Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!cbmvax!cbmehq!cbmger!peterk
From: peterk@cbmger.UUCP (Peter Kittel GERMANY)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: Info wanted on new IBM vide card hacks.
Message-ID: <1378@cbmger.UUCP>
Date: 18 Jun 91 07:34:15 GMT
References: <1991Jun17.103306.29343@news.iastate.edu>
Reply-To: peterk@cbmger.UUCP (Peter Kittel GERMANY)
Organization: Commodore Bueromaschinen GmbH, West Germany
Lines: 38

In article <1991Jun17.103306.29343@news.iastate.edu> taab5@isuvax.iastate.edu writes:
>
>  The ad is
>for an ordinary VGA card that comes equipped with something called the 
>"Edsun CEG DAC".  From the ad, this replacement DAC chip gives VGA cards 
>a resolution of 2048x1536 and 700,000+ colors "on a standard VGA monitor."
>
>   My question is, how can something like this possibly be achieved on a
>standard VGA monitor, and with ordinary VGA cards with 1M of video RAM?  
>This thing is obviously some sort of anti-aliasing hack, but I'd like 
>some information on how this thing works.

This chip is a normal DAC with built-in CLUT (color lookup table), as it
is common on VGA cards. So it is compatible with existing designs.
But it has the added capability to interpolate the colors between two
horizontal pixels in much finer color resolution. You give it certain
fake color values that are really control values and it makes a smooth
interpolation between two pixels. This way you can anti-alias very well.

Yet there *is* an overhead in setting up these control values. I heard
there are already drivers for standard Windows 3.0 available, but they
are *really* slow, though the result seems to be remarkable.

So, you perhaps should forget about animation with this.

You have a situation similar to HAM, in that you can easily draw one
single line in this mode on the screen, but get into difficulties, if
you want to draw another line in different color that crosses the first
one at some angle. So also here you have not only an organisational
overhead, but also some limitations to consider. And the drawing
programs yet have to consider this additional feature.

I guess this part could also be used on the Amiga in hacks like
DCTV or HAM-E, but it sure would remain a hack.

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk