main.py

# this allows us to use code from
# the open-source pygame library
# throughout this file
import pygame

from constants import *
from player import Player
from shot import Shot
from asteroid import Asteroid
from asteroidfield import AsteroidField

def main():
    # init game
    pygame.init()
    screen = pygame.display.set_mode((SCREEN_WIDTH, SCREEN_HEIGHT))

    # turn off text input (mac compatibility)
    pygame.key.stop_text_input()

    # game clock
    clock = pygame.time.Clock()
    dt = 0

    # set up object groups
    updatables = pygame.sprite.Group()
    drawables = pygame.sprite.Group()
    asteroids = pygame.sprite.Group()
    shots = pygame.sprite.Group()

    # create player
    Player.containers = (updatables, drawables)
    player = Player(SCREEN_WIDTH / 2, SCREEN_HEIGHT / 2)

    # set up shots
    Shot.containers = (shots, updatables, drawables)

    # create asteroids
    Asteroid.containers = (asteroids, updatables, drawables)
    AsteroidField.containers = (updatables)
    AsteroidField()

    while True:
        # handle events
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                return
        
        # set background
        screen.fill(pygame.Color('black'))

        # do updates on objects
        for obj in updatables:
            obj.update(dt)

        # check player collisions
        for asteroid in asteroids:
            if player.collision(asteroid):
                print("Game over!")
                return
        # check asteroid shot collision
        for asteroid in asteroids:
            for shot in shots:
                if asteroid.collision(shot):
                    asteroid.split()
                    shot.kill()

        # draw objects
        for obj in drawables:
            obj.draw(screen)

        # draw screen
        pygame.display.flip()

        # limit framerate
        dt = clock.tick(MAX_FRAMERATE) / 1000

if __name__ == "__main__":
    main()