def render_frame(self, text: Optional[Union[dict, str]] = None):
        """
        The real rendering is conducted by the igLoop task maintained by panda3d.
        Frame will be drawn and refresh, when taskMgr.step() is called.
        This function is only used to pass the message that needed to be printed in the screen to underlying renderer.
        :param text: A dict containing key and values or a string.
        :return: None
        """

        if self.on_screen_message is not None:
            self.on_screen_message.render(text)
        if self.mode != RENDER_MODE_NONE and self.sky_box is not None:
            self.sky_box.step()

        The real rendering is conducted by the igLoop task maintained by panda3d.
        Frame will be drawn and refresh, when taskMgr.step() is called.
        This function is only used to pass the message that needed to be printed in the screen to underlying renderer.
        :param text: A dict containing key and values or a string.
        :return: None
        
metadrive/engine/core/engine_core.py