cocos2d-x 3.0的入门程序：helloworld

#include "main.h"
#include "AppDelegate.h"
#include "cocos2d.h"

USING_NS_CC;

int APIENTRY _tWinMain(HINSTANCE hInstance,
                       HINSTANCE hPrevInstance,
                       LPTSTR    lpCmdLine,
                       int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // create the application instance
    AppDelegate app;
	//运行创建程序
    return Application::getInstance()->run();
}

#include "AppDelegate.h"
#include "HelloWorldScene.h"

USING_NS_CC;

AppDelegate::AppDelegate() {

}

AppDelegate::~AppDelegate() 
{
}

bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director创建导演
    auto director = Director::getInstance();
	//创建opengl窗口
    auto glview = director->getOpenGLView();
    if(!glview) {
        glview = GLView::create("My Game");
        director->setOpenGLView(glview);
    }

    // turn on display FPS 打开FPS
    director->setDisplayStats(true);

    // set FPS. the default value is 1.0/60 if you don't call thi 1秒60帧
    director->setAnimationInterval(1.0 / 60);

    // create a scene. it's an autorelease object创建场景和层
    auto scene = HelloWorld::createScene();

    // run启动场景
    director->runWithScene(scene);

    return true;
}
//当收到电话，游戏转入后台服务
// 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();
}
//当电话完成，选择恢复游戏时，响应这句
// 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();
}

#include "HelloWorldScene.h"

USING_NS_CC;

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;
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !Layer::init() )
    {
        return false;
    }
    //得到屏幕的大小，得到原点
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();

    /////////////////////////////
    // 2. add a menu item with "X" image, which is clicked to quit the program
    //    you may modify it.
	//   // 创建一个菜单项，它由两张图片来表现普通状态和按下状态，设置按下时调用menuCloseCallback函数响应关闭  
    // add a "close" icon to exit the progress. it's an autorelease object
    auto closeItem = MenuItemImage::create(
                                           "CloseNormal.png",
                                           "CloseSelected.png",
                                           CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));
    //指定菜单位置,菜单项
	closeItem->setPosition(Vec2(origin.x + visibleSize.width - closeItem->getContentSize().width/2 ,
                                origin.y + closeItem->getContentSize().height/2));

    // create menu, it's an autorelease object菜单项放到菜单里
    auto menu = Menu::create(closeItem, NULL);
    menu->setPosition(Vec2::ZERO);
    this->addChild(menu, 1);//放到当前的层

    /////////////////////////////
    // 3. add your codes below...

    // add a label shows "Hello World"
    // create and initialize a label
    //创建标签
    auto label = LabelTTF::create("Hello World", "Arial", 24);
    
    // position the label on the center of the screen标签位置
    label->setPosition(Vec2(origin.x + visibleSize.width/2,
                            origin.y + visibleSize.height - label->getContentSize().height));

    // add the label as a child to this layer将标签放到层中
    this->addChild(label, 1);

    // add "HelloWorld" splash screen"创建图片精灵
    auto sprite = Sprite::create("HelloWorld.png");

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

    // add the sprite as a child to this layer将精灵放到层中
    this->addChild(sprite, 0);
    
    return true;
}

//点close菜单项的时候来回调的
void HelloWorld::menuCloseCallback(Ref* pSender)
{
	////如果是WP8平台，弹出消息框提示一下。  
#if (CC_TARGET_PLATFORM == CC_PLATFORM_WP8) || (CC_TARGET_PLATFORM == CC_PLATFORM_WINRT)
	MessageBox("You pressed the close button. Windows Store Apps do not implement a close button.","Alert");
    return;
#endif
	//终止程序。
    Director::getInstance()->end();
	//如果是ios平台
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
    exit(0);
#endif
}