R.Wieser wrote:
Hello all,

Recently I noticed that in a program I wrote (using OpenGL) the texture
"moves" over the quad it was put upon as if its drunk (the texture sways
from side to side depending on the (horizontal) angle of the camera towards
it. Also, when I moved toward the (rather simple) scene the redrawing
started to stutter, as if the redraw took a lot of time - for me an
indication that the whole thing was running on software, instead of using
hardware accelleration.

I first presumed I must have done something stupid, but at some point I
noticed that it only happened when I started the program from the
commandprompt, but not when double-clicking it (already being in a GUI).

The thing is that the exact same program on another computer has zero
problems being started either way - an indication is driver/videocard
related.

Does anyone here recognise the problem and videocard, and knows if this is a
simple settings problem - and in that case which one ?

The OS is XPsp3 Pro. The videocard is an nvidia Geforce GTX 275.

Regards,
Rudy Wieser

I don't know all the details of how this works, but a dual
head video card seems to have two "accelerated channels" max
to use. If one of the accelerated channels loses its driver
(this has happened to me), then only the original context
is accelerated, and you could tell there was something
wrong when a second program wanted to use acceleration.
The second context would stutter.

I think one driver that came with the Windows OS install disc,
suffered from this problem. Installing a later proprietary
driver, fixed it. (I could iconify a game, and open a
second application that needed acceleration, without a problem.)

And I don't know if there are any utilities for detecting this either.
Stuff like GPU-Z provides a lot of info, but it's basically "card-wide"
properties. And there is also an OpenGL utility "glview500.exe"
which has "openglex.exe" as its installed executable. But it
does not illuminate the two display channels either. There's
no evidence that a context is missing because of a driver
problem when using that. I seem to have more than one version
of that floating around, and the installer for glview500 said
"there's already one installed" and perhaps that's an older
version.

C:\Program Files\realtech VR\OpenGL Extensions Viewer 3.0
openglex.exe 663,040 bytes (properties pane is blank!)

Paul