[Coco] Re: CoCo Monitor

John R. Hogerhuis jhoger at speakeasy.net
Fri Jun 25 02:02:41 EDT 2004

I remember Fred B. Scerbo had an article in RAINBOW that allowed you to
do area fills in PMODE 4 which used aliasing and cross hatches.
Actually, IIRC you could poke values into memory and when you did an
area fill you could get all kinds of wacky vertical striped patterns
with different colors.

The impressive thing was that it was reasonably fast and completely in

All the good Coco 1 & 2 graphics programs let you take advantage of "4
colors" in HiRes mode... white, black, red, blue. 

IIRC when I got my Coco 3 I hooked it to the TV since that was all I had
at first. With it's high res modes, I was able to do alternations of
colored lines that got a lot more colors than the Coco 3 was supposedly
capable of. It wasn't aliasing but probably just colors bleeding over
each other. Anyway it was of no consequence since everyone with the
means was getting the CM-8 or some Magnavox monitor that Marty Goodman
described how to make a cable for. And those monitors didn't bleed
(though the CM-8 wasn't really capable of a legible 80 columns...
eventually I got a nice cheap monochrome composite that worked just fine
for this).

-- John.

On Thu, 2004-06-24 at 19:23, Robert Gault wrote:
> Actually that was not a good example. What I should have said was:
> run
> 10 PMODE3,1:PCLS2
> 20 PMODE4,1:SCREEN1,1
> 30 GOTO30
> In a PMODE3 screen, PCLS2 will fill the screen automatically with every 
> other vertical line. Then changing the mode to PMODE4 on an RGB monitor 
> would show alternating black and white vertical lines but on a composite 
> monitor will show either all red or all blue artifact color.

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