//cocos2dx获取图片某一点的颜色
Color4B getColor(float posx,float posy)
{
    Image * _colorImage = new Image();
    _colorImage->initWithImageFile("original/yi001.png");
    unsigned char *m_pData = _colorImage->getData();

    int x =(int)posx;
    int y =(int)posy;
    Color4B c = { 0,0 };
   //转换GL坐标
    int ix = x - 1;
    int iy = _colorImage->getHeight()-y + 1;
    
    m_pData += (iy*_colorImage->getWidth() + ix) * 4;
    c.r = *(m_pData++);
    c.g = *(m_pData++);
    c.b = *(m_pData++);
    c.a = *(m_pData++);
    
    CCLOG("color r:%d g:%d b:%d a:%d ",c.r,c.g,c.b,c.a)
    return c;
}