cocos2d-x 《Flappy Bird 》二、物理世界搭建（Box2d物理引擎）

《flappy bird》是由来自越南的独立游戏开发者Dong Nguyen所开发的作品，游戏中玩家必须控制一只小鸟，跨越由各种不同长度水管所组成的障碍，而这只鸟其实是根本不会飞的……所以玩家每点击一下小鸟就会飞高一点，不点击就会下降，玩家必须控制节奏，拿捏点击屏幕的时间点，让小鸟能在落下的瞬间跳起来，恰好能够通过狭窄的水管缝隙，只要稍一分神，马上就会失败阵亡。

图片资源提取后使用PS5 处理，Zwoptex 重新打包。

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开发环境：

  Cocos2d-x  cocos2d-x-2.2.1

  MacBook Pro 13'  10.9

  Xcode 5.0.2

  iPhone5   IOS 7.0.4

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一、效果图

二、小鸟的实现

////  Bird.h//  Flappy////  Created by yuzai on 14-2-12.////#ifndef __Flappy__Bird__#define __Flappy__Bird__#include "cocos2d.h"#include "Box2D/Box2D.h"using namespace cocos2d;class Bird:public cocos2d::CCNode{public:    Bird(void);    virtual ~Bird(void);        virtual void onEnter();    virtual void onExit();            CREATE_FUNC(Bird);    b2Body* m_pBody;//物理private:    CCSprite *body;        };#endif /* defined(__Flappy__Bird__) */

三、物理世界搭建

////  GameLayer.h//  Flappy////  Created by yuzai on 14-2-12.////#ifndef __Flappy__GameLayer__#define __Flappy__GameLayer__#include "cocos2d.h"#include "Box2D.h"#include "Bird.h"using namespace cocos2d;class GameLayer:public cocos2d::CCLayer{public:GameLayer(void);~GameLayer(void);    //背景    CCSprite *bg;    //路    CCSprite *land1;    CCSprite *land2;    //水管    CCSprite *pipe1;    CCSprite *pipe2;    CCSprite *pipe3;    CCSprite *pipe4;    Bird *bird;    void setBackgroud(unsigned int bg);CREATE_FUNC(GameLayer);virtual bool init();    virtual void update(float time);    void initPhysics(); private:    b2World* world;//定义物理世界    b2BodyDef groundBodyDef;//定义物体（世界的）            };#endif /* defined(__Flappy__GameLayer__) */

////  GameLayer.cpp//  Flappy////  Created by yuzai on 14-2-12.////#include "GameLayer.h"#define PTM_RATIO 32.0  //设定每32像素为一米GameLayer::GameLayer(void){    }GameLayer::~GameLayer(void){     CC_SAFE_DELETE(world);}bool GameLayer::init(){    if (!CCLayer::init())    {        return false;    }    //屏幕宽高比 首先 适配IPHONE5    CCSize frameSize = CCEGLView::sharedOpenGLView()->getFrameSize();    float scales = (float) frameSize.width/ 288;    CCSize winSize=CCDirector::sharedDirector()->getWinSize();    CCSpriteFrameCache::sharedSpriteFrameCache()->addSpriteFramesWithFile("res/default.plist");    CCSpriteFrame *bg1Frame=CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName("bg_day.png");    bg=CCSprite::create();    bg->setAnchorPoint(ccp(0, 0));    bg->setDisplayFrame(bg1Frame);    bg->setScale(scales);    bg->setPosition(ccp(0,0));    addChild(bg);        //2.陆地        CCSpriteFrame *landFrame=CCSpriteFrameCache::sharedSpriteFrameCache()->spriteFrameByName("land.png");    land1=CCSprite::create();    land1->setAnchorPoint(ccp(0, 0));    land1->setDisplayFrame(landFrame);    land1->setScale(scales);    land1->setPosition(ccp(0, 0));    addChild(land1,1);    land2=CCSprite::create();    land2->setAnchorPoint(ccp(0, 0));    land2->setDisplayFrame(landFrame);    land2->setScale(scales);    land2->setPosition(ccp(frameSize.width, 0));    addChild(land2,1);        //3.添加小鸟    bird=new Bird();    bird->setPosition(winSize.width/2,winSize.height/2);    bird->setScale(scales);    addChild(bird,2);    //4.水管        //5.物理世界    this->initPhysics();    // Define the dynamic body.    //Set up a 1m squared box in the physics world    b2BodyDef bodyDef;    bodyDef.type = b2_dynamicBody;//小鸟是运动的 所有设置为动态刚体    bodyDef.position.Set(bird->getPositionX()/PTM_RATIO,bird->getPositionY()/PTM_RATIO);//转化真实世界坐标  Pix/PTM_RATIO    bodyDef.userData=bird;    bird->m_pBody=world->CreateBody(&bodyDef);        // Define another box shape for our dynamic body.    b2PolygonShape dynamicBox;    dynamicBox.SetAsBox(0.5f,0.5f);//These are mid points for our 1m box        // Define the dynamic body fixture.    b2FixtureDef fixtureDef;    fixtureDef.shape = &dynamicBox;    fixtureDef.density = 1.0f;    fixtureDef.friction = 0.3f;    fixtureDef.restitution=0.8f;    bird->m_pBody->CreateFixture(&fixtureDef);            scheduleUpdate();    return true;}//改变背景void GameLayer::setBackgroud(unsigned int bg){        switch (bg) {        case 1:        {                    }            break;                    default:            break;    }}void GameLayer::update(float time){    //land移动逻辑    CCSize frameSize = CCEGLView::sharedOpenGLView()->getFrameSize();    float dif=4;    land1->setPosition(ccp(land1->getPositionX()-dif,land1->getPositionY()));    land2->setPosition(ccp(land2->getPositionX()-dif,land2->getPositionY()));    if (land2->getPositionX()<0) {        float temp=land2->getPositionX()+frameSize.width;        land1->setPosition(ccp(temp,land2->getPositionY()));    }    if (land1->getPositionX()<0) {        float temp=land1->getPositionX()+frameSize.width;        land2->setPosition(ccp(temp,land1->getPositionY()));    }              float32 timeStep = 1.0f / 60.0f;    int32 velocityIterations = 6;        int32 positionIterations = 2;            world->Step(timeStep, velocityIterations, positionIterations);                b2Vec2 position = bird->m_pBody->GetPosition();                float32 angle = bird->m_pBody->GetAngle();                for (b2Body *body=world->GetBodyList(); body!=NULL; body=body->GetNext()) {            Bird *bir=(Bird*)body->GetUserData();            if (bir!=NULL) {                bir->setPosition(ccp(position.x*PTM_RATIO, position.y*PTM_RATIO));                bir->setRotation(CC_RADIANS_TO_DEGREES(body->GetAngle())*-1);            }        }                printf("%4.2f %4.2f %4.2f\n", position.x, position.y, angle);    }//初始化物理引擎的方法void GameLayer::initPhysics(){            //0.屏幕大小    CCSize winSize=CCDirector::sharedDirector()->getWinSize();    //1.重力向量    b2Vec2 gravity=b2Vec2(0.0f, -10.0f);//模拟真实世界        world = new b2World(gravity);        //2.设置是否持续物理模拟    world->SetAllowSleeping(true);        world->SetContinuousPhysics(true);        //3.设置世界盒子的位置    // Define the ground body. 定义 边缘刚体    groundBodyDef.position.Set(0,0); // bottom-left corner        // Call the body factory which allocates memory for the ground body    // from a pool and creates the ground box shape (also from a pool).    // The body is also added to the world.    //所有的b2Body都由b2World示例创建    b2Body* groundBody = world->CreateBody(&groundBodyDef);        // Define the ground box shape.//创建边缘刚体    b2PolygonShape groundBox;        b2FixtureDef boxShapeBox;    boxShapeBox.shape=&groundBox;    //屏幕宽高比 首先 适配IPHONE5    CCSize frameSize = CCEGLView::sharedOpenGLView()->getFrameSize();    float scales = (float) frameSize.width/ 288;            //定义物体边界    // bottom   112*scales 设置的是地面的高度    groundBox.SetAsBox(winSize.width/PTM_RATIO,112*scales/PTM_RATIO, b2Vec2(0, 0), 0);    groundBody->CreateFixture(&groundBox,0);        // top    groundBox.SetAsBox(winSize.width/PTM_RATIO, 0, b2Vec2(0, winSize.height/PTM_RATIO), 0);    groundBody->CreateFixture(&groundBox,0);        // left    groundBox.SetAsBox(0, winSize.height/PTM_RATIO, b2Vec2(0, 0), 0);    groundBody->CreateFixture(&groundBox,0);        // right    groundBox.SetAsBox(0, winSize.height/PTM_RATIO, b2Vec2(winSize.width/PTM_RATIO, 0), 0);    groundBody->CreateFixture(&groundBox,0);     }

注：代码迭代随时有变动