40 lines
1.2 KiB
Python
40 lines
1.2 KiB
Python
import pygame
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from pygame.sprite import Sprite
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class Alien(Sprite):
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"""表示单个外星人的类"""
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def __init__(self, ai_settings, screen):
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"""初始化外星人并设置其初始位置"""
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super().__init__()
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self.screen = screen
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self.ai_settings = ai_settings
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# 加载外星人头像，并设置其rect值
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self.image = pygame.image.load("./images/alien.bmp")
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self.rect = self.image.get_rect()
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# 每个外星人起初都在屏幕的左上角附近
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self.rect.x = self.rect.width
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self.rect.y = self.rect.height
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# 存储外星人的具体位置
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self.x = float(self.rect.x)
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def blitme(self):
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"""在指定位置绘制外星人"""
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self.screen.blit(self.image, self.rect)
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def check_edges(self):
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"""如果外星人位于屏幕边缘，返回true"""
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screen_rect = self.screen.get_rect()
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if self.rect.right >= screen_rect.right:
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return True
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elif self.rect.left <= 0:
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return True
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def update(self):
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"""向左或向右移动外星人"""
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self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)
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self.rect.x = self.x
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