alien_invasion.py

import sys
import pygame
from time import sleep
from game_stats import GameStats

from settings import Settings
from game_stats import GameStats
from scoreboard import Scoreboard
from button import Button
from ship import Ship
from bullet import Bullet
from alien import Alien

class AlienInvasion:
    """管理游戏资源和行为的类"""

    def __init__(self):
        """初始化游戏并创建游戏资源"""
        pygame.init()
        self.settings = Settings()

        # 设定窗口
        self.screen = pygame.display.set_mode(
            (self.settings.screen_width, self.settings.screen_height))
        pygame.display.set_caption("Alien Invasion")

        # 创建一个用于存储游戏统计信息的实例
        # 并创建记分牌
        self.stats = GameStats(self)
        self.sb = Scoreboard(self)

        self.ship = Ship(self)
        self.bullets = pygame.sprite.Group()
        self.aliens = pygame.sprite.Group()

        self._create_fleet()

        # 创建Play按钮
        self.play_button = Button(self, 'Play')

    def run_game(self):
        """开始游戏的主循环"""
        while True:
            self._check_events()

            # 游戏处于非活动状态时不更新游戏元素
            if self.stats.game_active:
                self.ship.update()
                self._update_bullets()
                self._update_aliens()
            
            self._update_screen()

    def _check_events(self):
        """响应键盘和鼠标事件"""
        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_events(event)
            elif event.type == pygame.MOUSEBUTTONDOWN:
                mouse_pos = pygame.mouse.get_pos()
                self._check_play_button(mouse_pos)
    
    def _check_play_button(self, mouse_pos):
        """在玩家单击Play按钮时开始新游戏"""
        if self.play_button.rect.collidepoint(mouse_pos) \
            and not self.stats.game_active:
            self._start_game()
    
    def _check_keydown_events(self, event):
        """响应按键"""
        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()
        elif event.key == pygame.K_p and not self.stats.game_active:
            self._start_game()
    
    def _check_keyup_events(self, event):
        """响应松开"""
        if event.key == pygame.K_RIGHT:
            self.ship.moving_right = False
        elif event.key == pygame.K_LEFT:
            self.ship.moving_left = False

    def _start_game(self):
        # 重置游戏设置
        self.settings.initialize_dynamic_settings()

        # 重置游戏统计信息
        self.stats.reset_stats()
        self.stats.game_active = True
        self.sb.prep_score()
        self.sb.prep_level()
        self.sb.prep_ships()

        # 清空余下的外星人和子弹
        self.aliens.empty()
        self.bullets.empty()

        # 创建一群新的外星人并让飞船居中
        self._create_fleet()
        self.ship.center_ship()

        # 隐藏鼠标光标
        pygame.mouse.set_visible(False)

    def _fire_bullet(self):
        """创建一颗子弹，并将其加入编组bullets中"""
        if len(self.bullets) < self.settings.bullets_allowed:
            new_bullet = Bullet(self)
            self.bullets.add(new_bullet)
    
    def _update_bullets(self):
        """更新子弹位置并删除消失子弹"""
        # 更新子弹位置
        self.bullets.update()
        # 删除消失的子弹
        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):
        """响应子弹和外星人碰撞"""
        # 删除发生碰撞的子弹和外星人
        collisions = pygame.sprite.groupcollide(
            self.bullets, self.aliens, True, True
        )
        # 记分
        if collisions:
            for aliens in collisions.values():
                self.stats.score += self.settings.alien_points * len(aliens)
            self.sb.prep_score()
            self.sb.check_high_score()
        # 如果外星人被全部消灭
        if not self.aliens:
            # 删除子弹并新建一群外星人
            self.bullets.empty()
            self._create_fleet()
            # 加快游戏节奏
            self.settings.increse_speed()
            # 提高等级
            self.stats.level += 1
            self.sb.prep_level()

    def _update_aliens(self):
        """检测边缘并更新外星人群的位置"""
        self._check_fleet_edges()
        self.aliens.update()

        # 检测外星人与飞船的碰撞
        if pygame.sprite.spritecollideany(self.ship, self.aliens):
            self._ship_hit()

        # 检查是否有外星人到达屏幕底端
        self._check_aliens_bottom()
    
    def _ship_hit(self):
        """响应飞船被外星人撞到"""
        if self.stats.ships_left > 0:
            # 飞船剩余数减1并更新记分牌
            self.stats.ships_left -= 1
            self.sb.prep_ships()

            # 清空外星人和子弹
            self.bullets.empty()
            self.aliens.empty()

            # 创建一群新的外星人，并将飞船放到屏幕底部中央
            self._create_fleet()
            self.ship.center_ship()

            # 暂停
            sleep(0.5)
        else:
            self.stats.game_active = False
            pygame.mouse.set_visible(True)

    def _check_aliens_bottom(self):
        """检查是否有外星人到达屏幕底端"""
        screen_rect = self.screen.get_rect()
        for alien in self.aliens.sprites():
            if alien.rect.bottom >= screen_rect.bottom:
                # 像飞船被撞到一样处理
                self._ship_hit()
                break

    def _check_fleet_edges(self):
        """有外星人到达边缘时采取相应措施"""
        for alien in self.aliens.sprites():
            if alien.check_edges():
                self._change_fleet_direction()
                break
    
    def _change_fleet_direction(self):
        """将整群外星人下移，并改变移动方向"""
        for alien in self.aliens.sprites():
            alien.rect.y += self.settings.fleet_drop_speed
        self.settings.fleet_direction *= -1

    def _create_fleet(self):
        """创建外星人群"""
        # 创建一个外星人
        alien = Alien(self)
        
        # 计算一行可容纳多少外星人
        alien_width, alien_height = alien.rect.size
        available_space_x = self.settings.screen_width - 2 * alien_width
        numbers_alien_x = available_space_x // (2 * alien_width)
        
        # 计算可容纳多少行外星人
        available_space_y = (self.settings.screen_height - 3 * alien_height
                                - self.ship.rect.height)
        numbers_rows = available_space_y // (2 * alien_height)

        # 创建外星人群
        for row_number in range(numbers_rows):
            for alien_number in range(numbers_alien_x):
                self._create_alien(alien_number, row_number)
            
    def _create_alien(self, alien_number, row_number):
        """根据行列位置创建一个外星人"""
        alien = Alien(self)
        alien_width, alien_height = alien.rect.size
        alien.x = alien_width + 2 * alien_width * alien_number
        alien.rect.x = alien.x
        alien.rect.y = alien_height + 2 * alien_height * row_number
        self.aliens.add(alien)

    def _update_screen(self):
        """更新屏幕图像，并刷新屏幕"""
        self.screen.fill(self.settings.bg_color)
        self.ship.blitme()
        for bullet in self.bullets.sprites():
            bullet.draw_bullet()
        self.aliens.draw(self.screen)

        # 显示得分
        self.sb.show_score()

        # 如果游戏处于非活动状态，就绘制Play按钮
        if not self.stats.game_active:
            self.play_button.draw_button()
        
        pygame.display.flip()

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