34 lines
1.1 KiB
Python
34 lines
1.1 KiB
Python
import pygame
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from pygame.sprite import Sprite
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class Alien(Sprite):
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"""A class to represent a single alien in the fleet."""
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def __init__(self, ai_game):
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"""Initialize the alien and set its starting position."""
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super().__init__()
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self.screen = ai_game.screen
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self.settings = ai_game.settings
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# Load the alien image and set its rect attribute.
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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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# Start each new alien near the top left of the screen.
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self.rect.x = self.rect.width
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self.rect.y = self.rect.height
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# Store the alien's exact horizontal position.
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self.x = float(self.rect.x)
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def check_edges(self):
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"""Return True if alien is at edge of screen."""
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screen_rect = self.screen.get_rect()
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return (self.rect.right >= screen_rect.right) or (self.rect.left <= 0)
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def update(self):
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"""Move the alien right or left."""
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self.x += self.settings.alien_speed * self.settings.fleet_direction
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self.rect.x = self.x |