如何在 pygame 中生成多个敌人

Question

所以我正在尝试制作一款游戏，让角色躲避从上方随机生成的敌人。问题是，我不知道如何在不实例化另一个 class 的情况下使随机值不同，我不想这样做。此外，使用 Screen.fill()，敌人不会出现，因为它们每帧都被颜色重叠，如果我不使用 Screen.fill()，我的角色每次移动都会留下痕迹.有什么建议吗？

import random

pygame.init()
Running = True
Screen = pygame.display.set_mode((800, 600))

player_img = pygame.image.load('/Users/kevinhadinata/Downloads/ufo.png')
player_updated = pygame.transform.scale(player_img,(60,60))

enemy_list = []
enemy_img = pygame.image.load('/Users/kevinhadinata/Downloads/alien.png')
SPAWNENEMY = pygame.USEREVENT
pygame.time.set_timer(SPAWNENEMY,1000)

class Player:
    def __init__(self):
        self.ypos = 540
        self.xpos = 325
        self.height = 60
        self.width = 60
        self.playerUpdated = player_updated
    def create_player(self):
        Playerss = pygame.Rect(self.xpos,self.ypos,self.height,self.width)
        pygame.draw.ellipse(Screen, (0, 0, 0), Playerss)
        Screen.blit(player_updated, (Playerss.x, Playerss.y))

sizee = random.randint(10,40)
randomX = random.randint(0,700)

class Enemy:
    def __init__(self):
            self.xval = random.randint(0,700)
            self.size = random.randint(10,40)
    def create_enemy(self):
        Enemy = pygame.Rect(self.xval, 0, self.size,self.size)
        #enemy_updated = pygame.transform.scale(enemy_img,(self.size,self.size))
        enemy_list.append(Enemy)
        pygame.draw.ellipse(Screen,(255,255,0),Enemy)

Player = Player()
Enemys = Enemy()

while Running:
    Screen.fill((0,0,0))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            Running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                Player.xpos -= 20
            if event.key == pygame.K_RIGHT:
                Player.xpos += 20
        if event.type == SPAWNENEMY:
            Enemys.create_enemy()

    Player.create_player()

    pygame.display.update()

Answer 1

您需要创建一个敌人列表并在主循环中迭代该列表以绘制每个敌人。使用randint随机放置敌人。

试试这个代码：

import random, pygame

pygame.init()
Running = True
Screen = pygame.display.set_mode((800, 600))

player_img = pygame.image.load('/Users/kevinhadinata/Downloads/ufo.png')
player_updated = pygame.transform.scale(player_img,(60,60))

enemy_list = []
enemy_img = pygame.image.load('/Users/kevinhadinata/Downloads/alien.png')
SPAWNENEMY = pygame.USEREVENT
pygame.time.set_timer(SPAWNENEMY,1000)

class Player:
    def __init__(self):
        self.ypos = 540
        self.xpos = 325
        self.height = 60
        self.width = 60
        self.playerUpdated = player_updated
    def create_player(self):
        self.Playerss = pygame.Rect(self.xpos,self.ypos,self.height,self.width)
        pygame.draw.ellipse(Screen, (0, 0, 0), self.Playerss)
        Screen.blit(player_updated, (self.Playerss.x, self.Playerss.y))
        
    def draw(self):  # draw player
        Screen.blit(player_updated, (self.xpos,self.ypos))

sizee = random.randint(10,40)
randomX = random.randint(0,700)

class Enemys:
    def __init__(self):
            #self.xval = random.randint(0,700)
            self.size = random.randint(10,40)
    def create_enemy(self):
        Enemy = pygame.Rect(random.randint(100,700), 0, self.size,self.size)
        #enemy_updated = pygame.transform.scale(enemy_img,(self.size,self.size))
        enemy_list.append(Enemy)
        pygame.draw.ellipse(Screen,(255,255,0),Enemy)
        
    def draw(self):  # draw all enemies
        for e in enemy_list:
            pygame.draw.ellipse(Screen,(255,255,0),e)
            

Player = Player()  # player object
Enemys = Enemys()  # collection of enemies
Player.create_player()

while Running:
    Screen.fill((0,0,0))
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            Running = False
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_LEFT:
                Player.xpos -= 20
            if event.key == pygame.K_RIGHT:
                Player.xpos += 20
        if event.type == SPAWNENEMY:
            Enemys.create_enemy()

    Player.draw()  # draw player
    Enemys.draw()  # draw all enemies
    pygame.display.update()

Answer 2

最好不要实例化一个新的敌人，因为只要将它回收到屏幕顶部就足够了。这相当于简单地改变尺寸 & x,y。

您的某些代码用 Enemy 变量名称遮挡了 Enemy class 名称。我已将此变量名称更改为 new_enemy.

class Enemy:
    def __init__(self):
        self.recycle()   # set the position & size initially

    def recycle( self ):
        # start or re-start an enemy position
        self.size = random.randint(10,40)
        self.xval = random.randint(0,700)
        self.yval = -self.size              # off the screen-top
        self.rect = pygame.Rect( self.xval, self.yval, self.size, self.size )

    def draw( self, screen ):
        pygame.draw.ellipse( screen, (255,255,0), self.rect )

    def create_enemy(self):
        global enemy_list
        new_enemy = Enemy()               # create a new Enemy
        enemy_list.append( new_enemy )    # add it to the list

然后在你的主循环中，你可以 recycle() 任何进入 off-screen 的敌人。

[...]    # in main loop

# draw all the enemies, and re-position any enemies that moved off the screen
for enemy in enemy_list:
    enemy.draw( screen )
    if ( enemy.ypos > 600 ):          # TODO - don't use a fixed size
        enemy.recycle()               # move back to top

绘制生成代码是 mixed-up，我已 re-arranged 将其放入单独的 .draw() 函数中。使用它也可以解决清除屏幕的问题。每一帧，代码都会清除屏幕，然后重新绘制所有项目。

如何在 pygame 中生成多个敌人

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