alien.py

import pygame
from pygame.sprite import Group, Sprite

class Alien(Sprite):
    """A class to represent a single alien in the fleet."""
    
    def __init__(self, ai_game):
        """Initialize the alien and set its starting position."""
        super().__init__()
        self.screen = ai_game.screen
        self.settings = ai_game.settings
        
        # Load the alien image and set its rect attribute
        self.image = pygame.image.load('D:\Alien Invasion\Images\Alien_Ship.bmp')
        self.rect = self.image.get_rect()
        
        #Start each new alien near the top left of the screen
        self.rect.x = self.rect.width
        self.rect.y = self.rect.height
        
        #Store the alien's exact horizontal position
        self.x = float(self.rect.x)
        self.y = float(self.rect.y)
        
    def check_edges(self):
        """Return True if alien is at the edge of screen."""
        screen_rect = self.screen.get_rect()
        if self.rect.right >= screen_rect.right or self.rect.left <= 0:
            return True
        return False

    def update(self):
        """Move the alien to right."""
        self.x += self.settings.alien_speed * self.settings.fleet_direction
        self.rect.x = self.x