下午学了一下box2d相关的内容，这里做个笔记。

1、创建头文件

#ifndef __HELLOWORLD_SCENE_H__#define __HELLOWORLD_SCENE_H__#include "cocos2d.h"#include "GLES-Render.h"USING_NS_CC;class HelloWorld : public cocos2d::CCLayer{public:   HelloWorld();   ~HelloWorld();                         static cocos2d::CCScene* scene();    CCSize _screenSize;    void initPhysics();    virtual void draw();    void update(float dt);     virtual void ccTouchesEnded(CCSet *pTouches, CCEvent *pEvent);    void addNewSpriteAtPosition(CCPoint p);private:    cocos2d::CCTexture2D* m_pSpriteTexture;    b2World* world;    GLESDebugDraw* m_debugDraw;};#endif // __HELLOWORLD_SCENE_H__

2、编写实现cpp

#include "HelloWorldScene.h"#include "VisibleRect.h"USING_NS_CC;#define PTM_RATIO 32.0fenum{    kTagParentNode = 1};HelloWorld::HelloWorld():m_pSpriteTexture(NULL),world(NULL){    _screenSize = CCDirector::sharedDirector()->getVisibleSize();    setTouchEnabled(true);    this->initPhysics();    //使用批处理方式加载图片    CCSpriteBatchNode *parent = CCSpriteBatchNode::create("blocks.png",100);    m_pSpriteTexture = parent->getTexture();    addChild(parent,0,kTagParentNode);    //在中间添加一个精灵    addNewSpriteAtPosition(ccp(_screenSize.width/2,_screenSize.height/2));    scheduleUpdate();}HelloWorld::~HelloWorld(){    delete world;    world = NULL;    delete m_debugDraw;}void HelloWorld::initPhysics(){    b2Vec2 gravity;    gravity.Set(0.0f,-10.0f);    //创建世界    world = new b2World(gravity);    //允许睡眠    world->SetAllowSleeping(true);    world->SetContinuousPhysics(true);    //创建GLESDebugDraw     m_debugDraw = new GLESDebugDraw( PTM_RATIO );     world->SetDebugDraw(m_debugDraw);    uint32 flags = 0;    flags += b2Draw::e_shapeBit;    flags += b2Draw::e_jointBit;     m_debugDraw->SetFlags(flags);    //定义边框    b2BodyDef groundBodyDef;    groundBodyDef.position.Set(0,0);    b2Body* groundBody = world->CreateBody(&groundBodyDef);    //定义ground box shape    b2EdgeShape groundBox;    //bottom    groundBox.Set(b2Vec2(0,0),        b2Vec2(_screenSize.width/PTM_RATIO,0/PTM_RATIO));    groundBody->CreateFixture(&groundBox,0);    //top    groundBox.Set(b2Vec2(0,_screenSize.height/PTM_RATIO),        b2Vec2(_screenSize.width/PTM_RATIO,_screenSize.height/PTM_RATIO));    groundBody->CreateFixture(&groundBox,0);    //left    groundBox.Set(b2Vec2(0,_screenSize.height/PTM_RATIO),        b2Vec2(0,0));    groundBody->CreateFixture(&groundBox,0);    //right    groundBox.Set(b2Vec2(_screenSize.width/PTM_RATIO,_screenSize.height/PTM_RATIO),        b2Vec2(_screenSize.width/PTM_RATIO,0));    groundBody->CreateFixture(&groundBox,0);}void HelloWorld::draw(){    CCLayer::draw();             glDisable(GL_TEXTURE_2D);    glDisableClientState(GL_COLOR_ARRAY);    glDisableClientState(GL_TEXTURE_COORD_ARRAY);     //进行绘制     world->DrawDebugData();    // restore default GL states    glEnable(GL_TEXTURE_2D);    glEnableClientState(GL_COLOR_ARRAY);    glEnableClientState(GL_TEXTURE_COORD_ARRAY);   }void HelloWorld::update(float dt){    world->Step(dt,8,1);    //同步精灵的物理动作    for(b2Body* b = world->GetBodyList();b;b=b->GetNext()){        if(b->GetUserData()!=NULL){            CCSprite* sprite = (CCSprite*)b->GetUserData();            sprite->setPosition(ccp(b->GetPosition().x * PTM_RATIO,b->GetPosition().y*PTM_RATIO));            sprite->setRotation(-1*CC_RADIANS_TO_DEGREES(b->GetAngle()));        }    }}CCScene* HelloWorld::scene(){    // 'scene' is an autorelease object    CCScene *scene = CCScene::create();                // 'layer' is an autorelease object    HelloWorld *layer = new HelloWorld();    // add layer as a child to scene    scene->addChild(layer);    layer->release();    // return the scene    return scene;}/************************************************************************//* 触摸方法                                                                     *//************************************************************************/void HelloWorld::ccTouchesEnded(CCSet *pTouches, CCEvent *pEvent){    CCSetIterator it;    CCTouch* touch;    for(it = pTouches->begin();it!=pTouches->end();it++){        touch = (CCTouch*)(*it);        if(!touch){            break;        }        CCPoint location = touch->getLocation();        //触摸后添加精灵        addNewSpriteAtPosition(location);    }}/************************************************************************//* 添加精灵                                                                     *//************************************************************************/void HelloWorld::addNewSpriteAtPosition(CCPoint p){    CCLOG("Add sprite %0.2f x %02.f",p.x,p.y);    CCNode* parent = this->getChildByTag(kTagParentNode);    int idx=(CCRANDOM_0_1()>0.5f?0:1);    int idy=(CCRANDOM_0_1()>0.5f?0:1);    //随机创建精灵    CCSprite* sprite = CCSprite::createWithTexture(m_pSpriteTexture,CCRectMake(32*idx,32*idy,32,32));    sprite->setPosition(p);    parent->addChild(sprite);    //定义动态刚体    b2BodyDef bodyDef;    bodyDef.type = b2_dynamicBody;    bodyDef.position.Set(p.x/PTM_RATIO,p.y/PTM_RATIO);    bodyDef.userData = sprite;    //创建刚体    b2Body* body = world->CreateBody(&bodyDef);    //创建长方形    b2PolygonShape dynamicBox;    dynamicBox.SetAsBox(sprite->getContentSize().width/PTM_RATIO/2,sprite->getContentSize().width/PTM_RATIO/2);    //定义夹角    b2FixtureDef fixtureDef;    fixtureDef.shape = &dynamicBox;    fixtureDef.density = 1.0f; //密度    fixtureDef.friction = 0.3f;//摩擦力    body->CreateFixture(&fixtureDef);         }

素材来源与cocos2d-x自带demo