解释cocos2dx的HelloWorldScene的类

//这里可以换场景de
// create a scene. it's an autorelease object
CCScene *pScene = HelloWorld::scene();

// run
pDirector->runWithScene(pScene);

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"

class HelloWorld : public cocos2d::CCLayer
{
public:
// Method 'init' in cocos2d-x returns bool, instead of 'id' in cocos2d-iphone (an object pointer)
//初始化函数
virtual bool init();

// there's no 'id' in cpp, so we recommend to return the class instance pointer
//静态创建函数
static cocos2d::CCScene* scene();

// a selector callback
//menu 菜单的一个回调函数  用于响应CCMenuItemImage
void menuCloseCallback(CCObject* pSender);

// preprocessor macro for "static create()" constructor ( node() deprecated )
//备注1
CREATE_FUNC(HelloWorld);
};

#endif // __HELLOWORLD_SCENE_H__

#include "HelloWorldScene.h"
#include "SimpleAudioEngine.h"

using namespace cocos2d;
using namespace CocosDenshion;

CCScene* HelloWorld::scene()
{
//创建一个场景
// 'scene' is an autorelease object
CCScene *scene = CCScene::create();
//创建一个HelloWorld的层
// 'layer' is an autorelease object
HelloWorld *layer = HelloWorld::create();
//将层放到场景中去
// 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()
{//  调用父类初始化函数
//////////////////////////////
// 1. super init first
if ( !CCLayer::init() )
{
return false;
}

/////////////////////////////
// 2. add a menu item with "X" image, which is clicked to quit the program
//    you may modify it.

// add a "close" icon to exit the progress. it's an autorelease object
//将一个相片创建菜单项 并调用方法menuCloseCallback
CCMenuItemImage *pCloseItem = CCMenuItemImage::create(
"CloseNormal.png",
"CloseSelected.png",
this,
menu_selector(HelloWorld::menuCloseCallback) );
//开关相片的位置
pCloseItem->setPosition( ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20) );

//将一个已经创建好的菜单项加入菜单中 并声称一个菜单对象的实例
// create menu, it's an autorelease object
CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);
// 设置菜单的位置
pMenu->setPosition( CCPointZero );
// 将菜单加入当前的layer里  并设置z轴为1
this->addChild(pMenu, 1);

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

// add a label shows "Hello World"
// create and initialize a label
//创建一个文本对象 并设置字体和大小
CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Thonburi", 34);

//    获取当前设备的尺寸
// ask director the window size
CCSize size = CCDirector::sharedDirector()->getWinSize();
//设置文本的位置
// position the label on the center of the screen
pLabel->setPosition( ccp(size.width / 2, size.height - 20) );

// add the label as a child to this layer
//    将文本放大layer层中  和menu的设置轴是一样的  就是同一层
this->addChild(pLabel, 1);

// add "HelloWorld" splash screen"
//    设置一个精灵  并且放入图片
CCSprite* pSprite = CCSprite::create("HelloWorld.png");
//精灵的位置
// position the sprite on the center of the screen
pSprite->setPosition( ccp(size.width/2, size.height/2) );
//把精灵放到layer中去   但是在底层
// add the sprite as a child to this layer
this->addChild(pSprite, 0);

return true;
}

void HelloWorld::menuCloseCallback(CCObject* pSender)
{
//    程序退出
CCDirector::sharedDirector()->end();
//判定是否为ios设备
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
exit(0);
#endif
}