python – 在pygame中每隔x(毫秒)做一些事情

我正在学习 Python和Pygame,而我正在做的第一件事是一个简单的Snake游戏.我试图让蛇每0.25秒移动一次.这是我的代码循环的一部分：

while True:
    check_for_quit()

    clear_screen()

    draw_snake()
    draw_food()

    check_for_direction_change()

    move_snake() #How do I make it so that this loop runs at normal speed, but move_snake() only executes once every 0.25 seconds?

    pygame.display.update()

我希望所有其他函数正常运行,但move_snake()只发生一次0.25秒.我查了一下并找到了一些答案,但对于那些制作他们的第一个Python脚本的人来说,它们看起来都太复杂了.

是否有可能真正得到我的代码应该是什么样子的例子,而不仅仅是告诉我需要使用哪个函数？谢谢！

有几种方法,如跟踪系统时间或使用时钟和计数滴答.

但最简单的方法是使用事件队列并使用pygame.time.set_timer()每隔x ms创建一个事件：

pygame.time.set_timer()

repeatedly create an event on the event queue

set_timer(eventid, milliseconds) -> None

Set an event type to appear on the event queue every given number of milliseconds. The first event will not appear until the amount of time has passed.

Every event type can have a separate timer attached to it. It is best to use the value between pygame.USEREVENT and pygame.NUMEVENTS.

To disable the timer for an event, set the milliseconds argument to 0.

这是一个小的,运行的例子,蛇每250毫秒移动一次：

import pygame
pygame.init()
screen = pygame.display.set_mode((300, 300))
player, dir, size = pygame.Rect(100,100,20,20), (0, 0), 20
MOVEEVENT, t, trail = pygame.USEREVENT+1, 250, []
pygame.time.set_timer(MOVEEVENT, t)
while True:
    keys = pygame.key.get_pressed()
    if keys[pygame.K_w]: dir = 0, -1
    if keys[pygame.K_a]: dir = -1, 0
    if keys[pygame.K_s]: dir = 0, 1
    if keys[pygame.K_d]: dir = 1, 0

    if pygame.event.get(pygame.QUIT): break
    for e in pygame.event.get():
        if e.type == MOVEEVENT: # is called every 't' milliseconds
            trail.append(player.inflate((-10, -10)))
            trail = trail[-5:]
            player.move_ip(*[v*size for v in dir])

    screen.fill((0,120,0))
    for t in trail:
        pygame.draw.rect(screen, (255,0,0), t)
    pygame.draw.rect(screen, (255,0,0), player)
    pygame.display.flip()