pygame uservent对象未在屏幕上显示

Question

我正在尝试创建一个青蛙游戏，在该游戏中，青蛙在穿越道路时必须躲避汽车。 我做了一个CAR1的用户活动，该活动将在延迟三秒钟后生产汽车。但是由于某种原因，它没有在屏幕上显示。

我还想知道如何创建从左到右移动的多个汽车对象，我应该将它们存储在变量中还是还有其他方法？

import random
import time
# Initialising the program
pygame.init()
# Creating the screen
screen = pygame.display.set_mode((700,700))
playerImg = pygame.image.load('images/golden-frog.png')
playerX = 330
playerY = 700
playerX_change = 0
playerY_change = 0
cars = {
    1: pygame.image.load('images/police.png'),
    2: pygame.image.load('images/motorcycle.png'),
    3: pygame.image.load('images/sports1.png')
}
road = pygame.image.load('images/road.png')
def car(a,x,y):
    screen.blit(cars.get(a),(x,y))
def player(x,y):
    screen.blit(playerImg,(x,y))
running = True
clock = pygame.time.Clock()
while running:
    screen.fill((0,0,0))
    screen.blit(road,(0,100))

    a = random.randint(1,len(cars.keys()))
    car1 = pygame.USEREVENT + 1
    pygame.time.set_timer(car1, 3000)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        if event.type == car1:

            car(1,0,120)
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT:
                playerX_change = 30
            if event.key == pygame.K_LEFT:
                playerX_change = -30
            if event.key == pygame.K_DOWN:
                playerY_change = 50
            if event.key == pygame.K_UP:
                playerY_change = -50
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_RIGHT or  event.key == pygame.K_LEFT:
                playerX_change = 0
            if event.key == pygame.K_UP or event.key == pygame.K_DOWN:
                playerY_change = 0
    playerX += playerX_change
    playerY += playerY_change
    if playerX < 0:
        playerX = 0
    if playerX > 674:
        playerX = 674
    if playerY < 0:
        playerY = 0
    if playerY > 674:
        playerY = 674
    player(playerX,playerY)
    clock.tick(11)
    pygame.display.update()```

Answer 1

在游戏循环的每次迭代中，您都在调用pygame.time.set_timer（）。调用 set_timer（）事件，因此您的car1计时器永远不会触发。

在语句中，将呼叫移至set_timer。

还请注意，您的car1事件处理程序将在三秒钟后触发，并将您的汽车表面闪烁到屏幕上。在您的游戏循环再次运行之前，您可以看到图像的第11秒，而背景则在您的汽车上吸引。您可以执行类似于player函数的操作，该功能称为每个循环。长期，您应该研究 sprites 。