实例介绍Cocos2d-x中Box2D物理引擎：碰撞检测

标签：cocos2d-x   游戏   cocos2d   

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


USING_NS_CC;


class ContactListener : public b2ContactListener
{
private:
	//两个物体开始接触时会响应
	virtual void BeginContact(b2Contact* contact);


	//持续接触时响应
	virtual void PreSolve(b2Contact* contact, const b2Manifold* oldManifold);
	//持续接触时响应，调用完preSolve后调用
	virtual void PostSolve(b2Contact* contact, const b2ContactImpulse* impulse);
	
	//分离时响应
	virtual void EndContact(b2Contact* contact);
};
在头文件中需要引入cocos2d.h和Box2D/Box2D.h头文件，否则会有编译错误。ContactListener采用共有继承b2ContactListener。
ContactListener.cpp文件代码如下：
#include "ContactListener.h"


void ContactListener::BeginContact(b2Contact* contact)							①
{
	log("BeginContact");


	b2Body* bodyA = contact->GetFixtureA()->GetBody();							②
	b2Body* bodyB = contact->GetFixtureB()->GetBody();							③
	auto spriteA = (Sprite*)bodyA->GetUserData();								④
	auto spriteB = (Sprite*)bodyB->GetUserData();								⑤
	
	if (spriteA != nullptr && spriteB != nullptr)									⑥
	{
        spriteA->setColor(Color3B::YELLOW);
        spriteB->setColor(Color3B::YELLOW);
	}
}


void ContactListener::EndContact(b2Contact* contact)							⑦
{
	log("EndContact");


	b2Body* bodyA = contact->GetFixtureA()->GetBody();
	b2Body* bodyB = contact->GetFixtureB()->GetBody();
	auto spriteA = (Sprite*)bodyA->GetUserData();
	auto spriteB = (Sprite*)bodyB->GetUserData();
	
	if (spriteA != nullptr && spriteB != nullptr)
	{
        spriteA->setColor(Color3B::WHITE);
        spriteB->setColor(Color3B::WHITE);
	}
}


void ContactListener::PreSolve(b2Contact* contact, const b2Manifold* oldManifold)			⑧
{
	log("PreSolve");
}


void ContactListener::PostSolve(b2Contact* contact, const b2ContactImpulse* impulse)		⑨
{
	log("PostSolve");
}

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__


#include "cocos2d.h"
#include "Box2D/Box2D.h"
#include "ContactListener.h"												①


#define PTM_RATIO 32


class HelloWorld : public cocos2d::Layer
{
	b2World* world;
	ContactListener* contactListener;											②


public:


	~HelloWorld();
    
    static cocos2d::Scene* createScene();
    virtual bool init();  


	virtual void update(float dt);
	virtual bool onTouchBegan(cocos2d::Touch* touch, cocos2d::Event* event);
    CREATE_FUNC(HelloWorld);
	
	void initPhysics();
	void addNewSpriteAtPosition(cocos2d::Vec2 p);


};


#endif // __HELLOWORLD_SCENE_H__

void HelloWorld::initPhysics()
{
	… …
   contactListener = new ContactListener();
	world->SetContactListener(contactListener);
	… …
}

使用CC_SAFE_DELETE(contactListener)安全释放contactListener成员变量的内存。

欢迎关注智捷iOS课堂微信公共平台

实例介绍Cocos2d-x中Box2D物理引擎：碰撞检测

标签：cocos2d-x   游戏   cocos2d   

原文地址：http://blog.csdn.net/tonny_guan/article/details/39936067