cocos2d-x 触摸偏移

转自：http://www.cnblogs.com/fjut/archive/2012/04/28/2475693.html

//ccTouchBegan必须实现，否则会报错
bool PicScan::ccTouchBegan(CCTouch* pTouch, CCEvent* event)
{
    return true;
}

void PicScan::ccTouchMoved(CCTouch *touch, CCEvent *event)
{
    //获得触摸点初始坐标
    CCPoint beginLoc = touch->locationInView(touch->view());
    beginLoc = CCDirector::sharedDirector()->convertToGL(beginLoc);

    //判断鼠标拖拉的区域是否在图片上
    if(CCRect::CCRectContainsPoint(lpSprite->boundingBox(), this->getParent()->convertTouchToNodeSpace(touch)) == true)
    {
        //固定图片在某个区域
        if(lpSprite->getPosition().y > s.height/+)
        {
            lpSprite->setPosition(ccp(lpSprite->getPosition().x, s.height/+));
        }

        if(lpSprite->getPosition().y < s.height/-)
        {
            lpSprite->setPosition(ccp(lpSprite->getPosition().x, s.height/-));
        }
        printf(" ccTouchMoved --------------\n");

        //获得前一个触摸点坐标
        CCPoint endLoc = touch->previousLocationInView(touch->view());
        endLoc = CCDirector::sharedDirector()->convertToGL(endLoc);

        //计算偏移量
        CCPoint offSet = ccpSub(beginLoc, endLoc);
        Drag(offSet);
    }

}

void PicScan::Drag(CCPoint offSet)
{
    //计算精灵坐标加上移动偏移量、并设置精灵位置
    CCPoint pos = ccpAdd(lpSprite->getPosition(), offSet);
    lpSprite->setPosition(pos);
    //.....<br>}