外星人入侵
1. 项目需求
- 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。
- 我们将添加一个Play按钮，用于根据需要启动游戏以及在游戏结束后重启游戏。我们还将修改这个游戏，使其在玩家的等级提高时加快节奏，并实现一个记分系统。
2. 代码
aliens_invasion.py
import sys
import pygame #包含开发游戏所需功能
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
#from alien import Alien
import game_functions as gf
def run_game():
#初始化游戏并创建一个屏幕对象
pygame.init() #初始化背景设置
ai_settings = Settings()
screen = pygame.display.set_mode(
(ai_settings.screen_width, ai_settings.screen_height)) #创建名为screen的显示窗口
pygame.display.set_caption("Alien 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
stats = GameStats(ai_settings)
sb = Scoreboard(ai_settings, screen, stats)
#创建一艘飞船
ship = Ship(ai_settings, screen) #必须在主while循环前面创建该实例，以免每次循环时都创建一艘飞船
#创建一个用于存储子弹的编组
bullets = Group()
#创建一个外星人
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:
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, screen, stats, sb, ship, aliens, bullets)
gf.update_screen(ai_settings, screen, stats, sb, ship, aliens, bullets, play_button)
run_game()
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 #定义子弹初始x轴坐标
self.rect.top = ship.rect.top #定义子弹初始y轴坐标
#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
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)
button.py
import pygame.font
class Button():
def __init__(self, ai_setting, 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
#按钮的标签只需创建一次
self.prep_msg(msg)
def prep_msg(self, msg):
"""将msg渲染为图像，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)
game_function.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, 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):
"""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 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 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:
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, stats, sb, play_button,
ship, aliens, bullets, mouse_x, mouse_y)
def check_play_button(ai_settngs, 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_settngs.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_settngs, 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)
#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):
"""影响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
sb.prep_score()
check_high_score(stats, sb)
if len(aliens) == 0:
#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)
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_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):
create_alien(ai_settings, screen, aliens, alien_number, row_number)
def ship_hit(ai_settings, screen, stats, sb, ship, aliens, bullets):
"""响应飞船被外星人撞到"""
if stats.ship_left > 0:
#将ship_left减1
stats.ship_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)
def check_aliens_bottom(ai_settings, screen, stats, sb, 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, screen, stats, sb, ship, aliens, bullets)
break
def update_aliens(ai_settings, screen, stats, sb, ship, aliens, bullets):
"""检查是否有外星人到达屏幕边缘
然后更新所有外星人的位置
"""
check_fleet_edges(ai_settings, aliens)
aliens.update()
#检查外星人和飞船之间的碰撞
if pygame.sprite.spritecollideany(ship, aliens):
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)
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 check_high_score(stats, sb):
"""检查是否诞生了新的高分"""
if stats.score > stats.high_score:
stats.high_score = stats.score
sb.prep_high_score()
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
#在任何情况下都不应重置最高得分
self.high_score = 0
def reset_stats(self):
"""初始化在游戏运行期间可能变化的统计信息"""
self.ship_left = self.ai_settings.ship_limit
self.score = 0
self.level = 1
scoreboard.py
import pygame.font
from pygame.sprite import Group
from ship import Ship
class Scoreboard():
"""显示得分信息的类"""
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_ships()
def prep_ships(self):
"""显示还余下多少艘飞船"""
self.ships = Group()
for ship_number in range(self.stats.ship_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 prep_level(self):
"""将等级转换为渲染的图像"""
self.level_image = self.font.render(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.score_rect.right
self.level_rect.top = self.score_rect.bottom + 10
def prep_high_score(self):
"""将最高得分转换为渲染的图像"""
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_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.screen_rect.top
def prep_score(self):
"""将得分转换为一幅渲染的图像"""
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_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 show_score(self):
"""在屏幕上显示飞船和得分"""
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)
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 = (0, 0, 0)
#飞船的设置
self.ship_speed_factor = 1.5
self.ship_limit = 3
#外星人设置
self.fleet_drop_speed = 10
#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()
#子弹设置
self.bullet_speed_factor = 2
self.bullet_width = 3
self.bullet_height = 15
self.bullet_color = (255, 255, 255)
self.bullets_allowed = 3
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表示向右；为-1表示向左
self.fleet_direction = 1
#记分
self.alien_points = 50
def increase_speed(self):
"""提高速度设置和外星人点数"""
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
import pygame
from pygame.sprite import Sprite
class Ship(Sprite): #Ship继承Sprite
def __init__(self, ai_settings, screen):
"""初始化飞船，并设置其起始位置"""
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('image/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
def 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): #如果使用elif代码块来处理向左移动，右箭头键始终处于优先地位
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):
"""让飞船在屏幕上居中"""
self.center = self.screen_rect.centerx
3. 执行结果：
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