Hi Peter, I'm afraid on just reading your email I can't get my head around the exact issue you are trying to address. Would it be possible for you to modify one of the OSG example to reproduce the problem?
Robert. On Fri, Dec 12, 2008 at 3:41 PM, Peter Hrenka <[email protected]> wrote: > Hi Robert, > > I have been chasing a bug in our osg-based application where a color change > resulted in a broken geometry (which uses VertexBufferObjects). > > The update of the VBO does not seem to work when "copyAll" is false > (i.e. total size did not change) and not all Arrays are modified: > > VertexBufferObject::compileBuffer(State& state) const > { > [...] > unsigned int offset = 0; > for(BufferEntryArrayPairs::const_iterator itr = > _bufferEntryArrayPairs.begin(); > itr != _bufferEntryArrayPairs.end(); > ++itr) > { > const BufferEntryArrayPair& bep = *itr; > const Array* de = bep.second; > if (de) > { > if (copyAll || > bep.first.modifiedCount[contextID] != > bep.second->getModifiedCount() || > bep.first.dataSize != bep.second->getTotalDataSize()) > { > // copy data across > bep.first.dataSize = bep.second->getTotalDataSize(); > bep.first.modifiedCount[contextID] = de->getModifiedCount(); > if (copyAll) > { > bep.first.offset = offset; > de->setVertexBufferObjectOffset((GLvoid*)offset); > offset += bep.first.dataSize; > } > [...] > > The "offset" variable is only updated when the particular Array > has changed. If only the second of two arrays changes it writes at offset 0 > (where the first array starts) so both arrays will have an > offset of 0. > > I think a proper fix which also properly handles array additions/removals > would have to use free-lists (or some > other memory management scheme). > > I can not think of a simple fix which still minimizes updates. > > Regards, > Peter > -- > Vorstand/Board of Management: > Dr. Bernd Finkbeiner, Dr. Florian Geyer, > Dr. Roland Niemeier, Dr. Arno Steitz, Dr. Ingrid Zech > Vorsitzender des Aufsichtsrats/ > Chairman of the Supervisory Board: > Prof. Dr. Hanns Ruder > Sitz/Registered Office: Tuebingen > Registergericht/Registration Court: Stuttgart > Registernummer/Commercial Register No.: HRB 382196 > > _______________________________________________ > 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
