Perform the stencil test during the MaterialFeatureFlag generation

Assets/ScriptableRenderPipeline/HDRenderPipeline/HDRenderPipeline.cs

 
         readonly GBufferManager m_gbufferManager = new GBufferManager();
 
-        Material m_CopyStencilBuffer;
+        Material m_CopyStencilForSplitLighting;
+        Material m_CopyStencilForRegularLighting;
 
         // Various set of material use in render loop
         ComputeShader m_SubsurfaceScatteringCS { get { return m_Asset.renderPipelineResources.subsurfaceScatteringCS; } }
             CreateSssMaterials(sssSettings.useDisneySSS);
             // <<< Old SSS Model
 
-            m_CopyStencilBuffer           = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/CopyStencilBuffer");
-            m_CameraMotionVectorsMaterial = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/CameraMotionVectors");
+            m_CopyStencilForSplitLighting   = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/CopyStencilBuffer");
+            m_CopyStencilForSplitLighting.EnableKeyword("EXPORT_HTILE");
+            m_CopyStencilForSplitLighting.SetInt("_StencilRef", (int)StencilLightingUsage.SplitLighting);
+            m_CopyStencilForRegularLighting = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/CopyStencilBuffer");
+            m_CopyStencilForRegularLighting.DisableKeyword("EXPORT_HTILE");
+            m_CopyStencilForRegularLighting.SetInt("_StencilRef", (int)StencilLightingUsage.RegularLighting);
+            m_CameraMotionVectorsMaterial   = Utilities.CreateEngineMaterial("Hidden/HDRenderPipeline/CameraMotionVectors");
 
             InitializeDebugMaterials();
 
                 using (new Utilities.ProfilingSample("Copy StencilBuffer", cmd))
                 {
                     cmd.SetRandomWriteTarget(1, GetHTile());
-                    Utilities.DrawFullScreen(cmd, m_CopyStencilBuffer, m_CameraStencilBufferCopyRT, m_CameraDepthStencilBufferRT);
+                    // Our method of exporting the stencil requires one pass per unique stencil value.
+                    Utilities.DrawFullScreen(cmd, m_CopyStencilForSplitLighting,   m_CameraStencilBufferCopyRT, m_CameraDepthStencilBufferRT);
+                    Utilities.DrawFullScreen(cmd, m_CopyStencilForRegularLighting, m_CameraStencilBufferCopyRT, m_CameraDepthStencilBufferRT);
                     cmd.ClearRandomWriteTargets();
                 }
             }
                     m_LightLoop.PrepareLightsForGPU(m_ShadowSettings, m_CullResults, camera);
                     m_LightLoop.RenderShadows(renderContext, cmd, m_CullResults);
                     renderContext.SetupCameraProperties(camera); // Need to recall SetupCameraProperties after m_ShadowPass.Render
-                    m_LightLoop.BuildGPULightLists(camera, cmd, m_CameraDepthStencilBufferRT);
+                    m_LightLoop.BuildGPULightLists(camera, cmd, m_CameraDepthStencilBufferRT, GetStencilTexture());
                 }
 
                 // Caution: We require sun light here as some sky use the sun light to render, mean UpdateSkyEnvironment

Assets/ScriptableRenderPipeline/HDRenderPipeline/Lighting/TilePass/TilePass.cs

                 cmd.DispatchCompute(buildPerVoxelLightListShader, s_GenListPerVoxelKernel, numTilesX, numTilesY, 1);
             }
 
-            public void BuildGPULightLists(Camera camera, CommandBuffer cmd, RenderTargetIdentifier cameraDepthBufferRT)
+            public void BuildGPULightLists(Camera camera, CommandBuffer cmd, RenderTargetIdentifier cameraDepthBufferRT, RenderTargetIdentifier stencilTextureRT)
             {
                 var w = camera.pixelWidth;
                 var h = camera.pixelHeight;
                         cmd.SetComputeIntParams(buildMaterialFlagsShader, "g_viDimensions", w, h);
                         cmd.SetComputeBufferParam(buildMaterialFlagsShader, buildMaterialFlagsKernel, "g_TileFeatureFlags", s_TileFeatureFlags);
 
-                        cmd.SetComputeTextureParam(buildMaterialFlagsShader, buildMaterialFlagsKernel, "g_depth_tex", cameraDepthBufferRT);
+                        cmd.SetComputeTextureParam(buildMaterialFlagsShader, buildMaterialFlagsKernel, "_StencilTexture", stencilTextureRT);
                         cmd.SetComputeTextureParam(buildMaterialFlagsShader, buildMaterialFlagsKernel, "_GBufferTexture0", Shader.PropertyToID("_GBufferTexture0"));
                         cmd.SetComputeTextureParam(buildMaterialFlagsShader, buildMaterialFlagsKernel, "_GBufferTexture1", Shader.PropertyToID("_GBufferTexture1"));
                         cmd.SetComputeTextureParam(buildMaterialFlagsShader, buildMaterialFlagsKernel, "_GBufferTexture2", Shader.PropertyToID("_GBufferTexture2"));

Assets/ScriptableRenderPipeline/HDRenderPipeline/Lighting/TilePass/materialflags.compute

 #pragma kernel MaterialFlagsGen_Write		MATERIALFLAGSGEN=MaterialFlagsGen_Write
 #pragma kernel MaterialFlagsGen_Or			MATERIALFLAGSGEN=MaterialFlagsGen_Or		USE_OR
 
-//#pragma #pragma enable_d3d11_debug_symbols
+// #pragma enable_d3d11_debug_symbols
 
 #include "../../../ShaderLibrary/common.hlsl"
 #include "ShaderBase.hlsl"
 #include "../../Material/Material.hlsl" // This includes Material.hlsl
+#include "../../Lighting/LightDefinition.cs.hlsl"
 
 #define USE_MATERIAL_FEATURE_FLAGS
 #define NR_THREADS	64
 uint g_BaseFeatureFlags;
 CBUFFER_END
 
-Texture2D g_depth_tex : register( t0 );
-
+TEXTURE2D(_StencilTexture);               // DXGI_FORMAT_R8_UINT is not supported by Unity
 DECLARE_GBUFFER_TEXTURE(_GBufferTexture);
 
 [numthreads(NR_THREADS, 1, 1)]
 		int idx = i * NR_THREADS + threadID;
 		uint2 uCrd = min( uint2(viTilLL.x + (idx & 0xf), viTilLL.y + (idx >> 4)), uint2(iWidth - 1, iHeight - 1));
 
-		if (FetchDepth(g_depth_tex, uCrd) < VIEWPORT_SCALE_Z) // This test is we are the sky/background or not
+		if (UnpackByte(LOAD_TEXTURE2D(_StencilTexture, uCrd).r) != STENCILLIGHTINGUSAGE_NO_LIGHTING) // This test is we are the sky/background or not
 		{
 			PositionInputs posInput = GetPositionInput(uCrd, invScreenSize);
 			FETCH_GBUFFER(gbuffer, _GBufferTexture, posInput.unPositionSS);

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Resources/CopyStencilBuffer.shader

 Shader "Hidden/HDRenderPipeline/CopyStencilBuffer"
 {
+    Properties
+    {
+        [HideInInspector] _StencilRef("_StencilRef", Int) = 1
+    }
+
     SubShader
     {
         Pass
-                Ref  1 // StencilLightingUsage.SplitLighting
+                Ref  [_StencilRef]
                 Comp Equal
                 Pass Keep
             }
             HLSLPROGRAM
             #pragma target 4.5
             #pragma only_renderers d3d11 ps4 metal // TEMP: until we go further in dev
+            #pragma multi_compile _ EXPORT_HTILE
-            #include "../../../../ShaderLibrary/Common.hlsl"
+            #include "../../../../ShaderLibrary/Packing.hlsl"
+            int _StencilRef;
             RW_TEXTURE2D(float, _HTile); // DXGI_FORMAT_R8_UINT is not supported by Unity
 
             struct Attributes
             {
                 uint2 positionSS = (uint2)input.positionCS.xy;
 
-                // There's no need for atomics as we are always writing the same value.
-                // Note: the GCN tile size is 8x8 pixels.
-                _HTile[positionSS / 8] = STENCILLIGHTINGUSAGE_SPLIT_LIGHTING;
+                #ifdef EXPORT_HTILE
+                    // There's no need for atomics as we are always writing the same value.
+                    // Note: the GCN tile size is 8x8 pixels.
+                    _HTile[positionSS / 8] = _StencilRef;
+                #endif
-                return float4(STENCILLIGHTINGUSAGE_SPLIT_LIGHTING, 0, 0, 0);
+                return PackByte(_StencilRef);
             }
             ENDHLSL
         }

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/Resources/SubsurfaceScattering.compute

 // Included headers
 //--------------------------------------------------------------------------------------------------
 
-#include "../../../../ShaderLibrary/Common.hlsl"
+#include "../../../../ShaderLibrary/Packing.hlsl"
 #include "../../../../ShaderLibrary/SpaceFillingCurves.hlsl"
 #include "../../../ShaderVariables.hlsl"
 #define UNITY_MATERIAL_LIT
     {
         // Unfortunately, our copy of HTile does not allow to accept at the tile rate.
         // Therefore, we have to additionally perform the stencil test at the pixel rate.
-        passedStencilTest = stencilRef == LOAD_TEXTURE2D(_StencilTexture, pixelCoord).r;
+        passedStencilTest = stencilRef == UnpackByte(LOAD_TEXTURE2D(_StencilTexture, pixelCoord).r);
     }
 
     return passedStencilTest;