alien_invasion.py

import pygame
from pygame.sprite import Group
import game_functions as gf
from settings import Settings
from ship import Ship
from alien import Alien

def run_game():
    
    # Initialize pygame, settings, and screen object
    pygame.init()

    ai_settings = Settings()
    screen = pygame.display.set_mode((ai_settings.screen_width, ai_settings.screen_height))
    pygame.display.set_caption("Alien Invasion")
    ai_settings.background_image = pygame.image.load('images/background_image.bmp').convert()

    # Make a ship.
    ship = Ship(ai_settings, screen)
    aliens = Alien(ai_settings, screen)
    bullets = Group()
    aliens = Group()
    gf.create_fleet(ai_settings, screen,ship, aliens)
    
    # Start the main loop for the game.
    while True:
        # Watch for keyboard and mouse events.
        gf.check_events(ai_settings, screen, ship, bullets)
        ship.update()
        bullets.update()
        gf.update_bullets(aliens, bullets)
        gf.update_aliens(ai_settings, aliens)
        gf.update_screen(ai_settings, screen, ship, aliens, bullets)

run_game()