Remove ClearMaterialsCache call when a material is destroyed in ogre2 (#1110)

Signed-off-by: Ian Chen <ichen@openrobotics.org>

Author: iche033

ogre2/include/gz/rendering/ogre2/Ogre2MeshFactory.hh

@@ -95,6 +95,7 @@ namespace gz
       protected: Ogre2ScenePtr scene;
 
       /// \brief Remove internal material cache for a specific material
+      /// \todo(iche033) Deprecate this function in gz-rendering10
       public: void ClearMaterialsCache(const std::string &_name);
 
       /// \brief Pointer to private data class

ogre2/include/gz/rendering/ogre2/Ogre2Scene.hh

@@ -457,6 +457,7 @@ namespace gz
 
       /// \brief Remove internal material cache for a specific material
       /// \param[in] _name Name of the template material to remove.
+      /// \todo(iche033) Deprecate this function in gz-rendering10
       public: void ClearMaterialsCache(const std::string &_name);
 
       /// \brief Create a shared pointer to self

ogre2/src/Ogre2Material.cc

@@ -277,8 +277,6 @@ void Ogre2Material::Destroy()
 
   if (textureToRemove && !textureIsUse)
   {
-    Ogre2ScenePtr s = std::dynamic_pointer_cast<Ogre2Scene>(this->Scene());
-    s->ClearMaterialsCache(this->textureName);
     this->Scene()->UnregisterMaterial(this->name);
     textureManager->destroyTexture(textureToRemove);
   }

ogre2/src/Ogre2MeshFactory.cc

@@ -57,9 +57,6 @@
 /// \brief Private data for the Ogre2MeshFactory class
 class gz::rendering::Ogre2MeshFactoryPrivate
 {
-  /// \brief Vector with the template materials, we keep the pointer to be
-  /// able to remove it when nobody is using it.
-  public: std::vector<MaterialPtr> materialCache;
 };
 
 /// \brief Private data for the Ogre2SubMeshStoreFactory class
@@ -91,22 +88,9 @@ void Ogre2MeshFactory::Clear()
 }
 
 //////////////////////////////////////////////////
-void Ogre2MeshFactory::ClearMaterialsCache(const std::string &_name)
+void Ogre2MeshFactory::ClearMaterialsCache(const std::string &)
 {
-  auto it = this->dataPtr->materialCache.begin();
-  for (auto &mat : this->dataPtr->materialCache)
-  {
-    std::string matName = mat->Name();
-    std::string textureName = mat->Texture();
-    if (textureName == _name)
-    {
-      this->scene->UnregisterMaterial(matName);
-      break;
-    }
-    ++it;
-  }
-  if (it != this->dataPtr->materialCache.end())
-    this->dataPtr->materialCache.erase(it);
+  // no-op
 }
 
 //////////////////////////////////////////////////
@@ -501,7 +485,6 @@ bool Ogre2MeshFactory::LoadImpl(const MeshDescriptor &_desc)
       if (material)
       {
         mat->CopyFrom(*material);
-        this->dataPtr->materialCache.push_back(mat);
       }
       else
       {