获取游戏设计的分辨率与真实设备的比例,并根据值来剪切显示区域

/*************************************
*函数名称：visit
*函数功能：获取游戏设计的分辨率与真实设备的比例,并根据值来剪切显示区域
*函数参数：void 
*函数返回值：void 
*笔记：
1.glEnable用于开启opengl相应的功能
2.GL_SCISSOR_TEST根据函数glScissor设置，启用图形剪切
3.glScissor
http://blog.csdn.net/augusdi/article/details/7282214
*************************************/
void CXSroll::visit()
{
    glEnable(GL_SCISSOR_TEST);

    CCRect tPrtScr(0, 0, 0, 0);
    if (this->getParent())
    {
        tPrtScr.origin = this->getParent()->convertToWorldSpace(this->getPosition());
    }
    else
    {
        tPrtScr.origin = this->getPosition();
    }

    tPrtScr.size.width = this->getContentSize().width;
    tPrtScr.size.height = this->getContentSize().height;

    //获取游戏设计的分辨率与真实设备的比例
    tPrtScr.origin.x /= CCDirector::sharedDirector()->getWinSize().width / CCDirector::sharedDirector()->getOpenGLView()->getFrameSize().width;
    tPrtScr.origin.y /= CCDirector::sharedDirector()->getWinSize().height / CCDirector::sharedDirector()->getOpenGLView()->getFrameSize().height;
    tPrtScr.size.width /= CCDirector::sharedDirector()->getWinSize().width / CCDirector::sharedDirector()->getOpenGLView()->getFrameSize().width;
    tPrtScr.size.height /= CCDirector::sharedDirector()->getWinSize().height / CCDirector::sharedDirector()->getOpenGLView()->getFrameSize().height;

    glScissor( tPrtScr.origin.x, tPrtScr.origin.y, tPrtScr.size.width, tPrtScr.size.height);

    CXWindow::visit();
    glDisable(GL_SCISSOR_TEST);
}