python - 不知道如何在我的 pygame 中乘以外星人？

Question

所以我刚刚使用 pygame 和 python 编写了一个 dodger 游戏来练习。我读了很多教程并查看了其他类似的游戏来帮助我。基本上，外星人从屏幕顶部落下(它们的大小和速度应该是随机的，它们的位置也应该是随机的)，玩家使用鼠标移动宇宙飞船以躲避坠落的外星人。

我有一个 if 语句，该语句应该使从顶部下来的外星人成倍增加，但是当我运行游戏时，只有一个外星人掉落，当它到达屏幕末尾时，它就消失了。没有其他外星人出现。程序仍在运行，所以游戏还没有结束。

这是我的完整代码。

import pygame
import random
import sys
from pygame.locals import *
alienimg = pygame.image.load('C:\\Python27\\alien.png')
playerimg = pygame.image.load('C:\\Python27\\spaceship.png')

def playerCollision(playerRect, aliens): # a function for when the player hits an alien
    for a in aliens:
        if playerRect.colliderect(a['rect']):
            return True
    return False

def screenText(text, font, screen, x, y): #text display function
    textobj = font.render(text, 1, (255, 255, 255))
    textrect = textobj.get_rect()
    textrect.topleft = (x,y)
    screen.blit(textobj, textrect)

def main(): #this is the main function that starts the game

    pygame.init()

    screen = pygame.display.set_mode((500,500))
    clock = pygame.time.Clock()
    pygame.mouse.set_visible(False)
    pygame.display.set_caption('Dodge the Aliens') 
    font = pygame.font.SysFont("monospace", 45)


    pressed = pygame.key.get_pressed()

    aliens = []
    score = 0
    alienAdd = 0
    addedaliens = 0
    gameOver = False
    moveLeft = moveRight = moveUp = moveDown = False
    topScore = 0
    while gameOver==False: #while loop that actually runs the game
        score += 1

        playerImage =   pygame.image.load('C:\\Python27\\spaceship.png').convert() # the player images
        playerRect = playerImage.get_rect()
        screen.blit(playerImage, [300, 250])
        alienImage = pygame.image.load('C:\\Python27\\alien.png').convert() #alien images
        alienRect = alienImage.get_rect()
        screen.blit(alienImage, [ 50, 50 ])
        pygame.display.flip()


        for event in pygame.event.get(): #key controls
            if event.type == KEYDOWN and event.key == pygame.K_ESCAPE: #escape ends the game
                gameOver = True
            elif event.type == MOUSEMOTION:
                playerRect.move_ip(event.pos[0] - playerRect.centerx, event.pos[1] - playerRect.centery)
        screen.fill((0,0,0))
        pygame.display.flip()


        if not gameOver:
            alienAdd += 1
        if alienAdd == 6: # randomly adding aliens of different sizes and speeds
            aliendAdd = 0
            alienSize = random.randint(8, 25)
            newAlien = {'rect': pygame.Rect(random.randint(0, 500 - alienSize), 0 -alienSize, alienSize, alienSize),
                    'speed': random.randint(1, 8),
                    'surface':pygame.transform.scale(alienImage, (alienSize, alienSize)),
                    }
            aliens.append(newAlien)

        if moveLeft and playerRect.left > 0:
            playerRect.move_ip(-1 * 5, 0)
        if moveRight and playerRect.right < 500:
            playerRect.move_ip(5, 0)
        if moveUp and playerRect.top > 0:
            playerRect.move_ip(0, -1 * 5)
        if moveDown and playerRect.bottom < 500:
            playerRect.move_ip(0, 5)

        for a in aliens:
            if not gameOver:
                a['rect'].move_ip(0, a['speed'])


        for a in aliens[:]:
            if a['rect'].top > 500:
                aliens.remove(a) #removes the aliens when they get to the bottom of the screen

        screenText('Score %s' % (score), font, screen, 10, 0)
        screen.blit(playerImage, playerRect)

        pygame.display.update()

        for a in aliens:
            screen.blit(a['surface'], a['rect'])
        pygame.display.flip()


        if playerCollision(playerRect, aliens):
            if score > topScore:
                topScore = score
            gameOver = True


        clock.tick(30)

    screenText('Game Over!', font, screen, (750 / 6), ( 750 / 6))
    screenText('Press ENTER To Play Again.', font, screen, ( 750 / 6) - 80, (750 / 6) + 50)
    pygame.display.update()

if __name__ == "__main__":
    main()

此外，旁注，每当我将代码放在这里时，我都会向下移动每一行并缩进它。有更简单的方法吗？

Answer 1

aliendAdd = 0 中有拼写错误，应该是 alienAdd = 0。这会导致您不断增加 alienAdd ，而不会再次命中 alienAdd == 6 的 if 语句。