Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!uoft02.utoledo.edu!desire!arc
From: arc@desire.wright.edu
Newsgroups: comp.sys.atari.st
Subject: Re: Pictures on the ST (Amiga's side!)
Message-ID: <672.26899914@desire.wright.edu>
Date: 28 Jun 90 10:43:48 GMT
References: <2701@mrsvr.UUCP> <4b28c24a.20b6d@apollo.HP.COM> <196@next.com>
Lines: 33

In article <196@next.com>, aozer@next.com (Ali Ozer) writes:
> In article <4b28c24a.20b6d@apollo.HP.COM> Steve Rehrauer writes:
>> ...  Spectrum does this, and can switch the palette quickly
>>enough to let you choose 48 of the possible 512 colors per each of the 200
>>lines in a low-resolution screen.  ...
>> ... there are Amiga programs that do similar tricks as Spectrum
>>does on the ST, giving you all 4096 colors at once.
> 
> Yes, there are. But you can get 4096 colors at once using the Amiga HAM mode
> (in 320x400 resolution) without the program doing any tricks or the processor
> having to do any extra work. This mode essentially compresses 4096 colors (12
> bits) down to 6 bits by encoding a pixel color as either one of 16 absolute
> entries (selectable as first 16 entries in the color palette) or as the
> previous pixel color plus a replacement of one color component (R, G, B).
> Photographs of people and scenery and most ray traced pictures end up looking
> great in this mode; some pictures suffer from fringing effects, though.
> 
> It's of course true that there are programs that resort to changing the color
> palette on the fly to give you modes such as 4096 colors at once in hi-res.
> 
> Ali Ozer

  Yes, Ali, HAM pics CAN suffer fringes, but if the raytracing programs better
selected the palette, there would be VERY few cases of this.  I find myself
going through some of these raytraces with a paint program and finding that
there are like 4 colors in the base palette that remain black.  They COULD have
used those, but NOoooooo, they're STUPID...  BTW, the Amiga, theoretically can
have 384 different colors per scanline (max. res. 384x480).  And the special
thing you were talking about there, was, for these ST people, 768x480 at 16
different colors per scanline.  Not bad, but I *THOUGHT* they could have done
better.