Hi Ralf, If you need to keep the memory around then use a ref_ptr<> to the HeightField, but... this will keep the memory around so if you do no longer need it you might want to implement a scheme to free it, such as watching when the ref count goes to one.
The other approach is to use an observer_ptr<> that doesn't change the ref count of the HeightFiled, and gets reset to 0 when the HeightField get deleted. You can also use a custom osg::Observer to watch for object deletions as well. Robert On Fri, Apr 3, 2009 at 11:22 AM, Ralf Stokholm <[email protected]>wrote: > 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 >
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