连续的侧面滚动会在背景图像的显示中产生异常

Question

当背景沿着侧面滚动时，图像的末端会拉伸，而图像的其余部分并不会出现在相同的山丘上。然后突然重置。此外，图像的一部分（矩形）从图像的其余部分移开，使其不均匀并保持不变，直到它从视图中消失。

这是我用来侧滚的代码

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

class Background(pygame.sprite.Sprite): #Creates space background
    def __init__(self, image_file, location):
        pygame.sprite.Sprite.__init__(self)  #call Sprite initializer
        self.bgimage = pygame.image.load(image_file)
        self.bgimage = pygame.transform.scale(self.bgimage, (1333, 600))
        self.rectBGimg = self.bgimage.get_rect()

        self.bgY1 = 0
        self.bgX1 = 0

        self.bgY2 = 0
        self.bgX2 = self.rectBGimg.width

        self.movingUpSpeed = 5

    def update(self):
        self.bgX1 -= self.movingUpSpeed
        self.bgX2 -= self.movingUpSpeed
        if self.bgX1 <= -self.rectBGimg.height:
            self.bgX1 = self.rectBGimg.height
        if self.bgX2 <= -self.rectBGimg.height:
            self.bgY2 = self.rectBGimg.height

    def render(self):
        screen.blit(self.bgimage, (self.bgX1, self.bgY1))
        screen.blit(self.bgimage, (self.bgX2, self.bgY2))


pygame.init()

FPS = 15  # frames per second setting
clock = pygame.time.Clock()

window_width = 1333
window_height = 600

# set up the window
screen = pygame.display.set_mode((window_width, window_height))
pygame.display.set_caption('Deterred Journey')

BackGround = Background('scrollingBackground.png', [0,0])

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


    #Adds images and text
    BackGround.render()
    BackGround.update()
    pygame.display.flip()
    pygame.display.update()
    clock.tick(30)

pygame.quit()
sys.exit()

Answer 1

看起来我的更新功能正在检查bgX1和bgX2对高度导致位移，我设置self.bgY2 = self.rectBGimg.height导致伸长。由于它需要垂直滚动，因此bgX2必须设置为宽度

更新的功能应该看起来像

def update(self):
    self.bgX1 -= self.movingUpSpeed
    self.bgX2 -= self.movingUpSpeed
    if self.bgX1 <= -self.rectBGimg.width:
        self.bgX1 = self.rectBGimg.width
    if self.bgX2 <= -self.rectBGimg.width:
        self.bgX2 = self.rectBGimg.width