python - pygame中的动画

Question

这个程序的目标是让一个绿色圆圈在屏幕上循环地上下弹跳。我已经让它下降并再次上升，但不是让它再次下降。

import pygame, sys, time, random
from pygame.locals import *
from time import *

pygame.init()
windowSurface = pygame.display.set_mode((500, 400), 0, 32)
pygame.display.set_caption("Bounce")

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

info = pygame.display.Info()
sw = info.current_w
sh = info.current_h
y= 0
yy= sh

while True:
    windowSurface.fill(BLACK)
    pygame.draw.circle(windowSurface, GREEN , (250,y), 13, 0)
    sleep(.006)
    y+= 1
    if y>sh:
        pygame.draw.circle(windowSurface, GREEN , (250,yy), 13, 0)
        sleep(.0001)
        yy +=-1
    if yy<-.00001:
        y=0
        y+= 1
        pygame.draw.circle(windowSurface, GREEN , (250,y), 13, 0)

    pygame.display.update()

    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()

Answer 1

在你的if yy < -.00001: block ，我认为你正在尝试将状态重置回程序开始时的状态。如果是这样，您忘记设置 yy = sh .

换句话说:

if yy<-.00001:
    y=0
    yy=sh   # <- add this line
    y+= 1
    pygame.draw.circle(windowSurface, GREEN , (250,y), 13, 0)

但总的来说，我同意半身人的观点。这段代码太复杂了。我建议使用状态变量来记录球是向上还是向下移动，然后在循环中检查该变量并增加或减少位置。当您到达屏幕的另一端时，交换状态变量以改变球的方向。

编辑:试试这个:

import pygame, sys, time, random
from pygame.locals import *
from time import *

pygame.init()
windowSurface = pygame.display.set_mode((500, 400), 0, 32)
pygame.display.set_caption("Bounce")

BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)

info = pygame.display.Info()
sw = info.current_w
sh = info.current_h
y = 0

# Initial direction is down
direction = 1

while True:
    windowSurface.fill(BLACK)
    pygame.draw.circle(windowSurface, GREEN , (250,y), 13, 0)
    #print "Drawing at 250,", y
    sleep(.006)
    y += direction
    if y >= sh:
        # Changes the direction from down to up
        direction = -1
    elif y <= 0:
        # Changes the direction from up to down
        direction = 1

    pygame.display.update()

    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()

注意:希望这对您有用。我没有安装 pygame，所以我只在注释掉 pygame 内容和 print 的情况下运行它调用替换而不是绘制命令。无论如何，它对我有用。