ShadowCascadeSplit1 = ShadowSettings.Default.directionalLightCascades.y,
-                m_ShadowCascadeSplit2 = ShadowSettings.Default.directionalLightCascades.z
+                m_SssProfileStdDev1    = SubsurfaceScatteringProfile.Default.stdDev1,
+                m_SssProfileStdDev2    = SubsurfaceScatteringProfile.Default.stdDev2,
+                m_SssProfileLerpWeight = SubsurfaceScatteringProfile.Default.lerpWeight,
+                m_SssBilateralScale    = SubsurfaceScatteringParameters.Default.bilateralScale
-       
+
         [SerializeField]
         private Settings m_Settings = Settings.s_Defaultsettings;
 

Assets/ScriptableRenderLoop/HDRenderPipeline/SceneSettings/Editor/CommonSettingsEditor.cs

             public readonly GUIContent shadowsCascades = new GUIContent("Cascade values");
             public readonly GUIContent[] shadowSplits = new GUIContent[] { new GUIContent("Split 0"), new GUIContent("Split 1"), new GUIContent("Split 2") };
 
+            public readonly GUIContent sssCategory          = new GUIContent("Subsurface scattering");
+            public readonly GUIContent sssProfileStdDev1    = new GUIContent("SSS profile standard deviation #1", "Determines the shape of the 1st Gaussian filter. Increases the strength and the radius of the blur of the corresponding color channel.");
+            public readonly GUIContent sssProfileStdDev2    = new GUIContent("SSS profile standard deviation #2", "Determines the shape of the 2nd Gaussian filter. Increases the strength and the radius of the blur of the corresponding color channel.");
+            public readonly GUIContent sssProfileLerpWeight = new GUIContent("SSS profile filter interpolation", "Controls linear interpolation between the two Gaussian filters.");
+            public readonly GUIContent sssBilateralScale    = new GUIContent("SSS bilateral filtering scale", "Larger values make the filter more tolerant to depth differences.");
         }
 
         private static Styles s_Styles = null;
         private SerializedProperty m_ShadowCascadeCount;
         private SerializedProperty[] m_ShadowCascadeSplits = new SerializedProperty[3];
 
+        // Subsurface scattering
+        private SerializedProperty m_SssProfileStdDev1;
+        private SerializedProperty m_SssProfileStdDev2;
+        private SerializedProperty m_SssProfileLerpWeight;
+        private SerializedProperty m_SssBilateralScale;
+
         void OnEnable()
         {
             m_SkyRenderer = serializedObject.FindProperty("m_SkyRendererTypeName");
             m_SkyRendererFullTypeNames.Add("");
             m_SkyRendererTypeValues.Add(m_SkyRendererTypeValues.Count);
             m_SkyRendererTypes.Add(null);
+
+            m_SssProfileStdDev1    = serializedObject.FindProperty("m_SssProfileStdDev1");
+            m_SssProfileStdDev2    = serializedObject.FindProperty("m_SssProfileStdDev2");
+            m_SssProfileLerpWeight = serializedObject.FindProperty("m_SssProfileLerpWeight");
+            m_SssBilateralScale    = serializedObject.FindProperty("m_SssBilateralScale");
         }
 
         void OnSkyInspectorGUI()
             EditorGUI.indentLevel--;
         }
 
-      /*  public override void OnInspectorGUI()
+        void OnSubsurfaceInspectorGUI()
+        {
+            EditorGUILayout.LabelField(styles.sssCategory);
+            EditorGUI.indentLevel++;
+            EditorGUILayout.PropertyField(m_SssProfileStdDev1,    styles.sssProfileStdDev1);
+            EditorGUILayout.PropertyField(m_SssProfileStdDev2,    styles.sssProfileStdDev2);
+            EditorGUILayout.PropertyField(m_SssProfileLerpWeight, styles.sssProfileLerpWeight);
+            EditorGUILayout.PropertyField(m_SssBilateralScale,    styles.sssBilateralScale);
+            EditorGUI.indentLevel--;
+        }
+
+        /*
+        public override void OnInspectorGUI()
+            OnSubsurfaceInspectorGUI();
-        }*/
+        }
+        */
     }
 }

Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderPass/ShaderPassForward.hlsl

 
 #endif // TESSELLATION_ON
 
-void Frag(  PackedVaryingsToPS packedInput,
-            out float4 outColor : SV_Target
-            #ifdef _DEPTHOFFSET_ON
-            , out float outputDepth : SV_Depth
-            #endif
-        )
+void Frag(PackedVaryingsToPS packedInput,
+          out float4 outColor : SV_Target0
+      #ifdef _DEPTHOFFSET_ON
+          , out float outputDepth : SV_Depth
+      #endif
+          )
 {
     FragInputs input = UnpackVaryingsMeshToFragInputs(packedInput.vmesh);
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Sky/HDRISky/Resources/SkyHDRI.shader

     #pragma fragment Frag
 
     #pragma target 4.5
-    #pragma only_renderers d3d11 ps4 metal // TEMP: unitl we go futher in dev
+    #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
 
     #include "Color.hlsl"
     #include "Common.hlsl"

Assets/ScriptableRenderLoop/HDRenderPipeline/Sky/ProceduralSky/Resources/SkyProcedural.shader

 
             HLSLPROGRAM
             #pragma target 4.5
-            #pragma only_renderers d3d11 ps4 metal  // TEMP: unitl we go futher in dev
+            #pragma only_renderers d3d11 ps4 metal  // TEMP: until we go further in dev
 
             #pragma vertex Vert
             #pragma fragment Frag

Assets/ScriptableRenderLoop/HDRenderPipeline/Sky/Resources/GGXConvolve.shader

 
             HLSLPROGRAM
             #pragma target 4.5
-            #pragma only_renderers d3d11 ps4 metal  // TEMP: unitl we go futher in dev
+            #pragma only_renderers d3d11 ps4 metal  // TEMP: until we go further in dev
 
             #pragma multi_compile _ USE_MIS
 

Assets/ScriptableRenderLoop/HDRenderPipeline/Utilities.cs

     [Flags]
     public enum ClearFlag
     {
-        ClearNone = 0,
+        ClearNone  = 0,
+    }
+
+    [Flags]
+    public enum StencilBits
+    {
+        None      = Lit.MaterialId.LitStandard, 
+        SSS       = Lit.MaterialId.LitSSS,
+        ClearCoat = Lit.MaterialId.LitClearCoat,
+        All       = 255 // 0xff
     }
 
     public class Utilities
                 m.DisableKeyword(keyword);
         }
 
+        public static void SelectKeyword(Material material, string keyword1, string keyword2, bool enableFirst)
+        {
+            material.EnableKeyword (enableFirst ? keyword1 : keyword2);
+            material.DisableKeyword(enableFirst ? keyword2 : keyword1);
+        }
+
+        public static void SelectKeyword(Material material, string[] keywords, int enabledKeywordIndex)
+        {
+            material.EnableKeyword(keywords[enabledKeywordIndex]);
+
+            for (int i = 0; i < keywords.Length; i++)
+            {
+                if (i != enabledKeywordIndex)
+                {
+                    material.DisableKeyword(keywords[i]);
+                }
+            }
+        }
+
         public static HDRenderPipeline GetHDRenderPipeline()
         {
             HDRenderPipeline renderContext = GraphicsSettings.renderPipelineAsset as HDRenderPipeline;
             }
 
             return renderContext;
+        }
+
+        static Mesh m_ScreenSpaceTriangle = null;
+
+        static Mesh GetScreenSpaceTriangle()
+        {
+            // If the assembly has been reloaded, the pointer will become NULL.
+            if (!m_ScreenSpaceTriangle)
+            {
+                m_ScreenSpaceTriangle = new Mesh
+                {
+                    // Note: neither the vertex nor the index data is actually used if the vertex shader computes vertices
+                    // using 'SV_VertexID'. However, there is currently no way to bind NULL vertex or index buffers.
+                    vertices  = new[] { new Vector3(-1, -1, 1), new Vector3(3, -1, 1), new Vector3(-1, 3, 1) },
+                    triangles = new[] { 0, 1, 2 }
+                };
+            }
+
+            return m_ScreenSpaceTriangle;
+        }
+
+        // Draws a full screen triangle as a faster alternative to drawing a full-screen quad.
+        public static void DrawFullscreen(CommandBuffer commandBuffer, Material material, HDCamera camera,
+                                          RenderTargetIdentifier colorBuffer,
+                                          MaterialPropertyBlock properties = null, int shaderPassID = 0)
+        {
+            SetupMaterialHDCamera(camera, material);
+            commandBuffer.SetRenderTarget(colorBuffer);
+            commandBuffer.DrawMesh(GetScreenSpaceTriangle(), Matrix4x4.identity, material, 0, shaderPassID, properties);
+        }
+
+        // Draws a full screen triangle as a faster alternative to drawing a full-screen quad.
+        public static void DrawFullscreen(CommandBuffer commandBuffer, Material material, HDCamera camera,
+                                          RenderTargetIdentifier colorBuffer, RenderTargetIdentifier depthStencilBuffer,
+                                          MaterialPropertyBlock properties = null, int shaderPassID = 0)
+        {
+            SetupMaterialHDCamera(camera, material);
+            commandBuffer.SetRenderTarget(colorBuffer, depthStencilBuffer);
+            commandBuffer.DrawMesh(GetScreenSpaceTriangle(), Matrix4x4.identity, material, 0, shaderPassID, properties);
+        }
+
+        // Draws a full screen triangle as a faster alternative to drawing a full-screen quad.
+        public static void DrawFullscreen(CommandBuffer commandBuffer, Material material, HDCamera camera,
+                                          RenderTargetIdentifier[] colorBuffers, RenderTargetIdentifier depthStencilBuffer,
+                                          MaterialPropertyBlock properties = null, int shaderPassID = 0)
+        {
+            SetupMaterialHDCamera(camera, material);
+            commandBuffer.SetRenderTarget(colorBuffers, depthStencilBuffer);
+            commandBuffer.DrawMesh(GetScreenSpaceTriangle(), Matrix4x4.identity, material, 0, shaderPassID, properties);
+        }
+
+        // Draws a full screen triangle as a faster alternative to drawing a full-screen quad.
+        // Important: the first RenderTarget must be created with 0 depth bits!
+        public static void DrawFullscreen(CommandBuffer commandBuffer, Material material, HDCamera camera,
+                                          RenderTargetIdentifier[] colorBuffers,
+                                          MaterialPropertyBlock properties = null, int shaderPassID = 0)
+        {
+            // It is currently not possible to have MRT without also setting a depth target.
+            // To work around this deficiency of the CommandBuffer.SetRenderTarget() API,
+            // we pass the first color target as the depth target. If it has 0 depth bits,
+            // no depth target ends up being bound.
+            DrawFullscreen(commandBuffer, material, camera, colorBuffers, colorBuffers[0], properties, shaderPassID);
         }
     }
 }

Assets/ScriptableRenderLoop/ShaderLibrary/Common.hlsl

     posInput.positionWS += V * depthOffsetVS;
 }
 
+
+// Generates a triangle in homogeneous clip space, s.t.
+// v0 = (-1, -1, 1), v1 = (3, -1, 1), v2 = (-1, 3, 1).
+float4 GetFullscreenTriangleVertexPosition(uint vertexID)
+{
+    float2 uv = float2((vertexID << 1) & 2, vertexID & 2);
+    return float4(uv * 2.0 - 1.0, 1.0, 1.0);
+}
+
 #endif // UNITY_COMMON_INCLUDED

Assets/ScriptableRenderLoop/ShaderLibrary/Hammersley.hlsl

 #endif
 }
 
-float RadicalInverse_VdC(uint bits)
+float VanDerCorputBase2(uint i)
-    return float(ReverseBits32(bits)) * 2.3283064365386963e-10; // 0x100000000
+    return float(ReverseBits32(i + 1)) * 2.3283064365386963e-10; // 0x100000000
-    return float2(float(i) / float(sequenceLength), RadicalInverse_VdC(i));
+    return float2(float(i) / float(sequenceLength), VanDerCorputBase2(i));
 }
 
 static const float2 k_Hammersley2dSeq16[] = {

Assets/TestScenes/HDTest/HDRenderLoopTest.meta

 fileFormatVersion: 2
-guid: e32d408209990884fb73c388f877fb95
+guid: bb067c1f82e9d8648b8909e905f6607b
-timeCreated: 1485526169
+timeCreated: 1484331444
 licenseType: Pro
 DefaultImporter:
   userData: 

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Resources/CombineSubsurfaceScattering.shader

+Shader "Hidden/HDRenderPipeline/CombineSubsurfaceScattering"
+{
+    Properties
+    {
+        _FilterRadius("", Float) = 20
+        _BilateralScale("", Float) = 0.1
+        [HideInInspector] _DstBlend("", Float) = 1 // Can be set to 1 for blending with specular
+    }
+
+    SubShader
+    {
+        Pass
+        {
+            Stencil
+            {
+                Ref  1 // StencilBits.SSS
+                Comp Equal
+                Pass Keep
+            }
+
+            ZTest  Always
+            ZWrite Off
+            Blend  One [_DstBlend], Zero [_DstBlend]
+
+            HLSLPROGRAM
+            #pragma target 4.5
+            #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
+
+            #pragma vertex Vert
+            #pragma fragment Frag
+
+            //-------------------------------------------------------------------------------------
+            // Include
+            //-------------------------------------------------------------------------------------
+
+            #include "Common.hlsl"
+            #include "Assets/ScriptableRenderLoop/HDRenderPipeline/ShaderVariables.hlsl"
+
+            //-------------------------------------------------------------------------------------
+            // Inputs & outputs
+            //-------------------------------------------------------------------------------------
+
+            #define N_SAMPLES 7
+
+            float  _BilateralScale;   // Uses world-space units
+            float  _DistToProjWindow; // The height of the projection window is 2 meters
+            float  _FilterHorizontal; // Vertical = 0, horizontal = 1
+            float4 _FilterKernel[7];  // RGB = weights, A = radial distance
+            float  _FilterRadius;     // Uses world-space units
+
+            TEXTURE2D(_CameraDepthTexture);
+            TEXTURE2D(_IrradianceSource);
+            SAMPLER2D(sampler_IrradianceSource);
+
+            #define bilinearSampler sampler_IrradianceSource
+
+            //-------------------------------------------------------------------------------------
+            // Implementation
+            //-------------------------------------------------------------------------------------
+
+            struct Attributes
+            {
+                uint vertexID : SV_VertexID;
+            };
+
+            struct Varyings
+            {
+                float4 positionCS : SV_Position;
+            };
+
+            Varyings Vert(Attributes input)
+            {
+                Varyings output;
+                output.positionCS = GetFullscreenTriangleVertexPosition(input.vertexID);
+                return output;
+            }
+
+            float4 Frag(Varyings input) : SV_Target
+            {
+                PositionInputs posInput = GetPositionInput(input.positionCS.xy, _ScreenSize.zw);
+
+                float rawDepth    = LOAD_TEXTURE2D(_CameraDepthTexture, posInput.unPositionSS).r;
+                float centerDepth = LinearEyeDepth(rawDepth, _ZBufferParams);
+                float radiusScale = _FilterRadius * _DistToProjWindow / centerDepth;
+
+                // Compute the filtering direction.
+                float2 unitDirection   = _FilterHorizontal ? float2(1, 0) : float2(0, 1);
+                float2 scaledDirection = radiusScale * unitDirection;
+
+                // Premultiply with the inverse of the screen size.
+                scaledDirection *= _ScreenSize.zw;
+
+                // Take the first (central) sample.
+                float3 sampleWeight   = _FilterKernel[0].rgb;
+                float2 samplePosition = posInput.unPositionSS;
+
+                float3 sampleIrradiance = LOAD_TEXTURE2D(_IrradianceSource, samplePosition).rgb;
+                float3 centerIrradiance = sampleIrradiance;
+
+                // Accumulate filtered irradiance (already weighted by (albedo / Pi)).
+                float3 filteredIrradiance = sampleIrradiance * sampleWeight;
+
+                [unroll]
+                for (int i = 1; i < N_SAMPLES; i++)
+                {
+                    sampleWeight   = _FilterKernel[i].rgb;
+                    samplePosition = posInput.positionSS + scaledDirection * _FilterKernel[i].a;
+
+                    sampleIrradiance = SAMPLE_TEXTURE2D_LOD(_IrradianceSource,   bilinearSampler, samplePosition, 0).rgb;
+                    rawDepth         = SAMPLE_TEXTURE2D_LOD(_CameraDepthTexture, bilinearSampler, samplePosition, 0).r;
+
+                    // Apply bilateral filtering.
+                    float sampleDepth = LinearEyeDepth(rawDepth, _ZBufferParams);
+                    float depthDiff   = abs(sampleDepth - centerDepth);
+                    float scaleDiff   = _BilateralScale * _FilterRadius * _DistToProjWindow;
+                    float t           = saturate(depthDiff / scaleDiff);
+
+                    // TODO: use real-world distances for weighting.
+                    filteredIrradiance += lerp(sampleIrradiance, centerIrradiance, t) * sampleWeight;
+                }
+
+                return float4(filteredIrradiance, 1.0);
+            }
+            ENDHLSL
+        }
+    }
+    Fallback Off
+}

Assets/ScriptableRenderLoop/HDRenderPipeline/Material/Lit/Resources/CombineSubsurfaceScattering.shader.meta

+fileFormatVersion: 2
+guid: 867b36db983aa0548889a66f8d685ff6
+timeCreated: 1485184880
+licenseType: Pro
+ShaderImporter:
+  defaultTextures: []
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/ScriptableRenderLoop/HDRenderPipeline/SceneSettings/SubsurfaceScatteringParameters.cs

+using System;
+
+namespace UnityEngine.Experimental.Rendering.HDPipeline
+{
+    [Serializable]
+    public class SubsurfaceScatteringProfile
+    {
+        public const int numSamples = 7;
+
+        Color     m_StdDev1;
+        Color     m_StdDev2;
+        float     m_LerpWeight;
+        Vector4[] m_FilterKernel;
+        bool      m_KernelNeedsUpdate;
+
+        // --- Methods ---
+
+        public Color stdDev1
+        {
+            get { return m_StdDev1; }
+            set { if (m_StdDev1 != value) { m_StdDev1 = value; m_KernelNeedsUpdate = true; } }
+        }
+
+        public Color stdDev2
+        {
+            get { return m_StdDev2; }
+            set { if (m_StdDev2 != value) { m_StdDev2 = value; m_KernelNeedsUpdate = true; } }
+        }
+
+        public float lerpWeight
+        {
+            get { return m_LerpWeight; }
+            set { if (m_LerpWeight != value) { m_LerpWeight = value; m_KernelNeedsUpdate = true; } }
+        }
+
+        public Vector4[] filterKernel
+        {
+            get { if (m_KernelNeedsUpdate) ComputeKernel(); return m_FilterKernel; }
+        }
+
+        public static SubsurfaceScatteringProfile Default
+        {
+            get
+            {
+                SubsurfaceScatteringProfile profile = new SubsurfaceScatteringProfile();
+                profile.m_StdDev1    = new Color(0.3f, 0.3f, 0.3f, 0.0f);
+                profile.m_StdDev2    = new Color(1.0f, 1.0f, 1.0f, 0.0f);
+                profile.m_LerpWeight = 0.5f;
+                profile.ComputeKernel();
+                return profile;
+            }
+        }
+
+        static float Gaussian(float x, float stdDev)
+        {
+            float variance = stdDev * stdDev;
+            return Mathf.Exp(-x * x / (2 * variance)) / Mathf.Sqrt(2 * Mathf.PI * variance);
+        }
+
+        static float GaussianCombination(float x, float stdDev1, float stdDev2, float lerpWeight)
+        {
+            return Mathf.Lerp(Gaussian(x, stdDev1), Gaussian(x, stdDev2), lerpWeight);
+        }
+
+        static float RationalApproximation(float t)
+        {
+            // Abramowitz and Stegun formula 26.2.23.
+            // The absolute value of the error should be less than 4.5 e-4.
+            float[] c = {2.515517f, 0.802853f, 0.010328f};
+            float[] d = {1.432788f, 0.189269f, 0.001308f};
+            return t - ((c[2] * t + c[1]) * t + c[0]) / (((d[2] * t + d[1]) * t + d[0]) * t + 1.0f);
+        }
+ 
+        // Ref: https://www.johndcook.com/blog/csharp_phi_inverse/
+        static float NormalCdfInverse(float p, float stdDev)
+        {
+            float x;
+
+            if (p < 0.5)
+            {
+                // F^-1(p) = - G^-1(p)
+                x = -RationalApproximation(Mathf.Sqrt(-2.0f * Mathf.Log(p)));
+            }
+            else
+            {
+                // F^-1(p) = G^-1(1-p)
+                x = RationalApproximation(Mathf.Sqrt(-2.0f * Mathf.Log(1.0f - p)));
+            }
+
+            return x * stdDev;
+        }
+
+        static float GaussianCombinationCdfInverse(float p, float stdDev1, float stdDev2, float lerpWeight)
+        {
+            return Mathf.Lerp(NormalCdfInverse(p, stdDev1), NormalCdfInverse(p, stdDev2), lerpWeight);
+        }
+
+        // Ref: http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
+        static float VanDerCorputBase2(uint i)
+        {
+            i = i + 1;
+            i = (i << 16) | (i >> 16);
+            i = ((i & 0x00ff00ff) << 8) | ((i & 0xff00ff00) >> 8);
+            i = ((i & 0x0f0f0f0f) << 4) | ((i & 0xf0f0f0f0) >> 4);
+            i = ((i & 0x33333333) << 2) | ((i & 0xcccccccc) >> 2);
+            i = ((i & 0x55555555) << 1) | ((i & 0xaaaaaaaa) >> 1);
+
+            return i * (1.0f / 4294967296);
+        }
+
+        void ComputeKernel()
+        {
+            if (m_FilterKernel == null)
+            {
+                m_FilterKernel = new Vector4[numSamples];
+            }
+
+            // Our goal is to blur the image using a filter which is represented
+            // as a product of a linear combination of two normalized 1D Gaussians
+            // as suggested by Jimenez et al. in "Separable Subsurface Scattering".
+            // A normalized (i.e. energy-preserving) 1D Gaussian with the mean of 0
+            // is defined as follows: G1(x, v) = exp(-x� / (2 * v)) / sqrt(2 * Pi * v),
+            // where 'v' is variance and 'x' is the radial distance from the origin.
+            // Using the weight 'w', our 1D and the resulting 2D filters are given as:
+            // A1(v1, v2, w, x)    = G1(x, v1) * (1 - w) + G1(r, v2) * w,
+            // A2(v1, v2, w, x, y) = A1(v1, v2, w, x) * A1(v1, v2, w, y).
+            // The resulting filter function is a non-Gaussian PDF.
+            // It is separable by design, but generally not radially symmetric.
+
+            // Find the widest Gaussian across 3 color channels.
+            float maxStdDev1 = Mathf.Max(m_StdDev1.r, m_StdDev1.g, m_StdDev1.b);
+            float maxStdDev2 = Mathf.Max(m_StdDev2.r, m_StdDev2.g, m_StdDev2.b);
+
+            Vector3 weightSum = new Vector3(0, 0, 0); 
+
+            // Importance sample the linear combination of two Gaussians.
+            for (uint i = 0; i < numSamples; i++)
+            {
+                float u   = VanDerCorputBase2(i);
+                float pos = GaussianCombinationCdfInverse(u, maxStdDev1, maxStdDev2, m_LerpWeight);
+                float pdf = GaussianCombination(pos, maxStdDev1, maxStdDev2, m_LerpWeight);
+
+                Vector3 val;
+                val.x = GaussianCombination(pos, m_StdDev1.r, m_StdDev2.r, m_LerpWeight);
+                val.y = GaussianCombination(pos, m_StdDev1.g, m_StdDev2.g, m_LerpWeight);
+                val.z = GaussianCombination(pos, m_StdDev1.b, m_StdDev2.b, m_LerpWeight);
+
+                m_FilterKernel[i].x = val.x / (pdf * numSamples);
+                m_FilterKernel[i].y = val.y / (pdf * numSamples);
+                m_FilterKernel[i].z = val.z / (pdf * numSamples);
+                m_FilterKernel[i].w = pos;
+
+                weightSum.x += m_FilterKernel[i].x;
+                weightSum.y += m_FilterKernel[i].y;
+                weightSum.z += m_FilterKernel[i].z;
+            }
+
+            // Renormalize the weights to conserve energy.
+            for (uint i = 0; i < numSamples; i++)
+            {
+                m_FilterKernel[i].x *= 1.0f / weightSum.x;
+                m_FilterKernel[i].y *= 1.0f / weightSum.y;
+                m_FilterKernel[i].z *= 1.0f / weightSum.z;
+            }
+
+            m_KernelNeedsUpdate = false;
+        }
+    }
+
+    [System.Serializable]
+    public class SubsurfaceScatteringParameters
+    {
+        public const int                     numProfiles = 1;
+        public SubsurfaceScatteringProfile[] profiles;
+        public float                         bilateralScale;
+
+        // --- Methods ---
+
+        public static SubsurfaceScatteringParameters Default
+        {
+            get
+            {
+                SubsurfaceScatteringParameters parameters = new SubsurfaceScatteringParameters();
+                parameters.profiles = new SubsurfaceScatteringProfile[numProfiles];
+
+                for (int i = 0; i < numProfiles; i++)
+                {
+                    parameters.profiles[i] = SubsurfaceScatteringProfile.Default;
+                }
+
+                parameters.bilateralScale = 0.1f;
+                return parameters;
+            }
+        }
+    }
+}

Assets/ScriptableRenderLoop/HDRenderPipeline/SceneSettings/SubsurfaceScatteringParameters.cs.meta

+fileFormatVersion: 2
+guid: e9493dbe9d624704d9a80a75d52835b3
+timeCreated: 1485361779
+licenseType: Pro
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/TestScenes/HDTest/GraphicTest/Two Sided/Prefabs/Materials.meta

+fileFormatVersion: 2
+guid: 0e2aa881811d0644896d4b5a732945cc
+folderAsset: yes
+timeCreated: 1485804900
+licenseType: Pro
+DefaultImporter:
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 

Assets/TestScenes/HDTest/Leaf.meta

-fileFormatVersion: 2
-guid: 01cfa4863006ad6499396fb0d4802c7e
-folderAsset: yes
-timeCreated: 1475755141
-licenseType: Pro
-DefaultImporter:
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: