如何让随机敌人从列表中出现？

Question

我试图让一辆随机车从保存在变量中的汽车列表中出现。这个问题似乎是它从列表中选择一辆随机赛车，并且在比赛进行时不会改变它。每次前一辆车离开屏幕时，我都想换车。

每次游戏开始时，它会从随机列表中选择一辆车，但每次游戏循环运行时都不会更改车辆。

我认为问题出在该位的代码

randomCars = [car1, car2, car3, car4, car5, car6, car7, car8] 
enemy = random.choice(randomCars) 

我已经粘贴了以下全码：

import pygame 
import time 
import random 

pygame.init() 

############# 

############# 

display_width = 800 
display_height = 600 

black = (0, 0, 0) 
white = (255, 255, 255) 
red = (200, 0, 0) 
green = (0, 200, 0) 
bright_red = (255, 0, 0) 
bright_green = (0, 255, 0) 
block_color = (53, 115, 255) 

crash_sound = pygame.mixer.Sound("crash.mp3") 

car_width = 55 

gameDisplay = pygame.display.set_mode((display_width, display_height)) 
pygame.display.set_caption('Super Racer') 
clock = pygame.time.Clock() 

gameIcon = pygame.image.load('carIcon.png') 

backgroundImage = pygame.image.load("background.png") 
backgroundImage = pygame.transform.scale(backgroundImage, (800, 600)) 
gameDisplay.blit(backgroundImage, (0, 0)) 





pygame.display.set_icon(gameIcon) 

pause = False 


# crash = True 

def score(count): 
    font = pygame.font.SysFont("comicsansms", 25) 
    text = font.render("SCORE: " + str(count), True, red) 
    gameDisplay.blit(text, (0, 0)) 

def load_image(name_img): 
    car = pygame.image.load(name_img) 
    car = pygame.transform.scale(car, (60, 100)) # resize graphic 
    return car.convert_alpha() # remove whitespace from graphic 

carImg = load_image('racecar.png') 
enemies_list = ['diablo.png', 'aventador.png', 'nsx.png', 'bike.png', 'Mach6.png', 'speeder.png', 'Stingray.png', 'slr.png' ] # add all other cars 
randomCars = [load_image(img) for img in enemies_list] 

def things(enemy, thingx, thingy, thingw, thingh, color): 
    gameDisplay.blit(enemy, [thingx, thingy, thingw, thingh]) 

def car(x, y): 
    gameDisplay.blit(carImg, (x, y)) 


def text_objects(text, font): 
    textSurface = font.render(text, True, black) 
    return textSurface, textSurface.get_rect() 


def crash(): 
    #################################### 

    pygame.mixer.Sound.play(crash_sound) 
    pygame.mixer.music.stop() 
    #################################### 
    largeText = pygame.font.SysFont("comicsansms", 115) 
    TextSurf, TextRect = text_objects("You Crashed", largeText) 
    TextRect.center = ((display_width/2), (display_height/2)) 
    gameDisplay.blit(TextSurf, TextRect) 

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

     button("Play Again", 150, 450, 100, 50, green, bright_green, game_loop) 
     button("Quit", 550, 450, 100, 50, red, bright_red, quitgame) 

     pygame.display.update() 
     clock.tick(15) 


def button(msg, x, y, w, h, ic, ac, action=None): 
    mouse = pygame.mouse.get_pos() 
    click = pygame.mouse.get_pressed() 

    if x + w > mouse[0] > x and y + h > mouse[1] > y: 
     pygame.draw.rect(gameDisplay, ac, (x, y, w, h)) 
     if click[0] == 1 and action != None: 
      action() 
    else: 
     pygame.draw.rect(gameDisplay, ic, (x, y, w, h)) 
    smallText = pygame.font.SysFont("comicsansms", 20) 
    textSurf, textRect = text_objects(msg, smallText) 
    textRect.center = ((x + (w/2)), (y + (h/2))) 
    gameDisplay.blit(textSurf, textRect) 


def quitgame(): 
    pygame.quit() 
    quit() 


def unpause(): 
    global pause 
    pygame.mixer.music.unpause() 
    pause = False 


def paused(): 
    ############ 
    pygame.mixer.music.pause() 
    ############# 
    largeText = pygame.font.SysFont("comicsansms", 115) 
    TextSurf, TextRect = text_objects("Paused", largeText) 
    TextRect.center = ((display_width/2), (display_height/2)) 
    gameDisplay.blit(TextSurf, TextRect) 

    while pause: 
     for event in pygame.event.get(): 
      if event.type == pygame.QUIT: 
       pygame.quit() 
       quit() 

     button("Continue", 150, 450, 100, 50, green, bright_green, unpause) 
     button("Quit", 550, 450, 100, 50, red, bright_red, quitgame) 

     pygame.display.update() 
     clock.tick(15) 


def game_intro(): 
    intro = True 

    while intro: 
     for event in pygame.event.get(): 
      # print(event) 
      if event.type == pygame.QUIT: 
       pygame.quit() 
       quit() 

     gameDisplay.fill(white) 
     largeText = pygame.font.SysFont("comicsansms", 115) 
     TextSurf, TextRect = text_objects("Super Racer", largeText) 
     TextRect.center = ((display_width/2), (display_height/2)) 
     gameDisplay.blit(TextSurf, TextRect) 

     button("LEGGO!", 150, 450, 100, 50, green, bright_green, game_loop) 
     button("Quit", 550, 450, 100, 50, red, bright_red, quitgame) 

     pygame.display.update() 
     clock.tick(15) 


def game_loop(): 
    global pause 
    enemy = random.choice(randomCars) 
    ############ 

    pygame.mixer.music.load('bgmusic.mp3') 
    pygame.mixer.music.play(-1) 
    ############ 
    x = (display_width * 0.45) 
    y = (display_height * 0.8) 

    x_change = 0 

    thing_startx = random.randrange(0, display_width) 
    thing_starty = -600 
    enemy_speed = 4 
    thing_width = 55 
    thing_height = 95 
    enemy = random.choice(randomCars) 
    thingCount = 1 

    dodged = 0 

    gameExit = False 

    while not gameExit: 

     for event in pygame.event.get(): 
      if event.type == pygame.QUIT: 
       pygame.quit() 
       quit() 

      if event.type == pygame.KEYDOWN: 
       if event.key == pygame.K_LEFT: 
        x_change = -5 
       if event.key == pygame.K_RIGHT: 
        x_change = 5 
       if event.key == pygame.K_p: 
        pause = True 
        paused() 

      if event.type == pygame.KEYUP: 
       if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT: 
        x_change = 0 

     x += x_change 

     gameDisplay.blit(backgroundImage, (0, 0)) 

     things(enemy, thing_startx, thing_starty, thing_width, thing_height, block_color) 

     thing_starty += enemy_speed 
     car(x, y) 
     score(dodged) 

     if x > display_width - car_width or x < 0: 
      crash() 

     if thing_starty > display_height: 
      thing_starty = 0 - thing_height 
      thing_startx = random.randrange(0, display_width) 
      dodged += 1 
      #enemy_speed += .25 
      if dodged % 5 == 0: 
       enemy_speed += (dodged * 1) 


     if y < thing_starty + thing_height: 
      #print('y crossover') 

      if x > thing_startx and x < thing_startx + thing_width or x + car_width > thing_startx and x + car_width < thing_startx + thing_width: 
       #print('x crossover') 
       crash() 

     pygame.display.update() 
     clock.tick(60) 


game_intro() 
game_loop() 
pygame.quit() 
quit() 

Answer 1

这里有一个小例子。只要使用random.choice即可在当前汽车离开屏幕后立即将新车从列表中移出。

import random 
import pygame 


pygame.init() 

CAR_IMG1 = pygame.Surface((30, 50)) 
CAR_IMG1.fill((10, 150, 200)) 
CAR_IMG2 = pygame.Surface((30, 50)) 
CAR_IMG2.fill((210, 150, 0)) 
CAR_IMG3 = pygame.Surface((30, 50)) 
CAR_IMG3.fill((10, 250, 0)) 

CARS = [CAR_IMG1, CAR_IMG2, CAR_IMG3] 


def main(): 
    screen = pygame.display.set_mode((640, 480)) 
    screen_rect = screen.get_rect() 
    clock = pygame.time.Clock() 
    car = random.choice(CARS) 
    pos_x = random.randrange(screen_rect.width-30) 
    pos_y = -50 

    done = False 

    while not done: 
     for event in pygame.event.get(): 
      if event.type == pygame.QUIT: 
       done = True 

     pos_y += 15 
     if pos_y > screen_rect.height: 
      car = random.choice(CARS) 
      pos_x = random.randrange(screen_rect.width-30) 
      pos_y = -50 

     screen.fill((30, 30, 30)) 
     screen.blit(car, (pos_x, pos_y)) 

     pygame.display.flip() 
     clock.tick(30) 


if __name__ == '__main__': 
    pygame.init() 
    main() 
    pygame.quit() 

Answer 2

首先初始化您的敌方汽车图像列表从中选择一个。

randomCars = [carImg1, carImg2, carImg3, carImg4]

里面的game_loop（）函数，但主循环之外设置enemy = random.choice(randomCars)

里面的game_loop（）函数检查的主要环路，看敌人去关闭屏幕。如果是这样，请将敌人变量设置为新的随机车。

if thing_starty > display_height: 
    # Reset enemy image 
    enemy = random.choice(randomCars) 
    # Reset thing co-ordinates 
    thing_starty = -600 
    thing_startx = random.randrange(0, display_width) 

如果enemy = random.choice(randomCars)行代码不工作，你也可以尝试用随机整数索引randomCars列表。

randomCarsIndex = random.randint(0, len(randomCars) - 1) enemy = randomCars[randomCarsIndex]

希望这有助于！