def get_drivable_region(self, center_point):
        """
        Get drivable area, consisting of all roads in map
        Returns: drivable area in boolean numpy array, or None if no map is found.
        """
        if self.engine.current_map:
            drivable_region = self.engine.current_map.get_height_map(
                center_point, self._heightmap_size, 1, self._drivable_area_extension
            )
            drivable_region = (drivable_region > 0).astype(bool)
        else:
            drivable_region = None
        return drivable_region

        Get drivable area, consisting of all roads in map
        Returns: drivable area in boolean numpy array, or None if no map is found.
        
metadrive/engine/core/terrain.py