pygame碰到边缘就反弹

以下是一个简单的pygame碰到边缘就反弹的例子：

import pygame

pygame.init()

# 设置窗口大小
screen_width = 800
screen_height = 600
screen = pygame.display.set_mode((screen_width, screen_height))

# 设置小球的初始位置和速度
ball_pos = [50, 50]
ball_speed = [5, 5]

# 游戏循环
while True:
    # 处理退出事件
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            exit()

    # 移动小球
    ball_pos[0] += ball_speed[0]
    ball_pos[1] += ball_speed[1]

    # 碰到左右边缘反弹
    if ball_pos[0] < 0 or ball_pos[0] > screen_width:
        ball_speed[0] = -ball_speed[0]

    # 碰到上下边缘反弹
    if ball_pos[1] < 0 or ball_pos[1] > screen_height:
        ball_speed[1] = -ball_speed[1]

    # 填充背景色
    screen.fill((230, 230, 230))

    # 绘制小球
    pygame.draw.circle(screen, (255, 0, 0), ball_pos, 20)

    # 更新屏幕
    pygame.display.update()