I am not an experienced OpenGL programmer, but with the help of our resident programmer we have identified a possible source for a recurrent problem with video synchronization on linux PCs
We are studying perception and using stimuli which flash on the screen for a 150 milliseconds. We are using swapbuffers and very simple stimuli (Big solid sqaures).
No matter how simple the display, we get a screen swap that is not tied to the moniter refresh (causing a very noticable flicker). The monitor runs at 76Hz, but it seems that OpenGL is defaulting to 60Hz for video sync. Furthermore, we have been unable to get access to the video blank signal to identify the start of a refresh. We have also used glXGetVideoSync without a success.
Is this problem our…
A. code. Is there some trick we don’t
B. video. Unsupported video card?
C. OS. Does Linux support video sync?
D. PC. Do PC’s have a video blank
command for vsync access?
[The same program had run without this problem on a SGI O2] We are using a Matrox G100 videocard and a good Mitsubishi monitor, Pentium 2 about 350MHz. This problem has also been seen with a newer machine running an Riva TNT card.
If you have any suggestions please email me at: