OpenSceneGraph/examples/osgscribe/osgscribe.cpp

#include <osg/Geode>
#include <osg/Group>
#include <osg/Notify>
#include <osg/Material>
#include <osg/PolygonOffset>
#include <osg/PolygonMode>
#include <osg/LineStipple>

#include <osgDB/Registry>
#include <osgDB/ReadFile>

#include <osgProducer/Viewer>

#include <osgUtil/Optimizer>

int main( int argc, char **argv )
{

    // use an ArgumentParser object to manage the program arguments.
    osg::ArgumentParser arguments(&argc,argv);

    // set up the usage document, in case we need to print out how to use this program.
    arguments.getApplicationUsage()->setDescription(arguments.getApplicationName()+" is the example which demonstrates how to use multi-pass and state inheritance to create a scribed rendered effect.");
    arguments.getApplicationUsage()->setCommandLineUsage(arguments.getApplicationName()+" [options] filename ...");
    arguments.getApplicationUsage()->addCommandLineOption("-h or --help","Display this information");
   
    // construct the viewer.
    osgProducer::Viewer viewer(arguments);

    // set up the value with sensible default event handlers.
    viewer.setUpViewer(osgProducer::Viewer::STANDARD_SETTINGS);

    // get details on keyboard and mouse bindings used by the viewer.
    viewer.getUsage(*arguments.getApplicationUsage());

    // if user request help write it out to cout.
    if (arguments.read("-h") || arguments.read("--help"))
    {
        arguments.getApplicationUsage()->write(std::cout);
        return 1;
    }

    // any option left unread are converted into errors to write out later.
    arguments.reportRemainingOptionsAsUnrecognized();

    // report any errors if they have occured when parsing the program aguments.
    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;
    }

    // load the nodes from the commandline arguments.
    osg::Node* loadedModel = osgDB::readNodeFiles(arguments);
    if (!loadedModel)
    {
        return 1;
    }
  
    // to do scribe mode we create a top most group to contain the
    // original model, and then a second group contains the same model
    // but overrides various state attributes, so that the second instance
    // is rendered as wireframe.
    
    osg::Group* rootnode = new osg::Group;

    osg::Group* decorator = new osg::Group;
    
    rootnode->addChild(loadedModel);
    
    
    rootnode->addChild(decorator);
    
    decorator->addChild(loadedModel);  

    // set up the state so that the underlying color is not seen through
    // and that the drawing mode is changed to wireframe, and a polygon offset
    // is added to ensure that we see the wireframe itself, and turn off 
    // so texturing too.
    osg::StateSet* stateset = new osg::StateSet;
    osg::Material* material = new osg::Material;
    osg::PolygonOffset* polyoffset = new osg::PolygonOffset;
    polyoffset->setFactor(-1.0f);
    polyoffset->setUnits(-1.0f);
    osg::PolygonMode* polymode = new osg::PolygonMode;
    polymode->setMode(osg::PolygonMode::FRONT_AND_BACK,osg::PolygonMode::LINE);
    stateset->setAttributeAndModes(material,osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON);
    stateset->setAttributeAndModes(polyoffset,osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON);
    stateset->setAttributeAndModes(polymode,osg::StateAttribute::OVERRIDE|osg::StateAttribute::ON);
    stateset->setMode(GL_LIGHTING,osg::StateAttribute::OVERRIDE|osg::StateAttribute::OFF);
    stateset->setTextureMode(0,GL_TEXTURE_2D,osg::StateAttribute::OVERRIDE|osg::StateAttribute::OFF);
    
//     osg::LineStipple* linestipple = new osg::LineStipple;
//     linestipple->setFactor(1);
//     linestipple->setPattern(0xf0f0);
//     stateset->setAttributeAndModes(linestipple,osg::StateAttribute::OVERRIDE_ON);
    
    decorator->setStateSet(stateset);
  
    
    // run optimization over the scene graph
    osgUtil::Optimizer optimzer;
    optimzer.optimize(rootnode);
     
    // add a viewport to the viewer and attach the scene graph.
    viewer.setSceneData( rootnode );
    
    // create the windows and run the threads.
    viewer.realize();

    while( !viewer.done() )
    {
        // wait for all cull and draw threads to complete.
        viewer.sync();

        // update the scene by traversing it with the the update visitor which will
        // call all node update callbacks and animations.
        viewer.update();
         
        // fire off the cull and draw traversals of the scene.
        viewer.frame();
        
    }
    
    // wait for all cull and draw threads to complete before exit.
    viewer.sync();

    return 0;
}