Path: utzoo!attcan!uunet!husc6!mailrus!utah-gr!utah-cs!sunset.utah.edu!u-jmolse
From: u-jmolse%sunset.utah.edu@utah-cs.UUCP (John M. Olsen)
Newsgroups: comp.graphics
Subject: Re: Amiga or PC-AT ?
Message-ID: <5646@utah-cs.UUCP>
Date: 6 Aug 88 19:40:34 GMT
References: <1820006@hpuamsa.UUCP> <554@gort.cme-durer.ARPA> <356@uwslh.UUCP> <3109@tekig5.PEN.TEK.COM>
Sender: news@utah-cs.UUCP
Reply-To: u-jmolse%sunset.utah.edu.UUCP@utah-cs.UUCP (John M. Olsen)
Organization: University of Utah, Computer Science Dept.
Lines: 42


In article <554@gort.cme-durer.ARPA> brickman@rosie (Jonathan E. Brickman) writes:
>(1) Awkward and rigid color mapping arrangement. (On Amiga)

>In article <356@uwslh.UUCP>, lishka@uwslh.UUCP (Fish-Guts) writes:
>      I am not sure what Mr. Brickman means by this.  The strangest
> color-mapping strategy on the Amiga is HAM mode (Hold-And-Modify mode)...

In article <3109@tekig5.PEN.TEK.COM> wayneck@tekig5.PEN.TEK.COM (Wayne Knapp) writes:
>I think the real problem is that you can only get 4 bit control over
>each color.  That is if you are working with prue blue, red, or green
>you can only get 16 shades of each.  That is a bit on the low side if
>you want to do true to life shading and avoid banding in your shading.
>A lot of VGA cards give you better color control.
>                                                Wayne Knapp

No matter which machine you choose, there are a couple of ways to improve 
the situation.  You can get another 16 "nearly correct" shades by 
incrimenting one of the other color values.  I do this to get 32 gray
shades that look like they have alternating hints of green and purple.
They work great as long as I stay away from large areas of a single
color.  I use this technique to draw 3D views of fractal landscape.

The best thing to do is to dither the stuff.  You can fake really high
numbers of colors if you do your dithering right. By using some of the 
dithering techniques recently discussed here you could probably get 
some really nice looking pictures out of 32 properly optimized colors.  
I'll let Leo Schwab or some other Amiga nut who's tinkered with it 
elaborate if they feel like it.

If you want to get photo quality, the Amiga is probably not the machine
for you, but if you only need to be near photo quality, you may want to
check it out and see if it really does fit your needs.

Don't ever plunk down cash for a system without using both it and the
alternate choices in the presence of someone who knows a lot about the
system and software.  (You usually can't do this in a computer store. :^)

 /|  |     /|||  /\|       | John M. Olsen, 1547 Jamestown Drive
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