Path: utzoo!attcan!uunet!wuarchive!sdd.hp.com!ucsd!ucselx!crash!jcs
From: jcs@crash.cts.com (John Schultz)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Non-Ham megacolour
Message-ID: <5287@crash.cts.com>
Date: 26 Oct 90 18:13:28 GMT
References: <901024.00324231.034868@CMR.CP6>
Organization: Crash TimeSharing, El Cajon, CA
Lines: 19

In article <901024.00324231.034868@CMR.CP6> Dennis_Grant@CMR001.BITNET writes:
>
>     The last little while, I've been studing the screens on some of my
>games *very* closely, and some of them are displaying more colour than they
>are supposed to be able to. How? (I've heard mutterings on changing the
>pallette on every scanline. Is this possible? How?)

  The copper can be used to reload the color registers every scanline. It
can also reload color registers on each scanline (about every 4 pixels, 
low-res, 8 pixels high-res). Thus, if you went nuts, you could load
a new palette each scanline of a 320x200x5 screen for a possible 6,400
(200x32) color screen. But, of course 12 bits of color combinations only
gives 4096 different colors. Further, so much processor bandwidth would
be eaten that any game using this scheme would barely move. Also, as
objects moved around on different scanlines, their colors would change.
Most games just modify the color palette on parts of the screen.


  John