game_functions.py

import sys
import pygame
from bullet import Bullet
from alien import Alien
from time import sleep
import highscore as hs


def check_keydown_events(event, 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(settings, screen, ship, bullets)
    elif event.key == pygame.K_ESCAPE:
        sys.exit()


def check_keyup_events(event, ship):
    """响应松开"""
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    if event.key == pygame.K_LEFT:
        ship.moving_left = False


def check_events(settings, screen, stats, sb, play_button, ship, aliens, bullets):
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event, 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(settings, screen, stats, sb, play_button, ship,
                              aliens, bullets, mouse_x, mouse_y)


def check_play_button(settings, 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
        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()

        # 创建一群新的外星人，并让飞船居中
        create_fleet(settings, screen, ship, aliens)
        ship.center_ship()


def fire_bullet(settings, screen, ship, bullets):
    """如果没有达到限制，就可以再发射子弹"""
    if len(bullets) < settings.bullet_allowed:
        new_bullet = Bullet(settings, screen, ship)
        bullets.add(new_bullet)


def update_screen(settings, screen, stats, sb, ship, aliens, bullets,
                  play_button):
    """更新屏幕上的图像，并切换到新屏幕"""
    # 每次循环是都重新绘制屏幕
    screen.fill(settings.bg_color)

    # 在飞船和外星人后面重绘所以子弹
    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(settings, screen, stats, sb, ship, aliens, bullets):
    """更新子弹位置，并删除已消失的子弹"""
    # 更新子弹位置
    bullets.update()

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

    check_bullet_alien_collisions(settings, screen, stats, sb, ship, aliens, bullets)


def check_bullet_alien_collisions(settings, screen, stats, sb, ship, aliens, bullets):
    """响应子弹和外星人的碰撞"""
    # 删除命中的子弹和外星人
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)

    if collisions:
        for aliens in collisions.values():
            stats.score += settings.alien_points * len(aliens)
            sb.prep_score()

    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()
        settings.increase_speed()

        # 提高游戏等级
        stats.level += 1
        sb.prep_level()

        create_fleet(settings, screen, ship, aliens)


def get_number_aliens_x(settings, alien_width):
    """计算每行可容纳多少个外星人"""
    available_space_x = settings.screen_width - 2 * alien_width
    number_aliens_x = int(available_space_x / (2 * alien_width))
    return number_aliens_x


def get_number_rows(settings, ship_height, alien_height):
    """计算屏幕可容纳多少行外星人"""
    available_space_y = settings.screen_height - (3 * alien_height) - ship_height
    number_rows = int(available_space_y / (2 * alien_height))
    return number_rows


def create_alien(settings, screen, aliens, alien_number, row_number):
    """创建一个外星人并将其放在当前行"""
    alien = Alien(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(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
    # 外星人间距为外星人宽度
    alien = Alien(settings, screen)
    number_aliens_x = get_number_aliens_x(settings, alien.rect.width)
    number_rows = get_number_rows(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(settings, screen, aliens, alien_number, row_number)


def check_fleet_edges(settings, aliens):
    """有外星人到达边缘时应采取相应的措施"""
    for alien in aliens.sprites():
        if alien.check_edges():
            change_fleet_direction(settings, aliens)
            break


def change_fleet_direction(settings, aliens):
    """将整群外星人往下移，并改变它们的方向"""
    for alien in aliens.sprites():
        alien.rect.y += settings.fleet_drop_speed
    settings.fleet_direction *= -1


def update_aliens(settings, screen, stats, sb, ship, aliens, bullets):
    """更新外星人群中所以外星人的位置"""
    check_fleet_edges(settings, aliens)
    aliens.update()

    # 检测外星人与飞船之间的碰撞
    if pygame.sprite.spritecollideany(ship, aliens):
        ship_hit(settings, screen, stats, sb, ship, aliens, bullets)

    # 检测外星人是否到达屏幕底端
    check_aliens_bottom(settings, screen, stats, sb, ship, aliens, bullets)


def ship_hit(settings, screen, stats, sb, ship, aliens, bullets):
    """响应被外星人撞到的飞船"""
    if stats.ships_left > 0:
        # 将ships_left减1
        stats.ships_left -= 1

        # 更新记分牌
        sb.prep_ships()

        # 清空外星人和子弹列表
        aliens.empty()
        bullets.empty()

        # 创建一群新的外星人，并将飞船放到屏幕底部中央
        create_fleet(settings, screen, ship, aliens)
        ship.center_ship()

        # 暂停
        sleep(1)

    else:
        stats.game_active = False
        pygame.mouse.set_visible(True)

    # 游戏结束时判断分数是否为最高分
    check_high_score(stats, sb)


def check_aliens_bottom(settings, screen, stats, sb, ship, aliens, bullets):
    """检测外星人是否到达了屏幕底端"""
    screen_rect = screen.get_rect()
    for alien in aliens.sprites():
        if alien.rect.bottom >= screen_rect.bottom:
            # 像飞船被撞到一样处理
            ship_hit(settings, screen, stats, sb, ship, aliens, bullets)
            break


def check_high_score(stats, sb):
    """检测是否诞生了最高分"""
    if stats.score > stats.high_score:
        stats.high_score = stats.score
        hs.save_json(stats.high_score)
        sb.prep_high_score()