如何使背景与Pygame连续滚动？

Question

我正计划创建一个太空射击游戏，我希望背景中的星星不断向下移动。您可以在下面查看我的代码。图片http://tinypic.com/r/9a8tj4/5

import pygame
import sys
import pygame.sprite as sprite

theClock = pygame.time.Clock()

background = pygame.image.load('background.gif')

background_size = background.get_size()
background_rect = background.get_rect()
screen = pygame.display.set_mode(background_size)
x = 0
y = 0
w,h = background_size
running = True

while running:
    screen.blit(background,background_rect)
    pygame.display.update()
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    if(y > h):
        y = 0
    else:
        y += 5
    screen.blit(background,(x,y))
    pygame.display.flip()
    pygame.display.update()
    theClock.tick(10)

Answer 1

这是我会做的：

BLIT与背景图像的表面两次在一个（0，0），另一个在（0， - img.height）然后将它们向下移动，并且当它们中的任处于POS（0，img.heigth）将其放置在POS（ 0，-img.height）。

import pygame
import sys
import pygame.sprite as sprite

theClock = pygame.time.Clock()

background = pygame.image.load('background.gif')

background_size = background.get_size()
background_rect = background.get_rect()
screen = pygame.display.set_mode(background_size)
w,h = background_size
x = 0
y = 0

x1 = 0
y1 = -h

running = True

while running:
    screen.blit(background,background_rect)
    pygame.display.update()
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
    y1 += 5
    y += 5
    screen.blit(background,(x,y))
    screen.blit(background,(x1,y1))
    if y > h:
        y = -h
    if y1 > h:
        y1 = -h
    pygame.display.flip()
    pygame.display.update()
    theClock.tick(10)