renderMapTiles :: WebGLRenderingContext
               -> ProjMatrix
               -> ViewMatrix
               -> RenderMTilesProgram
               -> IO ()
renderMapTiles _ _ _ rmtp | null (rmtTiles rmtp) = return ()
renderMapTiles :: WebGLRenderingContext
               -> ProjMatrix
               -> ViewMatrix
               -> RenderMTilesProgram
               -> IO ()
renderMapTiles _ _ _ rmtp | null (rmtTiles rmtp) = return ()
renderMapTiles _ _ _ rmtp | null (rmtTiles rmtp) = return ()