如何使Pygame不斷滾動背景？

Question

我打算創建一個太空射擊遊戲，我希望我的背景恆星不斷向下移動。你可以在下面看到我的代碼。圖片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

這裏就是我會做：

BLIT與背景圖像表面兩次一個在（0，0），另一個在（0， - img.height），然後將它們移動當它們中的任何一個都位於pos（0，img.heigth）時，它再次位於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)