OSG中嵌入一个opengl代码(且opengl图形能动态更新)

 OSG中嵌入一个opengl代码(且opengl图形能动态更新)

(1)继承osg::Drawable::DrawCallback，在

drawImplementation(osg::RenderInfo& renderInfo,const osg::Drawable* drawable)函数里添加opengl代码。

(2)Drawable设置绘制回调函数，并注意要把显示列表设置为false：

geometry->setUseDisplayList(false);

geometry->setDrawCallback(new DrawCallback);

 

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参考代码如下(改编自OSG的例子程序osgSpaceWarp)：

#include "stdafx.h"

 

#include <osgViewer/Viewer>

#include <osg/Group>

#include <osg/Geometry>

 

#pragma comment( lib, "osgd.lib"); //.在Debug版本下的库名都加d,如"osgd.lib"

#pragma comment( lib, "osgDBd.lib")

#pragma comment( lib, "osgViewerd.lib");

#pragma comment( lib, "osgUtild.lib");

 

//opengl的头文件和库文件

#include <gl/gl.h>

#include <gl/glu.h>

#pragma comment(lib,"opengl32.lib")

#pragma comment(lib,"glu32.lib")

 

class DrawCallback : public osg::Drawable::DrawCallback

{

    virtual void drawImplementation(osg::RenderInfo& renderInfo,const osg::Drawable* drawable) const

    {      

       static double dColor= 0;//颜色

       glColor3f( dColor, 0, 0);

      

       glBegin(GL_TRIANGLES);//在OSG中画一个opengl三角形   

         glVertex3f( 0.0, 0.0, -2.0);

         glVertex3f( 0.2, 0.0, -2.0);

         glVertex3f( 0.0, 0.4, -2.0);

       glEnd();

      

       dColor += 0.01;//颜色渐变      

       if ( dColor > 1.0)

       {

           dColor= 0.0;

       }     

    }

};

 

int main( int argc, char **argv )

{

    osgViewer::Viewer viewer;

 

    osg::Geometry* geometry = new osg::Geometry;

 

    //此处一定要把显示列表设置为false,

    //否则DrawCallback的drawImplementation()函数只会调用一次，而不是在画一帧时都动态更新opengl图形

    geometry->setUseDisplayList(false);

    geometry->setDrawCallback(new DrawCallback);//Drawable设置动态更新opengl图形

 

    osg::Geode* geode = new osg::Geode;

    geode->addDrawable(geometry);

    geode->getOrCreateStateSet()->setMode(GL_LIGHTING,osg::StateAttribute::OFF);

 

    osg::Group* group = new osg::Group;

    group->addChild(geode);

 

    viewer.setSceneData( group);

    //return viewer.run();

    osg::Matrix mt;

    mt.makeIdentity();

    while ( !viewer.done())

    {

       viewer.getCamera()->setViewMatrix( mt);

       viewer.frame();

    }

}