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From: knudsen@ihwpt.UUCP
Newsgroups: comp.sys.m6809
Subject: Fixing artifact colors on Coco 3
Message-ID: <1531@ihwpt.ATT.COM>
Date: Mon, 16-Mar-87 19:29:44 EST
Article-I.D.: ihwpt.1531
Posted: Mon Mar 16 19:29:44 1987
Date-Received: Wed, 18-Mar-87 01:24:30 EST
Organization: AT&T Bell Laboratories - Naperville, Illinois
Lines: 32
Keywords: Coco 3

Good news -- fixing artifacts on the Coco 3 and RGB
monitor isn't as hard as some folks have suggested.
(If you use a composite monitor or TV, artifacts
work as they always have, and HMODE artifacts are even
better!)  But I assume you need to run RGB.

For BASIC, just find the PMODE 4 statement(s) and
convert to PMODE 3.  This forces Coco to use "real"
colors.  Now the 4 colors you get may not be what
you wanted, so insert up to four PALETTE stmts to
get what you want.  See back of the manual.

The above could have been more complex -- to draw
artifacts in BASIC, you fake out the hardware to
display in PMODE4 but your software draws in PMODE3.
The SCREEN command is what updates the hardware to what
the software is doing.
But since you are making it draw AND show in PMODE3,
just converting the 4's to 3's should work.

Fixing machine code programs is harder, but the principle
is the same -- you want the equivalent of PMODE 3
and maybe some PALETTE zaps.

For some reason, ROM Paks that use PMODE 3 don't get
the right 4 colors on Coco 3 RGB -- still can't tell
the two teams' players apart in Baseball, nor can I fix
Chess or Backgammon to work on a B/W screen.  Oh well.

-- 
Mike J Knudsen    ...ihnp4!ihwpt!knudsen  Bell Labs(AT&T)
>>>DRUGS are for WIMPS who can't handle SCIENCE FICTION<<<