// Initialize GLUT & OpenSG and set up the scene
int doMain(int argc, char **argv)
{
    printf("Press key '1', '2', or '3' to toggle the light sources.\n");
    // OSG init
    OSG::osgInit(argc,argv);

    // GLUT init
    int winid = setupGLUT(&argc, argv);

    // the connection between GLUT and OpenSG
    OSG::GLUTWindowUnrecPtr gwin = OSG::GLUTWindow::create();

    gwin->setGlutId(winid);
    gwin->setSize( 800, 800 );
    gwin->init();

    // Create the shader material
    OSG::ChunkMaterialUnrecPtr cmat = OSG::ChunkMaterial::create();
    OSG::MaterialChunkUnrecPtr matc = OSG::MaterialChunk::create();

    matc->setAmbient(OSG::Color4f(0.1, 0.1, 0.1, 1.0));
    matc->setDiffuse(OSG::Color4f(0.3, 0.3, 0.3, 1.0));
    matc->setSpecular(OSG::Color4f(0.8, 0.8, 0.8, 1.0));
    matc->setShininess(100);
    matc->setLit(true);

    OSG::SHLChunkUnrecPtr shl = OSG::SHLChunk::create();

    shl->setVertexProgram(_vp_program);
    shl->setFragmentProgram(_fp_program);

    shl->addParameterCallback("OSGL0SpecialParameter", light0Active);
    shl->addParameterCallback("OSGL1SpecialParameter", light1Active);
    shl->addParameterCallback("OSGL2SpecialParameter", light2Active);

    cmat->addChunk(matc);
    cmat->addChunk(shl);

    // create root node
    _scene = OSG::Node::create();

    // create two light sources.

    OSG::TransformUnrecPtr point1_trans;

    OSG::NodeUnrecPtr point1        = OSG::makeCoredNode<OSG::PointLight>(&_point1_core);
    point1_beacon = OSG::makeCoredNode<OSG::Transform >(&point1_trans);

    point1_trans->editMatrix().setTranslate(-10.0, 5.0, 5.0);

    _point1_core->setAmbient(0.0f, 0.0f, 0.0f , 1.0f);
    _point1_core->setDiffuse(1.0f, 0.0f, 0.0f, 1.0f);
    _point1_core->setSpecular(1.0f, 1.0f, 1.0f, 1.0f);
    _point1_core->setBeacon(point1_beacon);
    _point1_core->setOn(true);


    OSG::TransformUnrecPtr point2_trans;

    OSG::NodeUnrecPtr point2        = OSG::makeCoredNode<OSG::PointLight>(&_point2_core);
    point2_beacon = OSG::makeCoredNode<OSG::Transform >(&point2_trans);

    point2_trans->editMatrix().setTranslate(10.0, 5.0, 5.0);

    _point2_core->setAmbient(0.0f, 0.0f, 0.0f, 1.0f);
    _point2_core->setDiffuse(0.0f, 1.0f, 0.0f, 1.0f);
    _point2_core->setSpecular(1.0f, 1.0f, 1.0f, 1.0f);
    _point2_core->setBeacon(point2_beacon);
    _point2_core->setOn(true);

    point1->addChild(point2);
    
    OSG::TransformUnrecPtr point3_trans;

    OSG::NodeUnrecPtr point3        = OSG::makeCoredNode<OSG::PointLight>(&_point3_core);
    
    point3_beacon = OSG::makeCoredNode<OSG::Transform >(&point3_trans);

    point3_trans->editMatrix().setTranslate(0.0, -12.0, 5.0);

    _point3_core->setAmbient(0.0f, 0.0f, 0.0f, 1.0f);
    _point3_core->setDiffuse(0.5f, 0.0f, 1.0f, 1.0f);
    _point3_core->setSpecular(1.0f, 1.0f, 1.0f, 1.0f);
    _point3_core->setBeacon(point3_beacon);
    _point3_core->setOn(true);

    point2->addChild(point3);


    // create a sphere.
    OSG::GeometryUnrecPtr geo = OSG::makeLatLongSphereGeo (100, 100, 1.0);

    geo->setMaterial(cmat);


    OSG::NodeUnrecPtr sphere = OSG::makeNodeFor(geo);

    point3->addChild(sphere);


    _scene->setCore(OSG::Group::create());
    _scene->addChild(point1);

    // create the SimpleSceneManager helper
    _mgr = new OSG::SimpleSceneManager;

    // tell the manager what to manage
    _mgr->setWindow(gwin );
    _mgr->setRoot(_scene);

    _mgr->turnHeadlightOff();

    // show the whole scene
    _mgr->showAll();

    // enable local lights.
    OSG::RenderAction *ract = dynamic_cast<OSG::RenderAction *>(_mgr->getRenderAction());

//    ract->setLocalLights(true);

    return 0;
}