[Backport 8.x.x] Diffusion Profile and Material references in HDRP materials are now correctly exported to unity packages.

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -58,6 +58,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed an issue that was collapsing the volume components in the HDRP default settings
 - Fixed warning about missing bound decal buffer
 - Fixed the debug exposure mode for display sky reflection and debug view baked lighting
+- Diffusion Profile and Material references in HDRP materials are now correctly exported to unity packages. Note that the diffusion profile or the material references need to be edited once before this can work properly.
 
 ### Changed
 - Rejecting history for ray traced reflections based on a threshold evaluated on the neighborhood of the sampled history.

com.unity.render-pipelines.high-definition/Editor/Material/DiffusionProfile/DiffusionProfileMaterialUI.cs

@@ -18,7 +18,7 @@ public static bool IsSupported(MaterialEditor materialEditor)
             });
         }
 
-        public static void OnGUI(MaterialProperty diffusionProfileAsset, MaterialProperty diffusionProfileHash)
+        public static void OnGUI(MaterialEditor materialEditor, MaterialProperty diffusionProfileAsset, MaterialProperty diffusionProfileHash, int profileIndex)
         {
             // We can't cache these fields because of several edge cases like undo/redo or pressing escape in the object picker
             string guid = HDUtils.ConvertVector4ToGUID(diffusionProfileAsset.vectorValue);
@@ -42,6 +42,16 @@ public static void OnGUI(MaterialProperty diffusionProfileAsset, MaterialPropert
                 // encode back GUID and it's hash
                 diffusionProfileAsset.vectorValue = newGuid;
                 diffusionProfileHash.floatValue = hash;
+
+                // Update external reference.
+                foreach (var target in materialEditor.targets)
+                {
+                    MaterialExternalReferences matExternalRefs = MaterialExternalReferences.GetMaterialExternalReferences(target as Material);
+                    if (matExternalRefs != null)
+                    {
+                        matExternalRefs.SetDiffusionProfileReference(profileIndex, diffusionProfile);
+                    }
+                }
             }
 
             DrawDiffusionProfileWarning(diffusionProfile);

com.unity.render-pipelines.high-definition/Editor/Material/MaterialExternalReferences.cs

@@ -0,0 +1,70 @@
+using UnityEngine;
+using UnityEngine.Rendering.HighDefinition;
+
+namespace UnityEditor.Rendering.HighDefinition
+{
+    // This class only purpose is to be used as a sub-asset to a material and store references to other assets.
+    // The goal is to be able to export the material as a package and not miss those referenced assets.
+    class MaterialExternalReferences : ScriptableObject
+    {
+        [SerializeField]
+        DiffusionProfileSettings[] m_DiffusionProfileReferences = new DiffusionProfileSettings[0];
+        [SerializeField]
+        Material[] m_MaterialReferences = new Material[0];
+
+        public void SetDiffusionProfileReference(int index, DiffusionProfileSettings profile)
+        {
+            if (index >= m_DiffusionProfileReferences.Length)
+            {
+                var newList = new DiffusionProfileSettings[index + 1];
+                for (int i = 0; i < m_DiffusionProfileReferences.Length; ++i)
+                    newList[i] = m_DiffusionProfileReferences[i];
+
+                m_DiffusionProfileReferences = newList;
+            }
+
+            m_DiffusionProfileReferences[index] = profile;
+            EditorUtility.SetDirty(this);
+        }
+
+        public void SetMaterialReference(int index, Material mat)
+        {
+            if (index >= m_MaterialReferences.Length)
+            {
+                var newList = new Material[index + 1];
+                for (int i = 0; i < m_MaterialReferences.Length; ++i)
+                    newList[i] = m_MaterialReferences[i];
+
+                m_MaterialReferences = newList;
+            }
+
+            m_MaterialReferences[index] = mat;
+            EditorUtility.SetDirty(this);
+        }
+
+        public static MaterialExternalReferences GetMaterialExternalReferences(Material material)
+        {
+            var subAssets = AssetDatabase.LoadAllAssetsAtPath(AssetDatabase.GetAssetPath(material));
+            MaterialExternalReferences matExternalRefs = null;
+            foreach (var subAsset in subAssets)
+            {
+                if (subAsset.GetType() == typeof(MaterialExternalReferences))
+                {
+                    matExternalRefs = subAsset as MaterialExternalReferences;
+                    break;
+                }
+            }
+
+            if (matExternalRefs == null)
+            {
+                matExternalRefs = CreateInstance<MaterialExternalReferences>();
+                matExternalRefs.hideFlags = HideFlags.HideInHierarchy | HideFlags.HideInInspector | HideFlags.NotEditable;
+                AssetDatabase.AddObjectToAsset(matExternalRefs, material);
+                EditorUtility.SetDirty(matExternalRefs);
+                EditorUtility.SetDirty(material);
+            }
+
+            return matExternalRefs;
+        }
+    }
+}

com.unity.render-pipelines.high-definition/Editor/Material/PBR/HDPBRLit.cs

@@ -8,7 +8,7 @@ class HDPBRLitGUI : ShaderGUI
         public override void OnGUI(MaterialEditor materialEditor, MaterialProperty[] props)
         {
             materialEditor.PropertiesDefaultGUI(props);
-            
+
             EmissionUIBlock.BakedEmissionEnabledProperty(materialEditor);
 
             // Make sure all selected materials are initialized.
@@ -40,7 +40,7 @@ public override void OnGUI(MaterialEditor materialEditor, MaterialProperty[] pro
             }
 
             if (DiffusionProfileMaterialUI.IsSupported(materialEditor))
-                DiffusionProfileMaterialUI.OnGUI(FindProperty("_DiffusionProfileAsset", props), FindProperty("_DiffusionProfileHash", props));
+                DiffusionProfileMaterialUI.OnGUI(materialEditor, FindProperty("_DiffusionProfileAsset", props), FindProperty("_DiffusionProfileHash", props), 0);
         }
     }
 }

com.unity.render-pipelines.high-definition/Editor/Material/UIBlocks/LayerListUIBlock.cs

@@ -154,8 +154,18 @@ void DrawLayerListGUI()
                         Undo.RecordObjects(new UnityEngine.Object[] { material, m_MaterialImporter }, "Change layer material");
                         LayeredLitGUI.SynchronizeLayerProperties(material, m_MaterialLayers, layerIndex, true);
                         layersChanged = true;
+
+                        // Update external reference.
+                        foreach (var target in materialEditor.targets)
+                        {
+                            MaterialExternalReferences matExternalRefs = MaterialExternalReferences.GetMaterialExternalReferences(target as Material);
+                            if (matExternalRefs != null)
+                            {
+                                matExternalRefs.SetMaterialReference(layerIndex, m_MaterialLayers[layerIndex]);
+                            }
+                        }
                     }
-                    
+
                     EditorGUI.DrawRect(colorRect, kLayerColors[layerIndex]);
 
                     m_WithUV[layerIndex] = EditorGUI.Toggle(uvRect, m_WithUV[layerIndex]);

com.unity.render-pipelines.high-definition/Editor/Material/UIBlocks/LitSurfaceInputsUIBlock.cs

@@ -557,7 +557,7 @@ void ShaderSSSAndTransmissionInputGUI()
             if (hdPipeline == null)
                 return;
 
-            DiffusionProfileMaterialUI.OnGUI(diffusionProfileAsset[m_LayerIndex], diffusionProfileHash[m_LayerIndex]);
+            DiffusionProfileMaterialUI.OnGUI(materialEditor, diffusionProfileAsset[m_LayerIndex], diffusionProfileHash[m_LayerIndex], m_LayerIndex);
 
             // TODO: does not work with multi-selection
             if ((int)materialID.floatValue == (int)MaterialId.LitSSS && materials[0].GetSurfaceType() != SurfaceType.Transparent)

com.unity.render-pipelines.high-definition/Editor/Material/UIBlocks/ShaderGraphUIBlock.cs

@@ -97,7 +97,7 @@ void DrawShaderGraphGUI()
             // Filter out properties we don't want to draw:
             PropertiesDefaultGUI(properties);
 
-            // If we change a property in a shadergraph, we trigger a material keyword reset 
+            // If we change a property in a shadergraph, we trigger a material keyword reset
             if (CheckPropertyChanged(properties))
             {
                 foreach (var material in materials)
@@ -219,7 +219,7 @@ void DrawShadowMatteToggle()
         void DrawDiffusionProfileUI()
         {
             if (DiffusionProfileMaterialUI.IsSupported(materialEditor))
-                DiffusionProfileMaterialUI.OnGUI(FindProperty("_DiffusionProfileAsset"), FindProperty("_DiffusionProfileHash"));
+                DiffusionProfileMaterialUI.OnGUI(materialEditor, FindProperty("_DiffusionProfileAsset"), FindProperty("_DiffusionProfileHash"), 0);
         }
     }
 }