OK thank you Bruce for the info. Cheers,
On Wed, Apr 21, 2010 at 8:53 AM, Bruce Wheaton <[email protected]>wrote: > Serge, as Robert says, TwinView is what you need. > > Here's the deal. On Nvidia non-Quadro cards on Linux, the only way to > guarantee no tearing on one screen is: > > UBB flipping enabled, > > full screen OpenGL app, no obstructions, > > Vsync flag with that screen number - there's an environment variable. > > For dual screens, TwinView, with both screens with the *exact* same res and > rate - same modeline, basically, > > one OpenGL window/context filling both screens. > > The way you're doing, with two contexts, will tear. > > On Quadro cards, almost all conditions are lifted. > > Bruce > > > > On Apr 20, 2010, at 6:44 AM, Serge Lages wrote: > > Hi all, > > I'm currently having a problem with NVidia hardware on Linux, it's not > directly OSG related, but I hope someone here can help me. > > Here is my setup : > > Ubuntu 9.10 > 195.36.15 NVidia drivers > 2 GTX 285 graphic cards (one DVI, one VGA and one HDMI port) > 4 screens (2 screens on each cards), all independents (no twinview) > Compiz disabled > > On this setup, I have an OSG application running full-screen on all 4 > screens (a CompositeViewer with 4 views). My app is running at 60fps when > VSync is on, it's the screens refresh rate. > > When I enable "Sync to VBlank" in the Nvidia-settings, here is the current > result : > - On the first screen of each cards (plugged on the DVI port), the VSync is > perfect, no tearing. > - On the second screen of each cards (plugged on the VGA port), tearing is > noticeable on the upper part of the screens (I have a line about 100 pixel > far from the top of the screens). > => Result : 2 screens without tearing, 2 screens with tearing in a specific > location. It seems VSync is not really performed on the second screen of > each cards. > > I have also tested on GTX285 cards with 2 DVI ports with the same result. > Another note : the 4 screens are the same, all plugged in VGA with the same > resolution (using an adaptor when plugged in the card DVI ports). I've > tested with other screens with the same result. > > Anyone knows where this problem comes from ? And any idea how to solve it ? > Is it a bug in recent drivers, maybe I should test olders ? > Thanks in advance for your help. > > Best regards, > > -- > Serge Lages > http://www.tharsis-software.com > _______________________________________________ > 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 > > -- Serge Lages http://www.tharsis-software.com
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