def _render_frame()

in gym/wrappers/human_rendering.py [0:0]

• 35 lines of code
• 7 McCabe index (conditional complexity)

    def _render_frame(self):
        """Fetch the last frame from the base environment and render it to the screen."""
        try:
            import pygame
        except ImportError:
            raise DependencyNotInstalled(
                "pygame is not installed, run `pip install gym[box2d]`"
            )
        if self.env.render_mode == "rgb_array_list":
            last_rgb_array = self.env.render()
            assert isinstance(last_rgb_array, list)
            last_rgb_array = last_rgb_array[-1]
        elif self.env.render_mode == "rgb_array":
            last_rgb_array = self.env.render()
        else:
            raise Exception(
                f"Wrapped environment must have mode 'rgb_array' or 'rgb_array_list', actual render mode: {self.env.render_mode}"
            )
        assert isinstance(last_rgb_array, np.ndarray)

        rgb_array = np.transpose(last_rgb_array, axes=(1, 0, 2))

        if self.screen_size is None:
            self.screen_size = rgb_array.shape[:2]

        assert (
            self.screen_size == rgb_array.shape[:2]
        ), f"The shape of the rgb array has changed from {self.screen_size} to {rgb_array.shape[:2]}"

        if self.window is None:
            pygame.init()
            pygame.display.init()
            self.window = pygame.display.set_mode(self.screen_size)

        if self.clock is None:
            self.clock = pygame.time.Clock()

        surf = pygame.surfarray.make_surface(rgb_array)
        self.window.blit(surf, (0, 0))
        pygame.event.pump()
        self.clock.tick(self.metadata["render_fps"])
        pygame.display.flip()