OSG漫游到指定坐标点位置

OSG中从当前场景位置漫游到指定点坐标位置，osg中场景的视口状态包括如下参数：

1、视点的位置

2、参考点的位置，该点通常为场景中的中心轴上的点

3、视点向上的方向向量

( const osg::Vec3d& eye, const osg::Vec3d& center, const osg::Vec3d& up );

通过这三个参数就可以确定视口中模型的状态位置

实现的漫游代码如下：

//是否漫游
//视角移动的 效果
void LargeScaleManipulator::setIsTrans(bool b)
{
    isTrans = b;
}
void LargeScaleManipulator::setcurrentviewmatrix(osg::Vec3 eye, osg::Vec3 center, osg::Vec3 up)
{
    currenteye = eye;
    currentcenter = center;
    currentup = up;
}

void LargeScaleManipulator::settargetviewmatrix(osg::Vec3 eye, osg::Vec3 center, osg::Vec3 up)
{
    targeteye = eye;
    targetcenter = center;
    targetup = up;
}

void LargeScaleManipulator::calintervalviewmatrix()
{
    intervalcenter = (targetcenter - currentcenter) / 60;
    intervaleye = (targeteye - currenteye) / 60;
    intervalup = (targetup - currentup) / 60;
}


bool LargeScaleManipulator::handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& us)
{    
    if (ea.getEventType() == osgGA::GUIEventAdapter::FRAME)
    {
        if (isTrans)
        {
            if (fabs(intervaleye[0]) < 1e-6 && fabs(intervaleye[1]) < 1e-6)
            {
                setTransformation(targeteye, targetcenter, targetup);
                isTrans = false;
            }
            if (((fabs(currenteye[0] - targeteye[0]) >= fabs(intervaleye[0])) || (fabs(currentcenter[0] - targetcenter[0]) >= fabs(intervalcenter[0])))
                &&((fabs(currenteye[1] - targeteye[1]) >= fabs(intervaleye[1])) || (fabs(currentcenter[1] - targetcenter[1]) >= fabs(intervalcenter[1]))))
            {
                if (fabs(currenteye[0] - targeteye[0]) >= fabs(intervaleye[0]))
                {
                    currenteye += intervaleye;
                }
                if (fabs(currentcenter[0] - targetcenter[0]) >= fabs(intervalcenter[0]))
                {
                    currentcenter += intervalcenter;
                }
                currentup += intervalup;
                setTransformation(currenteye, currentcenter, currentup);
            }
            else
            {
                setTransformation(targeteye, targetcenter, targetup);
                isTrans = false;
            }
        }
    }
    return OrbitManipulator::handle(ea, us);
}

以上就是通过传入一个当前位置状态，然后给定一个目标位置状态，通过设置漫游速度，场景就会一直朝着目标位置变换，也就有了漫游效果

调用代码如下：

　　osg::Vec3d target;
    target.set(x, y, z);
    osg::Vec3d currenteye;
    osg::Vec3d currentcenter;
    osg::Vec3d currentup;
    osg::Vec3d targeteye;
    osg::Vec3d targetcenter;
    osg::Vec3d targetup;

    m_pOsgView->getCamera()->getViewMatrixAsLookAt(currenteye, currentcenter, currentup);

    targeteye = target + currenteye - currentcenter;
    targetcenter = target;
    targetup = currentup;

    KeySwitchMatrixManipulator* keyswitchManipulator = dynamic_cast<KeySwitchMatrixManipulator*>(m_pDataManagerSingleton->getViewer()->getCameraManipulator());
    if (keyswitchManipulator)
    {
        keyswitchManipulator->selectMatrixManipulator(0);
        LargeScaleManipulator* mp = dynamic_cast<LargeScaleManipulator*>(keyswitchManipulator->getCurrentMatrixManipulator());
        if (mp)
        {
            mp->setcurrentviewmatrix(currenteye, currentcenter, currentup);
            mp->settargetviewmatrix(targeteye, targetcenter, targetup);
            mp->calintervalviewmatrix();
            mp->isTrans = true;
        }
    }