cocos2d-x 之虚拟摇杆实现

其实要实现这个功能并不难，直接把以前在java上实现的逻辑照搬过来就是了。。。直接看下文吧：

首先，把摇杆当成一个独立的类，具有自身的一系列功能，代码中只列举一部分最常用的功能点：

Joystick.h：

#include "cocos2d.h"

using namespace cocos2d;

class Joystick :
	public CCLayer
{
public:
	Joystick(void);
	~Joystick(void);
public:
	CCPoint centerPoint;	// 摇杆中心
	CCPoint currentPoint;	// 摇杆当前位置
	bool active;			// 是否激活摇杆
	float radius;			// 摇杆半径
	CCSprite *jsSprite;		// 摇杆实例

	//************************************
	// Method:    Active
	// FullName:  Joystick::Active
	// Access:    public 
	// Returns:   void
	// Qualifier: 设置摇杆功能可用
	//************************************
	void Active();
	//************************************
	// Method:    Inactive
	// FullName:  Joystick::Inactive
	// Access:    public 
	// Returns:   void
	// Qualifier: 设置摇杆功能不可用
	//************************************
	void Inactive();
	//************************************
	// Method:    getDirection
	// FullName:  Joystick::getDirection
	// Access:    public 
	// Returns:   cocos2d::CCPoint
	// Qualifier: 获取摇杆方向，这里返回的是单位向量
	//************************************
	CCPoint getDirection();
	//************************************
	// Method:    getVelocity
	// FullName:  Joystick::getVelocity
	// Access:    public 
	// Returns:   float
	// Qualifier: 获取摇杆的力度
	//************************************
	float getVelocity();
	//************************************
	// Method:    updatePos
	// FullName:  Joystick::updatePos
	// Access:    public 
	// Returns:   void
	// Qualifier: 刷新函数，交给日程管理器
	// Parameter: ccTime dt
	//************************************
	void updatePos(ccTime dt);

	//************************************
	// Method:    JoystickWithCenter
	// FullName:  Joystick::JoystickWithCenter
	// Access:    public static 
	// Returns:   Joystick*
	// Qualifier: 初始化摇杆
	// Parameter: CCPoint aPoint 摇杆中心
	// Parameter: float aRadius 摇杆半径
	// Parameter: CCSprite * aJsSprite 摇杆控制点
	// Parameter: CCSprite * aJsBg 摇杆背景
	//************************************
	static Joystick* JoystickWithCenter(CCPoint aPoint, float aRadius, CCSprite* aJsSprite, CCSprite* aJsBg);
	Joystick* initWithCenter(CCPoint aPoint, float aRadius, CCSprite* aJsSprite, CCSprite* aJsBg);

	// 以下是复写Touch响应函数
	virtual bool ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent);
	virtual void ccTouchMoved(CCTouch *pTouch, CCEvent *pEvent);
	virtual void ccTouchEnded(CCTouch *pTouch, CCEvent *pEvent);

	LAYER_NODE_FUNC(Joystick);
};

Joystick.cpp

#include "Joystick.h"

Joystick::Joystick(void)
{
}

Joystick::~Joystick(void)
{
}

void Joystick::updatePos(ccTime dt)
{
	jsSprite->setPosition(ccpAdd(jsSprite->getPosition(), ccpMult(ccpSub(currentPoint, jsSprite->getPosition()), 0.5)));
}

void Joystick::Active()
{
	if(!active)
	{
		active = true;
		schedule(schedule_selector(Joystick::updatePos));	// 添加刷新函数
		CCTouchDispatcher::sharedDispatcher()->addTargetedDelegate(this, 0, false);	// 添加触摸委托
	}
}

void Joystick::Inactive()
{
	if(active)
	{
		active = false;
		this->unschedule(schedule_selector(Joystick::updatePos));	// 删除刷新函数
		CCTouchDispatcher::sharedDispatcher()->removeDelegate(this);	// 删除委托
	}
}

bool Joystick::ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent)
{
	if(!active)
		return false;

	CCPoint touchPoint = pTouch->locationInView(pTouch->view());
	touchPoint = CCDirector::sharedDirector()->convertToGL(touchPoint);
	if(ccpDistance(touchPoint, centerPoint) > radius)
		return false;

	currentPoint = touchPoint;
	return true;
}

void Joystick::ccTouchMoved(CCTouch *pTouch, CCEvent *pEvent)
{
	CCPoint touchPoint = pTouch->locationInView(pTouch->view());
	touchPoint = CCDirector::sharedDirector()->convertToGL(touchPoint);
	if(ccpDistance(touchPoint, centerPoint) > radius)
	{
		currentPoint = ccpAdd(centerPoint, ccpMult(ccpNormalize(ccpSub(touchPoint, centerPoint)), radius));
	}
	else
	{
		currentPoint = touchPoint;
	}
}

void Joystick::ccTouchEnded(CCTouch *pTouch, CCEvent *pEvent)
{
	currentPoint = centerPoint;
}

CCPoint Joystick::getDirection()
{
	return ccpNormalize(ccpSub(centerPoint, currentPoint));  
}  

float Joystick::getVelocity()  
{  
	return ccpDistance(centerPoint, currentPoint);  
}  

Joystick* Joystick:: JoystickWithCenter(CCPoint aPoint, float aRadius, CCSprite* aJsSprite, CCSprite* aJsBg)
{  
	Joystick *jstick=Joystick::node();  
	jstick->initWithCenter(aPoint,aRadius,aJsSprite,aJsBg);  

	return jstick;  
}  

Joystick* Joystick::initWithCenter(CCPoint aPoint, float aRadius, CCSprite* aJsSprite, CCSprite* aJsBg)
{  
	active = false;  
	radius = aRadius;  
	centerPoint = aPoint;  
	currentPoint = centerPoint;  
	jsSprite = aJsSprite;  
	jsSprite->setPosition(centerPoint);  
	aJsBg->setPosition(centerPoint);  
	this->addChild(jsSprite);  
	this->addChild(aJsBg);  

	return this;  
}

完成了摇杆类后，直接在HelloWorld中测试效果吧，在init函数中加上下面的代码即可：

		CCSprite *testPointL = CCSprite::spriteWithFile("point.png");
		CCSprite *testBGL = CCSprite::spriteWithFile("joystickbg.png");
		Joystick *testJSL = Joystick::JoystickWithCenter(ccp(80.0f, 80.0f), 60.0f, testPointL, testBGL);
		this->addChild(testJSL);
		testJSL->Active();

看效果图：

资源文件：

Point.png     

joystickbg.png