Bernard Leclerc (bleclerc++at++cae.ca)
Fri, 31 Jan 1997 09:51:11 -0500
> I am having difficulty implementing an "automatic gain control" for my
> Performer app. By AGC, I mean the gain on each pixel is a function
> of the average pixel value (intensity... one color component) of the
> current frame (or previous frame, Ill take what I can get). The correct
> result would be constant overall brightness on the display.
[...]
> On the gain issue, I wonder if there is a way to apply a gain (analog or
> digital) in the DG... i.e. near the DAC or gamma tables?
Supposedly, an extension to the X server could do it for you. Look for
XSGIvc extensions and specifically for XSGIvcSetChannelGammaMap(). Refer
to Remi Arnaud <remi++at++asd.sgi.com> or Sharon Clay <src++at++asd.sgi.com> if you
can't find info on the subject.
> Apologies:
>
> Im sorry that these aren't -exactly- Performer questions, but they are
> SGI questions... and this list is the best resource I know of. Besides,
> it is difficult to get this kind of info from support.
No need to apologize. This is the perfect forum for this type of
questions.. and besides, we're all interested by the subject - well, at
least some of us.
--
Bernard Leclerc CAE Electronics Ltd., 8585 Cote De Liesse
Technical Leader Saint-Laurent, Quebec, Canada, H4L-4X4
3-D Graphics Applications tel: +1 514 341 2000 extension 2275
bleclerc++at++cae.ca fax: +1 514 340 5496
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