Fixed MeshManager Singleton (#451)

Signed-off-by: ahcorde <[email protected]>
Signed-off-by: Addisu Z. Taddese <[email protected]>

Author: ahcorde

graphics/include/gz/common/MeshManager.hh

@@ -57,6 +57,11 @@ namespace ignition
       /// Destroys the collada loader, the stl loader and all the meshes
       private: virtual ~MeshManager();
 
+      /// Return a pointer to the mesh manager
+      /// \todo(ahcorde) Remove inheritance from Singleton base class
+      /// \return a pointer to the mesh manager
+      public: static MeshManager* Instance();
+
       /// \brief Load a mesh from a file.
       /// The mesh will be searched on the global SystemPaths instance provided
       /// by Util.hh.

graphics/src/MeshManager.cc

@@ -1579,3 +1579,9 @@ void MeshManager::ConvertPolylinesToVerticesAndEdges(
     }
   }
 }
+
+//////////////////////////////////////////////////
+MeshManager* MeshManager::Instance()
+{
+  return SingletonT<MeshManager>::Instance();
+}