Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!uunet!proto!joe
From: joe@proto.com (Joe Huffman)
Newsgroups: comp.graphics
Subject: Re: How to display more than 16 colors in EGA ??
Message-ID: <1991Apr28.180038.10097@proto.com>
Date: 28 Apr 91 18:00:38 GMT
References: <12675@uhccux.uhcc.Hawaii.Edu>
Distribution: usa
Organization: Prototronics @ Sandpoint, Idaho
Lines: 19

sharik@wiliki.eng.hawaii.edu (Harikrishnan Sundararaghavan) writes:

>	I would like to know whether it is possible to show more than
>16 colors in 640x350 mode.  Will direct video memory access allow me to
>do this?

Assuming you mean with a true blue EGA board and not a VGA emulating the EGA 
or a 'Super EGA' board then the answer is that it is POSSIBLE to show up to 
64 colors simultaneously, but it isn't easy.  You have to look for the 
horizontal retrace signal and then change the palette on the fly, thus you 
can show up to 64 colors on the screen simultaneously but you are 
restricted to only one set of 16 in any horizontal line.  This restriction, 
and it being very cpu intensive, makes it more of a curiosity that a useful 
coding method.

If you are really interested I think I might be able to find the source for
a demo of this.
-- 
joe@proto.com