def render()

in gym/envs/classic_control/continuous_mountain_car.py [0:0]

• 86 lines of code
• 10 McCabe index (conditional complexity)

    def render(self):
        if self.render_mode is None:
            gym.logger.warn(
                "You are calling render method without specifying any render mode. "
                "You can specify the render_mode at initialization, "
                f'e.g. gym("{self.spec.id}", render_mode="rgb_array")'
            )
            return

        try:
            import pygame
            from pygame import gfxdraw
        except ImportError:
            raise DependencyNotInstalled(
                "pygame is not installed, run `pip install gym[classic_control]`"
            )

        if self.screen is None:
            pygame.init()
            if self.render_mode == "human":
                pygame.display.init()
                self.screen = pygame.display.set_mode(
                    (self.screen_width, self.screen_height)
                )
            else:  # mode == "rgb_array":
                self.screen = pygame.Surface((self.screen_width, self.screen_height))
        if self.clock is None:
            self.clock = pygame.time.Clock()

        world_width = self.max_position - self.min_position
        scale = self.screen_width / world_width
        carwidth = 40
        carheight = 20

        self.surf = pygame.Surface((self.screen_width, self.screen_height))
        self.surf.fill((255, 255, 255))

        pos = self.state[0]

        xs = np.linspace(self.min_position, self.max_position, 100)
        ys = self._height(xs)
        xys = list(zip((xs - self.min_position) * scale, ys * scale))

        pygame.draw.aalines(self.surf, points=xys, closed=False, color=(0, 0, 0))

        clearance = 10

        l, r, t, b = -carwidth / 2, carwidth / 2, carheight, 0
        coords = []
        for c in [(l, b), (l, t), (r, t), (r, b)]:
            c = pygame.math.Vector2(c).rotate_rad(math.cos(3 * pos))
            coords.append(
                (
                    c[0] + (pos - self.min_position) * scale,
                    c[1] + clearance + self._height(pos) * scale,
                )
            )

        gfxdraw.aapolygon(self.surf, coords, (0, 0, 0))
        gfxdraw.filled_polygon(self.surf, coords, (0, 0, 0))

        for c in [(carwidth / 4, 0), (-carwidth / 4, 0)]:
            c = pygame.math.Vector2(c).rotate_rad(math.cos(3 * pos))
            wheel = (
                int(c[0] + (pos - self.min_position) * scale),
                int(c[1] + clearance + self._height(pos) * scale),
            )

            gfxdraw.aacircle(
                self.surf, wheel[0], wheel[1], int(carheight / 2.5), (128, 128, 128)
            )
            gfxdraw.filled_circle(
                self.surf, wheel[0], wheel[1], int(carheight / 2.5), (128, 128, 128)
            )

        flagx = int((self.goal_position - self.min_position) * scale)
        flagy1 = int(self._height(self.goal_position) * scale)
        flagy2 = flagy1 + 50
        gfxdraw.vline(self.surf, flagx, flagy1, flagy2, (0, 0, 0))

        gfxdraw.aapolygon(
            self.surf,
            [(flagx, flagy2), (flagx, flagy2 - 10), (flagx + 25, flagy2 - 5)],
            (204, 204, 0),
        )
        gfxdraw.filled_polygon(
            self.surf,
            [(flagx, flagy2), (flagx, flagy2 - 10), (flagx + 25, flagy2 - 5)],
            (204, 204, 0),
        )

        self.surf = pygame.transform.flip(self.surf, False, True)
        self.screen.blit(self.surf, (0, 0))
        if self.render_mode == "human":
            pygame.event.pump()
            self.clock.tick(self.metadata["render_fps"])
            pygame.display.flip()

        elif self.render_mode == "rgb_array":
            return np.transpose(
                np.array(pygame.surfarray.pixels3d(self.screen)), axes=(1, 0, 2)
            )