// redraw the window
void display(void)
{
    mgr->redraw();
}

// react to mouse motions with pressed buttons
void motion(int x, int y)
{
    mgr->mouseMove(x, y);
    glutPostRedisplay();
}

// Initialize GLUT & OpenSG and set up the scene
int doMain(int argc, char **argv)
{
    // 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();

    // Read the image for the normal texture
    OSG::ImageUnrecPtr earth_map_img = OSG::Image::create();
    if(!earth_map_img->read("Earth.jpg"))
    {
        fprintf(stderr, "Couldn't read texture 'Earth.jpg'\n");
        return 1;
    }
    OSG::TextureObjChunkUnrecPtr tex_earth     = OSG::TextureObjChunk::create();
    OSG::TextureEnvChunkUnrecPtr tex_earth_env = OSG::TextureEnvChunk::create();

    tex_earth->setImage(earth_map_img);
    tex_earth->setMinFilter(GL_LINEAR_MIPMAP_LINEAR);
    tex_earth->setMagFilter(GL_LINEAR);
    tex_earth->setWrapS(GL_REPEAT);
    tex_earth->setWrapT(GL_REPEAT);

    tex_earth_env->setEnvMode(GL_MODULATE);

    // Read the image for the normal texture
    OSG::ImageUnrecPtr earth_night_map_img = OSG::Image::create();
    if(!earth_night_map_img->read("EarthNight.jpg"))
    {
        fprintf(stderr, "Couldn't read texture 'EarthNight.jpg'\n");
        return 1;
    }

    OSG::TextureObjChunkUnrecPtr tex_earth_night     = OSG::TextureObjChunk::create();
    OSG::TextureEnvChunkUnrecPtr tex_earth_night_env = OSG::TextureEnvChunk::create();

    tex_earth_night->setImage(earth_night_map_img);
    tex_earth_night->setMinFilter(GL_LINEAR_MIPMAP_LINEAR);
    tex_earth_night->setMagFilter(GL_LINEAR);
    tex_earth_night->setWrapS(GL_REPEAT);
    tex_earth_night->setWrapT(GL_REPEAT);

    tex_earth_night_env->setEnvMode(GL_MODULATE);
    
    // Read the image for the normal texture
    OSG::ImageUnrecPtr earth_clouds_map_img = OSG::Image::create();
    if(!earth_clouds_map_img->read("EarthClouds.jpg"))
    {
        fprintf(stderr, "Couldn't read texture 'EarthClouds.jpg'\n");
        return 1;
    }

    OSG::TextureObjChunkUnrecPtr tex_earth_clouds     = OSG::TextureObjChunk::create();
    OSG::TextureEnvChunkUnrecPtr tex_earth_clouds_env = OSG::TextureEnvChunk::create();

    tex_earth_clouds->setImage(earth_clouds_map_img);
    tex_earth_clouds->setMinFilter(GL_LINEAR_MIPMAP_LINEAR);
    tex_earth_clouds->setMagFilter(GL_LINEAR);
    tex_earth_clouds->setWrapS(GL_REPEAT);
    tex_earth_clouds->setWrapT(GL_REPEAT);

    tex_earth_clouds_env->setEnvMode(GL_MODULATE);


    _shl = OSG::SHLChunk::create();

    if(!_shl->readVertexProgram("Earth.vp"))
        fprintf(stderr, "Couldn't read vertex program 'Earth.vp'\n");
    if(!_shl->readFragmentProgram("Earth.fp"))
        fprintf(stderr, "Couldn't read fragment program 'Earth.fp'\n");

    _shl->addUniformVariable("EarthDay", 0);
    _shl->addUniformVariable("EarthNight", 1);
    _shl->addUniformVariable("EarthCloudGloss", 2);
    _shl->addUniformVariable("season", 0.0f);
    _shl->addUniformVariable("cos_time_0_2PI", -0.406652f);
    _shl->addUniformVariable("sin_time_0_2PI", -0.913583f);
//    _shl->setUniformParameter("foo", -0.913583f);

    
    cmat->addChunk(_shl);
    cmat->addChunk(tex_earth);
    cmat->addChunk(tex_earth_env);
    cmat->addChunk(tex_earth_night);
    cmat->addChunk(tex_earth_night_env);
    cmat->addChunk(tex_earth_clouds);
    cmat->addChunk(tex_earth_clouds_env);


//.........这里部分代码省略.........

// Initialize GLUT & OpenSG and set up the scene
int main(int argc, char **argv)
{
    // OSG init
    OSG::osgInit(argc,argv);

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

    // open a new scope, because the pointers below should go out of scope
    // before entering glutMainLoop.
    // Otherwise OpenSG will complain about objects being alive after shutdown.
    {
        // the connection between GLUT and OpenSG
        OSG::GLUTWindowRefPtr gwin = OSG::GLUTWindow::create();
        gwin->setGlutId(winid);
        gwin->init();
    
        // The scene group
        
        OSG::NodeRefPtr  scene = OSG::Node::create();
        OSG::GroupRefPtr g     = OSG::Group::create();
        
        scene->setCore(g);
        
        if(argc < 2)
        {
            FWARNING(("No file given!\n"));
            FWARNING(("Supported file formats:\n"));
            
            std::list<const char*> suffixes;
            OSG::SceneFileHandler::the()->getSuffixList(suffixes);
            
            for(std::list<const char*>::iterator it  = suffixes.begin();
                                                 it != suffixes.end();
                                               ++it)
            {
                FWARNING(("%s\n", *it));
            }
    
            fileroot = OSG::makeTorus(.5, 2, 16, 16);
        }
        else
        {
            fileroot = OSG::SceneFileHandler::the()->read(argv[1]);
            /*
                All scene file loading is handled via the SceneFileHandler.
            */
        }
    
        scene->addChild(fileroot);
        
        // Create a small geometry to show the ray and what was hit
        // Contains a line and a single triangle.
        // The line shows the ray, the triangle whatever was hit.
        
        OSG::SimpleMaterialRefPtr red = OSG::SimpleMaterial::create();
        
        red->setDiffuse     (OSG::Color3f( 1,0,0 ));   
        red->setTransparency(0.5);   
        red->setLit         (false);   
    
        isectPoints = OSG::GeoPnt3fProperty::create();
        isectPoints->addValue(OSG::Pnt3f(0,0,0));
        isectPoints->addValue(OSG::Pnt3f(0,0,0));
        isectPoints->addValue(OSG::Pnt3f(0,0,0));
        isectPoints->addValue(OSG::Pnt3f(0,0,0));
        isectPoints->addValue(OSG::Pnt3f(0,0,0));
    
        OSG::GeoUInt32PropertyRefPtr index = OSG::GeoUInt32Property::create();
        index->addValue(0);
        index->addValue(1);
        index->addValue(2);
        index->addValue(3);
        index->addValue(4);
    
        OSG::GeoUInt32PropertyRefPtr lens = OSG::GeoUInt32Property::create();
        lens->addValue(2);
        lens->addValue(3);
        
        OSG::GeoUInt8PropertyRefPtr type = OSG::GeoUInt8Property::create();
        type->addValue(GL_LINES);
        type->addValue(GL_TRIANGLES);
    
        testgeocore = OSG::Geometry::create();
        testgeocore->setPositions(isectPoints);
        testgeocore->setIndices(index);
        testgeocore->setLengths(lens);
        testgeocore->setTypes(type);
        testgeocore->setMaterial(red);
        
        OSG::NodeRefPtr testgeo = OSG::Node::create();
        testgeo->setCore(testgeocore);
        
        scene->addChild(testgeo);
    
        // create the SimpleSceneManager helper
        mgr = OSG::SimpleSceneManager::create();
    
        // tell the manager what to manage
//.........这里部分代码省略.........

//
// react to keys
//
void keyboard(unsigned char k, int, int)
{
    static OSG::Real32 val0 = 0.f;
    static OSG::Real32 val1 = 0.f;

    static OSG::Real32 x1 = 0.f;
    static OSG::Real32 y1 = 0.f;
    static OSG::Real32 z1 = 0.f;

    static OSG::Real32 x2 = 0.f;
    static OSG::Real32 y2 = 0.f;
    static OSG::Real32 z2 = 0.f;

    switch(k)
    {
    case ' ':
        {
            OSG::SceneGraphPrinter sgp(mgr->getRoot());
            sgp.printDownTree(std::cout);
        }
        break;

    case '1':   // enable/disable clip plane 0
        {
            vecClipPlaneData[0]._enabled = !vecClipPlaneData[0]._enabled;
            updateClipPlanes(vecClipPlaneData);
        }
        break;
    case '2':   // enable/disable clip plane 1
        {
            vecClipPlaneData[1]._enabled = !vecClipPlaneData[1]._enabled;
            updateClipPlanes(vecClipPlaneData);
        }
        break;
    case '3':   // enable/disable box geometry
        {
            if(vecGeometries[0] == NULL)
            {
                OSG::Matrix matrix;
                OSG::Vec3f v(10.f,  0.f, 15.f);
                matrix.setTranslate(v);

                OSG::GeometryRefPtr boxGeo  =
                    OSG::makeBoxGeo(15, 15, 15, 1, 1, 1);

                OSG::NodeRefPtr     boxTree = buildGeoTree(scene,
                                                           boxGeo,
                                                           matrix);

                vecGeometries[0] = boxTree;
                scene->addChild(boxTree);
            }
            else
            {
                scene->subChild(vecGeometries[0]);
                vecGeometries[0] = NULL;
            }

//             mgr->showAll();
//             mgr->redraw();
        }
        break;
    case '4':   // enable/disable torus geometry
        {
            if (vecGeometries[1] == NULL)
            {
                OSG::Matrix matrix;
                OSG::Vec3f v( 0.f, 10.f, 0.f);
                matrix.setTranslate(v);

                OSG::GeometryRefPtr torusGeo  = OSG::makeTorusGeo(2, 6, 8, 16);
                OSG::NodeRefPtr     torusTree = buildGeoTree(scene,
                                                             torusGeo, matrix);

                vecGeometries[1] = torusTree;
                scene->addChild(torusTree);
            }
            else
            {
                scene->subChild(vecGeometries[1]);
                vecGeometries[1] = NULL;
            }

//             mgr->showAll();
//             mgr->redraw();
        }
        break;

    case '5':
        {
            OSG::SceneFileHandler::the()->write(mgr->getRoot(), 
                                                "clipplane_model.osb", true);
        }
        break;
    case 'n':   // move clip plane 0 opposite to the normal direction of the plane
        {
            val0 -= 0.2;
//.........这里部分代码省略.........

int doMain(int argc, char **argv)
{
    //
    // This might be necessary depending on the
    // used platform to ensure that the corresponding
    // libraries get loaded.
    //
    OSG::preloadSharedObject("OSGFileIO");
    OSG::preloadSharedObject("OSGImageFileIO");
    OSG::preloadSharedObject("OSGContribPLY");

    OSG::osgInit(argc,argv);

    // GLUT init
    glutInit(&argc, argv);

    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_STENCIL | GLUT_DOUBLE);

    glutCreateWindow("OpenSG");

    glutReshapeFunc(reshape);
    glutDisplayFunc(display);
    glutIdleFunc(display);
    glutMouseFunc(mouse);
    glutMotionFunc(motion);
    glutKeyboardFunc(keyboard);

    OSG::PassiveWindowRefPtr pwin=OSG::PassiveWindow::create();
    pwin->init();

    // create the SimpleSceneManager helper
    mgr = OSG::SimpleSceneManager::create();

    // create the window and initial camera/viewport
    mgr->setWindow(pwin);

    //
    // for storing clipplane beacon we use a container
    // collection attachment which we attach to the scene
    // node. Otherwise the scene could not be saved correctly,
    // as the beacons would be lost.
    //
    container = OSG::ContainerCollection::create();

    //
    // Implementation details:
    //      For each clip plane we provide a ClipPlaneChunk, the plane geometry,
    //      the plane transform core and at least a plane color conveniently in
    //      a vector of type VecClipPlaneDetailsT. The next function call
    //      initializes this data structure.
    //
    createClipPlaneDetails();

    //
    // The scene
    //
    scene = OSG::Node::create();
    scene->setCore(OSG::Group::create());
    scene->addAttachment(container);

    //
    // A place for accessing the box and torus.
    //
    vecGeometries.push_back(NULL);
    vecGeometries.push_back(NULL);

    //
    // Build concrete clipping planes and update the clip plane details.
    //
    ClipPlaneData data1;
    ClipPlaneData data2;

    data1._equation = OSG::Vec4f(0,0,1,0);
    data1._enabled  = true;

    data2._equation = OSG::Vec4f(1,0,0,0);
    data2._enabled  = false;

    vecClipPlaneData.push_back(data1);
    vecClipPlaneData.push_back(data2);

    updateClipPlanes(vecClipPlaneData);

    keyboard('3',-1,-1);
    keyboard('4',-1,-1);

    // tell the manager what to manage
    mgr->setRoot(scene);

    // show the whole scene
    mgr->showAll();
    mgr->redraw();

    pwin->dumpExtensions();

    return 0;
}

// Initialize GLUT & OpenSG and set up the scene
int main(int argc, char **argv)
{
    printf("Usage: testCGShader <filename.vp> <filename.fp>\n");

    if( argc < 3 )
        return 0;
    
    // 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->readVertexProgram(argv[1]);
    shl->readFragmentProgram(argv[2]);

    cmat->addChunk(shl);


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

    // create torus
    OSG::GeometryUnrecPtr geo = OSG::makeTorusGeo(.8, 1.8, 128, 128);
    geo->setMaterial(cmat);

    OSG::NodeUnrecPtr torus = OSG::Node::create();
    torus->setCore(geo);

    // add torus to scene
    OSG::GroupUnrecPtr group = OSG::Group::create();
    _scene->setCore(group);
    _scene->addChild(torus);

    // create the SimpleSceneManager helper
    _mgr = OSG::SimpleSceneManager::create();

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

    /*
    // create point headlight
    _mgr->turnHeadlightOff();
    NodePtr headlight = _mgr->getHighlight();
    PointLightPtr light    = PointLight::create();
    beginEditCP(light);
        light->setAmbient  (.3, .3, .3, 1);
        light->setDiffuse  ( 1,  1,  1, 1);
        light->setSpecular ( 1,  1,  1, 1);
        light->setBeacon   (_mgr->getCamera()->getBeacon());
    endEditCP(light);
    beginEditCP(_scene);
        _scene->setCore(light);
    endEditCP(_scene);
    */

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

    // GLUT main loop
    glutMainLoop();

    return 0;
}

//
// Initialize GLUT & OpenSG and set up the scene
//
int main(int argc, char **argv)
{
    // OSG init
    OSG::osgInit(argc,argv);

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

    // open a new scope, because the pointers below should go out of scope
    // before entering glutMainLoop.
    // Otherwise OpenSG will complain about objects being alive after shutdown.
    {
        // the connection between GLUT and OpenSG
        OSG::GLUTWindowRefPtr gwin = OSG::GLUTWindow::create();
        gwin->setGlutId(winid);
        gwin->init();
    
        // create the SimpleSceneManager helper
        mgr = OSG::SimpleSceneManager::create();
        mgr->setWindow(gwin);

        // create a pretty simple graph: a Group with two Transforms as children,
        // each of which carries a single Geometry.
        
        // The scene
        
        OSG::NodeRefPtr  scene = OSG::Node::create();
        
        // The cylinder and its transformation
        OSG::NodeRefPtr     cyl    = OSG::Node::create();
        OSG::GeometryRefPtr cylgeo = OSG::makeCylinderGeo( 1.4f, .3f, 24, 
                                                           true, true, true );
        
        cyl->setCore(cylgeo);
    
        cyltrans = OSG::Transform::create();
    
        OSG::NodeRefPtr cyltransnode = OSG::Node::create();
        cyltransnode->setCore (cyltrans);
        cyltransnode->addChild(cyl     );
        
        // add it to the scene
        scene->addChild(cyltransnode);
        
        // The torus and its transformation
        OSG::NodeRefPtr     torus    = OSG::Node::create();
        OSG::GeometryRefPtr torusgeo = OSG::makeTorusGeo( .2f, 1, 24, 36 );
        
        torus->setCore(torusgeo);
            
        tortrans = OSG::Transform::create();
    
        OSG::NodeRefPtr tortransnode = OSG::Node::create();
        tortransnode->setCore (tortrans);
        tortransnode->addChild(torus   );
        
        // add it to the scene
        scene->addChild(tortransnode);

        //
        // create the shader program
        //
        OSG::ShaderProgramChunkRefPtr prog_chunk = OSG::ShaderProgramChunk::create();
        OSG::ShaderProgramRefPtr      vertShader = OSG::ShaderProgram::createVertexShader();
        OSG::ShaderProgramRefPtr      fragShader = OSG::ShaderProgram::createFragmentShader();

        vertShader->setProgram(get_vp_program());
        fragShader->setProgram(get_fp_program());

        //
        // binding the shader storage block to a buffer binding point can be performed 
        // either by calling the shaders's addShaderStorageBlock method or by
        // adding a 'buffer block' variable to a ShaderProgramVariableChunk.
        // In the following we use both variants for illustration.
        //
        fragShader->addShaderStorageBlock("ExampleBlock", 1); // block binding point

        prog_chunk->addShader(vertShader);
        prog_chunk->addShader(fragShader);

        //
        // create shader storage buffer object for block 'ExampleBlock'
        //
        OSG::MultiPropertySSBOChunkRefPtr ssbo_example_block = create_example_block_state();

        OSG::PolygonChunkRefPtr polygon_chunk = OSG::PolygonChunk::create();
        polygon_chunk->setFrontMode(GL_FILL);
        polygon_chunk->setBackMode(GL_FILL);
        polygon_chunk->setCullFace(GL_NONE);

        OSG::DepthChunkRefPtr depth_chunk = OSG::DepthChunk::create();
        depth_chunk->setEnable(true);

        OSG::ChunkMaterialRefPtr prog_state = OSG::ChunkMaterial::create();
        prog_state->addChunk(ssbo_example_block, 1);      // buffer binding point 1
        prog_state->addChunk(prog_chunk);
        prog_state->addChunk(polygon_chunk);
//.........这里部分代码省略.........

// react to keys
void keyboard(unsigned char k, int , int )
{
    switch (k)
    {
    case 27:
    {
        mgr = NULL;

        delete gTextStuff;
        
        OSG::commitChanges();
        OSG::osgExit();
        exit(0);
    }
    break;
    
    case '-':
        gTextStuff->incFaceSize(false);
        break;
    case '=':
        gTextStuff->incFaceSize(true);
        break;
    
    case '[':
        gTextStuff->incTextureSize(false);
        break;
    case ']':
        gTextStuff->incTextureSize(true);
        break;
    
    case '<':
        gTextStuff->incMaxExtent(false);
        break;
    case '>':
        gTextStuff->incMaxExtent(true);
        break;
    
    case ',':
        gTextStuff->incLineSpacing(false);
        break;
    case '.':
        gTextStuff->incLineSpacing(true);
        break;
    
    case '{':
        gTextStuff->incGeoScale(false);
        break;
    case '}':
        gTextStuff->incGeoScale(true);
        break;
    
    
    case 'f':
        gTextStuff->goToNextFamily();
        break;
    
    case 'd':
        OSG::SceneFileHandler::the()->write(mgr->getRoot(),"dump_scene.osb");
        std::cout << "Wrote out scene: dump_scene.osb" << std::endl;
        break;
    
    case 't':
        mgr->setNavigationMode(OSG::Navigator::TRACKBALL);
        break;
    
    case 'l':
        mgr->setHeadlight(!mgr->getHeadlightState());
        std::cout << "Set headlight: " << mgr->getHeadlightState() << std::endl;
        break;
    case 'z':
        glPolygonMode( GL_FRONT_AND_BACK, GL_POINT);
        std::cerr << "PolygonMode: Point." << std::endl;
        break;
    case 'x':   glPolygonMode( GL_FRONT_AND_BACK, GL_LINE);
        std::cerr << "PolygonMode: Line." << std::endl;
        break;
    case 'c':   glPolygonMode( GL_FRONT_AND_BACK, GL_FILL);
        std::cerr << "PolygonMode: Fill." << std::endl;
        break;
        
    case 'h':
        std::cerr << "Keys:" << std::endl;
        std::cerr << "- =: change face size" << std::endl;
        std::cerr << "{ }: change geo scale" << std::endl;
        std::cerr << "[ ]: change texture size" << std::endl;
        std::cerr << "< >: change max extend for 1st line" << std::endl;
        std::cerr << ", .: change line spacing" << std::endl;
        std::cerr << "f  : next font family" << std::endl;
        std::cerr << "d  : dump scene" << std::endl;
    }
}

// redraw the window
void display(void)
{
  // render scene
  _mgr->redraw();
}

// redraw the window
void display(void)
{
    mgr->idle();
    mgr->redraw();
}

// Initialize GLUT & OpenSG and set up the scene
int main(int argc, char **argv)
{
    // OSG init
    OSG::osgInit(argc,argv);

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

    // Args given?
    if(argc > 1)
    {
        if(sscanf(argv[1], "%u", &nlights) != 1)
        {
            FWARNING(("Number of lights '%s' not understood.\n", argv[1]));
            nlights = 3;
        }
    }
    
    // open a new scope, because the pointers below should go out of scope
    // before entering glutMainLoop.
    // Otherwise OpenSG will complain about objects being alive after shutdown.
    {
    
        // the connection between GLUT and OpenSG
        OSG::GLUTWindowRefPtr gwin = OSG::GLUTWindow::create();
        gwin->setGlutId(winid);
        gwin->init();
    
        /*
            A Light defines a source of light in the scene. Generally, two types
            of information are of interest: The position of the light source
            (geometry), and what elements of the scene are lit (semantics). 
    
            Using the position of the light in the graph for geometry allows
            moving the Light just like any other node, by putting it below a
            OSG::Transform Node and changing the transformation. This consistency
            also simplifies attaching Lights to moving parts in the scene: just
            put them below the same Transform and they will move with the object.
    
            The semantic interpretation also makes sense, it lets you restrict the
            influence area of the light to a subgraph of the scene. This can be
            used for efficiency, as every active light increases the amount of
            calculations necessary per vertex, even if the light doesn't influence
            the vertex, because it is too far away. It can also be used to
            overcome the restrictions on the number of lights. OpenSG currently
            only allows 8 concurrently active lights.
    
            It is also not difficult to imagine situations where both
            interpretations are necessary at the same time. Take for example a car
            driving through a night scene. You'd want to headlights to be fixed to
            the car and move together with it. But at the same time they should
            light the houses you're driving by, and not the mountains in the
            distance. 
    
            Thus there should be a way to do both at the same time. OpenSG solves
            this by splitting the two tasks to two Nodes. The Light's Node is for
            the sematntic part, it defines which object are lit by the Light. FOr
            the geometrc part the Light keeps a SFNodePtr to a different Node, the
            so called beacon. The local coordinate system of the beacon provides
            the reference coordinate system for the light's position.
    
    
            Thus the typical setup of an OpenSG scenegraph starts with a set of
            lights, which light the whole scene, followed by the actual geometry.
    
            Tip: Using the beacon of the camera (see \ref PageSystemWindowCamera)
            as the beacon of a light source creates a headlight.


            Every light is closely related to OpenGL's light specification. It has
            a diffuse, specular and ambient color. Additionally it can be switched
            on and off using the on field.
        */
    
    
        // Create the scene 
        
        OSG::NodeRefPtr  scene = OSG::Node::create();
        OSG::GroupRefPtr group = OSG::Group::create();
        scene->setCore(group);
    
        // create the scene to be lit
    
        // a simple torus is fine for now.
        // You can add more Geometry here if you want to.
        OSG::NodeRefPtr lit_scene = OSG::makeTorus(.5, 2, 32, 64);
    
        // helper node to keep the lights on top of each other
        OSG::NodeRefPtr lastnode = lit_scene;
    
        // create the light sources    
        OSG::Color3f colors[] = 
        {
            OSG::Color3f(1,0,0), OSG::Color3f(0,1,0), OSG::Color3f(0,0,1), 
            OSG::Color3f(1,1,0), OSG::Color3f(0,1,1), OSG::Color3f(1,0,1), 
            OSG::Color3f(1,1,1), OSG::Color3f(1,1,1)
        };
        if(nlights > 8)
        {
//.........这里部分代码省略.........

// react to keys
void keyboard(unsigned char k, int x, int y)
{
    switch(k)
    {
        case 27:    
        {
            // clean up global variables
            mgr = NULL;
            
            OSG::osgExit();
            exit(1);
        }
        break;
        
        case 'a':   // activate all lights
        {
            for(OSG::UInt16 i = 0; i < nlights; ++i)
            {
                lights[i]->setOn(true);
            }
        }
        break;
         
        case 's':   // deactivate all but the spot lights
        {
            for(OSG::UInt16 i = 0; i < nlights; ++i)
            {
                if(lights[i]->getTypeId() != OSG::SpotLight::getClassTypeId())
                {
                    lights[i]->setOn(false);
                }
                else
                {
                    lights[i]->setOn(true);
                }
            }
            OSG::commitChanges();
        }
        break;
         
        case 'd':   // deactivate all but the directional lights
        {
            for(OSG::UInt16 i = 0; i < nlights; ++i)
            {
                if(lights[i]->getTypeId() != 
                                      OSG::DirectionalLight::getClassTypeId())
                {
                    lights[i]->setOn(false);
                }
                else
                {
                    lights[i]->setOn(true);
                }
            }
            OSG::commitChanges();
        }
        break;
         
        case 'p':   // deactivate all but the point lights
        {
            for(OSG::UInt16 i = 0; i < nlights; ++i)
            {
                if(lights[i]->getTypeId() != OSG::PointLight::getClassTypeId())
                {
                    lights[i]->setOn(false);
                }
                else
                {
                    lights[i]->setOn(true);
                }
            }
            OSG::commitChanges();
        }
        break;

        case 'S':
        {
            mgr->setStatistics(!mgr->getStatistics());
        }
        break;
   }
}

int main(int argc, char **argv)
{
    g_error = 0.01f;

    if ( argc == 2 )
    {
        g_error = atof( argv[1] );
    }
    if ( g_error < 0.001 )
    {
        g_error = 0.001f;
    }
    
    OSG::osgInit(argc,argv);
    // GLUT init
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);

    int winid = glutCreateWindow("OpenSG");
    
    glutReshapeFunc(reshape);
    glutDisplayFunc(display);
    glutIdleFunc(display);
    glutMouseFunc(mouse);
    glutMotionFunc(motion);
    glutKeyboardFunc(keyboard);

    {
        OSG::GLUTWindowRefPtr gwin = OSG::GLUTWindow::create();
        gwin->setGlutId(winid);
        gwin->init();
    
        // create the scene
        OSG::NodeRefPtr scene;
        scene = makeScene( );
        
        if ( scene == NULL )
        {
            std::cerr<<"makeScene returned NullFC, exiting..."<<std::endl;
            return -1;
        }
    
        // create the SimpleSceneManager helper
        mgr = OSG::SimpleSceneManager::create();
    
        // create the window and initial camera/viewport
        mgr->setWindow( gwin );
        // tell the manager what to manage
        mgr->setRoot  ( scene );
        
        // show the whole scene
        mgr->showAll();
        mgr->redraw();
        OSG::SolidBackgroundRefPtr bgr = OSG::SolidBackground::create();
        bgr->setColor( OSG::Color3f( 0.7f, 0.7f, 0.7f ));
        mgr->getWindow()->getPort(0)->setBackground( bgr );
    }
    
    // GLUT main loop
    glutMainLoop();

    return 0;
}

//
// Initialize GLUT & OpenSG and set up the scene
//
int main(int argc, char **argv)
{
    // OSG init
    OSG::osgInit(argc,argv);

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

    // open a new scope, because the pointers below should go out of scope
    // before entering glutMainLoop.
    // Otherwise OpenSG will complain about objects being alive after shutdown.
    {
        // the connection between GLUT and OpenSG
        OSG::GLUTWindowRefPtr gwin = OSG::GLUTWindow::create();
        gwin->setGlutId(winid);
        gwin->init();
    
        // create the SimpleSceneManager helper
        mgr = OSG::SimpleSceneManager::create();
        mgr->setWindow(gwin);

        // create a pretty simple graph: a Group with two Transforms as children,
        // each of which carries a single Geometry.
        
        // The scene
        
        OSG::NodeRefPtr  scene = OSG::Node::create();
        
        // The cylinder and its transformation
        OSG::NodeRefPtr     cyl    = OSG::Node::create();
        OSG::GeometryRefPtr cylgeo = OSG::makeCylinderGeo( 1.4f, .3f, 24, 
                                                           true, true, true );
        
        cyl->setCore(cylgeo);
    
        cyltrans = OSG::Transform::create();
    
        OSG::NodeRefPtr cyltransnode = OSG::Node::create();
        cyltransnode->setCore (cyltrans);
        cyltransnode->addChild(cyl     );
        
        // add it to the scene
        scene->addChild(cyltransnode);
        
        // The torus and its transformation
        OSG::NodeRefPtr     torus    = OSG::Node::create();
        OSG::GeometryRefPtr torusgeo = OSG::makeTorusGeo( .2f, 1, 24, 36 );
        
        torus->setCore(torusgeo);
            
        tortrans = OSG::Transform::create();
    
        OSG::NodeRefPtr tortransnode = OSG::Node::create();
        tortransnode->setCore (tortrans);
        tortransnode->addChild(torus   );
        
        // add it to the scene
        scene->addChild(tortransnode);

        //
        // create the shader program
        //
        OSG::ShaderProgramChunkRefPtr prog_chunk = OSG::ShaderProgramChunk::create();
        OSG::ShaderProgramRefPtr      vertShader = OSG::ShaderProgram::createVertexShader();
        OSG::ShaderProgramRefPtr      fragShader = OSG::ShaderProgram::createFragmentShader();

        vertShader->setProgram(get_vp_program());
        fragShader->setProgram(get_fp_program());

        //
        // binding the unifrom block to a buffer binding point can be performed 
        // either by calling the shaders's addUniformBlock method or by
        // adding a 'uniform block' variable to a ShaderProgramVariableChunk.
        // In the following we use both variants for illustration.
        //
        fragShader->addUniformBlock("Materials", 1);    // block binding point
        fragShader->addUniformBlock("Lights",    2);    // block binding point

        //
        // The following is replaced by adding ShaderProgramVariableChunk objects
        // to the chunk material. See below...
        //
        // fragShader->addUniformBlock("GeomState", 3);    // block binding point

        prog_chunk->addShader(vertShader);
        prog_chunk->addShader(fragShader);

        //
        // create uniform buffer objects and corresponding materials
        //
        OSG::UniformBufferObjChunkRefPtr ubo_material_database = create_material_database_state(materials);
                                         ubo_light_state       = create_light_state(lights);

        OSG::PolygonChunkRefPtr polygon_chunk = OSG::PolygonChunk::create();
        polygon_chunk->setFrontMode(GL_FILL);
        polygon_chunk->setBackMode(GL_FILL);
        polygon_chunk->setCullFace(GL_NONE);
//.........这里部分代码省略.........

// react to size changes
void reshape(int w, int h)
{
    mgr->resize(w,h);
    glutPostRedisplay();
}

// Initialize GLUT & OpenSG and set up the scene
int main(int argc, char **argv)
{
    // OSG init
    OSG::osgInit(argc,argv);

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

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

        gwin->setGlutId(winid);
        gwin->init();

        // create the scene
        OSG::NodeRefPtr torus = OSG::makeTorus( .5, 2, 16, 32 );
        OSG::NodeRefPtr scene = OSG::Node::create();

        trans = OSG::Transform::create();

        scene->setCore(trans);
        scene->addChild(torus);

        // Create the parts needed for the video background
        OSG::UInt32 width  = 640;
        OSG::UInt32 height = 480;

        // get the desired size from the command line
        if(argc >= 3)
        {
            width  = atoi(argv[1]);
            height = atoi(argv[2]);
        }

        // To check OpenGL extensions, the Window needs to have run through
        // frameInit at least once. This automatically happens when rendering,
        // but we can't wait for that here.

        gwin->activate ();
        gwin->frameInit();

        // Now we can check for OpenGL extensions
        hasNPOT = gwin->hasExtension("GL_ARB_texture_non_power_of_two");

        // Print what we've got
        SLOG << "Got " << (isPOT?"":"non-") << "power-of-two images and "
            << (hasNPOT?"can":"cannot") << " use NPOT textures, changing "
            << (changeOnlyPart?"part":"all")
            << " of the screen"
            << std::endl;

        // Ok, now for the meat of the code...
        // first we need an Image to hold the picture(s) to show
        image = OSG::Image::create();

        // set the image's size and type, and allocate memory
        // this example uses RGB. On some systems (e.g. Windows) BGR
        // or BGRA might be faster, it depends on how the images are
        // acquired

        image->set(OSG::Image::OSG_RGB_PF, width, height);



        // Now create the texture to be used for the background
        texObj = OSG::TextureObjChunk::create();

        // Associate image and texture
        texObj->setImage(image);

        // Set filtering modes. LINEAR is cheap and good if the image size
        // changes very little (i.e. the window is about the same size as
        // the images).

        texObj->setMinFilter(GL_LINEAR);
        texObj->setMagFilter(GL_LINEAR);

        // Set the wrapping modes. We don't need repetition, it might actually
        // introduce artifactes at the borders, so switch it off.

        texObj->setWrapS(GL_CLAMP_TO_EDGE);
        texObj->setWrapT(GL_CLAMP_TO_EDGE);

        // Newer versions of OpenGL can handle NPOT textures directly.
        // OpenSG will do that internally automatically.
        //
        // Older versions need POT textures. By default OpenSG
        // will scale an NPOT texture to POT while defining it.
        // For changing textures that's too slow.
        // So tell OpenSG not to scale the image and adjust the texture
        // coordinates used by the TextureBackground (see below).

        texObj->setScale(false);

        // Create the background

        OSG::TextureBackgroundRefPtr back = OSG::TextureBackground::create();

//.........这里部分代码省略.........