为什么ai_game是指向alien invasion的实例呢?
ship.py
import pygame
class Ship:
"""A class to manage the ship."""
def __init__(self,ai_game):
"""Initialize the ship and set its starting position."""
self.screen = ai_game.screen
self.screen_rect = ai_game.screen.get_rect()
# Load the ship image and get its rect.
self.image = pygame.image.load('images/ship.bmp')
self.rect = self.image.get_rect()
# Start each new ship at the bottom center of the screen.
self.rect.midbottom = self.screen_rect.midbottom
def blitme(self):
"""Draw the ship at its current location."""
self.screen.blit(self.image, self.rect)
alien.py
import pygame
from settings import Settings
from ship import Ship
class AlienInvasion:
"""Overall class to manage game assets and behavior."""
def __init__(self):
"""Initialize the game, and create game resources."""
pygame.init()
self.settings = Settings()
self.screen = pygame.display.set_mode(
(self.settings.screen_width, self.settings.screen_height))
pygame.display.set_caption("Alien Invasion")
self.ship = Ship(self)
def run_game(self):
"""Start the main loop for the game."""
while True:
# Watch for keyboard and mouse events.
for event in pygame.event.get():
if event.type == pygame.QUIT:
sys.exit()
# Redraw the screen during each pass through the loop.
self.screen.fill(self.settings.bg_color)
self.ship.blitme()
# Make the most recently drawn screen visible.
pygame.display.flip()
if name == 'main':
# Make a game instance, and run the game.
ai = AlienInvasion()
ai.run_game()