game_functions.py

import sys
from bullet import Bullet
import pygame
from alien import Alien
from time import sleep

def check_keydown_events(event, ai_settings, screen, ship, bullets): #响应按下
    if event.key == pygame.K_RIGHT:
        # 向右移动飞船
        ship.moving_right = True
    elif event.key == pygame.K_LEFT:
        ship.moving_left = True
    elif event.key == pygame.K_SPACE:
        first_bullet(ai_settings,  screen, ship, bullets)
    elif event.key == pygame.K_q:
        sys.exit()


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_event(ai_settings, screen, stats, sb, play_button, ship, aliens, bullets):
    #相应按键和鼠标事件
    for event in pygame.event.get():  # 监听鼠标键盘的动作
        if event.type == pygame.QUIT:  # 监测到单击窗口关闭按钮 将检测到pygam.QUIT
            sys.exit()                 #调用sys.exit()来退出游戏

        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_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()

        #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_settings, screen, ship, aliens)
        ship.center_ship()

        #隐藏光标
        pygame.mouse.set_visible(False)

def update_screen(ai_settings, screen, stats, sb, ship, aliens, bullets, play_button):
    #更新屏幕上面的图像 并切换到新屏幕
    screen.fill(ai_settings.bg_color)  # 每次循环时都要重绘屏幕
    #在飞船和外星人后面重绘所有的子弹
    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，不断更新屏幕，以显示元素的新位置
    pygame.display.flip()

def update_bullets(ai_settings, screen, stats, sb, ship, aliens, bullets):
    #更新子弹的位置，并删除已经消失的子弹，首先更新子弹的位置
    bullets.update()
    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 first_bullet(ai_settings, screen, ship, bullets):
    #如果还没达到限制就发射一枚子弹
    # 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 get_number_aliens_x(ai_settings, alien_width):
    #计算每一行可以容纳多少外星人
    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):
    #计算屏幕可以容纳多少外星人
    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 creat_alien(ai_settings, screen, aliens, alien_number, row_number):
    # 创建一个外星人并加入当前行
    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，并计算可以容纳多少外星人（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):
            creat_alien(ai_settings, screen, aliens, alien_number, row_number)

def check_fleet_edges(ai_settings, aliens):
    #当外星人到达边缘时采取措施
    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，并改变他们的移动方向
    for alien in aliens.sprites():
        alien.rect.y += ai_settings.fleet_drop_speed
    ai_settings.fleet_direction *= -1

def ship_hit(ai_settings, screen, stats, sb, ship, aliens, bullets):
    #如果飞船被外星人撞到 ships_left-=1
    if stats.ships_left > 0:
        stats.ships_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，并将飞船放到屏幕低端
        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):
    #检查外星人是否处于屏幕边缘，并更新他们的位置
    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, 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_bullet_alien_collisions(ai_settings, screen, stats, sb, 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 collisions:
        for aliens in collisions.values():
            stats.score += ai_settings.alien_points * len(aliens)
            sb.prep_score()
        check_high_score(stats, sb)
    if len(aliens) == 0:
        #删除现有的子弹 加快游戏节奏
        bullets.empty()
        ai_settings.increase_speed()

        #如果整个外星人群都被消灭 将提高一个等级
        stats.level += 1
        sb.prep_level()

        create_fleet(ai_settings, screen, ship, aliens)

def check_high_score(stats, sb):
    #检查是否诞生了最高得分
    if stats.score > stats.high_score:
        stats.high_score = stats.score
        sb.prep_high_score()