source/blender/render/hydra/scene_delegate/blender_scene_delegate.cc

@@ -470,7 +470,6 @@ void BlenderSceneDelegate::update_collection()
     }
     else {
       obj_data = objects_.lookup_or_add(id, ObjectData::create(this, object, id)).get();
-      obj_data->init();
       obj_data->insert();
     }
   }

source/blender/render/hydra/scene_delegate/blender_scene_delegate.h

@@ -28,10 +28,7 @@ extern struct CLG_LogRef *LOG_RENDER_HYDRA_SCENE;
 class Engine;
 
 class BlenderSceneDelegate : public pxr::HdSceneDelegate {
-  friend ObjectData;   /* has access to instances */
-  friend CurvesData;   /* has access to materials */
-  friend VolumeData;   /* has access to materials */
-  friend MeshData;     /* has access to materials */
+  friend ObjectData;   /* has access to materials */
   friend MaterialData; /* has access to objects and instancers */
 
  public:

source/blender/render/hydra/scene_delegate/curves.cc

@@ -134,20 +134,7 @@ void CurvesData::write_materials()
   if (BKE_object_material_count_eval(object) > 0) {
     mat = BKE_object_material_get_eval(object, 0);
   }
-
-  if (!mat) {
-    mat_data_ = nullptr;
-    return;
-  }
-  pxr::SdfPath p_id = scene_delegate_->material_prim_id(mat);
-  mat_data_ = scene_delegate_->material_data(p_id);
-  if (!mat_data_) {
-    scene_delegate_->materials_.add_new(
-        p_id, std::make_unique<MaterialData>(scene_delegate_, mat, p_id));
-    mat_data_ = scene_delegate_->material_data(p_id);
-    mat_data_->init();
-    mat_data_->insert();
-  }
+  mat_data_ = get_or_create_material(mat);
 }
 
 void CurvesData::write_curves(Curves *curves)

source/blender/render/hydra/scene_delegate/mesh.cc

@@ -195,21 +195,7 @@ void MeshData::write_materials()
   for (int i = 0; i < submeshes_.size(); ++i) {
     SubMesh &m = submeshes_[i];
     Material *mat = BKE_object_material_get_eval(object, m.mat_index + 1);
-    if (!mat) {
-      m.mat_data = nullptr;
-      continue;
-    }
-
-    pxr::SdfPath p_id = scene_delegate_->material_prim_id(mat);
-    m.mat_data = scene_delegate_->material_data(p_id);
-    if (!m.mat_data) {
-      m.mat_data = scene_delegate_->materials_
-                       .lookup_or_add(p_id,
-                                      std::make_unique<MaterialData>(scene_delegate_, mat, p_id))
-                       .get();
-      m.mat_data->init();
-      m.mat_data->insert();
-    }
+    m.mat_data = get_or_create_material(mat);
   }
 }
 

source/blender/render/hydra/scene_delegate/object.cc

@@ -23,7 +23,7 @@ std::unique_ptr<ObjectData> ObjectData::create(BlenderSceneDelegate *scene_deleg
                                                Object *object,
                                                pxr::SdfPath const &prim_id)
 {
-  std::unique_ptr<ObjectData> data;
+  std::unique_ptr<ObjectData> obj_data;
 
   switch (object->type) {
     case OB_MESH:
@@ -31,22 +31,23 @@ std::unique_ptr<ObjectData> ObjectData::create(BlenderSceneDelegate *scene_deleg
     case OB_FONT:
     case OB_CURVES_LEGACY:
     case OB_MBALL:
-      data = std::make_unique<MeshData>(scene_delegate, object, prim_id);
+      obj_data = std::make_unique<MeshData>(scene_delegate, object, prim_id);
       break;
     case OB_CURVES:
-      data = std::make_unique<CurvesData>(scene_delegate, object, prim_id);
+      obj_data = std::make_unique<CurvesData>(scene_delegate, object, prim_id);
       break;
     case OB_LAMP:
-      data = std::make_unique<LightData>(scene_delegate, object, prim_id);
+      obj_data = std::make_unique<LightData>(scene_delegate, object, prim_id);
       break;
     case OB_VOLUME:
-      data = std::make_unique<VolumeData>(scene_delegate, object, prim_id);
+      obj_data = std::make_unique<VolumeData>(scene_delegate, object, prim_id);
       break;
     default:
       BLI_assert_unreachable();
       break;
   }
-  return data;
+  obj_data->init();
+  return obj_data;
 }
 
 bool ObjectData::is_supported(Object *object)
@@ -103,6 +104,24 @@ void ObjectData::write_transform()
 
 void ObjectData::write_materials() {}
 
+MaterialData *ObjectData::get_or_create_material(Material *mat)
+{
+  if (!mat) {
+    return nullptr;
+  }
+
+  pxr::SdfPath p_id = scene_delegate_->material_prim_id(mat);
+  MaterialData *mat_data = scene_delegate_->material_data(p_id);
+  if (!mat_data) {
+    scene_delegate_->materials_.add_new(
+        p_id, std::make_unique<MaterialData>(scene_delegate_, mat, p_id));
+    mat_data = scene_delegate_->material_data(p_id);
+    mat_data->init();
+    mat_data->insert();
+  }
+  return mat_data;
+}
+
 pxr::GfMatrix4d gf_matrix_from_transform(float m[4][4])
 {
   pxr::GfMatrix4d ret;

source/blender/render/hydra/scene_delegate/object.h

@@ -41,6 +41,7 @@ class ObjectData : public IdData {
  protected:
   virtual void write_transform();
   virtual void write_materials();
+  MaterialData *get_or_create_material(Material *mat);
 };
 
 using ObjectDataMap = Map<pxr::SdfPath, std::unique_ptr<ObjectData>>;

source/blender/render/hydra/scene_delegate/volume.cc

@@ -149,20 +149,7 @@ void VolumeData::write_materials()
   if (BKE_object_material_count_eval(object) > 0) {
     mat = BKE_object_material_get_eval(object, 0);
   }
-
-  if (!mat) {
-    mat_data_ = nullptr;
-    return;
-  }
-  pxr::SdfPath p_id = scene_delegate_->material_prim_id(mat);
-  mat_data_ = scene_delegate_->material_data(p_id);
-  if (!mat_data_) {
-    scene_delegate_->materials_.add_new(
-        p_id, std::make_unique<MaterialData>(scene_delegate_, mat, p_id));
-    mat_data_ = scene_delegate_->material_data(p_id);
-    mat_data_->init();
-    mat_data_->insert();
-  }
+  mat_data_ = get_or_create_material(mat);
 }
 
 }  // namespace blender::render::hydra