3.1 第一个场景 HelloWorldScene

HelloWorldScene.h

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"
#include "Box2D/Box2D.h"
#include "SimpleAudioEngine.h"

class HelloWorld : public cocos2d::CCLayer
{
public:
// Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
virtual bool init();

// there's no 'id' in cpp, so we recommand to return the exactly class pointer
static cocos2d::CCScene* scene();

// a selector callback
void menuCloseCallback(CCObject* pSender);

// implement the "static node()" method manually
CREATE_FUNC(HelloWorld);
};

#endif  // __HELLOWORLD_SCENE_H__

HelloWorldScene.cpp

#include "HelloWorldScene.h"
using namespace cocos2d;

CCScene* HelloWorld::scene()
{
CCScene * scene = NULL;
do
{
// 'scene' is an autorelease object
scene = CCScene::create();
CC_BREAK_IF(! scene);

// 'layer' is an autorelease object
HelloWorld *layer = HelloWorld::create();
CC_BREAK_IF(! layer);

// add layer as a child to scene
scene->addChild(layer);
} while (0);

// return the scene
return scene;
}

// on "init" you need to initialize your instance
bool HelloWorld::init()
{
bool bRet = false;
do
{
//p1 = this;
//////////////////////////////////////////////////////////////////////////
// super init first
//////////////////////////////////////////////////////////////////////////

CC_BREAK_IF(! CCLayer::init());

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

// 1. Add a menu item with "X" image, which is clicked to quit the program.

// Create a "close" menu item with close icon, it's an auto release object.
CCMenuItemImage *pCloseItem = CCMenuItemImage::create(
"CloseNormal.png",
"CloseSelected.png",
this,
menu_selector(HelloWorld::menuCloseCallback));
CC_BREAK_IF(! pCloseItem);

// Place the menu item bottom-right conner.
pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20));

// Create a menu with the "close" menu item, it's an auto release object.
CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);
pMenu->setPosition(CCPointZero);
CC_BREAK_IF(! pMenu);

// Add the menu to HelloWorld layer as a child layer.
this->addChild(pMenu, 1);

// 2. Add a label shows "Hello World".

// Create a label and initialize with string "Hello World".
CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", 24);
CC_BREAK_IF(! pLabel);

// Get window size and place the label upper.
CCSize size = CCDirector::sharedDirector()->getWinSize();
pLabel->setPosition(ccp(size.width / 2, size.height - 50));

// Add the label to HelloWorld layer as a child layer.
this->addChild(pLabel, 1);

// 3. Add add a splash screen, show the cocos2d splash image.
CCSprite* pSprite = CCSprite::create("HelloWorld.png");
CC_BREAK_IF(! pSprite);

// Place the sprite on the center of the screen
pSprite->setPosition(ccp(size.width/2, size.height/2));

// Add the sprite to HelloWorld layer as a child layer.
this->addChild(pSprite, 0);

bRet = true;
} while (0);

return bRet;
}

void HelloWorld::menuCloseCallback(CCObject* pSender)
{
// "close" menu item clicked
CCDirector::sharedDirector()->end();
}

这是一个 cocos2d-x 引擎使用者 最初级的入门篇章， 上面的注释已经很清楚了，没什么难点，你会看懂的 believe yourself！！！ Come on ， baby.

下面看一下 CREATE_FUNC 这个宏的定义：

/**
* define a create function for a specific type, such as CCLayer
* @__TYPE__ class type to add create(), such as CCLayer
*/
#define CREATE_FUNC(__TYPE__) \
static __TYPE__* create() \
{ \
__TYPE__ *pRet = new __TYPE__(); \
if (pRet && pRet->init()) \
{ \
pRet->autorelease(); \
return pRet; \
} \
else \
{ \
delete pRet; \
pRet = NULL; \
return NULL; \
} \
}

看似高端 大气 上档次 ， 其实也很容易理解

定义 CREATE_FUNC

创建实例（new）

判断成功与否（if） 自动释放内存（autorelease） 返回实例（return）
创建失败（else） 删除实例（delete）