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

I am a beginner in Python and trying to learn by building a Frogger Clone. I have created images of cars using a class, and looping them to create 6 cars. I have a problem in that how do i remove them when they reach the boundary of screen.

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()

How do i create an if condition to check when x position of a car reaches the boundary and remove it from the list of current cars.

CodePudding user response：

You have to remove the care from the list when the car goes out of bounds. Use pygame.Rect.colliderect to test if there is still a part of the car on the screen.

Load the car image in the constructor of the Car class instead of in each frame

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))

See How to remove items from a list while iterating?. Iterate through a shallow copy of the car list and remove the cars from the original car list if they are not on screen:

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)