alien.py

import pygame
from pygame.sprite import Sprite

class Alien(Sprite):
    #A class to represent a single alien in the fleet

    def __init__(self,ai_settings,screen):
        #Initialize the alien and set its starting position
        super(Alien,self).__init__()
        self.screen=screen
        self.ai_settings=ai_settings


        #Load the alien image and set its rect attribute
        self.image=pygame.image.load('ufo-Peter-LomasPixabay-625x352_1.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
        #print(self.rect.x)
        #Store the alien's exact position.
        self.x=float(self.rect.x)

    def blitme(self):
        #Draw the alien at its current location.
        self.screen.blit(self.image,self.rect)

    def update(self):
        #Move the alien right.
        self.x+=self.ai_settings.alien_speed_factor
        self.rect.x=self.x
        
    def check_edges(self):
        #Return true if alien is at edge of screen.
        screen_rect=self.screen.get_rect()
        if self.rect.right>=screen_rect.right:
            return True
        elif self.rect.left<=0:
            return True

    def update(self):
        #Move the alien right or left.
        self.x+=(self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)

        self.rect.x=self.x