protected void Dispose(bool isDisposing)
 {
     if (m_parent != null)
     {
         m_parent.DecrementDependencyCount();
     }
     m_parent          = null;
     m_ptr_render_mesh = IntPtr.Zero;
 }
 internal RenderPrimitive(RenderPrimitiveEnumerator parent, IntPtr ptrRenderMesh)
 {
     m_parent = parent;
     m_parent.IncrementDependencyCount();
     m_ptr_render_mesh = ptrRenderMesh;
 }