def env_render_passive_checker()

in gym/utils/passive_env_checker.py [0:0]

• 44 lines of code
• 12 McCabe index (conditional complexity)

def env_render_passive_checker(env, *args, **kwargs):
    """A passive check of the `Env.render` that the declared render modes/fps in the metadata of the environment is declared."""
    render_modes = env.metadata.get("render_modes")
    if render_modes is None:
        logger.warn(
            "No render modes was declared in the environment (env.metadata['render_modes'] is None or not defined), you may have trouble when calling `.render()`."
        )
    else:
        if not isinstance(render_modes, (list, tuple)):
            logger.warn(
                f"Expects the render_modes to be a sequence (i.e. list, tuple), actual type: {type(render_modes)}"
            )
        elif not all(isinstance(mode, str) for mode in render_modes):
            logger.warn(
                f"Expects all render modes to be strings, actual types: {[type(mode) for mode in render_modes]}"
            )

        render_fps = env.metadata.get("render_fps")
        # We only require `render_fps` if rendering is actually implemented
        if len(render_modes) > 0:
            if render_fps is None:
                logger.warn(
                    "No render fps was declared in the environment (env.metadata['render_fps'] is None or not defined), rendering may occur at inconsistent fps."
                )
            else:
                if not (
                    np.issubdtype(type(render_fps), np.integer)
                    or np.issubdtype(type(render_fps), np.floating)
                ):
                    logger.warn(
                        f"Expects the `env.metadata['render_fps']` to be an integer or a float, actual type: {type(render_fps)}"
                    )
                else:
                    assert (
                        render_fps > 0
                    ), f"Expects the `env.metadata['render_fps']` to be greater than zero, actual value: {render_fps}"

        # env.render is now an attribute with default None
        if len(render_modes) == 0:
            assert (
                env.render_mode is None
            ), f"With no render_modes, expects the Env.render_mode to be None, actual value: {env.render_mode}"
        else:
            assert env.render_mode is None or env.render_mode in render_modes, (
                "The environment was initialized successfully however with an unsupported render mode. "
                f"Render mode: {env.render_mode}, modes: {render_modes}"
            )

    result = env.render(*args, **kwargs)

    # TODO: Check that the result is correct

    return result