OSG拾取对应的实体_osg鼠标点击 提取实体位置点法线

#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
 
#include <osg/Node>
#include <osg/Geode>
#include <osg/Group>
 
#include <osgDB/ReadFile>
#include <osgDB/WriteFile>
 
#include <osgFX/Scribe>
 
#include <osgGA/GUIEventHandler>
 
#include <osgUtil/Optimizer>
 
#include <iostream>
 
//对象选取事件处理器
class PickHandler : public osgGA::GUIEventHandler 
{
public:
 
    PickHandler():
      _mx(0.0f),
      _my(0.0f)
      {
          //
      }
 
      ~PickHandler()
      {
        //
      }
        //事件处理函数
      bool handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& aa)
      {
          osg::ref_ptr<osgViewer::View> view = dynamic_cast<osgViewer::View*>(&aa);
          if (!view) return false;
 
          switch(ea.getEventType())
          {
              //鼠标按下
          case(osgGA::GUIEventAdapter::PUSH):
              {
                  //更新鼠标位置
                  _mx = ea.getX();
                  _my = ea.getY();
                  pick(view.get(), ea.getX(), ea.getY());
                  break;
              }
          case(osgGA::GUIEventAdapter::RELEASE):
              {
                  if (_mx==ea.getX() && _my==ea.getY())
                  {
                      //执行对象选取
                      //pick(view.get(), ea.getX(), ea.getY());
                  }
                  break;
              }
          default:
              break;
          }
          return false;
      }
        //对象选取事件处理器
      void pick(osg::ref_ptr<osgViewer::View> view, float x, float y)
      {
          osg::ref_ptr<osg::Node> node = new osg::Node();
          osg::ref_ptr<osg::Group> parent = new osg::Group();
            //创建一个线段交集检测函数
          osgUtil::LineSegmentIntersector::Intersections intersections;
          if (view->computeIntersections(x, y, intersections))
          {
              osgUtil::LineSegmentIntersector::Intersection intersection = *intersections.begin();
              osg::NodePath& nodePath = intersection.nodePath;//直接获取相交模型点的节点
              //得到选择的物体
              node = (nodePath.size()>=1)?nodePath[nodePath.size()-1]:0;
              parent = (nodePath.size()>=2)?dynamic_cast<osg::Group*>(nodePath[nodePath.size()-2]):0;
          }       
 
          //用一种高亮显示来显示物体已经被选中
          if (parent.get() && node.get())
          {
              osg::ref_ptr<osgFX::Scribe> parentAsScribe = dynamic_cast<osgFX::Scribe*>(parent.get());
              if (!parentAsScribe)
              {
                  //如果对象选择到，高亮显示
                  osg::ref_ptr<osgFX::Scribe> scribe = new osgFX::Scribe();
                  scribe->addChild(node.get());
                  parent->replaceChild(node.get(),scribe.get());
              }
              else
              {
                  //如果没有没有选择到，则移除高亮显示的对象
                  osg::Node::ParentList parentList = parentAsScribe->getParents();
                  for(osg::Node::ParentList::iterator itr=parentList.begin();
                      itr!=parentList.end();
                      ++itr)
                  {
                      (*itr)->replaceChild(parentAsScribe.get(),node.get());
                  }
              }
          }
 
      }
public:
    //得到鼠标的位置
    float _mx ;
    float _my;
 
};
 
int main()
{
    //创建Viewer对象，场景浏览器
    osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer();
    viewer->addEventHandler(new PickHandler());
 
    //创建场景组节点
    osg::ref_ptr<osg::Group> root = new osg::Group();
 
    //创建一个节点，读取牛的模型
    osg::ref_ptr<osg::Node> node = osgDB::readNodeFile("cow.osg");
 
    //添加到场景
    root->addChild(node.get());
 
    //优化场景数据
    osgUtil::Optimizer optimizer ;
    optimizer.optimize(root.get()) ;
 
    viewer->setSceneData(root.get());
 
    viewer->realize();
 
    viewer->run();
 
    return 0 ;
}