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cragwolf
05-11-2003, 03:41 PM
I am confused about something. I have a GeForce2 GTS, and in the Windows control panel I can enable 2X and 4X antialiasing. Now, I don't think they use the accumulation buffer jitter technique for this, because it would be too slow. So my next thought was that they were using the WGL_ARB_multisample extension, but then I found that my card doesn't support this extension. So how on Earth are they doing this AA and how can I access this functionality from within my own programs?

Korval
05-11-2003, 06:56 PM
Your card is probably doing some form of supersampling. However, it probably lacks the ability to do the filtering internally, so the driver is probably rendering at a higher resolution and down-sampling.

cragwolf
05-11-2003, 10:21 PM
What do you mean by down-sampling? Just shrinking it via some interpolation algorithm?

Nicolas Lelong
05-12-2003, 02:22 AM
Hi,

yep, down-sampling for AA involves some kind of filtering - somewhat like the way mipmaps are generated for a texture.

I backup this request about GeForce 1/2 Antialiasing control via an application.

The driver setting, when AA is not forced or disabled, is set to 'application'.

It would be kind if NVidia could expose this setting in a way or another ; or at least say if it is impossible fot them to do so.

Here, I have to deal with many GeForce 2 target machines, and I'd _really_ love to be able to control the AA for our apps !

Cheers,
Nicolas.

davepermen
05-12-2003, 08:53 AM
just create a 4x bigger offscreen buffer, render to it. and instead of calling SwapBuffers, call ShowUpDownsampledSuperSampleBuffer (wich you code, hehe)

something like this should do it.. the downsampling can be done in hw by using the buffer as a bilinear filtered texture into a smaller buffer, and again onto the screen (this for 4x aa)..

something like this..

cragwolf
05-13-2003, 04:23 AM
How about if I render into a large pbuffer, and then use that pbuffer as a texture which will be mapped onto a single polygon in orthographic projection mode which covers the opengl window? I think speedwise that would be pretty good, but I don't know what the quality would be like.

davepermen
05-13-2003, 06:04 AM
thats what i tried to say above http://www.opengl.org/discussion_boards/ubb/biggrin.gif

cragwolf
05-13-2003, 02:07 PM
Originally posted by davepermen:
thats what i tried to say above http://www.opengl.org/discussion_boards/ubb/biggrin.gif

I know, I just wanted to get a little more specific. http://www.opengl.org/discussion_boards/ubb/wink.gif