Python外星人入侵游戏

源码来源

《Python从入门到实践》

项目描述

在游戏《外星人入侵》中，玩家控制着一艘最初出现在屏幕底部中央的飞船。玩家可以使用箭头键左右移动飞船，还可使用空格键进行射击。游戏开始时，一群外星人出现在天空中，他们在屏幕中向下移动。玩家的任务是射杀这些外星人。玩家将所有外星人都消灭干净后，将出现一群新的外星人，他们移动的速度更快。只要有外星人撞到了玩家的飞船或到达了屏幕底部，玩家就损失一艘飞船。玩家损失三艘飞船后，游戏结束。
最终效果：

项目分析

（1）创建并设置背景窗口
（2）添加飞船图像，设置飞船移动方向、速度、活动范围等
（3）添加子弹图像，设置子弹移动方向、速度等
（4）添加外星飞船图像，设置飞船移动方向、速度、活动范围等
（5）创建计分系统

项目最终包含9个py文件。

源码下载地址

详细代码

(1) alien_invasion.py

import pygame
import game_functions as gf
from settings import Settings
from ship import Ship
from pygame.sprite import Group
from game_status import GameStatus
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_settings = Settings()
    screen = pygame.display.set_mode((ai_settings.screen_width, ai_settings.screen_height))
    pygame.display.set_caption("Aline Invasion")

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

    # 创建一个用于存储游戏统计信息的实例,并创建记分牌
    status = GameStatus(ai_settings)
    sb = Scoreboard(ai_settings, screen, status)

    # 颜色
    bg_color = (230, 230, 230)

    # 创建一个飞船
    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()

    # 创建一个外星人群
    gf.create_fleet(ai_settings, screen, aliens, ship)

    # 开始游戏主循环
    while True:
        # 检查玩家的输入
        gf.check_events(ai_settings, screen, status, sb, play_button, ship, aliens, bullets)

        if status.game_active:
            ship.update()
            # 更新屏幕上子弹
            gf.update_bullets(ai_settings, screen, status, sb, ship, aliens, bullets)
            # 更新屏幕上外星人
            gf.update_aliens(ai_settings, screen, status, sb, ship, aliens, bullets)
        # 更新后的位置重新绘制屏幕
        gf.update_screen(ai_settings, screen, status, sb, ship, aliens, bullets, play_button)


run_game()

(2) alien.py

import pygame
from pygame.sprite import Sprite


class Alien(Sprite):
    def __init__(self, ai_settings, screen):
        """初始化外星人并设置其他起始位置"""
        super(Alien, self).__init__()
        self.screen = screen
        self.ai_settings = ai_settings

        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角附近
        self.rect.x = self.rect.width
        self.rect.y = self.rect.height

        # 储存外星人的确切位置
        self.x = float(self.rect.x)

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

    def check_edges(self):
        """外星人处于边缘上，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):
        """向左或者向右移动外星人"""
        self.x += (self.ai_settings.alien_speed_factor *
                   self.ai_settings.fleet_direction)
        self.rect.x = self.x

(3) bullet.py

import pygame
from pygame.sprite import Sprite


class Bullet(Sprite):
    """对飞船发射的子弹进行管理的类"""
    def __init__(self, ai_settings, screen, ship):
        """创建一个子弹对象"""
        super(Bullet, self).__init__()
        self.screen = screen

        # 在(0,0)处创建以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

        # 存储用小数表示制单的位置
        self.y = float(self.rect.y)

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

    def update(self):
        # 更新表示制单位置的小数值
        self.y -= self.speed_factor

        # 更新表示子弹的rect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)

(4) button.py

import pygame.font


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

        # 设置安妮尺寸和其他属性
        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

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

    def prep_msg(self, msg):
        """将msg渲染未图像，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)

(5) game_functions.py

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


def check_events(ai_settings, screen, status, 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:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event, ai_settings, screen, 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, status, sb, play_button, ship, aliens, bullets, mouse_x, mouse_y)


def check_play_button(ai_settings, screen, status, sb, play_button, ship, aliens, bullets, mouse_x, mouse_y):
    """玩家代几Play按钮时开始新游戏"""
    button_clicked = play_button.rect.collidepoint(mouse_x, mouse_y)
    if button_clicked and not status.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
        status.reset_status()
        status.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, aliens, ship)
        ship.center_ship()


def check_keydown_events(event, ai_settings, screen, ship, bullets):
    """响应按键"""
    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:
        sys.exit()


def fire_bullet(ai_settings, screen, ship, bullets):
    """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):
    """响应松开"""
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    elif event.key == pygame.K_LEFT:
        ship.moving_left = False


def update_bullets(ai_settings, screen, status, 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, status, sb, ship, aliens, bullets)


def check_bullet_alien_collisions(ai_settings, screen, status, sb, ship, aliens, bullets):
    """响应子弹和外星人的碰撞"""

    # 击中敌人则删除相应的子弹和外星人
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
    if collisions:
        for aliens in collisions.values():
            status.score += ai_settings.alien_points * len(aliens)
            sb.prep_score()
        check_high_score(status, sb)
    if len(aliens) == 0:

        # 删除子弹建立新的外星人
        bullets.empty()
        ai_settings.increase_speed()

        # 提高等级
        status.level += 1
        sb.prep_level()
        create_fleet(ai_settings, screen, aliens, ship)


def update_screen(ai_setting, screen, status, sb, ship, aliens, bullets, paly_button):
    """更换屏幕上图像，并切换到新屏幕"""

    # 每次循环时都重绘屏幕
    screen.fill(ai_setting.bg_color)

    # 在飞船和外星人后买你重绘所有子弹
    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 status.game_active:
        paly_button.draw_button()

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


def create_fleet(ai_settings, screen, aliens, ship):
    """创见外星人群"""
    alien = Alien(ai_settings, screen)

    # 外星人间距是外星人的宽度
    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
    for row_number in range(number_rows):
        for alien_number in range(number_aliens_x):
            create_alien(ai_settings, screen, aliens, alien_number, row_number)


def get_number_aliens_x(ai_settings, alien_width):
    """计算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个外星人"""
    available_space_y = (ai_settings.screen_height - (3 * alien_height) - ship_height)
    num_rows = int(available_space_y / (2 * alien_height))
    return num_rows


def create_alien(ai_settings, screen, aliens, alien_number, row_number):
    """创建一个外星人并将其打入当前行"""
    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 check_fleet_edges(ai_settings, aliens):
    """外星人到达边缘采取相应措施"""
    for alien in aliens.sprites():
        if alien.check_edges():
            change_fleet_direction(ai_settings, aliens)
            break


def change_fleet_direction(ai_settings, aliens):
    """将外星人下移，并该改变他们方向"""
    for alien in aliens.sprites():
        alien.rect.y += ai_settings.fleet_drop_speed
    ai_settings.fleet_direction *= -1


def ship_hit(ai_settings, screen, status, sb, ship, aliens, bullets):
    """响应被外星人撞到的飞船"""
    if status.ships_left > 0:
        status.ships_left -= 1
        sb.prep_ships()
        aliens.empty()
        bullets.empty()
        create_fleet(ai_settings, screen, aliens, ship)
        ship.center_ship()
        sleep(0.5)
    else:
        status.game_active = False
        pygame.mouse.set_visible(True)


def check_aliens_bottom(ai_settings, screen, status, sb, ship, aliens, bullets):
    """检查是否有外星人达到了屏幕顶端"""
    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, screen, status, sb, ship, aliens, bullets)
            break


def update_aliens(ai_settings, screen, status, sb, ship, aliens, bullets):
    """更新外星人群中外星人的位置"""
    check_fleet_edges(ai_settings, aliens)
    aliens.update()
    if pygame.sprite.spritecollideany(ship, aliens):
        ship_hit(ai_settings, screen, status, sb, ship, aliens, bullets)

    # 检查是否有外星人达到屏幕底端
    check_aliens_bottom(ai_settings, screen, status, sb, ship, aliens, bullets)


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

(6) game_status.py

class GameStatus():
    """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_status()

        # 游戏处于非活动状态
        self.game_active = False

        # 在任何情况下不应该重置最高得分
        self.high_score = 0

    def reset_status(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

(7) scoreboard.py

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


class Scoreboard():
    def __init__(self, ai_settings, screen, status):
        """初始化希纳是得分所涉及属性"""
        self.screen = screen
        self.screen_rect = screen.get_rect()
        self.ai_settings = ai_settings
        self.status = status

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

        # 准备最高得分与当前得分图像
        self.prep_score()
        self.prep_high_score()
        self.prep_level()
        self.prep_ships()

    def prep_score(self):
        """将得分转换成一副渲染的图像"""
        rounded_score = int(round(self.status.score, -1))
        score_str = "{:,}".format(rounded_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):
        """将得分转换成一副渲染的图像"""
        high_score = int(round(self.status.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_settings.bg_color)

        # 将最高得分放在屏幕中央
        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.high_score_rect.top

    def show_score(self):
        """在屏幕上显示得分与等级"""
        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)

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

        # 将等级放在得分的下面
        self.level_rect = self.level_image.get_rect()
        self.level_rect.right = self.score_rect.right
        self.level_rect.top = self.high_score_rect.bottom + 10

    def prep_ships(self):
        """显示余下的多少飞船"""
        self.ships = Group()
        for ship_number in range(self.status.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)

(8) settings.py

class Settings():
    """存储所有所有设置的类"""

    def __init__(self):
        # 屏幕设置
        self.screen_width = 1200
        self.screen_height = 800
        self.bg_color = (230, 230, 230)
        self.ship_speed_factor = 1.5

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

        # 外星人设置
        self.alien_speed_factor = 1
        self.fleet_drop_speed = 10
        self.fleet_direction = 1

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

        # 提高游戏难度
        self.speedup_scale = 1.1
        self.initialize_dynamic_settings()

        # 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 = 3
        self.alien_speed_factor = 1

        # fleet_direction为1表似乎向右；为-1表示向左
        self.fleet_direction = 1
        self.alien_points = 50

    def increase_speed(self):
        """提高游戏速度设置"""
        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)
        print(self.alien_points)

(9) 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

        # 加载船图像
        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 blitme(self):
        """当前位置绘制飞船"""
        self.screen.blit(self.image, self.rect)

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

    def update(self):
        """根据移动表纸调整飞船的位置"""
        # 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