cocos2d-x之box2d使用笔记

#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__

#include "HelloWorldScene.h"
#include "VisibleRect.h"
USING_NS_CC;
#define PTM_RATIO 32.0f
enum{
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);

}