void gis_opengl_set_height_func(GisOpenGL *self, GisTile *tile,
RoamHeightFunc height_func, gpointer user_data, gboolean update);
void gis_opengl_set_height_func(GisOpenGL *self, GisTile *tile,
RoamHeightFunc height_func, gpointer user_data, gboolean update);