[UUM-134522][UUM-136056][URP 2D][6000.6] Fix 2d shadow volumetric bugs

Author: kennytann

Packages/com.unity.render-pipelines.universal/Runtime/2D/Lights/Light2DCullResult.cs

@@ -74,7 +74,7 @@ public LightStats GetLightStatsByLayer(int layerID, ref LayerBatch layer)
                     returnStats.totalNormalMapUsage++;
                 if (light.volumeIntensity > 0 && light.volumetricEnabled)
                     returnStats.totalVolumetricUsage++;
-                if (light.volumeIntensity > 0 && light.volumetricEnabled && RendererLighting.CanCastShadows(light, layerID))
+                if (RendererLighting.CanCastVolumetricShadows(light, layer.endLayerValue))
                     returnStats.totalVolumetricShadowUsage++;
 
                 returnStats.blendStylesUsed |= (uint)(1 << light.blendStyleIndex);

Packages/com.unity.render-pipelines.universal/Runtime/2D/Passes/Utility/RendererLighting.cs

@@ -153,6 +153,11 @@ internal static bool CanCastShadows(Light2D light, int layerToRender)
             return light.shadowsEnabled && light.shadowIntensity > 0 && light.IsLitLayer(layerToRender);
         }
 
+        internal static bool CanCastVolumetricShadows(Light2D light, int endLayerValue)
+        {
+            return light.volumeIntensity > 0 && light.volumetricEnabled && light.renderVolumetricShadows && light.GetTopMostLitLayer() == endLayerValue;
+        }
+
         internal static void SetLightShaderGlobals(IRasterCommandBuffer cmd, Light2DBlendStyle[] lightBlendStyles, int[] blendStyleIndices)
         {
             for (var i = 0; i < blendStyleIndices.Length; i++)

Packages/com.unity.render-pipelines.universal/Runtime/2D/Rendergraph/DrawLight2DPass.cs

@@ -86,7 +86,8 @@ private static void Execute(RasterCommandBuffer cmd, PassData passData, LayerBat
                     layerBatch.endLayerValue != light.GetTopMostLitLayer()))
                     continue;
 
-                var useShadows = passData.layerBatch.lightStats.useShadows && layerBatch.shadowIndices.Contains(j);
+                var useShadows = (!passData.isVolumetric && passData.layerBatch.lightStats.useShadows) || (passData.isVolumetric && passData.layerBatch.lightStats.useVolumetricShadowLights);
+                useShadows &= layerBatch.shadowIndices.Contains(j);
                 var lightMaterial = passData.rendererData.GetLightMaterial(light, passData.isVolumetric, useShadows);
                 var lightMesh = light.lightMesh;
 

Packages/com.unity.render-pipelines.universal/Runtime/2D/Rendergraph/DrawShadow2DPass.cs

@@ -33,6 +33,7 @@ internal class PassData
             internal Renderer2DData rendererData;
             internal TextureHandle[] shadowTextures;
             internal TextureHandle shadowDepth;
+            internal bool isVolumetric;
         }
 
         public void Render(RenderGraph graph, ContextContainer frameData, int batchIndex, bool isVolumetric = false)
@@ -52,6 +53,7 @@ public void Render(RenderGraph graph, ContextContainer frameData, int batchIndex
 
             using (var builder = graph.AddUnsafePass<PassData>(passName, out var passData, LayerDebug.GetProfilingSampler(passName, profilingSampler)))
             {
+                passData.isVolumetric = isVolumetric;
                 passData.layerBatch = layerBatch;
                 passData.rendererData = rendererData;
                 passData.shadowTextures = universal2DResourceData.shadowTextures[batchIndex];
@@ -72,6 +74,9 @@ public void Render(RenderGraph graph, ContextContainer frameData, int batchIndex
                         var index = data.layerBatch.shadowIndices[i];
                         var light = data.layerBatch.lights[index];
 
+                        if (data.isVolumetric && !RendererLighting.CanCastVolumetricShadows(light, data.layerBatch.endLayerValue))
+                            continue;
+
                         // Shadow Pass
                         ExecuteShadowPass(cmd, data, light, i);
                     }

Packages/com.unity.render-pipelines.universal/Runtime/2D/Rendergraph/Renderer2DRendergraph.cs

@@ -207,6 +207,13 @@ private RenderPassInputSummary GetRenderPassInputs()
                 inputSummary.requiresColorTexture |= needsColor;
             }
 
+            // Volumetric shadow pass requires intermediate texture
+            bool hasVolumetricShadowPass = false;
+            var layerBatches = frameData.Get<Universal2DRenderingData>().layerBatches;
+            var batchCount = frameData.Get<Universal2DRenderingData>().batchCount;
+            for (int i = 0; i < batchCount; ++i)
+                hasVolumetricShadowPass |= layerBatches[i].lightStats.useVolumetricShadowLights;
+
             inputSummary.requiresColorTexture |= cameraData.postProcessEnabled
                     || cameraData.isHdrEnabled
                     || cameraData.isSceneViewCamera
@@ -217,7 +224,8 @@ private RenderPassInputSummary GetRenderPassInputs()
                     || m_Renderer2DData.useCameraSortingLayerTexture
                     || !Mathf.Approximately(cameraData.renderScale, 1.0f)
                     || (DebugHandler != null && DebugHandler.WriteToDebugScreenTexture(cameraData.resolveFinalTarget))
-                    || cameraData.captureActions != null;
+                    || cameraData.captureActions != null
+                    || hasVolumetricShadowPass;
 
             return inputSummary;
         }

Packages/com.unity.render-pipelines.universal/Shaders/2D/Include/LightingUtility.hlsl

@@ -59,8 +59,8 @@
     if(intensity < 1)\
     {\
         half4 shadowTex = SAMPLE_TEXTURE2D(_ShadowTex, sampler_ShadowTex, input.shadowUV); \
-        half4 shadowIntensity = 1-max(shadowTex.r, shadowTex.g * 1-shadowTex.b);\
-        color.rgb = (color.rgb * shadowIntensity.rgb) + (color.rgb * intensity*(1 - shadowIntensity.rgb));\
+        half shadowIntensity = 1 - max(shadowTex.r, shadowTex.g * (1 - shadowTex.b));\
+        color.rgb = (color.rgb * shadowIntensity) + (color.rgb * intensity * (1 - shadowIntensity));\
      }
 
 #define TRANSFER_SHADOWS(output)\