From: John Eagan <76130.2225@CompuServe.COM>
Subject: Re: TECH: U of I Powerglove update 8-24-92
Originator: hlab@milton.u.washington.edu
Organization: University of Washington
Date: Tue, 25 Aug 1992 17:38:05 GMT



From: jlb31348@uxa.cso.uiuc.edu (Jim Brain) writes:

>(stuff del.)
>I have been in contact with Michael Starks of 3DTV in CA, and he is
>working on getting a low-cost SEGA circuit in preoduction.  he has
>been toying with a parallel port interface, but I hope to convince him
>to keep it serial to ensure compatibility with earlier work by Dave
>Stampe and Glen Harris.
>
>(stuff del.)
>
>I hear that a good book called "Virtual Relality Playhouse" is out now
>that has a lot of goodies on PG and SEGA stuff, so you might want to
>check it out.  I intend to.

John Swenson from the COMART forum on CompuServe came up with some
fairly simple modifications to the stock Sega interface circuit board
several months ago, to make the Sega glasses work on a parallel port.
He also came up with a little image viewer for DOS to use for that.
The mods that JS came up with, along with the still image viewer are
detailed in "Virtual Reality Playhouse", and are available in the
COMART library.

As of now, Group 3 in COMART hasn't used the parallel glasses hookup
in any VR software (for a few reasons, see below), but the raytrace
people in COMART have grabbed ahold of the idea with some enthusiasm!
:-) There are a few examples in COMART of raytraces using the Multiple
Image GIF format (MIG...one of the interesting little quirks/features
of the GIF standard is that you can combine multiple images in one GIF
file, for really short little "animations", or in this case, a
left/right pair to use with shutter glasses!).

Anyway, one of the nice things about John Swenson's mods is that the
Sega glasses are hooked up to different pins than the parallel glove
hookup used in Dave Stampe's parallel port glove hookup, so you only
use one port to hook up both devices.

The downside is, we want to work across platforms as time goes by, and
using a parallel interface means no Mac. (can somebody tell me why
Macs don't have parallel ports on them? please, no religious
wars...I'm just asking :-)

Another aspect is that many people who know loads more than I do seem
to think the serial interface is the technically preferable. No small
consideration is that Dave and Bernie are using serial port interface
for the glasses already, and we've pretty much come to the conclusion
that for the sake of general progress on the "PC" VR front, we should
strive to keep our efforts here in sync with Dave and Bernie's work on
Rend386 as much as possible, so that we'll compliment each other's
work, rather than duplicate efforts trying to reinvent Dave and
Bernie's virtual wheel when we could be working on helping the file
standard evolve, work on tools/utilities, etc.

All things considered, we'll probably go with the serial interface
approach when all is said and done.

>(Braindude's thrashing of himself deleted :-)

Don't flog yourself too badly yet, Jim. There are big companies who
have done far worse in delayed products and vaporware. As far as I'm
concerned you get One Big Attaboy for having the huevos to tackle this
at all, and it'll pay off in the end, so stay with it.

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