View Full Version : OpenGL / Windows Vista problem

09-25-2008, 02:35 AM
I'm using OpenGL through QT on windows Vista. GDI isn't used.
However the screen (windowed mode) seems to ignore all GL calls once a drawing is loaded. That is, my background is grey and the cursor which is rendering with GL lines is not visible.
Alt-Tab'ing applications fix this however, everything becomes visible.
I read through few docs about OpenGL on Vista and tried out things. Someone has experience in that or any general hits about Vista/OpenGL?


btw. Does Vista handle 2 monitors as 2 separate back/front buffers?

09-25-2008, 03:18 AM
It may be a problem with Qt, like not passing the refresh events.
Try to force redisplay on the Qt canvas, ie. by sending repaint messages after start ?

About backbuffers, I would say it depends on the card and driver, and on the display mode (pan vs dual-view).

09-25-2008, 05:22 AM
Thanks ZbuffeR.

To the monitor problem:
I have 2 monitors connected and reading pixels from first screen via glCopySubPixels2d() returns pixels that are actually in the backbuffer whereas moving the window to another screen gives me trash data instead. I am using pan view to drag windows from one screen to another. All works fine under XP though. Cant figure out if it's the code or the model of Vista or ... ?

09-25-2008, 11:32 AM
what card and drivers ? you tried more recent ones ?

09-26-2008, 02:18 AM
It's a Quadro FX 1400. All recent drivers installed. Guess its something with Windows Vista. I actually never did something on Vista before up untill now. So really in the dark here.
Wondering if something might do with glReadBuffer() values other the GL_BACK or GL_FRONT here.

09-28-2008, 11:06 AM
Don't use front buffer with vista.
Some older articles, but that may help you :

09-29-2008, 02:32 AM
Thanks ZBufferR. I read those already. What you mean by not using front buffers.
I mean why? Im actually always on GL_BACK to read data i once rendered before swapping buffers.

09-29-2008, 08:21 AM
Sorry I misread your previous comment, I though you were reading from GL_FRONT.
No more ideas.