box2d创建简单的入门示例：
实现功能：
1.实现刚体的创建
2.能够创建自定义的精灵刚体
3.精灵之间的相互碰撞
工具的使用：
要创建一个 自定义的刚体精灵(不规则形状)，就要用到一个工具PhysicalEditor，下载地址：http://yun.baidu.com/share/link?shareid=1782518146&uk=1209145999&third=0
我们将图片添加到工程中，但要确保图片精灵周围是透明的才行，然后选择Exporter->Box2D generic(PLIST)，最后直接publish就可以了，然后将plist文件和原图片资源一起导入到工程的Resource下。
操作步骤：
1.导入外部的GLES-Render类
2.主场景类:
class QueryCallback : public b2QueryCallback
{
public:
b2Vec2 m_point;
b2Fixture * m_fixture;
QueryCallback(const b2Vec2 & point)
{
m_point = point;
m_fixture = NULL;
}
bool ReportFixture(b2Fixture * fixture)
{
b2Body * body = fixture->GetBody();
if (body->GetType() == b2_dynamicBody)
{
bool inside = fixture->TestPoint(m_point);
if(inside)
{
m_fixture = fixture;
return false;
}
}
return true;
}
};
class SecondScene : public CCLayer
{
public:
~SecondScene();
SecondScene();
static CCScene* scene();
void initPhysics();
void addNewSpriteAtPosition(CCPoint p);
virtual void draw();
void update(float dt);
void ccTouchesBegan(CCSet *pTouches, CCEvent *pEvent);
void ccTouchesMoved(CCSet *pTouches, CCEvent *pEvent);
void ccTouchesEnded(CCSet* touches, CCEvent* event);
bool MouseDown(const b2Vec2 & p);
void MouseMove(const b2Vec2 & p);
void MouseUp();
private:
GLESDebugDraw * m_debugDraw;
b2World * world;
CCTexture2D * m_pSpriteTexture;
b2MouseJoint * m_mouseJoint; //鼠标关节节点
b2Body * m_groundBody;
};
#endif /* defined(__box2dDemo__SecondHelloScene__) */
cpp
#include "SecondHelloScene.h"
#include "SimpleAudioEngine.h"
#include "GLES-Render.h"
#include "GB2ShapeCache-x.h"
#include "ContactListener.h" //碰撞检测
using namespace cocos2d;
using namespace CocosDenshion;
#define PTM_RATIO 32
enum {
kTagParentNode = 1,
};
//PhysicsSprite::PhysicsSprite()
//: m_pBody(NULL)
//{
//
//}
//
//void PhysicsSprite::setPhysicsBody(b2Body * body)
//{
// m_pBody = body;
//}
//
//bool PhysicsSprite::isDirty(void)
//{
// return true;
//}
//
//// returns the transform matrix according the Chipmunk Body values
//CCAffineTransform PhysicsSprite::nodeToParentTransform(void)
//{
// b2Vec2 pos = m_pBody->GetPosition();
//
// float x = pos.x * PTM_RATIO;
// float y = pos.y * PTM_RATIO;
//
// if ( isIgnoreAnchorPointForPosition() ) {
// x += m_obAnchorPointInPoints.x;
// y += m_obAnchorPointInPoints.y;
// }
//
// // Make matrix
// float radians = m_pBody->GetAngle();
// float c = cosf(radians);
// float s = sinf(radians);
//
// if( ! m_obAnchorPointInPoints.equals(CCPointZero) ){
// x += c*-m_obAnchorPointInPoints.x + -s*-m_obAnchorPointInPoints.y;
// y += s*-m_obAnchorPointInPoints.x + c*-m_obAnchorPointInPoints.y;
// }
//
// // Rot, Translate Matrix
// m_sTransform = CCAffineTransformMake( c, s,
// -s, c,
// x, y );
//
// return m_sTransform;
//}
SecondScene::SecondScene()
{
setTouchEnabled( true );
setAccelerometerEnabled( true );
CCSize s = CCDirector::sharedDirector()->getWinSize();
this->initPhysics();
addNewSpriteAtPosition(ccp(s.width / 2, s.height / 2));
// CCSpriteBatchNode *parent = CCSpriteBatchNode::create("blocks.png", 100);
// m_pSpriteTexture = parent->getTexture();
//
// addChild(parent, 0, kTagParentNode);
//
//
// addNewSpriteAtPosition(ccp(s.width/2, s.height/2));
//
// CCLabelTTF *label = CCLabelTTF::create("Tap screen", "Marker Felt", 32);
// addChild(label, 0);
// label->setColor(ccc3(0,0,255));
// label->setPosition(ccp( s.width/2, s.height-50));
scheduleUpdate();
}
SecondScene::~SecondScene()
{
delete world;
world = NULL;
//delete m_debugDraw;
}
void SecondScene::initPhysics()
{
//添加自定义的精灵
GB2ShapeCache::sharedGB2ShapeCache()->addShapesWithFile("zhizhu.plist");
CCSize s = CCDirector::sharedDirector()->getWinSize();
b2Vec2 gravity;
gravity.Set(0.0f, -10.0f);
world = new b2World(gravity);
b2BodyDef bodydef;
m_groundBody = world->CreateBody(&bodydef);
world->SetAllowSleeping(true);
world->SetContinuousPhysics(false);//隧道效应，穿透，true表示不能穿透
//接触监听，碰撞检测
b2ContactListener *contactListener = new ContactListener();
world->SetContactListener(contactListener);
//静态刚体
m_debugDraw = new GLESDebugDraw( PTM_RATIO );
world->SetDebugDraw(m_debugDraw);
uint32 flags = 0;
flags += b2Draw::e_shapeBit;
// flags += b2Draw::e_jointBit;
// flags += b2Draw::e_aabbBit;
// flags += b2Draw::e_pairBit;
// flags += b2Draw::e_centerOfMassBit;
m_debugDraw->SetFlags(flags);
// Define the ground body.
b2BodyDef groundBodyDef;
groundBodyDef.position.Set(5, 1);
b2Body* groundBody = world->CreateBody(&groundBodyDef);
// Define the ground box shape.
b2EdgeShape groundBox;
// bottom
groundBox.Set(b2Vec2(0,0), b2Vec2(s.width/PTM_RATIO,0));
groundBody->CreateFixture(&groundBox,0);
// top
groundBox.Set(b2Vec2(0,s.height/PTM_RATIO), b2Vec2(s.width/PTM_RATIO,s.height/PTM_RATIO));
groundBody->CreateFixture(&groundBox,0);
// left
groundBox.Set(b2Vec2(0,s.height/PTM_RATIO), b2Vec2(0,0));
groundBody->CreateFixture(&groundBox,0);
// right
groundBox.Set(b2Vec2(s.width/PTM_RATIO,s.height/PTM_RATIO), b2Vec2(s.width/PTM_RATIO,0));
groundBody->CreateFixture(&groundBox,0);
}
void SecondScene::draw()
{
CCLayer::draw();
ccGLEnableVertexAttribs( kCCVertexAttribFlag_Position );
kmGLPushMatrix();
world->DrawDebugData();
kmGLPopMatrix();
}
void SecondScene::addNewSpriteAtPosition(CCPoint p)
{
string name = "alien";
CCSprite * sprite = CCSprite::create((name + ".png").c_str());
sprite->setPosition(p);
this->addChild(sprite);
// CCSprite * sp = CCSprite::create("Icon.png");
// sp->setPosition(CCPointMake(100, 100));
// this->addChild(sp);
b2BodyDef bodyDef;
bodyDef.type = b2_dynamicBody;
bodyDef.position.Set(p.x/PTM_RATIO, p.y/PTM_RATIO);
bodyDef.userData = sprite;
b2Body *body = world->CreateBody(&bodyDef);
// Define another box shape for our dynamic body.
//通过vertexHelper工具生成多边形
b2PolygonShape dynamicBox;
// b2Vec2 verts[] = {
// b2Vec2(-12.8f / PTM_RATIO, 50.9f / PTM_RATIO),
// b2Vec2(-48.8f / PTM_RATIO, 2.3f / PTM_RATIO),
// b2Vec2(-30.7f / PTM_RATIO, -37.9f / PTM_RATIO),
// b2Vec2(28.8f / PTM_RATIO, -18.9f / PTM_RATIO),
// b2Vec2(30.8f / PTM_RATIO, 16.9f / PTM_RATIO),
// b2Vec2(20.8f / PTM_RATIO, 44.9f / PTM_RATIO)
// };
// dynamicBox.Set(verts, 6);
//dynamicBox.SetAsBox(.5f, .5f);//These are mid points for our 1m box
// b2FixtureDef fixtureDef;
// fixtureDef.shape = &dynamicBox;
// fixtureDef.density = 1.0f;//密度
// fixtureDef.friction = 0.3f;//摩擦
// fixtureDef.restitution = 0.5f;//恢复，也可看成弹性系数
//
//
// body->CreateFixture(&fixtureDef);
GB2ShapeCache * sc = GB2ShapeCache::sharedGB2ShapeCache();
sc->addFixturesToBody(body, name);
sprite->setAnchorPoint(sc->anchorPointForShape(name));
}
void SecondScene::update(float dt)
{
int velocityIterations = 8;
int positionIterations = 1;
world->Step(dt, velocityIterations, positionIterations);
for (b2Body* b = world->GetBodyList(); b; b = b->GetNext())
{
if (b->GetUserData() != NULL) {
//Synchronize the AtlasSprites position and rotation with the corresponding body
CCSprite* myActor = (CCSprite*)b->GetUserData();
myActor->setPosition( CCPointMake( b->GetPosition().x * PTM_RATIO, b->GetPosition().y * PTM_RATIO) );
myActor->setRotation( -1 * CC_RADIANS_TO_DEGREES(b->GetAngle()) );//CC_RADIANS_TO_DEGREES弧度转角度
}
}
}
CCScene* SecondScene::scene()
{
// 'scene' is an autorelease object
CCScene *scene = CCScene::create();
// add layer as a child to scene
CCLayer* layer = new SecondScene();
scene->addChild(layer);
layer->release();
return scene;
}
void SecondScene::ccTouchesBegan(cocos2d::CCSet *pTouches, cocos2d::CCEvent *pEvent)
{
CCSetIterator it;
CCTouch * touch;
for(it = pTouches->begin(); it != pTouches->end(); it++)
{
touch = (CCTouch *)(*it);
if(!touch)
break;
CCPoint location = touch->getLocation();
if(!this->MouseDown(b2Vec2(location.x / PTM_RATIO, location.y / PTM_RATIO)))
{
this->addNewSpriteAtPosition(location);
}
}
}
void SecondScene::ccTouchesMoved(cocos2d::CCSet *pTouches, cocos2d::CCEvent *pEvent)
{
CCSetIterator it;
CCTouch * touch;
for(it = pTouches->begin(); it != pTouches->end(); it++)
{
touch = (CCTouch *)(*it);
if(!touch)
break;
CCPoint location = touch->getLocation();
this->MouseMove(b2Vec2(location.x / PTM_RATIO,location.y / PTM_RATIO));
}
}
void SecondScene::ccTouchesEnded(CCSet* touches, CCEvent* event)
{
CCSetIterator it;
CCTouch* touch;
for( it = touches->begin(); it != touches->end(); it++)
{
touch = (CCTouch*)(*it);
if(!touch)
break;
CCPoint location = touch->getLocationInView();
location = CCDirector::sharedDirector()->convertToGL(location);
addNewSpriteAtPosition( location );
}
this->MouseUp();
}
bool SecondScene::MouseDown(const b2Vec2 &p)
{
if(m_mouseJoint != NULL)
{
return false;
}
b2AABB aabb;
b2Vec2 d;
d.Set(0.001f, 0.001f);
aabb.lowerBound = p - d;
aabb.upperBound = p + d;
QueryCallback callback(p);
world->QueryAABB(&callback, aabb);
if (callback.m_fixture)
{
b2Body * body = callback.m_fixture->GetBody();
b2MouseJointDef md;
md.bodyA = m_groundBody; //m_groundBody需要在上面init方法里定义一下
md.bodyB = body;
md.target = p;
md.maxForce = 1000.0f * body->GetMass();
m_mouseJoint = (b2MouseJoint *)world->CreateJoint(&md);
body->SetAwake(true);
return true;
}
return true;
}
void SecondScene::MouseMove(const b2Vec2 &p)
{
if(m_mouseJoint)
{
m_mouseJoint->SetTarget(p);
}
}
void SecondScene::MouseUp()
{
if(m_mouseJoint)
{
world->DestroyJoint(m_mouseJoint);
m_mouseJoint = NULL;
}
}
3.碰撞检测类（ContactListener）
#ifndef __box2dDemo__ContactListener__
#define __box2dDemo__ContactListener__
//碰撞检测
#include <iostream>
#include "cocos2d.h"
#include "Box2D.h"
using namespace cocos2d;
class ContactListener : public b2ContactListener
{
void BeginContact(b2Contact * contact);
void EndContact(b2Contact *contact);
};
#endif /* defined(__box2dDemo__ContactListener__) */
cpp
#include "ContactListener.h"
void ContactListener::BeginContact(b2Contact *contact)
{
b2Body *bodyA = contact->GetFixtureA()->GetBody();
b2Body *bodyB = contact->GetFixtureB()->GetBody();
CCSprite *spriteA = (CCSprite *)bodyA->GetUserData();
CCSprite *spriteB = (CCSprite *)bodyB->GetUserData();
if (spriteA != NULL && spriteB != NULL) {
spriteA->setColor(ccMAGENTA);
spriteB->setColor(ccMAGENTA);
}
}
void ContactListener::EndContact(b2Contact *contact)
{
b2Body *bodyA = contact->GetFixtureA()->GetBody();
b2Body *bodyB = contact->GetFixtureB()->GetBody();
CCSprite *spriteA = (CCSprite *)bodyA->GetUserData();
CCSprite *spriteB = (CCSprite *)bodyB->GetUserData();
if (spriteA != NULL && spriteB != NULL) {
spriteA->setColor(ccWHITE);
spriteB->setColor(ccWHITE);
}
}
运行效果：
cocos2d-x游戏开发QQ交流群：280818155
备注：加入者必须修改：地区-昵称，很少有动态的将定期清理
时间： 2024-08-03 20:36:42