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Old May 29th 19, 09:18 AM posted to microsoft.public.windowsxp.general
R.Wieser
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Posts: 1,302
Default Geforce GTX 275 - OpenGL initialisation problem when program is started from the commmand console.

Paul,

I don't know all the details of how this works, but a dual head video card
seems to have two "accelerated channels" max ....


Thanks for the explanation. I was not even aware that there was more than a
single hardware acceleration "pipe" present.


After mulling over what you wrote I realized I forgot to mention something
thats (most likely) important : My "command prompt" window is full-screen
(80x25 char). So when a GUI program is started the OS first has to switch
from text to graphics mode.

In other words, My hunch is that the mode switching is the culprit here (the
OpenGL 3D initialisation done when the display isn't fully in graphics
mode).

and you could tell there was something wrong when a second program wanted
to use acceleration. The second context would stutter.


For a test I started the program three times (present at the same time) :
The first from a fullscreen commandprompt. It has the 'drunken' texture.
The second from a windowed commandprompt. It works OK. The last one by
doubleclicking the program (in the file explorer). It works OK too.

If its a "no more acceleration pipes available" I would have expected the
latter two to have problems too.

I also started them in reverse order. Still only the program started from
the fullscreen commandprompt has the 'drunken' texture.


For another test I made the program display a messagebox before creating the
dialog (causing the OS to switch to GUI mode before initializing the 3D
environment), and surprise, surprise, no more 'drunken' texture or
stuttering.

In other words, all of the above tests seems to confirm my suspicion that
the switching from text to graphics mode causes the problem ...


I still wonder why that the Geforce GTX 275 videocard has a problem with it
(or which settings gouvern it), but a build-in videocard (and accompanying
drivers) of my Optiplex 745 'puter doesn't.

By the way: I also tried to change the hardware acceleration support itself
(rightclick on desktop - properties - settings - advanced -
troubleshoot - slider), but that didn't change anything.


.... crap. I wanted to keep it an small question. Not a waterfall of tests
and hunches. :-\

Regards,
Rudy Wieser


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