2 Mar
2016
2 Mar
'16
10:25 a.m.
Message: 12
Date: Tue, 1 Mar 2016 19:30:27 -0800
From: Josh Dersch <derschjo at gmail.com>
Subject: Random VGA question: 160x200 "high color" mode?
Awhile back a "pre-alpha" version of the PC classic "DOOM" was
unearthed
(dated Feb 28, 1993), and it claims to support a "high color" VGA mode.
From the README.TXT:
"Use High-color DAC (160 x200, but great color!)
(Only newer VGA cards have this-if it looks OK, ya got it)
(This may--okay, will--REALLY screw up the playscreen's
graphics. Just look at the neat colors and don't worry.)"
I've tried it on a number of machines (from the 386 era to a modern PC)
and they all just end up showing garbage when this mode is enabled. I
cannot for the life of me find a reference to this mode existing
anywhere, but I assume it must have worked on *some* SVGA chipset of the
era since ID programmed in support for it. I'm guessing it was cut
because nothing else supported it (and because 160x200 must have looked
awful, even with lots of colors...)
Does this odd video mode ring any bells with anyone out there? Any idea
what hardware to look for that might support it? At this point I'm more
curious about the actual hardware than getting this pre-alpha to run
with it...
- Josh
Try sending a message to Jim Leonard (trixter at oldskool.org).
He has done a lot of work with old PC graphics modes and might know about this mode.
Bob
2 Mar
2 Mar
10:45 a.m.
> I've tried it on a number of machines (from
the 386 era to a modern PC)
> and they all just end up showing garbage when this mode is enabled. I
> cannot for the life of me find a reference to this mode existing
> anywhere, but I assume it must have worked on *some* SVGA chipset of the
> era since ID programmed in support for it. I'm guessing it was cut
> because nothing else supported it (and because 160x200 must have looked
> awful, even with lots of colors...)
VGA has analog RGB signals.
VGA card uses DAC chip, 8 bit would give the 256 color and 16 bit would
give the 65536, and 24 bit would give the 16.7 million color depth. RAM
was a big issue as well on these cards, since more memory needed to store
color info.
The one thing I would wonder is -- even if some video card had the ability
to sacrifice resolution for color depth (reconfigurable RAMDAC?) -- were
the textures and tiles in Doom supplied in true color/16 bit color or were
they 256 colors?
--
Ethan O'Toole
9:32 p.m.
On 3/2/16 10:45 AM, ethan at 757.org wrote:
The graphics were only 256 colors, but
the engine provided for varying
lighting levels per-sector so having more colors would allow for
better-looking rendering.
- Josh
> I've
tried it on a number of machines (from the 386 era to a modern PC)
> and they all just end up showing garbage when this mode is enabled. I
> cannot for the life of me find a reference to this mode existing
> anywhere, but I assume it must have worked on *some* SVGA chipset of
> the
> era since ID programmed in support for it. I'm guessing it was cut
> because nothing else supported it (and because 160x200 must have looked
> awful, even with lots of colors...)
VGA has analog RGB signals.
VGA card uses DAC chip, 8 bit would give the 256 color and 16 bit
would give the 65536, and 24 bit would give the 16.7 million color
depth. RAM was a big issue as well on these cards, since more memory
needed to store color info.
The one thing I would wonder is -- even if some video card had the
ability to sacrifice resolution for color depth (reconfigurable
RAMDAC?) -- were the textures and tiles in Doom supplied in true
color/16 bit color or were they 256 colors?
--
Ethan O'Toole
2999
days inactive
3000
days old
2 comments
3 participants
participants (3)
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derschjo＠gmail.com -
ethan＠757.org -
r_a_feldman＠hotmail.com