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: