OSG之框选节点的功能实现方式

class BoxPicker : public osgGA::GUIEventHandler
{
public:
        BoxPicker()
        {
                x=0.0f;
                y=0.0f;
                OK= false;
        }

        osg::observer_ptr geometry;

        virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
        {

                bool doit = false;

                osgViewer::Viewer* viewer = dynamic_cast(&aa);
                if (!viewer)
                {
                        return false;
                }

                if(ea.getEventType() == osgGA::GUIEventAdapter::PUSH)
                {
                        x = ea.getXnormalized();
                        y = ea.getYnormalized();
                       
                        x_pick = ea.getX();
                        y_pick = ea.getY();
                       
                        OK = true;

                }

                if (ea.getEventType() == osgGA::GUIEventAdapter::DRAG)
                {
                        if (OK)
                        {
                                float end_x = ea.getXnormalized();
                                float end_y = ea.getYnormalized();

                                if (geometry.valid())
                                {
                                        osg::Vec3Array* vertex = new osg::Vec3Array(4);
                                        (*vertex)[0]=osg::Vec3(x,0,y);
                                        (*vertex)[1]=osg::Vec3(x,0,end_y);
                                        (*vertex)[2]=osg::Vec3(end_x,0,end_y);
                                        (*vertex)[3]=osg::Vec3(end_x,0,y);
                                        geometry->setVertexArray(vertex);
                                        geometry->dirtyDisplayList();

                                        //std::cout< intersector =
                                new osgUtil::PolytopeIntersector(osgUtil::Intersector::WINDOW, xMin, yMin, xMax, yMax);

                        osgUtil::IntersectionVisitor iv( intersector.get() );
                        viewer->getCamera()->accept( iv );
                       
                        if ( intersector->containsIntersections() )
                        {
                                std::cout<<"OK"<getIntersections().begin();
                                        hitr != intersector->getIntersections().end();
                                        ++hitr)
                                {
                                       
                                        osg::NodePath np = hitr->nodePath;
                                        for (osg::NodePath::iterator itr = np.begin(); itr != np.end(); itr++)
                                        {
                                                if (!(*itr)->getName().empty())
                                                {
                                                        std::cout<<(*itr)->getName()<setVertexArray(vertex);
                                geometry->dirtyDisplayList();
                        }
                }
               
                return doit;
        }

        float x,y;
        float x_pick, y_pick;

        bool OK;
};

int _tmain(int argc, char* argv[])
{
        osg::ArgumentParser argument(&argc,argv);

        osg::Node* model1 = osgDB::readNodeFile("axes.osgt");
        model1->setName("COW1");
        osg::MatrixTransform* mt1 = new osg::MatrixTransform;
        mt1->setMatrix(osg::Matrix::translate(osg::Vec3(10,0,0)));
        mt1->addChild(model1);

        osg::Node* model2 = osgDB::readNodeFile("axes.osgt");
        model2->setName("COW2");
       
        osgViewer::Viewer viewer;

        osg::ref_ptr picker = new BoxPicker;
        viewer.addEventHandler(picker.get());

        osg::ref_ptr geo = new osg::Geometry;
        geo->setDataVariance(osg::Object::DYNAMIC);
        geo->setUseDisplayList(false);
        osg::Vec3Array* vertex = new osg::Vec3Array(4);
        (*vertex)[0] = osg::Vec3(-0.5, 0.0, -0.5);
        (*vertex)[1] = osg::Vec3(0.5, 0.0, -0.5);
        (*vertex)[2] = osg::Vec3(0.5, 0.0, 0.5);
        (*vertex)[3] = osg::Vec3(-0.5, 0.0, 0.5);
        geo->setVertexArray(vertex);

        osg::Vec4Array* colors = new osg::Vec4Array;
        colors->push_back(osg::Vec4(1.0,1.0,0.0,1.0));
        geo->setColorArray(colors);
        geo->setColorBinding(osg::Geometry::BIND_OVERALL);

        osg::Vec3Array* normal = new osg::Vec3Array(1);
        (*normal)[0]=osg::Vec3(0,-1,0);
        geo->setNormalArray(normal);
        geo->setNormalBinding(osg::Geometry::BIND_OVERALL);

        osg::ref_ptr pri = new osg::DrawArrays(osg::PrimitiveSet::LINE_LOOP,0,4);

        geo->addPrimitiveSet(pri.get());

        osg::ref_ptr polyMode = new osg::PolygonMode;
        polyMode->setMode(osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::LINE);
        geo->getOrCreateStateSet()->setAttributeAndModes(polyMode.get());
        geo->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
        picker->geometry = geo;

        osg::Camera* camera = new osg::Camera;
        camera->setProjectionMatrix(osg::Matrix::ortho2D(-1.0,1.0,-1.0,1.0));
        camera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
        camera->setViewMatrixAsLookAt(osg::Vec3(0,-1,0), osg::Vec3(0,0,0), osg::Vec3(0,0,1));
        camera->setClearMask(GL_DEPTH_BUFFER_BIT);
        camera->setRenderOrder(osg::Camera::POST_RENDER);
        camera->setAllowEventFocus(false);
       
        osg::ref_ptr geode = new osg::Geode;
        geode->addDrawable(geo.get());

        camera->addChild(geode.get());
        osg::ref_ptr root = new osg::Group;
        root->addChild(camera);
        root->addChild(mt1);
        root->addChild(model2);

        viewer.setSceneData(root.get());
        viewer.setCameraManipulator(new osgGA::OrbitManipulator);
        viewer.run();
        return 0;
}