Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!oakhill!val!ben
From: ben@val.com (Ben Thornton)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Super Duper VGA boards
Message-ID: <1989Nov30.174050.12453@val.com>
Date: 30 Nov 89 17:40:50 GMT
References: <8911250811.AA26716@cie.uoregon.edu> <10401@attctc.Dallas.TX.US> <4033@peora.ccur.com>
Organization: Video Associates Labs, Inc.
Lines: 31

joel@peora.ccur.com (Joel Upchurch) writes:

>In article <10401@attctc.Dallas.TX.US>, chasm@attctc.Dallas.TX.US (Charles Marslett) writes:

>> The Tseng Labs ET4000 chip (going into full production early next year)
>> will support 65536 colors and is a VGA chip, so it will handle all the
>> standard VGA modes as well.  The 16-bit/pixel modes do require some ....

>It seems to me that if a board supports 16-bits/pixel that it would be
>better to have the colors map directly rather than going through a
>mapping table. With 5 bits each for red, green and blue that would
>give you 32k colors to work with one bit left over. This would eliminate
>the overhead of setting up the color mapping table as well the
>hardware to do the mapping.

>Does anyone know how many different colors a normal monitor can display
>that the human eye can actually tell apart?

Actually, a color mapping table is useful for a lot more than just making
lots of colors.  A real strong argument in favor of using them is their
ability to shift color maps in real time.  This makes it possible for
multitasking OS's to assign different color maps to different areas of
the screen to support different applications' requirements.  There are
few other way to accomplish this without the use of color mapping
hardware.

-- 

Ben Thornton             packet:  WD5HLS @ KB5PM   Internet:  ben@val.com
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