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. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
