Add support of clearcoat mask map and change coat mask as material feature

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/LayeredLit/LayeredLitUI.cs

             EditorGUI.indentLevel--;
             EditorGUILayout.Space();
 
-            DoLayerGUI(material, layerIndex);
+            DoLayerGUI(material, layerIndex, true);
 
             if (layerIndex == 0)
                 EditorGUILayout.Space();

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Material/Lit/LitUI.cs

 
         protected MaterialProperty coatMask = null;
         protected const string kCoatMask = "_CoatMask";
+        protected MaterialProperty coatMaskMap = null;
+        protected const string kCoatMaskMap = "_CoatMaskMap";
 
         protected MaterialProperty emissiveColorMode = null;
         protected const string kEmissiveColorMode = "_EmissiveColorMode";
 
             // clear coat
             coatMask = FindProperty(kCoatMask, props);
+            coatMaskMap = FindProperty(kCoatMaskMap, props);            
 
             // Transparency
             refractionMode = FindProperty(kRefractionMode, props, false);
 
         protected void ShaderClearCoatInputGUI()
         {
-            m_MaterialEditor.ShaderProperty(coatMask, Styles.coatMaskText);
+            m_MaterialEditor.TexturePropertySingleLine(Styles.coatMaskText, coatMaskMap, coatMask);
         }
 
         protected void ShaderAnisoInputGUI()
             }
         }
 
-        protected void DoLayerGUI(Material material, int layerIndex)
+        protected void DoLayerGUI(Material material, int layerIndex, bool isLayeredLit)
         {
             EditorGUILayout.LabelField(Styles.InputsText, EditorStyles.boldLabel);
 
 
             switch ((BaseLitGUI.MaterialId)materialID.floatValue)
             {
-                case BaseLitGUI.MaterialId.LitSSS:
+                case BaseLitGUI.MaterialId.LitSSSAndTransmission:
                     ShaderSSSInputGUI(material, layerIndex);
                     break;
                 case BaseLitGUI.MaterialId.LitStandard:
                 case BaseLitGUI.MaterialId.LitSpecular:
                     ShaderSpecularColorInputGUI(material);
                     break;
-                case BaseLitGUI.MaterialId.LitClearCoat:
-                    ShaderClearCoatInputGUI();
-                    break;
+
+            if (!isLayeredLit)
+            {
+                ShaderClearCoatInputGUI();
+            }            
+
             EditorGUILayout.Space();
 
             EditorGUI.BeginChangeCheck();
 
         protected override void MaterialPropertiesGUI(Material material)
         {
-            DoLayerGUI(material, 0);
+            DoLayerGUI(material, 0, false);
             DoEmissiveGUI(material);
             // The parent Base.ShaderPropertiesGUI will call DoEmissionArea
         }
 
             BaseLitGUI.MaterialId materialId = (BaseLitGUI.MaterialId)material.GetFloat(kMaterialID);
 
-            CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_SUBSURFACE_SCATTERING", materialId == BaseLitGUI.MaterialId.LitSSS);
-            CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_TRANSMISSION", materialId == BaseLitGUI.MaterialId.LitSSS);
+            CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_SUBSURFACE_SCATTERING", materialId == BaseLitGUI.MaterialId.LitSSSAndTransmission);
+            CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_TRANSMISSION", materialId == BaseLitGUI.MaterialId.LitSSSAndTransmission);
-            CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_CLEAR_COAT", materialId == BaseLitGUI.MaterialId.LitClearCoat);
+            // No material Id for clear coat, just test the attribute
+            CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_CLEAR_COAT", material.GetFloat(kCoatMask) > 0.0 || material.GetTexture(kCoatMaskMap);
             CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_IRIDESCENCE", materialId == BaseLitGUI.MaterialId.LitIridescence);
             CoreUtils.SetKeyword(material, "_MATERIAL_FEATURE_SPECULAR_COLOR", materialId == BaseLitGUI.MaterialId.LitSpecular);
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/Lit.shader

         _ThicknessMap("Thickness Map", 2D) = "white" {}
         _ThicknessRemap("Thickness Remap", Vector) = (0, 1, 0, 0)
 
-        _CoatMask("Coat Mask", Range(0.0, 1.0)) = 1.0
+        _CoatMask("Coat Mask", Range(0.0, 1.0)) = 0.0
+        _CoatMaskMap("CoatMaskMap", 2D) = "white" {}
 
         [ToggleUI] _EnergyConservingSpecularColor("_EnergyConservingSpecularColor", Float) = 1.0
         _SpecularColor("SpecularColor", Color) = (1, 1, 1, 1)

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/LitDataIndividualLayer.hlsl

     surfaceData.transmittanceMask = 0.0;
 #endif
 
+#ifdef _MATERIAL_FEATURE_CLEAR_COAT
+    // To shader feature for keyword to limit the variant
+    surfaceData.coatMask *= SAMPLE_UVMAPPING_TEXTURE2D(ADD_IDX(_coatMaskMap), ADD_ZERO_IDX(sampler_coatMaskMap), ADD_IDX(layerTexCoord.base)).r;
+#else
+    surfaceData.coatMask = 0.0;
+#endif
+
 
     surfaceData.thicknessIrid = 0.0;
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/LitProperties.hlsl

 TEXTURE2D(_TransmittanceColorMap);
 SAMPLER(sampler_TransmittanceColorMap);
 
+TEXTURE2D(_CoatMaskMap);
+SAMPLER(sampler_CoatMaskMap);
+
 #else
 
 // Set of users variables

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Material/Lit/LitTessellation.shader

         _ThicknessMap("Thickness Map", 2D) = "white" {}
         _ThicknessRemap("Thickness Remap", Vector) = (0, 1, 0, 0)
 
-        _CoatMask("Coat Mask", Range(0.0, 1.0)) = 1.0
+        _CoatMask("Coat Mask", Range(0.0, 1.0)) = 0.0
+        _CoatMaskMap("CoatMaskMap", 2D) = "white" {}
 
         [ToggleUI] _EnergyConservingSpecularColor("_EnergyConservingSpecularColor", Float) = 1.0
         _SpecularColor("SpecularColor", Color) = (1, 1, 1, 1)