[osg-users] [Any feedback welcome] possible lack of robustness of the VAO path

[Julien Valentin]

The following code exibits crashes with VAO path 
 
Code:

#include <osgUtil/MeshOptimizers>
#include <osgGA/TrackballManipulator>
#include <osgGA/FirstPersonManipulator>

#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>

#include <osgDB/ReadFile>
#include <osgDB/WriteFile>


class GeomLoaderCB : public osg::Camera::DrawCallback//  osg::NodeCallback
{
public:
    int _thresremoval;int _nbaddedatatime;
    GeomLoaderCB(int thresremoval=1,int nbaddedatatime=1):_nbaddedatatime(nbaddedatatime),_thresremoval(thresremoval) {}
    mutable std::list<osg::ref_ptr<osg::Geometry> > _geoms;
    void setGeometryList(osgUtil::GeometryCollector::GeometryList c) {
        for(auto f : c)
            _geoms.push_back(f);
    }
    virtual void operator () (const osg::Camera&  camera ) const {
        osg::Node * node=const_cast<osg::Camera*>(&camera)->getChild(0);

        if(_geoms.empty())return;
        osg::ref_ptr<osg::Group>  gr = node->asGroup();

        if(gr->getNumChildren()>_thresremoval)
        {
            OSG_WARN<<"removing "<<  gr->getChild(0)<<std::endl;
            gr->removeChildren(0,1);
            return;
        }

        std::list<osg::ref_ptr<osg::Geometry> > ::iterator it= _geoms.begin();
        int cpt=0;
        while(it!=_geoms.end()&&cpt++<_nbaddedatatime ) {
            gr->addChild((osg::Drawable*) (*it)->clone(osg::CopyOp::DEEP_COPY_ALL));
            OSG_WARN<<"add "<<  (*it ) ->getVertexArray()->getNumElements()<<std::endl;
            it=_geoms.erase(it);
        }
        return;
    }

};


/// This demo reproduce a bug with OSG_VERTEX_BUFFER_HINT=VAO
/// it collecte drawables given in arg then add and remove them at runtime
int main(int argc, char **argv)
{
    osg::ArgumentParser args(&argc,argv);
    unsigned int  geomcountaddedatatime=1,geomcountabovewichweremove=1;
    while(args.read("--add",geomcountaddedatatime) ) { }
    while(args.read("--remove",geomcountabovewichweremove) ) { }
    osgUtil::GeometryCollector geomcollector(0,osgUtil::Optimizer::ALL_OPTIMIZATIONS);

    args.getApplicationUsage()->setApplicationName(args.getApplicationName());

    osg::ref_ptr<osg::Node > loaded=osgDB::readNodeFiles(args);
    if(loaded.valid())
    {
        loaded->accept(geomcollector);

        osg::Group * root=new osg::Group;
        //osg::Camera * root=new osg::Camera;
        GeomLoaderCB * loader=new GeomLoaderCB(geomcountabovewichweremove,geomcountaddedatatime);
        loader->setGeometryList(   geomcollector.getGeometryList() );

        osgViewer::Viewer viewer;
        viewer.addEventHandler(new osgViewer::StatsHandler);
        viewer.addEventHandler(new osgViewer::WindowSizeHandler);
        viewer.addEventHandler(new osgViewer::ThreadingHandler);

        viewer.realize();
        viewer.setSceneData( root);

        viewer.getCamera()->setFinalDrawCallback(loader);
        loaded=0;

        viewer.run();
    }
}




if you want my test sample:
https://drive.google.com/file/d/0BxIH-jcsgYDdTG5ha21HZE1jX1E/view?usp=sharing
for ex It fails  with args :
BIGCITY.ive --remove 150 --add 100 

I believe there's a bug....so I'd be glad if someone validate it...
note: toggling statshandler prevent crash

Thanks in advance
Cheers




mp3butcher wrote:
> Hi all,
> I wrote a sample code exibiting crash with my scene
> https://github.com/openscenegraph/OpenSceneGraph/issues/692
> 
> If you'd have 5 min to waste, i would be glad you confirm with your own scene...
> 
> Thank you!
> 
> Cheers,
> Julien


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