osg::ref_ptr
     
       loadedModel = osgDB::readNodeFile("cow.osg"); osg::ref_ptr
      
        viewer = new osgViewer::Viewer; {  osg::ref_ptr
       
         traits = new osg::GraphicsContext::Traits;  traits->x = 40;  traits->y = 40;  traits->width = 600;  traits->height = 480;  traits->windowDecoration = true;  traits->doubleBuffer = true;  traits->sharedContext = 0;  osg::ref_ptr
        
          gc = osg::GraphicsContext::createGraphicsContext(traits.get());  osg::ref_ptr
         
           camera = new osg::Camera;  camera->setGraphicsContext(gc.get());  camera->setViewport(new osg::Viewport(0,0, traits->width, traits->height));  GLenum buffer = traits->doubleBuffer ? GL_BACK : GL_FRONT;  camera->setDrawBuffer(buffer);  camera->setReadBuffer(buffer);  // add this slave camera to the viewer, with a shift left of the projection matrix  viewer->addSlave(camera.get()); } osgUtil::Optimizer optimizer; optimizer.optimize(loadedModel.get()); viewer->setSceneData(loadedModel.get());//viewer->setUpViewOnSingleScreen(0);//这里是单屏幕显示  return viewer->run();