cocos2d-x游戏摇杆的实现方法

虚拟摇杆类起名为：HRocker 

下面是 HRocker.h 文件：

[cpp] view plaincopy

#include <iostream>  

#include "cocos2d.h"  

using namespace cocos2d;  

  

//枚举型：用于标识摇杆与摇杆的背景  

typedef enum{  

      

    tag_rocker,  

    tag_rockerBG,  

      

}tagForHRocker;  

  

class HRocker : public CCLayer  

{  

public:  

    //创建摇杆，摇杆图片，摇杆背景图片，起始坐标  

    static HRocker* createHRocker(const char* rockerImageName, const char* rockerBGImageName, CCPoint position);  

      

    //启动摇杆  

    void startRocker(bool _isStopOther);  

  

    //停止摇杆  

    void stopRocker();  

  

private:  

      

    void rockerInit(const char* rockerImageName, const char* rockerBGImageName, CCPoint position);  

  

    //得到半径为r的圆周运动上一个角度应对应的x,y坐标  

    CCPoint getAnglePosition(float r, float angle);  

      

    //是否可操作摇杆  

    bool isCanMove;  

  

    //得到摇杆与用户触屏点的角度  

    float getRad(CCPoint pos1, CCPoint pos2);  

  

    //摇杆背景的坐标  

    CCPoint rockerBGPosition;  

  

    //摇杆背景的半径  

    float rockerBGR;  

  

    //触屏事件  

    virtual bool ccTouchBegan(CCTouch* touch, CCEvent* event);  

    virtual void ccTouchMoved(CCTouch* touch, CCEvent* event);  

    virtual void ccTouchEnded(CCTouch* touch, CCEvent* event);  

      

    CREATE_FUNC(HRocker);  

};  

  

#endif  



HRocker.cpp文件

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#include "HRocker.h"  

  

HRocker* HRocker::createHRocker(const char *rockerImageName, const char *rockerBGImageName, cocos2d::CCPoint position)  

{  

    HRocker* layer = HRocker::create();  

    if(layer)  

    {  

        layer->rockerInit(rockerImageName, rockerBGImageName, position);  

        return layer;  

    }  

      

    CC_SAFE_DELETE(layer);  

    return NULL;  

      

}  

  

void HRocker::rockerInit(const char *rockerImageName, const char *rockerBGImageName, cocos2d::CCPoint position)  

{  

    //添加摇杆背景图  

    CCSprite* spRockerBG = CCSprite::create(rockerBGImageName);  

    spRockerBG->setVisible(false);  

    spRockerBG->setPosition(position);  

    addChild(spRockerBG, 0, tag_rockerBG);  

      

    //添加摇杆上方那个可移动的图  

    CCSprite* spRocker = CCSprite::create(rockerImageName);  

    spRocker->setVisible(false);  

    spRocker->setPosition(position);  

    addChild(spRocker, 1, tag_rocker);  

      

    //摇杆背景图坐标  

    rockerBGPosition = position;  

      

    //摇杆背景图半径  

    rockerBGR = spRockerBG->getContentSize().width*0.5;  

}  

  

//启动摇杆  

void HRocker::startRocker(bool _isStopOther)  

{  

    //精灵设置可见，设置监听  

    CCSprite* rocker = (CCSprite*) getChildByTag(tag_rocker);  

    rocker->setVisible(true);  

      

    CCSprite* rockerBG = (CCSprite*) getChildByTag(tag_rockerBG);  

    rockerBG->setVisible(true);  

      

    CCDirector::sharedDirector()->getTouchDispatcher()->addTargetedDelegate(this, -1, _isStopOther);  

}  

  

//停止摇杆  

void HRocker::stopRocker()  

{  

    //精灵设置不可见，取消监听  

    CCSprite* rocker = (CCSprite*)getChildByTag(tag_rocker);  

    rocker->setVisible(false);  

      

    CCSprite* rockerBG = (CCSprite*)getChildByTag(tag_rockerBG);  

    rockerBG->setVisible(false);  

      

    CCDirector::sharedDirector()->getTouchDispatcher()->removeDelegate(this);  

}  

  

//得到两坐标的角度值  

float HRocker::getRad(cocos2d::CCPoint pos1, cocos2d::CCPoint pos2)  

{  

    //得到两点的坐标x,y坐标值  

    float px1 = pos1.x;  

    float py1 = pos1.y;  

    float px2 = pos2.x;  

    float py2 = pos2.y;  

      

    //求出两边长度  

    float x = px2 - px1;  

    float y = py1 - py2;  

      

    //开方   与  几次方 公式  

    float xie = sqrt(pow(x, 2) + pow(y , 2));  

    float cos = x/xie;  

      

    //反余弦定理，知道两边长求角度：cos = 邻边/斜边  

    float rad = acos(cos);  

      

    //当触屏Y坐标 <摇杆的Y坐标时，取反值  

    if(py1 > py2)  

    {  

        rad = -rad;  

    }  

      

    return rad;  

      

}  

   

//得到与角度对应的半径为r的圆上一坐标点  

CCPoint HRocker::getAnglePosition(float r, float angle)  

{  

    return ccp(r*cos(angle), r*sin(angle));  

}  

  

  

bool HRocker::ccTouchBegan(cocos2d::CCTouch *touch, cocos2d::CCEvent *event)  

{  

    CCSprite* sp = (CCSprite*)getChildByTag(tag_rocker);  

      

    //得到触屏点坐标  

    CCPoint point = touch->getLocation();  

      

    //判断是否点击到sp这个精灵：boundingBox()精灵大小之内的所有坐标  

    if(sp->boundingBox().containsPoint(point))  

       {  

           isCanMove = true;  

       }  

  

      

    return true;  

}  

  

void HRocker::ccTouchMoved(cocos2d::CCTouch *touch, cocos2d::CCEvent *event)  

{  

    if(!isCanMove)  

    {  

        return;  

    }  

      

    CCSprite* sp = (CCSprite*)getChildByTag(tag_rocker);  

      

    CCPoint point = touch->getLocation();  

      

    //判断两个圆心的距离是否大于摇杆背景的半径  

    if(sqrt(pow(point.x - rockerBGPosition.x, 2) + pow(point.y - rockerBGPosition.y, 2)) >= rockerBGR)  

    {  

        //得到触点与摇杆背景圆心形成的角度  

        float angle = getRad(rockerBGPosition, point);  

          

        //确保小圆运动范围在背景圆内  

        sp->setPosition(ccpAdd(getAnglePosition(rockerBGR, angle), ccp(rockerBGPosition.x, rockerBGPosition.y)));  

          

    }  

    else {  

        //触点在背景圆内则跟随触点运动  

        sp->setPosition(point);  

    }  

    

}  

  

void HRocker::ccTouchEnded(cocos2d::CCTouch *touch, cocos2d::CCEvent *event)  

{  

    if(!isCanMove)  

    {  

        return;  

    }  

      

    CCSprite* rocker = (CCSprite*)getChildByTag(tag_rocker);  

      

    CCSprite* rockerBG = (CCSprite*)getChildByTag(tag_rockerBG);  

      

    rocker->stopAllActions();  

      

    rocker->runAction(CCMoveTo::create(0.08, rockerBG->getPosition()));  

     

    isCanMove = false;  

}  

示例项目代码：

[cpp] view plaincopy

HRocker* rocker = HRocker::createHRocker("rocker.png", "rockerBG.png", ccp(240, 160));  

    addChild(rocker);  

    rocker->startRocker(true);