cocos2d-x游戏摇杆的实现方法

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虚拟摇杆类起名为：HRocker 

下面是 HRocker.h 文件：

#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

#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：

HRocker* rocker = HRocker::createHRocker("rocker.png", "rockerBG.png", ccp(240, 160));    addChild(rocker);    rocker->startRocker(true);