Artifacts in dual screen mode, probably related to vertical sync

Hey all,
the project I am working on has been working perfectly until it has been tried on the Mac Mini running Lion that will be used during the installation,with GLUT in extended desktop mode spanning across tow screens. The image gets cut in horizontal bars and they all get scrambled (see the picture of the wall, whose should be lines, not segments).
For what I can guess, being no expert, this is related to the vertical sync. I have tried both enabling and disabling the “Default synchronize to vertical blank” checkbox in the GLUT options panel (and saved in the GLUT prefs), and I have tried to disable vertical sync from the code. I still haven’t tried to call ofSetVerticalSync(true) being at some 10k km from the installation site I need a person to go there each time I give it a try… very annoying.

The mac mini is attached to 2 projectors with a total resolution of 2560x800 using this

Thunderbolt to vga adapter (1280x800)
hdmi to vga adpater (1280x800)

Do you think all this messing up with digital/analog and various port types can be the cause of the problem? Any suggestion to get it working?
Thank you
Alessandro

Update!

In light of what they have reported from the installation site, I got that it was something related to the FBOs I am using. Removing double buffering… and voila, the program works fine on the mac mini too. I have no idea about why the fbos and double buffering are not working together on the macmini, but oh well, it works now :slight_smile:
things that start working at 20:00 of a saturday evening, that is a bless, time for a beer!