尝试在 pygame 中为视图设置动画，但仅在我移动鼠标时才有效

问题描述

我刚刚开始学习 PyGame，现在我正在尝试为我的视图设置动画，但出乎意料的是，它只会在我移动鼠标时发生。我不知道为什么会这样。你知道是什么原因造成的吗？

代码如下：

import pygame,sys,random

pygame.init()

screenWidth = 1280
screenHeight = 720
screen = pygame.display.set_mode((screenWidth,screenHeight))

clock = pygame.time.Clock()
    
wood_bg = pygame.image.load('my_pic.jpg') # Background
land_bg = pygame.image.load('archive/Land_BG.png') # Animated
land_pos = 650
land_dir = "UP"
water_bg = pygame.image.load('archive/Water_BG.png') # Animated
water_pos = 630
water_dir = "UP"


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

        screen.blit(wood_bg,(0,0))
        screen.blit(land_bg,land_pos))
        screen.blit(water_bg,water_pos))

        # Animate water and land
        if land_pos <= 520:
            land_dir = "DOWN"
        elif land_pos >= 620:
            land_dir = "UP"  
        
        if land_dir == 'UP':
            land_pos -= 2
        else:
            land_pos += 2
        
        if water_pos <= 630:
            water_dir = "DOWN"
        elif water_pos >= 680:
            water_dir = "UP"  
        
        if water_dir == 'UP':
            water_pos -= 1
        else:
            water_pos += 1

        pygame.display.update()
        clock.tick(120)

解决方法

这是一个小的缩进错误。您拥有其余代码（在 for loop 之后：for event in pygame.event.get(): 嵌套在此 for loop 下。这意味着下面的代码仅在收到 event 时才运行。为什么它仅在您的鼠标移动时移动，因为每次 event 都是您的鼠标移动事件。如果您的鼠标静止不动，则不会调用任何事件。

以下是修改后的代码供参考：

import pygame,sys,random

pygame.init()

screenWidth = 1280
screenHeight = 720
screen = pygame.display.set_mode((screenWidth,screenHeight))

clock = pygame.time.Clock()
    
wood_bg = pygame.image.load('my_pic.jpg') # Background
land_bg = pygame.image.load('archive/Land_BG.png') # Animated
land_pos = 650
land_dir = "UP"
water_bg = pygame.image.load('archive/Water_BG.png') # Animated
water_pos = 630
water_dir = "UP"


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

    # >>> All this code below had an extra indent,thus running under the "for loop" above
    screen.blit(wood_bg,(0,0))
    screen.blit(land_bg,land_pos))
    screen.blit(water_bg,water_pos))

    # Animate water and land
    if land_pos <= 520:
        land_dir = "DOWN"
    elif land_pos >= 620:
        land_dir = "UP"  
    
    if land_dir == 'UP':
        land_pos -= 2
    else:
        land_pos += 2
    
    if water_pos <= 630:
        water_dir = "DOWN"
    elif water_pos >= 680:
        water_dir = "UP"  
    
    if water_dir == 'UP':
        water_pos -= 1
    else:
        water_pos += 1

    pygame.display.update()
    clock.tick(120)

,

这是Indentation的问题。您必须在应用程序循环而不是事件循环中绘制场景并更新显示：

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

    # INDENTATION

    #<--|

    screen.blit(wood_bg,water_pos))

    # Animate water and land
    if land_pos <= 520:
        land_dir = "DOWN"
    elif land_pos >= 620:
        land_dir = "UP"  
    
    if land_dir == 'UP':
        land_pos -= 2
    else:
        land_pos += 2
    
    if water_pos <= 630:
        water_dir = "DOWN"
    elif water_pos >= 680:
        water_dir = "UP"  
    
    if water_dir == 'UP':
        water_pos -= 1
    else:
        water_pos += 1

    pygame.display.update()
    clock.tick(120)