Cocos2d-x实例：设置背景音乐与音效-HelloWorld场景实现

HelloWorld场景就是游戏中的主菜单场景。HelloWorld.h文件代码如下：

#define __HELLOWORLD_SCENE_H__


#include "cocos2d.h"
#include "SimpleAudioEngine.h"                                          ①
#include "SettingScene.h"


class HelloWorld : public cocos2d::Layer
{
public:
    static cocos2d::Scene* createScene();


    virtual bool init();                                                    ②
    virtual void onEnter();
    virtual void onEnterTransitionDidFinish();
    virtual void onExit();
    virtual void onExitTransitionDidStart();
    virtual void cleanup();                                                 ③


    void menuItemHelpCallback(cocos2d::Ref* pSender);
    void menuItemStartCallback(cocos2d::Ref* pSender);
    void menuItemSettingCallback(cocos2d::Ref* pSender);
    CREATE_FUNC(HelloWorld);
};




bool HelloWorld::init()
{
    if ( !Layer::init() )
    {
        return false;
    }


    log("HelloWorld init");


    Size visibleSize = Director::getInstance()->getVisibleSize();
    Point origin = Director::getInstance()->getVisibleOrigin();


    Sprite *bg = Sprite::create("background.png");


    bg->setPosition(Point(origin.x + visibleSize.width/2,
        origin.y + visibleSize.height /2));
    this->addChild(bg);


    //开始精灵
    Sprite *startSpriteNormal = Sprite::create("start-up.png");
    Sprite *startSpriteSelected = Sprite::create("start-down.png");


    MenuItemSprite *startMenuItem = MenuItemSprite::create(startSpriteNormal,
        startSpriteSelected,
        CC_CALLBACK_1(HelloWorld::menuItemStartCallback, this));
    startMenuItem->setPosition(Director::getInstance()->convertToGL(Point(700, 170)));


    // 设置图片菜单
    MenuItemImage *settingMenuItem = MenuItemImage::create(
        "setting-up.png",
        "setting-down.png",
        CC_CALLBACK_1(HelloWorld::menuItemSettingCallback, this));
    settingMenuItem->setPosition(Director::getInstance()->convertToGL(Point(480, 400)));


    // 帮助图片菜单
    MenuItemImage *helpMenuItem = MenuItemImage::create(
        "help-up.png",
        "help-down.png",
        CC_CALLBACK_1(HelloWorld::menuItemHelpCallback, this));
    helpMenuItem->setPosition(Director::getInstance()->convertToGL(Point(860, 480)));


    Menu* mu = Menu::create(startMenuItem, settingMenuItem, helpMenuItem, NULL);
    mu->setPosition(Point::ZERO);
    this->addChild(mu);


    return true;
}


void HelloWorld::menuItemSettingCallback(Ref* pSender)
{
    auto sc = Setting::createScene();
    auto reScene = TransitionJumpZoom::create(1.0f, sc);
    Director::getInstance()->pushScene(reScene);
    SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");                  ②
}


void HelloWorld::menuItemHelpCallback(Ref* pSender)
{
    MenuItem* item = (MenuItem*)pSender;
    log("Touch Help %p", item);
    SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");                  ③
}


void HelloWorld::menuItemStartCallback(Ref* pSender)
{
    MenuItem* item = (MenuItem*)pSender;
    log("Touch Start %p", item);
    SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav");                  ④
}


void HelloWorld::onEnter()
{
    Layer::onEnter();
    log("HelloWorld onEnter");
}


void HelloWorld::onEnterTransitionDidFinish()
{
    Layer::onEnterTransitionDidFinish();
    log("HelloWorld onEnterTransitionDidFinish");
    //播放
    SimpleAudioEngine::getInstance()->playBackgroundMusic("sound/Jazz.mp3", true);       ⑤
}


void HelloWorld::onExit()
{
    Layer::onExit();
    log("HelloWorld onExit");
}


void HelloWorld::onExitTransitionDidStart()
{
    Layer::onExitTransitionDidStart();
    log("HelloWorld onExitTransitionDidStart");
}


void HelloWorld::cleanup()
{
    Layer::cleanup();
    log("HelloWorld cleanup");
    //停止
    SimpleAudioEngine::getInstance()->stopBackgroundMusic("sound/Jazz.mp3");         ⑥
}

上述代码第①行using namespace CocosDenshion是使用命名空间CocosDenshion，它是CocosDenshion引擎所需要的。代码②、③、④行SimpleAudioEngine::getInstance()->playEffect("sound/Blip.wav")是在点击菜单时候播放音效。第⑤行代码是onEnterTransitionDidFinish()函数中播放背景音乐。第⑥行代码是cleanup()函数中停止播放背景音乐。

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