Hi guys, We have performance issues when using many FBOs (5-10 buffers, 6-15 passes per frame), only occuring in later drivers. I just thought to ask here about this as well, to see if anyone else has seen this problem (and have a solution?)
Below is a short description of the problem. Any insight is greatly appreciated (as always :). Cheers /Marcus _________________ The performance problems that we have with the post 81.95 drivers are related to the "frame buffer objects" extension, and render-to-texture. Binding a frame buffer object and clearing render targets is significantly slower than in previous driver releases. Since we use many different targets in our volume rendering algorithm, the increased cost has a big impact on the rendering time. Times spent in affected functions: Driver version glClear glBindFramebufferEXT 81.95 4.1% 5.3% 93.71 31.4% 42.8% There are a number of possible explanations to this problem: * There is a bug in NVIDIA’s driver. * NVIDIA has optimized the latest drivers for different usage. * The way we use the API and the extensions is not correct, and the new drivers are not as forgiving as the older ones. Things to consider: * In one of the examples that come with Open Scene Graph (osgprerendercubemap) there is an identical performance problem. * gDEBugger does not report fallbacks to software emulation. * There is a support function in the frame buffer objects extension (glCheckFramebuffersEXT) which indicates that the buffers are valid. * NVIDIA use one code base for all of their drivers, which means that adding support for new cards and features, may reduce the performance for older cards. ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Opensg-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/opensg-users
