intersections

bool getHOTAndNormal(osgViewer::CompositeViewer& viewer, const osg::Vec3d& position, osg::Vec3d& hot, osg::Vec3& normal)
{
    if (!viewer.getView(0)->getSceneData()) return false;

    osg::Vec3d startVertex = position + osg::Vec3d(0, 0, 1000);
    osg::Vec3d endVertex = position - osg::Vec3d(0, 0, 10000);

    osg::ref_ptr< osgUtil::LineSegmentIntersector > picker = new osgUtil::LineSegmentIntersector(startVertex, endVertex);

    osgUtil::IntersectionVisitor iv(picker.get());
    viewer.getView(0)->getSceneData()->accept(iv);

    if (picker->containsIntersections())
    {
        osgUtil::LineSegmentIntersector::Intersections& intersections = picker->getIntersections();

        std::ostringstream os;

        bool once = true;
        for (osgUtil::LineSegmentIntersector::Intersections::iterator hitr = intersections.begin();
            hitr != intersections.end();
            ++hitr)
        {
            os << "        local coords vertex(" << hitr->getLocalIntersectPoint() << ")" << "  normal(" << hitr->getLocalIntersectNormal() << ")" << std::endl;
            os << "        world coords vertex(" << hitr->getWorldIntersectPoint() << ")" << "  normal(" << hitr->getWorldIntersectNormal() << ")" << std::endl;

            if (once)
            {
                once = false;
                hot = hitr->getWorldIntersectPoint();
                normal = hitr->getWorldIntersectNormal();
            }
        }

        std::cout << os.str() << std::endl;
        if (!once) return true;
    }
    return false;
}