if (ea.getButton() == osgGA::GUIEventAdapter::RIGHT_MOUSE_BUTTON)
{
	osg::ref_ptr<osgUtil::PolytopeIntersector> picker = new osgUtil::PolytopeIntersector(osgUtil::Intersector::WINDOW, ea.getX()-5.0, ea.getY()-5.0,ea.getX()+5.0,ea.getY()+5.0);
	osgUtil::IntersectionVisitor iv(picker.get());
	//osgViewer::View* pView = dynamic_cast<osgViewer::View*>(&us);
 

	_view->getCamera()->accept(iv);
	if (picker->containsIntersections())
	{
		osg::Vec3f ptWorldIntersectPointFirst = picker->getFirstIntersection().intersectionPoints[0];
		osg::ref_ptr<osg::Sphere> sphere = new osg::Sphere(ptWorldIntersectPointFirst, 2.0);
		osg::ref_ptr<osg::ShapeDrawable>
 
 sd = new osg::ShapeDrawable(sphere);
		sd->setColor(osg::Vec4(1.0, 0.0, 0.0, 1.0));
		_view->getSceneData()->asGroup()->addChild(sd.release());
	}
}

其中之意自己翻原始碼，只可意會不可言傳。