PR cleanup

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

                         ScriptableRenderContext.EmitWorldGeometryForSceneView(camera);
                     }
 #endif
-
-                    // decal system needs to be updated with current camera
+                    
+                        // decal system needs to be updated with current camera, it needs it to set up culling and light list generation parameters
-                        DecalSystem.instance.UpdateCachedMaterialData(cmd);
                         DecalSystem.instance.BeginCull();
                     }
 
                     {
                         if (m_FrameSettings.enableDBuffer)
                         {                            
-                            DecalSystem.instance.EndCull();                            
-                            DecalSystem.instance.CreateDrawData();
+                            DecalSystem.instance.EndCull();               
+                            DecalSystem.instance.UpdateCachedMaterialData(cmd);     // textures, alpha or fade distances could've changed                                       
+                            DecalSystem.instance.CreateDrawData();                  // prepare data is separate from draw              
                         }
                     }
                     renderContext.SetupCameraProperties(camera, m_FrameSettings.enableStereo);
                 m_DbufferManager.SetHTile(m_DbufferManager.bufferCount, cmd);
                 DecalSystem.instance.RenderIntoDBuffer(cmd);
                 m_DbufferManager.UnSetHTile(cmd);
-                m_DbufferManager.SetHTileTexture(cmd);
-                DecalSystem.instance.SetAtlas(cmd);
+                m_DbufferManager.SetHTileTexture(cmd);  // mask per 8x8 tile used for optimization when looking up dbuffer values               
             }
         }
 
                 else
                 {
                     HDUtils.SetRenderTarget(cmd, hdCamera, m_CameraColorBuffer, m_CameraDepthStencilBuffer);
+                    DecalSystem.instance.SetAtlas(cmd); // for clustered decals
                     RenderTransparentRenderList(cullResults, camera, renderContext, cmd, m_AllTransparentPassNames, m_currentRendererConfigurationBakedLighting, pass == ForwardPass.PreRefraction ? HDRenderQueue.k_RenderQueue_PreRefraction : HDRenderQueue.k_RenderQueue_Transparent);
                 }
             }

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDStringConstants.cs

 
         public static readonly int g_LayeredSingleIdxBuffer = Shader.PropertyToID("g_LayeredSingleIdxBuffer");
         public static readonly int _EnvLightIndexShift = Shader.PropertyToID("_EnvLightIndexShift");
-        public static readonly int _DecalIndexShift = Shader.PropertyToID("_DecalIndexShift");
         public static readonly int g_isOrthographic = Shader.PropertyToID("g_isOrthographic");
         public static readonly int g_iNrVisibLights = Shader.PropertyToID("g_iNrVisibLights");
         public static readonly int g_mScrProjection = Shader.PropertyToID("g_mScrProjection");
         public static readonly int _EnvLightCount = Shader.PropertyToID("_EnvLightCount");
         public static readonly int _EnvProxyCount = Shader.PropertyToID("_EnvProxyCount");
         public static readonly int _ShadowDatas = Shader.PropertyToID("_ShadowDatas");
-        public static readonly int _DecalCount = Shader.PropertyToID("_DecalCount");
-        public static readonly int _DecalDatas = Shader.PropertyToID("_DecalDatas");
         public static readonly int _NumTileFtplX = Shader.PropertyToID("_NumTileFtplX");
         public static readonly int _NumTileFtplY = Shader.PropertyToID("_NumTileFtplY");
         public static readonly int _NumTileClusteredX = Shader.PropertyToID("_NumTileClusteredX");
         public static readonly int _SSSHTile = Shader.PropertyToID("_SSSHTile");
         public static readonly int _StencilTexture = Shader.PropertyToID("_StencilTexture");
 
+        // all decal properties
+        public static readonly int _DecalIndexShift = Shader.PropertyToID("_DecalIndexShift");
+        public static readonly int _DecalCount = Shader.PropertyToID("_DecalCount");
+        public static readonly int _DecalDatas = Shader.PropertyToID("_DecalDatas");
 
         public static readonly int _ViewMatrix = Shader.PropertyToID("_ViewMatrix");
         public static readonly int _InvViewMatrix = Shader.PropertyToID("_InvViewMatrix");

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/LightLoop/LightLoop.cs

         public const int k_MaxDirectionalLightsOnScreen = 4;
         public const int k_MaxPunctualLightsOnScreen    = 512;
         public const int k_MaxAreaLightsOnScreen        = 64;
-        public const int k_MaxDecalsOnScreen = 2048;
+        public const int k_MaxDecalsOnScreen = 512;
         public const int k_MaxLightsOnScreen = k_MaxDirectionalLightsOnScreen + k_MaxPunctualLightsOnScreen + k_MaxAreaLightsOnScreen + k_MaxDecalsOnScreen;
         public const int k_MaxEnvLightsOnScreen = 64;
         public const int k_MaxShadowOnScreen = 16;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/Decal.hlsl

 TEXTURE2D_ARRAY(_DecalAtlas);          
 SAMPLER(sampler_DecalAtlas);
 
+// define these specifically for decal normal map sampling to not be dependent on surface gradient
+#if defined(UNITY_NO_DXT5nm)
+#define DECAL_UNPACK_NORMAL_FUNC UnpackNormalRGB
+#else
+#define DECAL_UNPACK_NORMAL_FUNC UnpackNormalmapRGorAG
+#endif
+
 // Must be in sync with RT declared in HDRenderPipeline.cs ::Rebuild
 void EncodeIntoDBuffer( DecalSurfaceData surfaceData,
                         out DBufferType0 outDBuffer0,

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/DecalData.hlsl

 #include "CoreRP/ShaderLibrary/Packing.hlsl"
 #include "CoreRP/ShaderLibrary/Sampling/SampleUVMapping.hlsl"
 
-#if defined(UNITY_NO_DXT5nm)
-#define UNPACK_NORMAL_FUNC UnpackNormalRGB
-#else
-#define UNPACK_NORMAL_FUNC UnpackNormalmapRGorAG
-#endif
-
 void GetSurfaceData(float2 texCoordDS, float4x4 decalToWorld, out DecalSurfaceData surfaceData)
 {
 	surfaceData.baseColor = float4(0,0,0,0);
 	surfaceData.HTileMask |= DBUFFERHTILEBIT_DIFFUSE;
 #endif
 #if _NORMALMAP
-	surfaceData.normalWS.xyz = mul((float3x3)decalToWorld, UNPACK_NORMAL_FUNC(SAMPLE_TEXTURE2D(_NormalMap, sampler_NormalMap, texCoordDS))) * 0.5f + 0.5f;
+	surfaceData.normalWS.xyz = mul((float3x3)decalToWorld, DECAL_UNPACK_NORMAL_FUNC(SAMPLE_TEXTURE2D(_NormalMap, sampler_NormalMap, texCoordDS))) * 0.5f + 0.5f;
 	surfaceData.normalWS.w = totalBlend;
 	surfaceData.HTileMask |= DBUFFERHTILEBIT_NORMAL;
 #endif
 	surfaceData.HTileMask |= DBUFFERHTILEBIT_MASK;
 #endif
 }
-
-#undef UNPACK_NORMAL_FUNC

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/DecalUtilities.hlsl

     return _DecalDatas[j];
 }
 
-#if defined(UNITY_NO_DXT5nm)
-#define UNPACK_NORMAL_FUNC UnpackNormalRGB
-#else
-#define UNPACK_NORMAL_FUNC UnpackNormalmapRGorAG
-#endif
-
-	src.xyz =  mul(decalToWorld, UNPACK_NORMAL_FUNC(SAMPLE_TEXTURE2D_ARRAY(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex))) * 0.5f + 0.5f;
+	src.xyz =  mul(decalToWorld, DECAL_UNPACK_NORMAL_FUNC(SAMPLE_TEXTURE2D_ARRAY(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex))) * 0.5f + 0.5f;
 	src.w = blend;
 	dst.xyz = src.xyz * src.w + dst.xyz * (1.0f - src.w);
 	dst.w = dst.w * (1.0f - src.w);
-#undef UNPACK_NORMAL_FUNC
-
 void ApplyBlendDiffuse(inout float4 dst, inout int matMask, float2 texCoords, int sliceIndex, int mapMask, float blend)
 {
 	float4 src = SAMPLE_TEXTURE2D_ARRAY(_DecalAtlas, sampler_DecalAtlas, texCoords, sliceIndex);
 		// the code in the macros, gets moved inside the conditionals by the compiler
 		FETCH_DBUFFER(DBuffer, _DBufferTexture, posInput.positionSS);
 
-#ifdef _SURFACE_TYPE_TRANSPARENT
+#ifdef _SURFACE_TYPE_TRANSPARENT	// forward transparent using clustered decals
         uint decalCount, decalStart;
 		DBuffer0 = float4(0.0f, 0.0f, 0.0f, 1.0f);
 		DBuffer1 = float4(0.5f, 0.5f, 0.5f, 1.0f);
 			int diffuseIndex = decalData.normalToWorld[1][3];
 			int normalIndex = decalData.normalToWorld[2][3];
 			int maskIndex = decalData.normalToWorld[3][3];
-			if((all(positionDS.xyz > 0.0f) && all(1.0f - positionDS.xyz > 0.0f)))
+			if((all(positionDS.xyz > 0.0f) && all(1.0f - positionDS.xyz > 0.0f))) // clip to decal space
 			{
 				if(diffuseIndex != -1)
 				{
 		}
 	}
 }
+
+