OSG程序设计之Hello World 4.0

代码如下：　　//需要添加两个库：osgUtild.lib、osgTextd.lib

#include <osgDB/ReadFile>
#include <osgUtil/Optimizer>
#include <osg/CoordinateSystemNode>
#include <osg/Switch>
#include <osgText/Text>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>

#include <osgGA/TrackballManipulator>
#include <osgGA/FlightManipulator>
#include <osgGA/DriveManipulator>
#include <osgGA/KeySwitchMatrixManipulator>
#include <osgGA/StateSetManipulator>
#include <osgGA/AnimationPathManipulator>
#include <osgGA/TerrainManipulator>
#include <iostream>
int main(int argc, char **argv)
{
    osg::ArgumentParser arguments(&argc, argv);
    arguments.getApplicationUsage()->setApplicationName(arguments.getApplicationName());
    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName() + 
        " is the standard OpenSceneGraph example which loads and visualises 3d models.");
    arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName() + 
        " [options] filename...");
    arguments.getApplicationUsage()->addCommandLineOption("--image <filename>", "Load an image and render it on quad");
    arguments.getApplicationUsage()->addCommandLineOption("--dem <filename>", "Load an image/DEM and render it on a HeightField");
    arguments.getApplicationUsage()->addCommandLineOption("-h or -help", "Display command line parameters");
    arguments.getApplicationUsage()->addCommandLineOption("--help-env", "Display environmental variables available");
    arguments.getApplicationUsage()->addCommandLineOption("--help-keys", "Display keyboard & mouse bindings available");
    arguments.getApplicationUsage()->addCommandLineOption("--help-all", "Display command line, env vars and keyboard & mouse bindings.");
    arguments.getApplicationUsage()->addCommandLineOption("--SingleThreaded", "Select SingleThreaded threading model for viewer.");
    arguments.getApplicationUsage()->addCommandLineOption("-CullDrawThreadPerContext", 
        "Select CullDrawThreadPerContext threading model for viewer.");
    arguments.getApplicationUsage()->addCommandLineOption("--DrawThreadPerContext", 
        "Select DrawThreadPerContext threading model for viewer.");
    arguments.getApplicationUsage()->addCommandLineOption("--CullThreadPerCameraDrawThreadPerContext",
        "Select CullThreadPerCameraDrawThreadPerContext threading model for viewer.");
    bool helpAll = arguments.read("--help-all");
    unsigned int helpType = ((helpAll || arguments.read("-h") || arguments.read("--help")) ?
        osg::ApplicationUsage::COMMAND_LINE_OPTION : 0 ) | 
                    ((helpAll || arguments.read("--help-env")) ?
        osg::ApplicationUsage::ENVIRONMENTAL_VARIABLE : 0) |
                    ((helpAll || arguments.read("--help-keys")) ?
        osg::ApplicationUsage::KEYBOARD_MOUSE_BINDING : 0);
    if (helpType)
    {
        arguments.getApplicationUsage()->write(std::cout, helpType);
        return 1;
    }

    osgViewer::Viewer viewer(arguments);
    if (arguments.errors())
    {
        arguments.writeErrorMessages(std::cout);
        return 1;
    }
    if (arguments.argc() <= 1)
    {
        arguments.getApplicationUsage()->write(std::cout, osg::ApplicationUsage::COMMAND_LINE_OPTION);
        return 1;
    }
    
    //添加一些操作器
    osg::ref_ptr<osgGA::KeySwitchMatrixManipulator> keyswitchManipulator = new osgGA::KeySwitchMatrixManipulator;
    keyswitchManipulator->addMatrixManipulator('1', "Trackball", new osgGA::TrackballManipulator());
    keyswitchManipulator->addMatrixManipulator('2', "Flight", new osgGA::FlightManipulator());
    keyswitchManipulator->addMatrixManipulator('3', "Drive", new osgGA::DriveManipulator());
    keyswitchManipulator->addMatrixManipulator('4', "Terrain", new osgGA::TerrainManipulator());
    
    std::string pathfile;
    char keyForAnimationPath = '5';
    while (arguments.read("-p", pathfile))
    {
        osgGA::AnimationPathManipulator *apm = new osgGA::AnimationPathManipulator(pathfile);
        if (apm || !apm->valid())
        {
            unsigned int num = keyswitchManipulator->getNumMatrixManipulators();
            keyswitchManipulator->addMatrixManipulator(keyForAnimationPath, "Path", apm);
            keyswitchManipulator->selectMatrixManipulator(num);
            ++keyForAnimationPath;
        }
    }
    viewer.setCameraManipulator(keyswitchManipulator.get());

    //添加状态事件
    viewer.addEventHandler(new osgGA::StateSetManipulator(viewer.getCamera()->getOrCreateStateSet()));
    viewer.addEventHandler(new osgViewer::ThreadingHandler);
    //窗口大小变化事件
    viewer.addEventHandler(new osgViewer::WindowSizeHandler);
    //添加一些常用状态设置
    viewer.addEventHandler(new osgViewer::StatsHandler);
    viewer.addEventHandler(new osgViewer::HelpHandler(arguments.getApplicationUsage()));
    viewer.addEventHandler(new osgViewer::RecordCameraPathHandler);

    osg::ref_ptr<osg::Node> loadedModel = osgDB::readNodeFiles(arguments);
    if (!loadedModel)
    {
        std::cout<<arguments.getApplicationName()<<": No data loaded"<<std::endl;
        return 1;
    }
    arguments.reportRemainingOptionsAsUnrecognized();
    if (arguments.errors())
    {
        arguments.writeErrorMessages(std::cout);
        return 1;
    }
    osgUtil::Optimizer optimizer;
    optimizer.optimize(loadedModel.get());
    viewer.setSceneData(loadedModel.get());

    viewer.realize();
    viewer.run();
}

　　吐槽一下作者，作为新手教程，搞这些乱七八糟的东西有什么用呢？

　　这个例子相比3.0版本，唯一的新东西就是有个模型优化。