One last question, your client that got a solid 60Hz, what kind of CPU usage did they see?
-Ken. I can't really add much as I've explained about the osgTerrain database sampling already - you just need to try it. As for the hardware, yep this should be able to cope, the client I worked with in the VPB work is using similar hardware and OS and getting solid 60Hz so I would expect you to be able to achieve similar. W.r.t checking for VBO issue, go read the recent thread on this Intel VBO crash. Robert. On Fri, Aug 15, 2008 at 3:25 PM, Sewell, Kenneth R Civ USAF AFMC AFRL/RYZW <[EMAIL PROTECTED]> wrote: > Hi Robert, > > I can't speak for the hardware on the windows machine, but the linux box > I tested with was a Quad core 2.6Ghz machine with 4GB memory and a > GeForce 8800 GTX 768MB with the latest Nvidia drivers(with Sync to > VBlank set). I'm pretty sure the hardware specs are not the problem, so > what's to best way to check for VBO issues? I've never had to down > sample any of the OSG databases before, so I was surprised when I tried > the --terrain option. I'm not sure I understand all the benefits of > --terrain over the default. The --terrain option doesn't do any > simplification of the terrain during build time, it just produces a > regular triangulated grid and expects you to use it or sample it in some > way at runtime, correct? But the default does do terrain > simplification, so you get longer build times but much less polygons at > runtime. Assuming I'm not way off base there, --terrain would only seem > to be recommended if you plan on doing some custom sampling or other > manipulation at runtime. I apologize if this has been addressed before, > but I haven't had much luck finding a clear explanation on the wiki or > mailing list archives. > To put my results in context, the database I'm testing with is a > whole earth model with SRTM and DTED(1&2) elevation, and 2 texture > layers consisting of Bluemarble NG, Landsat7, Quickbird and CADRG > imagery. > > - Ken. > > Hi Ken et. al, > > On Thu, Aug 14, 2008 at 7:01 PM, Sewell, Kenneth R Civ USAF AFMC > AFRL/RYZW <[EMAIL PROTECTED]> wrote: >> We had similar issues with terrain recently. On windows it was single > digit >> framerates and the same database on Linux was 30 fps but %100 on 2 > cores. >> Rebuilding our terrain without the -terrain flag solved the issue. >> Framerates on windows jumped up to 30 fps, Linux to 60 fps with %30 on > 1 >> core. We tried this with several databases and the ones without > -terrain >> always performed better. > > Performance problems when using --terrain (i.e. an > osgTerrain::TerrainTile based database) suggests either problems with > VBO's or that your graphics hardware simply isn't up to the amount of > geometry being pushed to the graphics hardware. The osgTerrain based > databases deliberately use high resolution (64x64 by default) tiles, > and the default GeometryTechnique used doesn't do any simplification > in its default settings. What you get is very high fidelity databases > but... lots and lots of polygons. > > The solution is very simple - as osgTerrain tessellates the > TerrainTile on loading its able to down sample the tiles to a user > defined level, so on hardware that is less capable you can use a lower > sample ration, and better hardware use a sample ration of 1.0. To > control this you simply decorate your paged database with an > osgTerrain::Terrain and set the SampleRatio here. The > osgmultitexturecontrol example provides code to do this, as well as an > event handle to vary the sample density. > > The osgmultitexturecontrol example has an -r <sampleratio> command > line option so try: > > osgmultitexturecontrol -r 0.25 mydatabase.ive > > Robert. > > _______________________________________________ > 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.or g _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
