问题遇到的现象和发生背景
我让敌人一直左右移动，在撞到屏幕边缘时会改变水平移动方向，并向下移动一段距离。但是发射子弹打到敌人时，敌人直接飞出屏幕了。
用代码块功能插入代码，请勿粘贴截图
主函数
from alien_invasion import run_game
if __name__ == '__main__':
run_game()
游戏初始化和主循环
import pygame
from settings import Settings
from ship import Ship
import game_function as gf
from pygame.sprite import Group
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("Aircraft War Game")
# 创建一艘飞船
ship = Ship(ai_settings, screen)
# 创建一个外星人编组
aliens = Group()
gf.create_fleet(ai_settings, screen, ship, aliens)
# 创建一个子弹编组
bullets = Group()
# 开始游戏的主循环
while True:
gf.check_events(ai_settings, screen, ship, bullets)
ship.update()
gf.update_bullets(aliens, bullets)
gf.update_alien(ai_settings, aliens)
gf.update_screen(ai_settings, screen, ship, aliens, bullets)
游戏主要函数
import sys
import pygame
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(event, ai_settings, screen, ship, bullets)
elif event.type == pygame.KEYUP:
check_up(event, ship)
def check_keydown(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 check_up(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_screen(ai_settings, screen, ship, aliens, bullets):
"""更新屏幕图像"""
screen.fill(ai_settings.bg_color)
ship.blitme()
aliens.draw(screen)
# 重绘子弹
for bullet in bullets.sprites():
bullet.draw_bullet()
# 让最近绘制的屏幕可见
pygame.display.flip()
def update_bullets(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)
# 检查是否有子弹击中外星人
collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
def fire_bullet(ai_settings, screen, ship, bullets):
# 创建一颗子弹
if len(bullets) < ai_settings.bullet_allowed:
new_bullet = Bullet(ai_settings, screen, ship)
bullets.add(new_bullet)
def create_fleet(ai_settings, screen, ship, aliens):
"""创建外星人群"""
alien = Alien(ai_settings, screen)
number_alien_x = get_number_aliens_x(ai_settings, alien.rect.width)
number_alien_y = get_number_rows(ai_settings, ship.rect.height, alien.rect.height)
#创建外星人群
for row_number in range(number_alien_y-2):
for alien_number in range(number_alien_x):
create_alien(ai_settings, screen, aliens, alien_number, row_number)
def get_number_aliens_x(ai_settings, alien_width):
"""计算每行有多少外星人"""
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 create_alien(ai_settings, screen, aliens, alien_number, row_number):
#创建一个外星人
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 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 update_alien(ai_settings ,aliens):
check_fleet_edges(ai_settings, aliens)
aliens.update()
def check_fleet_edges(ai_settings, aliens):
"""有外星人到达边缘采取措施"""
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，并改变方向"""
for alien in aliens.sprites():
alien.rect.y += ai_settings.alien_drop_speed
ai_settings.fleet_direction *= -1
外星人模块
import pygame
from pygame.sprite import Sprite
class Alien(Sprite):
def __init__(self, ai_settings, screen):
"""初始化外星人"""
super(Alien, self).__init__()
self.ai_settings = ai_settings
self.screen = screen
#加载外星人图像，设置rect属性
self.image = pygame.image.load('images/alien-1.png')
self.rect = self.image.get_rect()
#每个外星人最初都在屏幕左上角
self.rect.x = self.rect.width
self.rect.y = self.rect.height
self.x = float(self.rect.x)
def blitme(self):
"""绘制外星人"""
self.screen.blit(self.image, self.rect)
def update(self):
"""向右移动外星人"""
self.x += self.ai_settings.alien_speed * self.ai_settings.fleet_direction
self.rect.x = self.x
def check_edges(self):
"""外星人是否撞到屏幕边缘"""
screen_rect = self.screen.get_rect()
if self.rect.right >= screen_rect.right:
return True
elif self.rect.left <= 0:
return True
子弹模块
import pygame
from pygame.sprite import Sprite
class Bullet(Sprite):
"""子弹管理类"""
def __init__(self, ai_settings, screen, ship):
"""在飞船所处的位置发射子弹"""
super(Bullet, self).__init__()
self.screen = screen
#在（0，0）处创建一个子弹，再设置位置
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
#存储子弹小数位置
self.y = float(self.rect.y)
self.color = ai_settings.bullet_color
self.speed = ai_settings.bullet_speed
def update(self):
"""移动子弹"""
self.y -= self.speed
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)
飞船模块
import pygame
class Ship():
def __init__(self, ai_settings, screen):
"""初始化飞船"""
self.screen = screen
self.ai_settings = ai_settings
#加载飞船图像
self.image = pygame.image.load('images/ship.jpeg')
self.rect = self.image.get_rect()
self.screen_rect = screen.get_rect()
#将每艘飞船放在屏幕底部
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 update(self):
if self.moving_right and self.rect.right < self.screen_rect.right:
self.center += self.ai_settings.ship_speed
if self.moving_left and self.rect.left > self.screen_rect.left:
self.center -= self.ai_settings.ship_speed
self.rect.centerx = self.center
def blitme(self):
"""在指定位置绘制飞船"""
self.screen.blit(self.image, self.rect)
基本设置保存模块
class Settings():
"""保存设置类"""
def __init__(self):
"""初始化游戏设置"""
#屏幕设置
self.screen_width = 1200
self.screen_height = 800
self.bg_color = (230, 230, 230)
#飞船设置
self.ship_speed = 1.5
#子弹设置
self.bullet_speed = 1
self.bullet_width = 5
self.bullet_height = 15
self.bullet_color = (60, 60, 60)
self.bullet_allowed = 3
#外星人设置
self.alien_speed = 1
self.alien_drop_speed = 10
#fleet_direction等于1向右移动，等于－1向左移动
self.fleet_direction = 1
