Hi Robert (list) Im trying to use the ReadFileCallback to load the heightfield int my physics engine.
So far I have been using a CullVisitor to grap the triangles from the finished scene, but it has major drawback in that it forces me to load the data as meshes which is terrible for memmory and takes a long time to load. It seams im able to load the data as heightfields from the ReadFileCallback, but this leads to my next problem. I need a way to reference the data later, to be able to remove it when tiles are deletet and disable it when tiles are disabled by the scene cullvisitor. Is there a way to relate the nodes i visit in my ReadFileCallback to nodes i visit in a special cullvisitor for the final scenegraph? Basically do you have any hints on how to syncronise the state of my physics engine with the state of my Paged VPB terrain? Brgs. Ralf Stokholm 2009/4/2 Ralf Stokholm <[email protected]>: > Hi Robert > > Thanks a lot, was starting to get at this but using a more primitive > approach of running through all the children of the node that I did > get. > > Will try to implement your method. > > Brgs. > > Ralf Stokholm > > 2009/4/2 Robert Osfield <[email protected]>: >> Hi Ralf, >> >> You'll need to write a custom NodeVisitor that traverses through the loaded >> scene graph and picks out the TerrainTile using dyanmic cast. It just so >> happens that I'm actually working on a ReadFileCallback/custom Visitor that >> does pick out all the TerrainTile's in a subgraph (there will typically be >> one, two or four due to the quad tree structure generated by VPB.) >> >> The visitor looks like: >> >> class FindTerrainTileVisitor : public osg::NodeVisitor >> { >> public: >> FindTerrainTileVisitor(): >> osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN) >> { >> } >> >> void reset() >> { >> _terrainTiles.clear(); >> } >> >> void apply(osg::Group& group) >> { >> osgTerrain::TerrainTile* terrainTile = >> dynamic_cast<osgTerrain::TerrainTile*>(&group); >> if (terrainTile) >> { >> _terrainTiles.push_back(terrainTile); >> } >> else >> { >> traverse(group); >> } >> } >> >> typedef std::list< osg::ref_ptr<osgTerrain::TerrainTile> > TerrainTiles; >> TerrainTiles _terrainTiles; >> }; >> >> The custom ReadFileCallback's readNode method looks like: >> >> virtual osgDB::ReaderWriter::ReadResult readNode(const std::string& >> filename, const osgDB::ReaderWriter::Options* options) >> { >> osg::notify(osg::NOTICE)<<"Loading tile "<<filename<<std::endl; >> osgDB::ReaderWriter::ReadResult result = >> osgDB::Registry::instance()->readNodeImplementation(filename,options); >> if (result.validNode()) >> { >> FindTerrainTileVisitor fttv; >> result.getNode()->accept(fttv); >> for(FindTerrainTileVisitor::TerrainTiles::iterator itr = >> fttv._terrainTiles.begin(); >> itr != fttv._terrainTiles.end(); >> ++itr) >> { >> osgTerrain::TerrainTile* terrainTile = itr->get(); >> ///.... my stuff omitted, put your stuff here >> } >> } >> } >> >> >> Robert. >> >> On Thu, Apr 2, 2009 at 1:05 PM, Ralf Stokholm <[email protected]> >> wrote: >>> >>> Hi List >>> >>> Im trying to get the heightfiled data from a VPB terrain using >>> ReadFileCallback. >>> >>> I use the code from readfile callback like this. >>> >>> class MyReadFileCallback : public osgDB::Registry::ReadFileCallback >>> { >>> public: >>> virtual osgDB::ReaderWriter::ReadResult readNode(const >>> std::string& fileName, const osgDB::ReaderWriter::Options* options) >>> { >>> // note when calling the Registry to do the read you have to >>> call readNodeImplementation NOT readNode, as this will >>> // cause on infinite recusive loop. >>> osgDB::ReaderWriter::ReadResult result = >>> osgDB::Registry::instance()->readNodeImplementation(fileName,options); >>> if (result.validHeightField()) >>> { >>> LOG_ERROR("Found a valid HeightField"); >>> } >>> return result; >>> } >>> }; >>> >>> The idea was simply to see if I had the heightfield available, but >>> even though I have verified that it gets called it is never a valid >>> heightfield. >>> >>> This is on a terrain build using VPB with the --TERRAIN option. >>> >>> Shouldent I be able to get the heightfieldnodes? >>> >>> Brgs. >>> >>> Ralf Stokholm >>> _______________________________________________ >>> osg-users mailing list >>> [email protected] >>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> >> >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> >> > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
