OGRE 鼠标拾取模型并显示

之前想做个编辑器那样的，需要拾取功能，于是研究了下。

拾取模型用射线相交的方法。通过摄像机的getCameraToViewportRay把鼠标坐标转换成RAY，然后通过 RaySceneQueryResult来进行场景查询，可以得到场景上所有与该射线相交的对象。然后取1个距离最近的相交对象作为拾取的对象，这样拾取 的对象就获得了。为了显示该对象被拾取，获取下该MESH的BOUNDINGBOX，我偷懒用了Ogitor的Box绘制类，直接把获取到的 BOUNDINGBOX设置上去，再在对象的父节点下创建个子节点，attachObject设置好的BOX，设置节点显示，然后就OK了。

code:

Ogre::MovableObject* WFreeRotateManipulator::_VaneBoxRayQuery(int x,int y,float view_left,float view_top,float view_width,float view_height)
{
    float rect_left = mWindowWidth*view_left;
    float rect_top = mWindowHeight*view_top;
    float rect_right = rect_left+mWindowWidth*view_width;
    float rect_bottom = rect_top+mWindowHeight*view_height;

    float rect_width = mWindowWidth * view_width;
    float rect_height = mWindowHeight * view_height;

    if(x<rect_left || x>rect_right || y<rect_top || y>rect_bottom) return NULL;

    float sx = float(x-rect_left)/rect_width;
    float sy = float(y-rect_top)/rect_height;

    if(!mRaySceneQuery || !mVaneBoxCamera) return NULL;

    Ogre::Ray mouseRay = mVaneBoxCamera->getCameraToViewportRay(sx, sy);
    mRaySceneQuery->setRay(mouseRay);
    mRaySceneQuery->setSortByDistance(true);
    mRaySceneQuery->setQueryMask(VANE_BOX_MASK);
    //mRaySceneQuery->setQueryTypeMask(Ogre::SceneManager::FX_TYPE_MASK);

    // Execute query
    Ogre::RaySceneQueryResult &result = mRaySceneQuery->execute();
    Ogre::RaySceneQueryResult::iterator itr = result.begin();
     // Get results, create a node/entity on the position
    for ( itr = result.begin(); itr != result.end(); itr++ )
    {
        if (itr->movable && itr->movable->isVisible() && itr->movable->getQueryFlags() == VANE_BOX_MASK)
        {
            return itr->movable;
        } // if
    } // for
    return NULL;

}