FYI "push_back() on an pre-reserved() vector/container should not be a performance issue."
Under debug in visual studio, if you are storing anything other than a pointer, then a push_back etc will still incure a 'new and a copy' and this can get expensive if your doing a lot of them, under release this handled more efficiently Gordon Product Manager 3d __________________________________________________________ Gordon Tomlinson Email : gtomlinson @ overwatch.textron.com __________________________________________________________ -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Peter Hrenka Sent: Thursday, March 26, 2009 8:16 AM To: OpenSceneGraph Users Subject: Re: [osg-users] Most efficient way to use osg::DrawElementsUInt? Hi Jesper, Jesper D. Thomsen schrieb: > Hi, and thank you. > > I naturally tried to use reserve() (but thanks for suggesting it) and this of course helped somewhat, but it still seems to be the primary bottleneck. I've changed most of the rest of the per-frame geometry generation code to use static arrays rather than std::vector and this caused a major speedup (factor 10 or more) of my own part of the code, but I'm still stuck with the push_backs on osg::DrawElementsUInt. > Maybe there's just no faster way to do it, or maybe I'm just using OSG in a somewhat un-intended way. > > Jesper D. Thomsen Just some more ideas/comments: Are you testing a release build? Debug-Verions (especially on Windows) are known to have dramatically slower implementations. What profiling tool are you using? Sometimes the output is misleading and can point you in the wrong direction. As from my experience push_back() on an pre-reserved() vector should not be a performace issue. If you can spare the memory you could also try swap(), implementing your own double-buffering for your osg::DrawElements. Cheers, Peter > ________________________________________ > From: [email protected] > [[email protected]] On Behalf Of Peter Hrenka > [[email protected]] > Sent: Thursday, March 26, 2009 12:00 PM > To: OpenSceneGraph Users > Subject: Re: [osg-users] Most efficient way to use osg::DrawElementsUInt? > > Hi Jesper, > > Jesper D. Thomsen schrieb: >> Hi all, I'm developing an application where I have to create up to >> 1000 osg:geometry objects per frame during certain interaction modes. >> I'm using osg::DrawElementsUInt push_back() to define the geometry >> primitive sets, and this push_back() seems to be the primary >> bottleneck for my applications graphical performance. Is there a more >> efficient way to define the primitive sets than to fill a >> osg::DrawElementsUInt by push_back and add it to the geometry? >> >> This is currently bringing me down to about 1 second per frame, which >> is kind of a roadblock. > > You can use reserve() to pre-allocate the needed memory. > After that push_back() will not perform any reallocations/copies until > the limit is reached. > >> regards, >> >> >> Jesper D. Thomsen >> > > Cheers, > > Peter -- Vorstand/Board of Management: Dr. Bernd Finkbeiner, Dr. Roland Niemeier, Dr. Arno Steitz, Dr. Ingrid Zech Vorsitzender des Aufsichtsrats/ Chairman of the Supervisory Board: Michel Lepert 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.or g _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
