Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!rutgers!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: Ideas for New Custom Chips (a SERIOUS one!)
Message-ID: <4211@cbmvax.UUCP>
Date: 8 Jul 88 19:27:56 GMT
References: <613@myrias.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 35

in article <613@myrias.UUCP>, cg@myrias.UUCP (Chris Gray) says:
> Keywords: Chips HAM animation
> Summary: modified HAM allows on-the-fly area fills

> What I would like to see is a HAM mode that would work with 2, 3, 4, and 5
> bit deep displays as follows: (example for 5 bits/pixel)

>         5-bits
> 	 00000	    - use same colour as previous pixel
> 	 xxxxx	    - select one of lower 32 colour table registers
> 			(the 0th entry is not accessible, but is still used
> 			 as the border colour)

> The same pattern holds for other depths - all bits zero means use the same
> colour as the horizontally previous pixel.

I seem to recall the Apple II Gee-Wiz having a similar mode.  I don't recall
if the details are the same, but the basic gist of it is that you draw lines
and get free area filling from the colored pixel on to the end of that line, 
or the next colored pixel, whichever comes first.

The thing I liked about it is that your area filling is just a color lookup
table trick, like HAM, not a real area fill.  At least as long as you stick
to line drawing and are happy with everything filled in.  When you get to the
point of needing a large number of per-line transitions, this starts to loose.

Maybe the Apple II community would be a good test case of whether this 
is really useful or not?

> Chris Gray		Myrias Research, Edmonton	+1 403 428 1616
> 	{uunet!mnetor,ubc-vision,watmath,vax135}!alberta!myrias!cg
-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {ihnp4|uunet|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
		"I can't relax, 'cause I'm a Boinger!"