Synchro to video blank on Windows.

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Synchro to video blank on Windows. Richard Lemieux Apr 17, 2013 top right image
Hi everyone,

I am developing an application showing running sonograms on an FLTK panel and I am having a hard time understanding how tho have VBlank synchro work on Windows.  The same app is running without a glitch on Linux.

I have made tests on 1) an ASUS based Intel PC with NVIDIA video running Windows8 and 2) on a TabletPC with Intel video running Windows7.

I am not sure the TabletPC handles VBlank, but my tests show that it behaves differently depending on whether I use,

  wglSwapIntervalEXT1(1) or wglSwapIntervalEXT1(0)

in the OpenGL context of the panel (the ::draw() function).

The NVIDIA based PC definitely supports VBlank but the display still looks choppy in full screen mode although it is not too bad otherwise.

The program is usable but I would much prefer to solve this issue since most users would run the Windows version.

I welcome any clue on how to setup VBlank on a FLTK app on Windows.  Of course I already played with the NVIDIA setting utilities and tried all related settings there.  I have checked the timings and I can check that the painting of the video buffer occurs just before the VBlank is due (if I understand correctly).  The same timing approach works well on Linux.
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