import sys
import pygame

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)

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)
        
def check_keyup_events(event,ship):
    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,ship,bullets):
    """响应按键和鼠标事件"""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            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)
                

def update_screen(ai_settings,screen,ship,bullets):
    """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()
    
    #让最近绘制的屏幕可见
    pygame.display.flip()

def update_bullets(bullets):
    """更新子弹的位置，并删除已消失的子弹"""
    bullets.update()

    #删除已消失的子弹
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)
    

import sys
import pygame

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)

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)
        
def check_keyup_events(event,ship):
    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,ship,bullets):
    """响应按键和鼠标事件"""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            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)
                

def update_screen(ai_settings,screen,ship,bullets):
    """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()
    
    #让最近绘制的屏幕可见
    pygame.display.flip()

def update_bullets(bullets):
    """更新子弹的位置，并删除已消失的子弹"""
    bullets.update()

    #删除已消失的子弹
    for bullet in bullets.copy():
        if bullet.rect.bottom <= 0:
            bullets.remove(bullet)
    

响应按键 如果还没有到达限制，就发射一颗子弹 #创建一颗子弹，并将其加入到编组bullets中 响应按键和鼠标事件 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 #在飞船和外星人后面重绘所有子弹 #让最近绘制的屏幕可见 更新子弹的位置，并删除已消失的子弹 #删除已消失的子弹