增加 pygame 中使用的变量

Question

我正在 pygame 编写一个 space 入侵者游戏，并希望当玩家达到 50 分时，游戏将入侵者的数量从 6 增加到 10。在游戏中，敌人死后立即在屏幕上半部分重生。游戏运行正常，直到您达到 50 分，然后立即崩溃。如何使存储敌人数量 (num_of_enemies) 的变量增加，而游戏仍然是运行?

在我放在这里的代码中，我删除了更改 num_of_enemies 变量的尝试，但是仅供参考，我将它放在“pygame.display.update()”上方。我解决问题的蹩脚尝试归结为：

if score_value >= 50: num_of_enemies += 10

我在分配 num_of_enemies 全局值时也尝试过此代码，但它只会让游戏缺陷，并再次搞砸。

代码：

import pygame
from pygame import mixer
import random
import math


pygame.init()

screen = pygame.display.set_mode((800, 600))

background = pygame.image.load('Background.jpg')
background = pygame.transform.scale(background, (800, 600))

mixer.music.load('background.wav')
mixer.music.play(-1)

pygame.display.set_caption("Space Invaders")
icon = pygame.image.load('ufo.png')
pygame.display.set_icon(icon)

playerImg = pygame.image.load('spaceship.png')
playerX = 370
playerY = 480
playerX_change = 0

enemyImg = []
enemyX = []
enemyY = []
enemyX_change = []
enemyY_change = []
num_of_enemies = 6

for i in range(num_of_enemies):
    enemyImg.append(pygame.image.load('ufo.png'))
    enemyX.append(random.randint(0, 750))
    enemyY.append(random.randint(50, 200))
    enemyX_change.append(0.5)
    enemyY_change.append(40)

bulletImg = pygame.image.load('bullet.png')
bulletX = 0
bulletY = 480
bulletX_change = 0
bulletY_change = 1
bullet_state = "ready"

score_value = 0
font = pygame.font.Font('freesansbold.ttf', 32)

textX = 10
textY = 10

over_font = pygame.font.Font('freesansbold.ttf', 64)

def show_score(x,y):
    score = font.render("Score : " + str(score_value), True, (255, 255, 255))
    screen.blit(score, (x,y))
    
def game_over_text():
    over_text = over_font.render("GAME OVER", True, (255, 255, 255))
    screen.blit(over_text, (200, 250))
    
def player(x,y): 
    screen.blit(playerImg,(x, y))
    
def enemy(x,y, i):
    screen.blit(enemyImg[i],(x,y))
    
def fire_bullet(x,y):
    global bullet_state
    bullet_state = "fire"
    screen.blit(bulletImg,(x + 16, y + 10))
    
    
def isCollision(enemyX, enemyY, bulletX, bulletY):
    distance = math.sqrt((math.pow(enemyX-bulletX,2)) + (math.pow(enemyY-bulletY,2)))
    if distance < 27:
        return True
    else:
        return False
    
running = True
while running:
    
    screen.fill((0, 0, 0))
    
    screen.blit(background,(0,0))
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

            
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                playerX_change = -1
            if event.key == pygame.K_RIGHT:
                playerX_change = 1
        if event.type == pygame.KEYUP:
            if event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT:
                playerX_change = 0
            if event.key == pygame.K_SPACE:
                if bullet_state == "ready":
                    bullet_sound = mixer.Sound('laser.wav')
                    bullet_sound.play()
                    bulletX = playerX
                    fire_bullet(bulletX,bulletY)
                

    
    playerX += playerX_change
    
    if playerX <= 0:
        playerX = 0
    elif playerX >= 768:
        playerX = 768

    
    for i in range(num_of_enemies):
        
        
        if enemyY[i] > 440:
            for j in range(num_of_enemies):
                enemyY[j] = 2000
                
            game_over_text()
            break
        
        
        enemyX[i] += enemyX_change[i]
        if enemyX[i] <= 0:
            enemyX_change[i] = 0.5
            enemyY[i] += enemyY_change[i]
        elif enemyX[i] >= 768:
            enemyX_change[i] = -0.5
            enemyY[i] += enemyY_change[i]
            
            
        collision = isCollision(enemyX[i], enemyY[i], bulletX, bulletY)
        if collision:
            explosion_Sound = mixer.Sound('explosion.wav')
            explosion_Sound.play()
            bulletY = 480
            bullet_state = "ready"
            score_value += 1
            print(f"score = {score_value}")
            enemyX[i] = random.randint(50, 768)
            enemyY[i] = random.randint(50, 200)
        
        enemy(enemyX[i], enemyY[i], i)
        
    
    
    if bulletY <= 0:
        bulletY = 480
        bullet_state = "ready"
    if bullet_state == "fire":
        fire_bullet(bulletX,bulletY)
        bulletY -= bulletY_change
    
    
    player(playerX, playerY)
    
    show_score(textX, textY)
    

    pygame.display.update()```

Answer 1

仅更改是不够的num_of_enemies您还需要在列表中添加新项目。

编写一个将敌人装箱的函数：

def create_enemies(new_enemies):
    global num_of_enemies
    
    enemy_image = pygame.image.load('ufo.png')
    for i in range(new_enemies):
        enemyImg.append(enemy_image)
        enemyX.append(random.randint(0, 750))
        enemyY.append(random.randint(50, 200))
        enemyX_change.append(0.5)
        enemyY_change.append(40)

    # now the number of enemies has changed
    num_of_enemies += new_enemies

在应用程序开始时调用函数：

enemyImg = []
enemyX = []
enemyY = []
enemyX_change = []
enemyY_change = []

num_of_enemies = 0  # 0! actually you have 0 enemies
create_enemies(6)   # create 6 new enemies

如果你想改变敌人的数量，请再次调用该函数：

# create 4 more enemies, now the number of enemies changes from 6 to 10
create_enemies(4)

增加 pygame 中使用的变量

Increasing variables that are in use in pygame

python

pygame