Re: ZVG special pricing

On Wed, 11 Sep 2002 12:07:16 -0700 (PDT), Neil Bradley <nb@synthcom.com> wrote:

>> I have a silly question for the ZVG team will the ZVG take advantage of
>> the Ampliphone's higher resolution and skew rate?
>
>I'm sure Zonn will correct me, but the ZVG's overall output resolution is
>1200x944 with a display area of 1024x768 (overscan is a good thing!). The
>resolution of the ZVG is higher than that of any vector generator.

All the games I had information on used 1024x768 end points or less, so we
decided to give the ZVG a resolution of 1200x944 end points. This allows one to
set the size of the screen so that 1024x768 end points appear on the screen. As
you go outside these points the beam will start to be drawn off the edge of the
screen. But only for a limited amount (about an inch and a half or so), so no
monitor damage is done. This allows games like Asteroids and the Cinematronics
games to be displayed in their full original resolution of 1024x768 end points,
and still allows games like Tempest to zoom off the screen when changing levels.

Note the "end point resolution" has nothing to do with monitor resolution. It
indicates the number of positions a vector can start and stop on. This is an
analog vector generator and there are no "steps" to the vectors. They are all
drawn as a smooth continuous line between end points. On an Amplifone monitor,
or any other monitor with a medium resolution tube, the vector will appear
sharper because the tube's pixels are smaller. B&W monitors are very sharp since
there are no pixels at all. Tempest looks great on a G05 because you can see
what's in the little boxes *way* before what you see on a WG6101 monitor, just
not what color they are. ;-)

>> If not, will games like Major Havoc run slower on an Amplipnone monitor
>> just like the tempest conversions (WG6100) due to the monitor inability
>> to handle the drawing?
>
>IIRC, Zonn told me that the ZVG has the capability of outpacing any
>monitor it's connected to, so I don't believe this will be a problem. As
>long as the monitor can keep up.

We've added jumpers to the board that allow it to drive monitors at 4 different
speeds.

The G05 and Amplifone and Sega are fast monitors, the WG6101 is slower and the
Vectrex, of course is slowest. The jumper selection allows for:

   15us per inch (G05, G08, Amplifone, WG6401)
   30us per inch (WG6101)
   40us per inch (Possible Vectrex if you're lucky)
   50us per inch (Guaranteed Vectrex)

It doesn't hurt to try and drive a monitor faster, all the happens is that the
vectors don't make it to their end points before the next vector is being drawn.

As a comparison here are some game speeds I calculated by looking through the
schematics. The first column is maximum draw speed, the second column is the
average draw speed of the game:

   Atari DVG: 47us / inch, 70us Normalized Avg
   Omega Race: 47us / inch, 70us Normalized Avg
   Sega DVG: 27us / inch, 40us Normalized Avg
   Cosmic Chasm: 24us / inch, 36us Normalized Avg

Those were DVGs, AVGs are a little different, their speeds go up as the scaling
factor is increased, so it's hard to tell what the game really runs at.

 This table is the absolute maximum speeds the AVG is capable of:

   Atari AVG: 51us / inch, 76us Normalized Avg (Tempest)
   Atari AVG: 6.3us / inch, 9.4us Normalized Avg (Star Wars)

There are no vector monitors capable of running 6.3us per inch, so Star Wars
obviously does not run at that speed, but is slowed down by software to a speed
capable of running a monitor. But I currently have no idea what that speed is,
I'd have to run a debugger on an emulator, or something to determine that.

The ZVG does not have the same averaging problem the older VG had, so my vectors
are consistently drawn at full speed, allowing me to get more vectors per
refresh than the older VGs.

My hope is to run many of the faster games on the slower monitors, but I haven't
had time yet to just *play* the games, so I haven't been able to tell yet how
well I can pull off running things like Star Wars on a WG6101.

>> Last question, Mame allows use of overlays to simulate color on the pc
>> for games like star castle and the like, could this be done on the ZVG,
>> if so what are the possibility to add color to B/W games?
>
>That is all up to the developer! Of course you won't get backdrops on
>games like Warrior and whatnot, but if a MAMEdevian wishes to modify MAME
>to do such a thing, it's technically possible!

Limited of course to the maximum number of vectors that can physically be
displayed per refresh. ;-)

-Zonn
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Received on Wed Sep 11 13:36:21 2002