Introduces GZ_MESH_FORCE_ASSIMP flag

graphics/include/gz/common/MeshManager.hh

@@ -240,8 +240,12 @@ namespace gz
                                const gz::math::Vector2d &_segments,
                                const gz::math::Vector2d &_uvTile);
 
+      /// \brief Sets the forceAssimp flag by reading the GZ_MESH_FORCE_ASSIMP
+      /// environment variable. If forceAssimp true, MeshManager uses Assimp
+      /// for loading all mesh formats, otherwise only for GLTF and FBX.
+      public: void SetAssimpEnvs();
+
       /// \brief Tesselate a 2D mesh
-      ///
       /// Makes a zigzag pattern compatible with strips
       /// \param[in] _sm the mesh to tesselate
       /// \param[in] _meshWith mesh width

graphics/src/MeshManager.cc

@@ -70,6 +70,9 @@ class gz::common::MeshManager::Implementation
 
   /// \brief Mutex to protect the mesh map
   public: std::mutex mutex;
+
+  /// \brief True if assimp is used for loading all supported mesh formats
+  public: bool forceAssimp;
 #ifdef _WIN32
 #pragma warning(pop)
 #endif
@@ -145,21 +148,27 @@ const Mesh *MeshManager::Load(const std::string &_filename)
     std::transform(extension.begin(), extension.end(),
         extension.begin(), ::tolower);
     MeshLoader *loader = nullptr;
-
-    loader = &this->dataPtr->assimpLoader;
-    /*
-    if (extension == "stl" || extension == "stlb" || extension == "stla")
-      loader = &this->dataPtr->stlLoader;
-    else if (extension == "dae")
-      loader = &this->dataPtr->colladaLoader;
-    else if (extension == "obj")
-      loader = &this->dataPtr->objLoader;
+    this->SetAssimpEnvs();
+    if (this->dataPtr->forceAssimp)
+    {
+      loader = &this->dataPtr->assimpLoader;
+    }
     else
     {
-      gzerr << "Unsupported mesh format for file[" << _filename << "]\n";
-      return nullptr;
+      if (extension == "stl" || extension == "stlb" || extension == "stla")
+          loader = &this->dataPtr->stlLoader;
+      else if (extension == "dae")
+        loader = &this->dataPtr->colladaLoader;
+      else if (extension == "obj")
+        loader = &this->dataPtr->objLoader;
+      else if (extension == "gltf" || extension == "glb" || extension == "fbx")
+        loader = &this->dataPtr->assimpLoader;
+      else
+      {
+        gzerr << "Unsupported mesh format for file[" << _filename << "]\n";
+        return nullptr;
+      }
     }
-    */
     // This mutex prevents two threads from loading the same mesh at the
     // same time.
     std::lock_guard<std::mutex> lock(this->dataPtr->mutex);
@@ -1623,3 +1632,16 @@ void MeshManager::ConvertPolylinesToVerticesAndEdges(
     }
   }
 }
+
+//////////////////////////////////////////////////
+void MeshManager::SetAssimpEnvs()
+{
+  std::string forceAssimpEnv;
+  common::env("GZ_MESH_FORCE_ASSIMP", forceAssimpEnv);
+  this->dataPtr->forceAssimp = false;
+  if (forceAssimpEnv == "true")
+  {
+    gzmsg << "Using assimp to load all mesh formats"  << std::endl;
+    this->dataPtr->forceAssimp = true;
+  }
+}