各模块代码

1.alien_invasion.py

import pygame
from pygame.sprite import Group
from settings import Settings
from game_stats import GameStats
from scoreboard import Scoreboard
from button import Button
from ship import Ship
import game_functions as gf


def run_game():
    # 初始化游戏并创建一个屏幕对象
    pygame.init()
    ai_settings = Settings()
    screen = pygame.display.set_mode(
        (ai_settings.screen_width, ai_settings.screen_height))
    pygame.display.set_caption("Alien_Invasion")

    # 创建Play按钮
    play_button = Button(ai_settings, screen, "Play")

    # 创建一个用于储存游戏统计信息的实例
    stats = GameStats(ai_settings)

    # 创建记分牌
    sb = Scoreboard(ai_settings, screen, stats)

    # 创建一艘飞船
    ship = Ship(ai_settings, screen)

    # 创建一个用于存储子弹的编组
    bullets = Group()

    # 创建一个外星人编组
    aliens = Group()

    # 创建外星人群
    gf.create_fleet(ai_settings, screen, ship, aliens)

    # 开始游戏主循环
    while True:
        # 监视键盘和鼠标事件
        gf.check_events(ai_settings, screen, stats, sb, play_button, ship,
                        aliens, bullets)
        if stats.game_active:
            ship.update()
            gf.update_bullets(ai_settings, screen, stats, sb, ship, aliens,
                              bullets)
            gf.update_aliens(ai_settings, stats, sb, screen, ship, aliens, bullets)

        gf.update_screen(ai_settings, screen, stats, sb, ship, aliens,
                         bullets, play_button)


run_game()

2.game_stats.py

class GameStats():
    """跟踪游戏的统计信息"""

    def __init__(self, ai_settings):
        """初始化统计信息"""
        self.ai_settings = ai_settings
        self.reset_stats()

        # 游戏刚启动时处于活动状态
        self.game_active = False

    def reset_stats(self):
        """初始化在游戏运行期间可能变化的统计信息"""
        self.ships_left = self.ai_settings.ship_limit
        self.score = 0
        self.level = 1
        self.load_high_score()

    def save_high_score(self):
        """保存最高得分"""
        with open('score.txt', 'w') as file_object:
            file_object.write(str(self.high_score))
            file_object.close()

    def load_high_score(self):
        """加载最高得分"""
        try:
            with open('score.txt') as file_object:
                h_s = file_object.read()
                try:
                    self.high_score = int(h_s)
                except ValueError:
                    self.high_score = 0
                file_object.close()
        except FileNotFoundError:
            with open('score.txt', 'w') as file_object:
                file_object.close()

3.game_functions.py

import sys
import pygame
from bullet import Bullet
from alien import Alien
from time import sleep


def check_keydown_events(event, ai_settings, screen, stats, ship, bullets):
    # 检测按键按下
    if event.key == pygame.K_RIGHT:
        ship.moving_right = True
    elif event.key == pygame.K_LEFT:
        ship.moving_left = True
    elif event.key == pygame.K_SPACE:
        fire_bullet(ai_settings, screen, ship, bullets)
    elif event.key == pygame.K_q:
        stats.save_high_score()
        sys.exit()


def fire_bullet(ai_settings, screen, ship, bullets):
    """如果还没到达限制，就发射一颗子弹"""
    # 创建新子弹，并将其加入到编组bullets中
    if len(bullets) < ai_settings.bullets_allowed:
        new_bullet = Bullet(ai_settings, screen, ship)
        bullets.add(new_bullet)


def check_keyup_events(event, ship):
    # 检测按键松开
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        ship.moving_left = False


def check_events(ai_settings, screen, stats, sb, play_button, ship, aliens,
                 bullets):
    """响应按键和鼠标事件"""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            stats.save_high_score()
            sys.exit()

        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event, ai_settings, screen, stats, ship, bullets)

        elif event.type == pygame.KEYUP:
            check_keyup_events(event, ship)

        elif event.type == pygame.MOUSEBUTTONDOWN:
            mouse_x, mouse_y = pygame.mouse.get_pos()
            check_play_button(ai_settings, screen, stats, sb, play_button, ship, aliens,
                              bullets, mouse_x, mouse_y)


def check_play_button(ai_settings, screen, stats, sb, play_button, ship, aliens,
                      bullets, mouse_x, mouse_y):
    """在玩家单击Play按钮时开始新游戏"""
    button_clicked = play_button.rect.collidepoint(mouse_x, mouse_y)
    if button_clicked and not stats.game_active:
        # 重置游戏设置
        ai_settings.initialize_dynamic_settings()

        # 隐藏光标
        pygame.mouse.set_visible(False)

        # 重置游戏统计信息
        stats.reset_stats()
        stats.game_active = True

        # 重置记分牌图像
        sb.prep_score()
        sb.prep_high_score()
        sb.prep_level()
        sb.prep_ship()

        # 清空外星人列表和子弹列表
        aliens.empty()
        bullets.empty()

        # 创建一群新的外星人，并让飞船居中
        create_fleet(ai_settings, screen, ship, aliens)
        ship.center_ship()


def update_screen(ai_settings, screen, stats, sb, ship, aliens,
                  bullets, play_button):
    """更新屏幕上的图片，并切换到新的屏幕"""
    # 每次循环时都重绘屏幕
    screen.fill(ai_settings.bg_color)
    ship.blitme()

    # 在飞船和外星人后面重绘所有子弹
    for bullet in bullets.sprites():
        bullet.draw_bullet()
    ship.blitme()
    aliens.draw(screen)

    # 显示得分
    sb.show_score()

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

    # 让最近绘制的屏幕可见
    pygame.display.flip()


def update_bullets(ai_settings, screen, stats, sb, ship, aliens, bullets):
    """更新子弹的位置，并删除已消失的子弹"""
    # 更新子弹的位置
    bullets.update()

    # 删除已消失的子弹
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)

    check_bullet_alien_collisions(ai_settings, screen, stats, sb, ship,
                                  aliens, bullets)


def check_bullet_alien_collisions(ai_settings, screen, stats, sb, ship,
                                  aliens, bullets):
    """响应子弹和外星人的碰撞"""
    # 删除发生碰撞的子弹和外星人
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)

    if collisions:
        for aliens in collisions.values():
            stats.score += ai_settings.alien_points * len(aliens)
            sb.prep_score()
        check_high_score(stats, sb)

    if len(aliens) == 0:
        # 删除现有的子弹并新建一群外星人
        bullets.empty()
        ai_settings.increase_speed()

        # 提高等级
        stats.level += 1
        sb.prep_level()

        create_fleet(ai_settings, screen, ship, aliens)


def get_number_aliens_x(ai_settings, alien_width):
    """计算每行可容纳多少个外星人"""
    available_space_x = ai_settings.screen_width - 2 * alien_width
    number_aliens_x = int(available_space_x / (2 * alien_width))
    return number_aliens_x


def get_number_rows(ai_settings, ship_height, alien_height):
    """计算屏幕可容纳多少行外星人"""
    available_space_y = (ai_settings.screen_height -
                         (3 * alien_height) - ship_height)
    number_rows = int(available_space_y / (2 * alien_height))
    return number_rows


def create_alien(ai_settings, screen, aliens, alien_number, row_number):
    """创建一个外星人并将其放在当前行"""
    alien = Alien(ai_settings, screen)
    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
    aliens.add(alien)


def create_fleet(ai_settings, screen, ship, aliens):
    """创建外星人群"""
    # 创建一个外星人，并计算一行可容纳多少个外星人
    # 外星人间距为外星人宽度
    alien = Alien(ai_settings, screen)
    number_aliens_x = get_number_aliens_x(ai_settings, alien.rect.width)
    number_rows = get_number_rows(ai_settings, ship.rect.height,
                                  alien.rect.height)

    # 创建第一行外星人
    for row_number in range(number_rows):
        for alien_number in range(number_aliens_x):
            # 创建一个外星人并假期加入当前行
            create_alien(ai_settings, screen, aliens, alien_number, row_number)


def check_fleet_edges(ai_settings, aliens):
    """有外星人到达边缘时采取相应的措施"""
    for alien in aliens.sprites():
        if alien.check_edges():
            change_fleet_direction(ai_settings, aliens)
            break


def change_fleet_direction(ai_settings, aliens):
    """将整群外星人下移，并改变它们的方向"""
    for alien in aliens.sprites():
        alien.rect.y += ai_settings.fleet_drop_speed
    ai_settings.fleet_direction *= -1


def ship_hit(ai_settings, stats, sb, screen, ship, aliens, bullets):
    """响应被外星人撞到的飞船"""
    if stats.ships_left > 0:
        # 将ship_left减1
        stats.ships_left -= 1

        # 更新记分牌
        sb.prep_ship()

        # 清空外星人列表和子弹列表
        aliens.empty()
        bullets.empty()

        # 创建一批新的外星人，并将飞船放在屏幕底端中央
        create_fleet(ai_settings, screen, ship, aliens)
        ship.center_ship()

        # 暂停
        sleep(0.5)

    else:
        stats.game_active = False
        stats.save_high_score()
        pygame.mouse.set_visible(True)


def check_aliens_bottom(ai_settings, stats, sb, screen, ship, aliens, bullets):
    """检查是否有外星人到达屏幕底端"""
    screen_rect = screen.get_rect()
    for alien in aliens.sprites():
        if alien.rect.bottom >= screen_rect.bottom:
            # 像飞船被撞到一样进行处理
            ship_hit(ai_settings, stats, sb, screen, ship, aliens, bullets)
            break


def update_aliens(ai_settings, stats, sb, screen, ship, aliens, bullets):
    """检测是否有外星人位于屏幕边缘，并更新整群外星人的位置"""
    check_fleet_edges(ai_settings, aliens)
    aliens.update()

    # 检测外星人和飞船之间的碰撞
    if pygame.sprite.spritecollideany(ship, aliens):
        ship_hit(ai_settings, stats, sb, screen, ship, aliens, bullets)

    # 检测是否有外星人到达屏幕底端
    check_aliens_bottom(ai_settings, stats, sb, screen, ship, aliens, bullets)


def check_high_score(stats, sb):
    """检查是否诞生了新的最高得分"""
    if stats.score > stats.high_score:
        stats.high_score = stats.score
        sb.prep_high_score()

4.scoreboard.py

import pygame.font
from pygame.sprite import Group
from ship import Ship


class Scoreboard():
    """显示得分信息"""

    def __init__(self, ai_settings, screen, stats):
        """初始化显示得分涉及的属性"""
        self.screen = screen
        self.screen_rect = screen.get_rect()
        self.ai_settings = ai_settings
        self.stats = stats

        # 显示得分信息时使用的字体设置
        self.text_color = (30, 30, 30)
        self.font = pygame.font.SysFont(None, 48)

        # 准备包含最高得分和当前得分的图像
        self.prep_score()
        self.prep_high_score()
        self.prep_level()
        self.prep_ship()

    def prep_score(self):
        """将得分转换为一幅渲染的图像"""
        round_score = round(self.stats.score, -1)
        score_str = 'Score: ' + "{:,}".format(round_score)
        self.score_image = self.font.render(score_str, True, self.text_color,
                                            self.ai_settings.bg_color)

        # 将得分放在屏幕右上角
        self.score_rect = self.score_image.get_rect()
        self.score_rect.right = self.screen_rect.right - 20
        self.score_rect.top = 20

    def prep_high_score(self):
        """将最高得分转换为渲染的图像"""
        high_score = round(self.stats.high_score, -1)
        high_score_str = 'High_Score: ' + "{:,}".format(high_score)
        self.high_score_image = self.font.render(high_score_str, True, self.text_color,
                                                 self.ai_settings.bg_color)

        # 将最高得分放在屏幕顶部中央
        self.high_score_rect = self.high_score_image.get_rect()
        self.high_score_rect.centerx = self.screen_rect.centerx
        self.high_score_rect.top = self.score_rect.top

    def prep_level(self):
        """将等级转换为渲染的图像"""
        self.level_image = self.font.render('Level: ' + str(self.stats.level), True, self.text_color,
                                            self.ai_settings.bg_color)

        # 将等级放在得分下方
        self.level_rect = self.level_image.get_rect()
        self.level_rect.right = self.screen_rect.right - 20
        self.level_rect.top = self.score_rect.bottom + 10

    def prep_ship(self):
        """显示还余下多少艘飞船"""
        self.ships = Group()
        for ship_number in range(self.stats.ships_left):
            ship = Ship(self.ai_settings, self.screen)
            ship.rect.x = 10 + ship_number * ship.rect.width
            ship.rect.y = 10
            self.ships.add(ship)

    def show_score(self):
        """在屏幕上显示当前得分和最高得分"""
        self.screen.blit(self.score_image, self.score_rect)
        self.screen.blit(self.high_score_image, self.high_score_rect)
        self.screen.blit(self.level_image, self.level_rect)

        # 绘制飞船
        self.ships.draw(self.screen)

5.button.py

import pygame.font


class Button():

    def __init__(self, ai_settings, screen, msg):
        """初始化按钮的属性"""
        self.screen = screen
        self.screen_rect = screen.get_rect()

        # 设置按钮的尺寸和其他属性
        self.width, self.height = 200, 50
        self.button_color = (0, 255, 0)
        self.text_color = (255, 255, 255)
        self.font = pygame.font.SysFont(None, 48)

        # 创建按钮的rect对象，并使其居中
        self.rect = pygame.Rect(0, 0, self.width, self.height)
        self.rect.center = self.screen_rect.center

        # 按钮的标签只需要创建一次
        self.prep_msg(msg)

    def prep_msg(self, msg):
        """将msg渲染成图像，并使其在按钮上居中"""
        self.msg_image = self.font.render(msg, True, self.text_color,
                                          self.button_color)
        self.msg_image_rect = self.msg_image.get_rect()
        self.msg_image_rect.center = self.rect.center

    def draw_button(self):
        """绘制一个用颜色填充的按钮，再绘制文本"""
        self.screen.fill(self.button_color, self.rect)
        self.screen.blit(self.msg_image, self.msg_image_rect)

6.ship.py

import pygame
from pygame.sprite import Sprite


class Ship(Sprite):

    def __init__(self, ai_settings, screen):
        """初始化飞船并设置其初始位置"""
        super(Ship, self).__init__()
        self.screen = screen
        self.ai_settings = ai_settings

        # 加载飞船图像并获取其外接矩形
        self.image = pygame.image.load('images/ship.bmp')
        self.rect = self.image.get_rect()
        self.screen_rect = screen.get_rect()

        # 将每艘新飞船放在屏幕底部中央
        self.rect.centerx = self.screen_rect.centerx
        self.rect.bottom = self.screen_rect.bottom

        # 在飞船的属性中存储小数值
        self.center = float(self.rect.centerx)

        # 移动标志
        self.moving_right = False
        self.moving_left = False

    def update(self):
        """根据移动标志调整飞船位置"""
        # 更新飞船的center值，而不是rect
        if self.moving_right and self.rect.right < self.screen_rect.right:
            self.center += self.ai_settings.ship_speed_factor
        if self.moving_left and self.rect.left > 0:
            self.center -= self.ai_settings.ship_speed_factor

        # 根据self.center更新rect对象
        self.rect.centerx = self.center

    def blitme(self):
        """在指定位置绘制飞船"""
        self.screen.blit(self.image, self.rect)

    def center_ship(self):
        """使飞船在屏幕上居中"""
        self.center = self.screen_rect.centerx

7.alien.py

import pygame
from pygame.sprite import Sprite


class Alien(Sprite):
    """表示单个外星人的类"""

    def __init__(self, ai_settings, screen):
        """初始化外星人并设置起始位置"""
        super().__init__()
        self.ai_settings = ai_settings
        self.screen = screen

        # 加载外星人图像，并设置其rect属性
        self.image = pygame.image.load('images/alien.bmp')
        self.rect = self.image.get_rect()

        # 每个外星人最初都在屏幕左上方位置
        self.rect.x = self.rect.width
        self.rect.y = self.rect.height

        # 存储外星人的准确位置
        self.x = float(self.rect.x)

    def check_edges(self):
        """如果外星人位于屏幕边缘，就返回True"""
        screen_rect = self.screen.get_rect()
        if self.rect.right >= screen_rect.right:
            return True
        elif self.rect.left <= 0:
            return True

    def update(self):
        """向左或向右移动外星人"""
        self.x += (self.ai_settings.alien_speed_factor *
                   self.ai_settings.fleet_direction)
        self.rect.x = self.x

    def blitme(self):
        """在指定位置绘制外星人"""
        self.screen.blit(self.image, self.rect)

8.settings.py

class Settings():
    """存储《外星人入侵》的所有设置的类"""

    def __init__(self):
        # 初始化游戏的静态设置
        # 屏幕设置
        self.screen_width = 1200
        self.screen_height = 800
        self.bg_color = (230, 230, 230)

        # 飞船的设置
        self.ship_limit = 3

        # 子弹设置
        self.bullet_width = 3
        self.bullet_height = 15
        self.bullet_color = 60, 60, 60
        self.bullets_allowed = 5

        # 外星人设置
        self.fleet_drop_speed = 3

        # 加快游戏节奏的速度
        self.speedup_scale = 1.1
        # 外星人点数提高的速度
        self.score_scale = 1.5

        self.initialize_dynamic_settings()

    def initialize_dynamic_settings(self):
        """初始化随游戏进行而变化的设置"""
        self.ship_speed_factor = 1.5
        self.bullet_speed_factor = 1
        self.alien_speed_factor = 0.2

        # fleed_direction为1表示向右移，为-1表示向左移
        self.fleet_direction = 1

        # 计分
        self.alien_points = 50

    def increase_speed(self):
        """提高游戏设置"""
        self.ship_speed_factor *= self.speedup_scale
        self.bullet_speed_factor *= self.speedup_scale
        self.alien_speed_factor *= self.speedup_scale

        self.alien_points = int(self.alien_points * self.score_scale)

9.bullet.py

import pygame
from pygame.sprite import Sprite


class Bullet(Sprite):
    """一个对飞船发射的子弹进行管理的类"""

    def __init__(self, ai_settings, screen, ship):
        """在飞船所处的位置创建一个子弹对象"""
        super(Bullet, self).__init__()
        self.screen = screen

        # 在(0,0)处创建一个表示子弹的矩形，再设置正确的位置
        self.rect = pygame.Rect(0, 0, ai_settings.bullet_width,
                                ai_settings.bullet_height)
        self.rect.centerx = ship.rect.centerx
        self.rect.top = ship.rect.top

        # 存储用小鼠表示的子弹位置
        self.y = float(self.rect.y)

        self.color = ai_settings.bullet_color
        self.speed_factor = ai_settings.bullet_speed_factor

    def update(self):
        """向上移动子弹"""
        # 更新表示子弹位置的小数值
        self.y -= self.speed_factor
        # 更新表示子弹的rect的位置
        self.rect.y = self.y

    def draw_bullet(self):
        """在屏幕上绘制子弹"""
        pygame.draw.rect(self.screen, self.color, self.rect)