Hi Alex, If your frame rate drops when you zoom it suggests you are fill limited which shouldn't be related to the FBO/PixelBuffer/FrameBuffer choice for the RTT as it's res is fixed. Hight RT cost would make give the app less time to do this fill so perhaps the extra fill is just the final straw that broke the camels back.
W.r.t FBO RTT performance - it should be better than PixelBufer/FrameBuffer as it will avoid the need to a copy to texture (there isn't GLX support for PixelBuffer Render To Texture). If you are getting worse performance then this is a driver issue. What drivers/hardware are you using? Robert. On Mon, Oct 13, 2008 at 5:03 PM, Alexander Löffler <[EMAIL PROTECTED]> wrote: > Hi all, > > I am using OSG 2.6.0 on Linux. I am currently trying to render a subgraph of > my > scene to texture and then use that rendering again visibly at another place in > my scene. I am experiencing some performance problems I would not expect: > > When using an unmodified osgprerender example on a 1680x1050 screen and moving > the camera closer to the waving flag, my frame rate drops from 60fps to 30fps > (I > am using a v-synced setting). > > The GPU load seems unusually high for me with 20+ms spent on the GPU in that > case. Is this a normal value? > > Why is the performance better when rendering the texture to frame buffer or > pixel buffer (both ~12-14ms) than when rendering to frame buffer object > (20+ms), > which AFAIK is the standard for doing rendering to texture? > > Thanks for your help, > Alex. > _______________________________________________ > 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
