for event in pygame.event.get(): # 响应用户的偶然操作
if event.type == QUIT:
# 如果用户按下屏幕上的关闭按钮,触发QUIT事件,程序退出elif event.type == double_bullet_timer:
is_double_bullet = False
pygame.time.set_timer(double_bullet_timer, 0)