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JNK
12-15-2003, 12:52 AM
The combination in the subject line seems to be a bit off-mainstream. At least, nobody seems to know hard facts about it.
Some people say it works only on special video cards, some say it works only with special drivers, and some say it doesn't work at all.

I neeed to display full screen images on the secondary display on Win2k as fast as possible.
Can this be done with OpenGL?

bunny
12-15-2003, 03:40 AM
Yes. I run exactly the same spec. Windows just treats the entire desktop as a single display. Just set the window x offset to be equal to the width of the primary display when you create the window.

ZbuffeR
12-15-2003, 03:46 AM
Originally posted by bunny:
Windows just treats the entire desktop as a single display.
True, but Windows won't let you have accelerated opengl this way, unless you have ONE card with 2 monitor outputs, as is found on many recent cards.

bunny
12-15-2003, 05:31 AM
I'm assuming that's what he's doing.

JNK
12-15-2003, 07:25 AM
I have tried two cards with 2 monitor outputs (Matrox G550 Dualhead and ATI Radeon 9200). What I'm trying to do is displaying images synchronized to vsync in 60Hz. Copying buffers is simply not fast enough, so I need to do it fullscreen (not just in a big window that covers the entire screen). The result: I experience tearing (the upper 1/5 of the display is out of sync). This does not happen on the primary display, which can be switched in "real" fullscreen mode. (And, by the way, it does not happen on my old nVidia Riva TNT.)
Sorry if this sounds a bit confusing, but it's a difficult problem!

azazello
12-15-2003, 03:00 PM
Nvidia & 3DLabs can accelerate second output on monitor in OpenGL (becouse original MS OpenGL entry point is only for 1st monitor and they use some kind of hack in implementation).

rgpc
12-15-2003, 05:23 PM
Originally posted by ZbuffeR:

True, but Windows won't let you have accelerated opengl this way, unless you have ONE card with 2 monitor outputs, as is found on many recent cards.



I seem to remember having read that you can get acceleration on your second card - but it must be of the same type as your primary (ie. Two geforces etc...). I guess the problem is that there's probably no PCI versions of anything later than a geforce 256 or maybe a gf2... But a "dual head" card is more than likely a better way to go anyway...

knackered
12-15-2003, 11:36 PM
No, you just can't get OpenGL acceleration on 2 individual cards, but you can get GL acceleration on the primary and D3D acceleration on the secondary, which could be regarded as a work around.

JNK
12-15-2003, 11:40 PM
I don't want to use two individual cards but one card with two outputs. I just tried two of them which both didn't work. Sorry if this was unclear.

knackered
12-16-2003, 04:59 AM
Well, it will work on nvidia and 3dlabs cards, that's almost 100% sure - as for ati and matrox, well, it sort of depends whether their driver writers have had a good nights sleep come release day.