//在指定目录下新建一个项目
cocos.py new YourGameTitle -p com.yourcompany.gametitle -l cpp -d C:\YourGameTitle
//在当前目录下新建一个项目
cocos.py new YourGameTitle -p com.yourcompany.gametitle -l cpp

//游戏启动完成
bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    //创建导演
    auto director = Director::getInstance();
    auto glview = director->getOpenGLView();
    if(!glview) {
        glview = GLViewImpl::create("My Game");
        director->setOpenGLView(glview);
    }

    // turn on display FPS
    //展示当前帧率
    director->setDisplayStats(true);

    // set FPS. the default value is 1.0/60 if you don't call this
    //设置帧率
    director->setAnimationInterval(1.0 / 60);

    // create a scene. it's an autorelease object
    //创建并设置初始场景
    auto scene = HelloWorld::createScene();

    // run
    director->runWithScene(scene);

    return true;
}

//应用程序进入后台
// This function will be called when the app is inactive. When comes a phone call,it's be invoked too
void AppDelegate::applicationDidEnterBackground() {
    Director::getInstance()->stopAnimation();

    // if you use SimpleAudioEngine, it must be pause
    // SimpleAudioEngine::getInstance()->pauseBackgroundMusic();
}

//游戏从后台恢复
// this function will be called when the app is active again
void AppDelegate::applicationWillEnterForeground() {
    Director::getInstance()->startAnimation();

    // if you use SimpleAudioEngine, it must resume here
    // SimpleAudioEngine::getInstance()->resumeBackgroundMusic();
}

class HelloWorld : public cocos2d::Layer
{
public:
    // there's no 'id' in cpp, so we recommend returning the class instance pointer
    //场景
    static cocos2d::Scene* createScene();

    // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
    //初始化helloworld
    virtual bool init();
    
    // a selector callback
    //退出按钮的函数
    void menuCloseCallback(cocos2d::Ref* pSender);
    
    // implement the "static create()" method manually
    //宏，创建helloworld对象，注意HelloWorld是单例的
    CREATE_FUNC(HelloWorld);
};

Scene* HelloWorld::createScene()
{
    // 'scene' is an autorelease object
    auto scene = Scene::create();
    
    // 'layer' is an autorelease object
    auto layer = HelloWorld::create();

    // add layer as a child to scene
    scene->addChild(layer);

    // return the scene
    return scene;
}

  //HelloWorld::init()
    auto closeItem = MenuItemImage::create("CloseNormal.png",
                                           "CloseSelected.png",
            CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));
  //png来自Resource  
	closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 , origin.y + closeItem->getContentSize().height/2));

    // create menu, it's an autorelease object
    auto menu = Menu::create(closeItem, NULL);
    menu->setPosition(Vec2::ZERO);
    this->addChild(menu, 1);//第二个参数表示z轴，数字越大越靠前


    //创建一个label
    auto label = Label::createWithTTF("Hello World", "fonts/Marker Felt.ttf", 24);
    
    // position the label on the center of the screen
    label->setPosition(Vec2(origin.x + visibleSize.width/2,
                            origin.y + visibleSize.height - label->getContentSize().height));

    // add the label as a child to this layer
    this->addChild(label, 1);

    // add "HelloWorld" splash screen"
    //创建一个精灵
    auto sprite = Sprite::create("HelloWorld.png");

    // position the sprite on the center of the screen
    sprite->setPosition(Vec2(visibleSize.width/2 + origin.x, visibleSize.height/2 + origin.y));

    // add the sprite as a child to this layer
    this->addChild(sprite, 0);
    
    return true;