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) / ;
     intervaleye = (targeteye - currenteye) / ;
     intervalup = (targetup - currentup) / ;
 }
 
 bool LargeScaleManipulator::handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& us)
 {
     if (ea.getEventType() == osgGA::GUIEventAdapter::FRAME)
     {
         if (isTrans)
         {
             if (fabs(intervaleye[]) < 1e- && fabs(intervaleye[]) < 1e-)
             {
                 setTransformation(targeteye, targetcenter, targetup);
                 isTrans = false;
             }
             if (((fabs(currenteye[] - targeteye[]) >= fabs(intervaleye[])) || (fabs(currentcenter[] - targetcenter[]) >= fabs(intervalcenter[])))
                 &&((fabs(currenteye[] - targeteye[]) >= fabs(intervaleye[])) || (fabs(currentcenter[] - targetcenter[]) >= fabs(intervalcenter[]))))
             {
                 if (fabs(currenteye[] - targeteye[]) >= fabs(intervaleye[]))
                 {
                     currenteye += intervaleye;
                 }
                 if (fabs(currentcenter[] - targetcenter[]) >= fabs(intervalcenter[]))
                 {
                     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();
         LargeScaleManipulator* mp = dynamic_cast<LargeScaleManipulator*>(keyswitchManipulator->getCurrentMatrixManipulator());
         if (mp)
         {
             mp->setcurrentviewmatrix(currenteye, currentcenter, currentup);
             mp->settargetviewmatrix(targeteye, targetcenter, targetup);
             mp->calintervalviewmatrix();
             mp->isTrans = true;
         }
     }