如何在汽车到达屏幕边缘时将其移走？

Question

我是 Python 的初学者，正在尝试通过构建 Frogger Clone 来学习。我使用 class 创建了汽车图像，并循环创建了 6 辆汽车。我有一个问题，当它们到达屏幕边界时如何删除它们。

import random

import pygame

pygame.init()
screen = pygame.display.set_mode((600, 600))
# Dictionary of Car Images
cars = {
    1: pygame.image.load('images/police.png'),
    2: pygame.image.load('images/motorcycle.png'),
    3: pygame.image.load('images/sports1.png')
}
current_cars = []


class Car():
    def __init__(self, a,x, y):
        self.a = a
        self.x = x
        self.y = y



    def move(self):
        self.x += 5
        screen.blit(cars.get(self.a), (self.x, self.y))

# Creates 6 cars
for i in range(6):
    a = random.randint(1,3)
    current_cars.append(Car(a,0, 100 + (100*i)))

start = pygame.time.get_ticks()
clock = pygame.time.Clock()
running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    screen.fill((0, 0, 0))
    now = pygame.time.get_ticks()
    # Creates new enemy after every 6 seconds.
    if now - start > 6000:
        start = now
        a = random.randint(1,3)
        b = random.randrange(1,501,100)
        object = Car(a, 0, 100 + b)
        current_cars.append(object)
       
        # moves all the cars in list
    for i in range(len(current_cars)):
        current_cars[i].move()

    clock.tick(11)
    pygame.display.update()

我如何创建一个 if 条件来检查汽车的 x 位置何时到达边界并将其从当前汽车列表中删除。

Answer 1

当汽车出界时，您必须从列表中删除护理。使用pygame.Rect.colliderect测试屏幕上是否还有汽车的一部分。

在 Car class 的构造函数中加载汽车图像，而不是在每个帧中加载

class Car():
    def __init__(self, a, x, y):
        self.image = cars.get(a)
        self.x = x
        self.y = y

    def move(self):
        self.x += 5
        screen.blit(self.image, (self.x, self.y))

参见 How to remove items from a list while iterating?。遍历汽车列表的浅表副本，如果汽车不在屏幕上，则将其从原始汽车列表中移除：

while running:
    # [...]

    for car in current_cars:     # iterate list of cars
        car.move()

    screen_rect = screen.get_rect()
    for car in current_cars[:]:  # iterate shallow copy of car list
        car_rect = car.image.get_rect(topleft = (car.x, car.y))
        if not screen_rect.collidrect(car_rect):
            current_cars.remove(car)

如何在汽车到达屏幕边缘时将其移走？

How do I remove a car when it reaches the edge of screen?

python

pygame

python-3.x