Pygame封装player类后无输出无报错问题求助

核心错误点 #

• pygame.draw.rect()返回的是Rect矩形区域对象，不是可绘制的Surface对象，原代码中用blit()绘制该返回值属于API调用错误
• 按键移动逻辑修改的是全局变量x，没有修改player实例的x属性，实例坐标始终未更新
• pygame.display.update()缩进错误，写在主循环外导致循环过程中屏幕不会刷新，看不到任何绘制内容
• 自定义player类的绘制逻辑错误，不需要调用blit，直接在类内实现矩形绘制即可

修正后可运行代码 #

import pygame
pygame.init()
 
FPS = 60
SCREEN = pygame.display.set_mode((400,500))
pygame.display.set_caption('test')

x = 50
y = 450
vel = 3
width = 20
height = 20

class Player(object):
    def __init__(self, x, y, width, height):
        self.x = x
        self.y = y
        self.width = width
        self.height = height
        self.vel = 3
    def draw(self, screen):
        # 直接在类内完成矩形绘制
        pygame.draw.rect(screen, (0,0,0), (self.x, self.y, self.width, self.height))

player = Player(x, y, width, height)
running = True
clock = pygame.time.Clock()

while running:
    clock.tick(FPS)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    keys = pygame.key.get_pressed()
    # 修改实例的x属性，不是全局x
    if keys[pygame.K_a] and player.x > 0:
        player.x -= player.vel
    if keys[pygame.K_d] and player.x < 400 - player.width:
        player.x += player.vel

    SCREEN.fill((255, 255, 255))
    # 调用实例的draw方法绘制角色
    player.draw(SCREEN)
    # 放到循环内刷新屏幕
    pygame.display.update()

pygame.quit()

内容的提问来源于stack exchange，提问作者user