alien_invasion.py

import imp
import sys
import pygame
from time import sleep

from ship import Ship
from setting import Settings
from bullet import Bullet
from alien import Alien
from game_stats import GameStats

class AlienInvasion:
    def __init__(self):
        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.stats = GameStats(self)
        self.ship = Ship(self)
        self.bullets = pygame.sprite.Group()
        self.aliens = pygame.sprite.Group()

        self._create_fleet()
        pygame.display.set_caption("Alien Invasion")

    def _create_fleet(self):
        alien = Alien(self)
        alien_width,alien_height = alien.rect.size
        available_space_x = self.settings.screen_width-(2*alien_width)
        number_aliens_x = available_space_x//(2*alien_width)
        ship_height = self.ship.rect.height
        available_space_y = (self.settings.screen_height-
                             (3*alien_height)-ship_height)
        number_rows = available_space_y//(2*alien_height)
        for row_number in range(number_rows):
            for alien_number in range(number_aliens_x):
                self._create_alien(alien_number,row_number)

    def _create_alien(self,alien_number,row_number):
        alien = Alien(self)
        alien_width = alien.rect.width
        alien.x = alien_width + 2*alien_width*alien_number
        alien.rect.x = alien.x
        alien.rect.y = alien.rect.height+2*alien.rect.height*row_number
        self.aliens.add(alien)

    def run_game(self):
        while True:
            self._check_events()
            self.ship.update()
            self._update_bullets()
            self._update_aliens()
            self._update_screen()

    def _update_aliens(self):
        self._check_fleet_edges()
        self.aliens.update()
        if pygame.sprite.spritecollideany(self.ship,self.aliens):
            self._ship_hit()
        self._check_aliens_bottom()

    def _update_bullets(self):
        self.bullets.update()
            
        for bullet in self.bullets.copy():
            if bullet.rect.bottom <= 0:
                self.bullets.remove(bullet)

        self._check_bullet_alien_collisions() 
            

    def _check_bullet_alien_collisions(self):
        collisions = pygame.sprite.groupcollide(
            self.bullets,self.aliens,True,True
        )
        if not self.aliens:
            self.bullets.empty()
            self._create_fleet()
    
    def _check_events(self):
        """ 响应按键和鼠标事件 """
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()
            elif event.type == pygame.KEYDOWN:
                self._check_keydown_events(event)
            elif event.type == pygame.KEYUP:
                self._check_keyup_event(event)

    def _check_keydown_events(self,event):
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = True
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = True
        elif event.key == pygame.K_q:
            sys.exit()
        elif event.key == pygame.K_SPACE:
            self._fire_bullet()

    def _check_keyup_event(self,event):
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = False
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = False

    def _fire_bullet(self):
        if len(self.bullets) < self.settings.bullets_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)

    def _update_screen(self):
        self.screen.fill(self.settings.bg_color)
        self.ship.blitme()
        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        self.aliens.draw(self.screen)
        pygame.display.flip()

    def _change_fleet_direction(self):
        for alien in self.aliens.sprites():
            alien.rect.y += self.settings.fleet_drop_speed
        self.settings.fleet_direction *= -1
    
    def _check_fleet_edges(self):
        for alien in self.aliens.sprites():
            if alien.check_edges():
                self._change_fleet_direction()
                break

    def _ship_hit(self):
        if self.stats.ship_left > 0:
            self.stats.ship_left -= 1
            self.aliens.empty()
            self.bullets.empty()
            self._create_fleet()
            self.ship.center_ship()

            sleep(1)
        else:
            self.stats.game_active = False
    
    def _check_aliens_bottom(self):
        screen_rect = self.screen.get_rect()
        for alien in self.aliens.sprites():
            if alien.rect.bottom >= screen_rect.bottom:
                self._ship_hit()
                break

if __name__ == '__main__':
    ai = AlienInvasion()
    ai.run_game()