Cleanup PR, add decal HTile mask defines

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Decal/DecalProjectorComponent.cs

                 DecalSystem.instance.AddDecal(this);
                 m_OldMaterial = m_Material;
 
+                // notify the editor that material has changed so it can update the shader foldout
 				if (OnMaterialChange != null)
 				{
 					OnMaterialChange();
 
         public bool IsValid()
         {
+            // don't draw if no material or if material is the default decal material (empty)
+
+            var hdrp = GraphicsSettings.renderPipelineAsset as HDRenderPipelineAsset;
+            if ((hdrp != null) && (m_Material == hdrp.GetDefaultDecalMaterial()))
+                return false;
+
             return true;
         }
     }

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/Decal/DecalProjectorComponentEditor.cs

             // Create an instance of the MaterialEditor
             m_DecalProjectorComponent = (DecalProjectorComponent)target;
             m_MaterialEditor = (MaterialEditor)CreateEditor(m_DecalProjectorComponent.Mat);
-			m_DecalProjectorComponent.OnMaterialChange += new DecalProjectorComponent.OnMaterialChangeDelegate(this.OnMaterialChange);
+			m_DecalProjectorComponent.OnMaterialChange += OnMaterialChange;
-			m_DecalProjectorComponent.OnMaterialChange -= new DecalProjectorComponent.OnMaterialChangeDelegate(this.OnMaterialChange);
+			m_DecalProjectorComponent.OnMaterialChange -= OnMaterialChange;
-			if (m_MaterialEditor != null)
-			{
-				// Draw the material's foldout and the material shader field
-				m_MaterialEditor = (MaterialEditor)CreateEditor(m_DecalProjectorComponent.Mat);
-			}
+			// Update material editor with the new material
+			m_MaterialEditor = (MaterialEditor)CreateEditor(m_DecalProjectorComponent.Mat);
 		}
 
         public override void OnInspectorGUI()

ScriptableRenderPipeline/HDRenderPipeline/HDRP/HDRenderPipeline.cs

             cmd.SetRandomWriteTarget(bindSlot, m_HTile);
         }
 
+        public void UnSetHTile(CommandBuffer cmd)
+        {
+            cmd.ClearRandomWriteTargets();
+        }
+
         public void PushGlobalParams(CommandBuffer cmd)
         {
             cmd.SetGlobalInt(HDShaderIDs._EnableDBuffer, vsibleDecalCount > 0 ? 1 : 0);
                         RenderOpaqueRenderList(cull, camera, renderContext, cmd, HDShaderPassNames.s_GBufferName, m_currentRendererConfigurationBakedLighting, HDRenderQueue.k_RenderQueue_AllOpaque, m_DepthStateOpaque);
                     }
                 }
+
+                if (m_FrameSettings.enableDBuffer)
+                {
+                    m_DbufferManager.UnSetHTile(cmd);
+                }
             }
         }
 
 				CoreUtils.SetRenderTarget(cmd, m_DbufferManager.GetDBuffers(), m_CameraDepthStencilBufferRT); // do not clear anymore
                 m_DbufferManager.SetHTile(m_DbufferManager.dbufferCount, cmd);
                 DecalSystem.instance.Render(renderContext, camera, cmd);
-                cmd.ClearRandomWriteTargets();
+                m_DbufferManager.UnSetHTile(cmd);
             }
         }
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Decal/Decal.cs

             Count = 3
         };
 
+        [GenerateHLSL(PackingRules.Exact)]
+        public enum DBufferHTileBit
+        {            
+            Diffuse = 1,
+            Normal = 2,
+            Mask = 4
+        };
+
         //-----------------------------------------------------------------------------
         // DBuffer management
         //-----------------------------------------------------------------------------

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

 //
 #define DBUFFERMATERIAL_COUNT (3)
 
+//
+// UnityEngine.Experimental.Rendering.HDPipeline.Decal+DBufferHTileBit:  static fields
+//
+#define DBUFFERHTILEBIT_DIFFUSE (1)
+#define DBUFFERHTILEBIT_NORMAL (2)
+#define DBUFFERHTILEBIT_MASK (4)
+
 // Generated from UnityEngine.Experimental.Rendering.HDPipeline.Decal+DecalSurfaceData
 // PackingRules = Exact
 struct DecalSurfaceData

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

 {
 	if(_EnableDBuffer)
 	{
+		// the code in the macros, gets moved inside the conditionals by the compiler
-		// using alpha compositing https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch23.html
-		if(mask & 1)
+		// using alpha compositing https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch23.html
+		if(mask & DBUFFERHTILEBIT_DIFFUSE)
-		if(mask & 2)
+		if(mask & DBUFFERHTILEBIT_NORMAL)
-		if(mask & 4)
+		if(mask & DBUFFERHTILEBIT_MASK)
 		{
 			surfaceData.metallic = surfaceData.metallic * decalSurfaceData.mask.w + decalSurfaceData.mask.x;
 			surfaceData.ambientOcclusion = surfaceData.ambientOcclusion * decalSurfaceData.mask.w + decalSurfaceData.mask.y;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/ShaderPass/ShaderPassDBuffer.hlsl

     DecalSurfaceData surfaceData;
 	float3x3 decalToWorld = (float3x3)UNITY_ACCESS_INSTANCED_PROP(matrix, normalToWorld);
     GetSurfaceData(positionDS.xz, decalToWorld, surfaceData);
+
+	// have to do explicit test since compiler behavior is not defined for RW resources and discard instructions
-		mask = 1;
+		mask |= DBUFFERHTILEBIT_DIFFUSE;
-		mask |= 2;
+		mask |= DBUFFERHTILEBIT_NORMAL;
-		mask |= 4;
+		mask |= DBUFFERHTILEBIT_MASK;
 #endif
 		uint oldVal = UnpackByte(_DecalHTile[posInput.positionSS.xy / 8]);
 		oldVal |= mask;