添加外星人代码

主文件：
alien_invasion.py

import pygame
from settings import Settings
from game_stats import GameStats
from ship import Ship
from alien import Alien
import game_functions as gf
from pygame.sprite import Groupdef 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")#创建一个外星人alien = Alien(ai_settings,screen)#创建一个用于存储游戏统计信息的实例stats = GameStats(ai_settings)#创建一艘非飞船ship = Ship(ai_settings,screen)#创建一个用于存储子弹的编组bullets = Group()aliens = Group()#创建外星人群gf.create_fleet(ai_settings,screen,ship,aliens)#开始游戏的主循环while True:sys.pause()#监视键盘和鼠标事件gf.check_events(ai_settings,screen,ship,bullets)if stats.game_active:ship.update()gf.update_bullets(ai_settings,screen,ship,aliens,bullets)gf.update_aliens(ai_settings,stats,screen,ship,aliens,bullets)gf.update_screen(ai_settings,screen,ship,bullets,aliens)run_game()

游戏状态文件:
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_settingsself.reset_stats()#游戏刚启动时处于活动状态self.game_active = Truedef 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

飞船和子弹设置文件：
settings.py

class Settings():"""存储<<外星人入侵>>的所有设置的类"""def __init__(self):"""初始化游戏的设置"""#屏幕设置self.screen_width = 800self.screen_height = 600self.bg_color = (230,230,230)#飞船的设置self.ship_speed_factor = 1.5self.ship_limit = 3#子弹设置self.bullet_speed_factor = 3self.bullet_width = 3self.bullet_height = 15self.bullet_color = (60 , 60 , 60)self.bullets_allowed = 5   #将在屏幕内可以存在的子弹限制为3颗#外星人设置self.alien_speed_factor = 1self.fleet_drop_speed = 10#fleet_direction为1表示向右移，为-1表示向左移self.fleet_direction = 1

外星人文件：
alien.py

import pygame
from pygame.sprite import Spriteclass 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其起始位置"""super(Alien,self).__init__()self.screen = screenself.ai_settings = ai_settings#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角附近self.rect.x = self.rect.widthself.rect.y = self.rect.height#存储外星人的准确位置self.x = float(self.rect.x)def blitme(self):"""在指定位置绘制外星人"""self.screen.blit(self.image,self.rect)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 Trueelif self.rect.left <= 0:return Truedef update(self):"""向左或右移动外星人"""self.x += (self.ai_settings.alien_speed_factor * self.ai_settings.fleet_direction)self.rect.x = self.x

游戏逻辑控制文件
game_functions.py

import sys
import pygame
from bullet import Bullet
from alien import Alien
from time import sleepdef check_keydown_events(event,ai_settings,screen, ship,bullets):"""响应按键"""if event.key == pygame.K_RIGHT:ship.moving_right = Trueelif event.key == pygame.K_LEFT:ship.moving_left = Trueelif event.key == pygame.K_SPACE:fire_bullet(ai_settings,screen,ship,bullets)elif event.key == pygame.K_q:sys.exit(0)def check_keyup_events(event,ship):"""响应松开"""if event.key == pygame.K_RIGHT:ship.moving_right = Falseif event.key == pygame.K_LEFT:ship.moving_left = Falsedef check_events(ai_settings,screen, ship, bullets):"""响应按键和鼠标事件"""for event in pygame.event.get():if event.type == pygame.QUIT:sys.exit(0)  #在这里的exit()中需要传递参数，他么的，竟然这么坑吗？elif event.type == pygame.KEYDOWN:check_keydown_events(event, ai_settings,screen,ship, bullets)elif event.type == pygame.KEYUP:check_keyup_events(event,ship)def update_screen(ai_settings,screen,ship,bullets,aliens):"""更新屏幕上的图像，并切换到新屏幕"""#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)#让最近绘制的屏幕可见pygame.display.flip()def update_bullets(ai_settings,screen,ship,aliens,bullets):"""更新子弹的位置，并删除已销失的子弹"""#更新子弹的位置bullets.update()#删除已销失的子弹for bullet in bullets.copy():if bullet.rect.bottom <= 0:bullets.remove(bullet)if len(bullets) != 0:print(len(bullets))#检查是否有子弹击中了外星人#如果这样，就删除相应的子弹和外星人check_bullet_alien_collisions(ai_settings,screen,ship,aliens,bullets)def check_bullet_alien_collisions(ai_settings,screen,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 len(aliens) == 0:#删除现有的子弹并新建一群外星人bullets.empty()create_fleet(ai_settings,screen,ship,aliens)def fire_bullet(ai_settings,screen,ship,bullets):"""如果还没有到达限制，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 get_number_aliens_x(ai_settings,alien_width):"""计算每行可容纳多少外星人"""available_space_x = ai_settings.screen_width - 2 * alien_widthnumber_alien_x = int(available_space_x / (2 * alien_width))return number_alien_xdef 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_rowsdef create_alien(ai_settings,screen,aliens,alien_number,row_number):"""创建一个外星人并将其加入当前行"""alien = Alien(ai_settings,screen)alien_width = alien.rect.widthalien.x = alien_width + 2 * alien_width * alien_numberalien.rect.x = alien.xalien.rect.y = alien.rect.height + 2 * alien.rect.height * row_numberaliens.add(alien)def create_fleet(ai_settings,screen,ship,aliens):"""创建外星人"""#创建一个外星人，并计算一行可容纳多少外星人#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):create_alien(ai_settings,screen,aliens,alien_number,row_number)def update_aliens(ai_settings,ship,aliens):"""更新外星人群中所有外星人的位置"""aliens.update()#检测外星人和飞船之间的碰撞if pygame.sprite.spritescollideany(ship,aliens):print("Ship hit!!!")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)breakdef 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_speedai_settings.fleet_direction *= -1def ship_hit(ai_settings,stats,screen,ship,aliens,bullets):"""相应被外星人撞到的飞船"""if stats.ships_left > 0:#将ships_left 减1stats.ships_left -= 1#清空外星人到列表和子弹列表aliens.empty()bullets.empty()#创建一群外星人，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)sys.exit(0)else:stats.game_active = Falsedef check_aliens_bottom(ai_settings,stats,screen,ship,aliens,bullets):"""检查是否有外星人到达了屏幕底端"""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,screen,ship,aliens,bullets)breakdef update_aliens(ai_settings,stats,screen,ship,aliens,bullets):"""检查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()if pygame.sprite.spritecollideany(ship,aliens):ship_hit(ai_settings,stats,screen,ship,aliens,bullets)#检查是否有外星人到达屏幕底端check_aliens_bottom(ai_settings,stats,screen,ship,aliens,bullets)

image属性文件：
ship.py

import pygameclass Ship():def __init__(self,ai_settings,screen):"""初始化飞船并设置其初始化位置"""self.screen = screenself.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.centerxself.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 = Falseself.moving_left = Falseself.moving_up = Falseself.moving_down = Falsedef update(self):"""根据移动标志调整飞船的位置"""#更新飞船的center值，而不是rectif self.moving_right and self.rect.right < self.screen_rect.right:self.center += self.ai_settings.ship_speed_factorelif self.moving_left and self.rect.left > 0:self.center -= self.ai_settings.ship_speed_factorelif self.moving_up and self.rect.up < self.screen_rect.up:self.center += self.ai_settings.ship_speed_factorelif self.moving_down and self.rect.down > 0:self.center -= self.ai_settings.ship_speed_factor#根据self.center更新rect对象self.rect.centerx = self.centerdef blitme(self):"""在指定位置绘制飞船"""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

子弹类文件：
bullet.py

import pygame
from pygame.sprite import Spriteclass 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的对象"""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.centerxself.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_colorself.speed_factor = ai_settings.bullet_speed_factordef 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.ydef draw_bullet(self):"""在屏幕上绘制子弹"""pygame.draw.rect(self.screen,self.color,self.rect)