osg点选pick物体

osg已经实现了通过屏幕坐标直接与物体求交的方法。

能得到pick的物体，也能得到坐标。

我希望点击大地形，根据点击的点画出直线。

屏幕坐标与世界坐标的转换都会了，随后实现这个功能。

#pragma once

#include <osgGA/GUIEventHandler>
#include <osgUtil/LineSegmentIntersector>
#include <osgViewer/Viewer>

class CPickHandler : public osgGA::GUIEventHandler
{
public:
    CPickHandler(osgViewer::Viewer *viewer);
    ~CPickHandler(void);

    osgViewer::Viewer *m_pViewer;

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

    void pick(float fX,float fY);
};

#include "StdAfx.h"
#include "PickHandler.h"

CPickHandler::CPickHandler(osgViewer::Viewer *viewer):m_pViewer(viewer)
{
}


CPickHandler::~CPickHandler(void)
{
}

bool CPickHandler::handle( const osgGA::GUIEventAdapter& ea,osgGA::GUIActionAdapter& aa )
{
    switch (ea.getEventType())
    {
    case(osgGA::GUIEventAdapter::PUSH):
        {
            if (ea.getButton() == 1)
            {
                pick(ea.getX(),ea.getY());
            }
            return true;
        }
    }

    return false;
}

void CPickHandler::pick( float fX,float fY )
{
    osgUtil::LineSegmentIntersector::Intersections intersections;
    if (m_pViewer->computeIntersections(fX,fY,intersections))
    {
        for (auto itr=intersections.begin();itr!=intersections.end();++itr)
        {
            if (!itr->nodePath.empty())
            {
                const osg::NodePath& np = itr->nodePath;
                for (int i=np.size()-1;i>=0;--i)
                {
                    osg::ref_ptr<osg::Node> node = dynamic_cast<osg::Node *>(np[i]);
                    if (NULL != node && node->getName().compare("cow") == 0)
                    {
                        node->setNodeMask(0);
                        //itr->getWorldIntersectPoint();//得到坐标
                    }
                }
            }
        }
    }
}

屏幕坐标与世界坐标转换

osg::Vec3 DrawCallback::getPoint()
{
    osg::Vec3 vec3;

    osg::ref_ptr<osgViewer::Viewer> viewer = dynamic_cast<osgViewer::Viewer *>(m_pAA);
    osg::ref_ptr<osg::Camera> camera = viewer->getCamera();
    osgViewer::Renderer *render = dynamic_cast<osgViewer::Renderer *>(camera->getRenderer());
    osgUtil::SceneView *sceneView = render->getSceneView(0);

    osg::Vec3 vScreen(m_pEA->getX(),m_pEA->getY(),0);
    osg::Vec3 window;
    sceneView->projectWindowIntoObject(vScreen,window);

    osg::Matrix mVPW = camera->getViewMatrix() * camera->getProjectionMatrix() * camera->getViewport()->computeWindowMatrix();
    osg::Matrix invertVPW;
    invertVPW.invert(mVPW);

    vec3 = window * invertVPW;

    return vec3;
}

1.配置MD

2.配置x64

3.找到mfc example

4.写callback

5.创建一个节点挂到根节点下，为这个节点设置一个回调器。

响应事件改变节点。
url:http://greatverve.cnblogs.com/archive/2013/04/21/osg-pick.html