用Python编写的外星人入侵游戏

前言

代码来源《python编程从入门到实践》Eric Matthes 署 袁国忠 译

使用软件：PyCharm Community Editor 2022

目的：记录一下按照书上敲的代码

alien_invasion.py

游戏的一些初始化设置，调用已经封装好的函数方法，一个函数的调用实现一个游戏的部分。

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


def run_game():
    # 初始化游戏并创建一个屏幕对象
    pygame.init()
    ai_settigns = Settings()
    # 里面是一个元组
    screen = pygame.display.set_mode((ai_settigns.screen_width, ai_settigns.screen_height))
    # 窗口尺寸，宽高
    # screen=pygame.display.set_mode((1200,800))
    # 窗口标题
    pygame.display.set_caption("Alien Invasion")
    # 创建Play按钮
    play_button = Button(ai_settigns, screen, "Play")
    # 创建一个用于存储游戏统计信息的实例
    stats = GameStats(ai_settigns)
    # 创建储存游戏统计信息的实例，并创建记分牌
    sb = Scoreboard(ai_settigns, screen, stats)

    # 设置背景色
    # bg_color=(230,230,230)
    # 创建一艘飞船、一个子弹编组和一个外星人编组
    ship = Ship(ai_settigns, screen)
    # 创建一个用于存储子弹的编组
    bullets = Group()
    # 创建一个外星人
    # alien=Alien(ai_settigns,screen)
    aliens = Group()
    # 创建外星人群
    gf.create_fleet(ai_settigns, screen, ship, aliens)

    # 开始游戏的主循环
    while True:
        gf.check_events(ai_settigns, screen, stats, sb, play_button, ship, aliens, bullets)
        if stats.game_active:
            ship.update()
            gf.update_bullets(ai_settigns, screen, stats, sb, ship, aliens, bullets)
            gf.update_aliens(ai_settigns, screen, stats, sb, ship, aliens, bullets)
        # print(len(bullets))

        gf.update_screen(ai_settigns, screen, stats, sb, ship, aliens, bullets, play_button)
        # 监视键盘和鼠标事件
        # for event in pygame.event.get():
        #     if event.type==pygame.QUIT:
        #         sys.exit()
        # 每次循环都重绘屏幕
        # screen.fill(bg_color)
        # screen.fill(ai_settigns.gb_color)
        # ship.blitme()
        # 让最近绘制的屏幕可见
        # pygame.display.flip()


run_game()

game_functions.py

 游戏主体，具体功能的实现被封装在里面，按下按键、松开按键的响应，界面的更新、子弹的发射、外星人和飞船之间碰撞的检查等等。

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


# 响应按键
def check_keydown_events(event, ai_settings, screen, ship, bullets):
    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)
    # 按下键盘上的q键同样关闭游戏界面(需要是英文状态下)
    elif event.key == pygame.K_q:
        sys.exit()


# 响应松开
def check_keyup_events(event, ship):
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        ship.moving_left = False


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

        elif event.type == pygame.KEYDOWN:
            # if event.key == pygame.K_RIGHT:
            #     ship.moving_right = True
            # elif event.key == pygame.K_LEFT:
            #     ship.moving_left = True
            check_keydown_events(event, ai_settings, screen, ship, bullets)
        elif event.type == pygame.KEYUP:
            # if event.key == pygame.K_RIGHT:
            #     ship.moving_right = False
            # elif event.key == pygame.K_LEFT:
            #     ship.moving_left = False
            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)


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


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

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

    # 检查是否有子弹击中了外星人
    # 如果是这样，就删除相应的子弹和外星人
    check_bullet_alien_collision(ai_settings, screen, stats, sb, ship, aliens, bullets)


# 响应子弹和外星人的碰撞
def check_bullet_alien_collision(ai_settings, screen, stats, sb, ship, aliens, bullets):
    # 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
            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(如果整群外星人都被消灭，就提高一个等级)
        bullets.empty()
        ai_settings.increase_speed()
        # 提高等级
        stats.level += 1
        sb.prep_level()

        create_fleet(ai_settings, screen, ship, aliens)


# 如果还没有到达限制，就发射一颗子弹
def fire_bullet(ai_settings, screen, ship, bullets):
    # 创建一颗子弹,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)


# 创建一个外星人群
def create_fleet(ai_settings, screen, ship, aliens):
    # 创建一个外星人，并计算每行可容纳多少个外星人
    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)

    # 创建外星人群
    for row_number in range(number_rows):
        for alien_number in range(number_aliens_x):
            # 创建一个外星人并将其加入当前行
            create_alien(ai_settings, screen, aliens, alien_number, row_number)


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


# 创建一个外星人并将其放在当前行
def create_alien(ai_settings, screen, aliens, alien_number, row_number):
    # 外星人间距为外星人的宽度
    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)


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


# 检查是否有外星人位于屏幕边缘，更新外星人群中所有外星人的位置
def update_aliens(ai_settings, screen, stats, sb, ship, aliens, bullets):
    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):
        # print("Ship hit!!!")
        ship_hit(ai_settings, screen, stats, sb, ship, aliens, bullets)

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


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


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


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

        # 更新记分牌
        sb.prep_ships()

        # 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，并将飞船放到屏幕底端中央
        create_fleet(ai_settings, screen, ship, aliens)
        ship.center_ship()

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


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


# 在玩家单机Play按钮时开始新游戏
def check_play_button(ai_settings, screen, stats, sb, play_button, ship, aliens, bullets, mouse_x, mouse_y):
    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_ships()

        # 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()


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

settings.py

游戏的一些初始化数据的储存，子弹的速度，大小，屏幕的大小等等。

# 储存《外星人入侵》所设置的类
class Settings():
    # 初始化游戏的静态属性
    def __init__(self):
        # 屏幕设置
        self.screen_width = 1200
        self.screen_height = 800
        self.bg_color = (230, 230, 230)

        # 飞船设置
        # 位置
        self.ship_speed_factor = 1.5
        self.ship_limit = 3

        # 子弹设置(宽高，颜色)
        self.bullet_speed_factor = 1  # 速度
        self.bullet_width = 3  # 宽度
        self.bullet_height = 15  # 高度
        self.bullet_color = 60, 60, 60  # 颜色
        self.bullets_allowed = 3

        # 外星人设置
        self.alien_speed_factor = 1
        self.fleet_drop_speed = 10
        # fleet_direction为1表示向右移，为-1表示向左移
        self.fleet_direction = 1

        # 以什么样的速度加快游戏节奏
        self.speedup_scale = 1.1
        # 外星人点数的提高速度
        self.score_scale = 1.5
        self.initialize_dynamic_settings()

        # 记分
        self.alien_points = 50

    # 初始化随游戏进行而变化的设置
    def initialize_dynamic_settings(self):
        self.ship_speed_factor = 1.5
        self.bullet_speed_factor = 3
        self.alien_speed_factor = 1

        # fleet_direction为1表示向右；为-1表示向左
        self.fleet_direction = 1

    # 提高速度和外星人点数设置
    def increase_speed(self):
        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)
        print(self.alien_points)

ship.py

 飞船的初始化信息（在屏幕上面显示的位置）和移动。

import pygame
from pygame.sprite import Sprite

class Ship(Sprite):
    # 初始化飞船并设置其初始位置
    def __init__(self, ai_settings, screen):
        super(Ship, self).__init__()
        self.screen = screen
        self.ai_settings = ai_settings
        # 加载飞船图像并获取外接矩形
        self.image = pygame.image.load('images/ship.png')
        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center中存储小数值
        self.center = float(self.rect.centerx)

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

    # 根据移动标志调整飞船的位置
    def update(self):
        # 更新飞船的center值，而不是rect
        # if self.moving_right:
        # 增加不能越界的条件
        if self.moving_right and self.rect.right < self.screen_rect.right:
            # self.rect.centerx += 1
            self.center += self.ai_settings.ship_speed_factor
        # elif self.moving_left:
        if self.moving_left and self.rect.left > 0:
            # self.rect.centerx -= 1
            self.center -= self.ai_settings.ship_speed_factor

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

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

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

alien.py

外星人的初始信息（在屏幕上面显示的位置）和移动。

import pygame
from pygame.sprite import Sprite


# 表示单个外星人的类
class Alien(Sprite):
    # 初始化外星人并设置起始位置
    def __init__(self, ai_settings, screen):
        super(Alien, self).__init__()
        self.screen = screen
        self.ai_settins = ai_settings

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

        # 每个外星人最初都在屏幕左上角附近
        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)

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

    # 向右、左移动外星人
    def update(self):
        # self.x += self.ai_settins.alien_speed_factor
        self.x += (self.ai_settins.alien_speed_factor * self.ai_settins.fleet_direction)
        self.rect.x = self.x

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

bullet.py

子弹的显示和移动。

import pygame
from pygame.sprite import Sprite


# 一个对飞船发射的子弹进行管理的类
class Bullet(Sprite):
    # 在飞船所处的位置创建一个子弹对象
    def __init__(self, ai_settings, screen, ship):
        super(Bullet, self).__init__()
        self.screen = screen

        # 在(0,0)处创建一个表示子弹的矩形，在设置正确的位置
        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

        # 存储用小数表示的子弹位置
        self.y = float(self.rect.y)
        self.color = ai_settings.bullet_color
        self.speed_factor = ai_settings.bullet_speed_factor

    # 向上移动子弹
    def update(self):
        # 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

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

game_stats.py

游戏是否结束，统计游戏运行期间的变化。

# 跟踪游戏的统计信息
class GameStats():
    # 初始化统计信息
    def __init__(self, ai_settings):
        self.ai_settings = ai_settings
        self.reset_stats()
        # 游戏刚启动时处于非活动状态
        self.game_active = False
        # 在任何情况下都不应重置最高得分
        self.high_score = 0

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

 button.py

开始按钮

import pygame.font


class Button():
    # 初始化按钮的属性
    def __init__(self, ai_setting, screen, msg):
        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, 0, 0)
        self.text_color = (255, 255, 255)
        self.font = pygame.font.SysFont(None, 48)

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

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

    # 将msg渲染为图像，并使其在按钮上居中
    def prep_msg(self, msg):
        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

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

scoreboard.py

当前得分，和最高得分

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


# 显示得分信息的类
class Scoreboard():
    def __init__(self, ai_setting, screen, stats):
        self.screen = screen
        self.screen_rect = screen.get_rect()
        self.ai_setting = ai_setting
        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)

        # 准备初始得分图像
        self.prep_score()
        self.prep_high_score()
        self.prep_level()
        self.prep_ships()

    # 将得分转换为一幅渲染的图像
    def prep_score(self):
        rounded_score = int(round(self.stats.score, -1))
        score_str = "{:,}".format(rounded_score)
        self.score_image = self.font.render(score_str, True, self.text_color, self.ai_setting.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

    # 在屏幕上显示得分和飞船
    def show_score(self):
        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)

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

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

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

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

我们的飞船和下面的飞船相撞或者撞到下面的墙都会输出：“Ship hit!!!”(程序中已经注释)

 图片可以自己去找，如果想修改图片可以运用电脑的“画图”工具来实现。

总结

主要是记录一下这个，毕竟敲了这么久了，不过还是要理解。

整个游戏的结构还是是否清晰的，游戏的流程储存在alien_invasion中，为了让程序的可读性更好，把功能封装成对应的函数，把这些函数全部储存到game_functions中，把游戏需要初始化的数据（子弹的大小，颜色，速度等等）全部储存到settings中，ship是对飞船的抽象表示，alien是对外星人的抽象表示，bullet是对子弹的抽象表示，通过button来开始游戏，game_stats来记录整个游戏，用scoreboard统计游戏得分。