Subject: Idea: PC/Amiga as glove driver

From: Gregory B. Newby <[email-masked]>
Date: Mon, 20 Jan 92 14:43:39 -0600

Someone asked me a question, and I had this idea.  How about using
an old PC or Amiga as the "external data processor" for the PowerGlove?

What I mean is, take the code in the list archives and run it on a PC
or Amiga (whichever you choose).  Modify the code to send data OUT
(via serial port or wherever), and read it in to your other computer.

This would allow your more powerful computer to perform graphical 
manipulations on the glove data, and keep the timing right on the 
less powerful one.

Can anyone think of any serious problems with such a method?  Since
old PCs and Amigas are dirt cheap (is there anyone who doesn't have
one or two lying around?), this could be an alternate solution to 
the 68HC11 or AGE external microprocessor.

I realize that the code in the archives is generally for faster machines,
but I didn't see any reason why the timing couldn't be adjusted for
an XT or AT class machine, or for an Amiga 500 or 1000.

Just thinking out loud....  Happy MLK's birthday, everybody!
-- Greg
[email-masked]

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From: [email-masked] (Daniel Jimenez)
Date: Mon, 20 Jan 92 23:58:45 CST

[email-masked] writes:
>[...]

This is exactly what we are doing here at UTSA.  Using a port of the
original "manfredo" code (I can't get the stuff from karazm to 
work, either), I have the Power Glove interacting with a 286 PC clone.
The PC sends the glove data through our local Ethernet to a Sun 
SPARCstation ELC, which draws graphics stuff based on the glove
info (hence my question about X a few days ago).

>the 68HC11 or AGE external microprocessor.

Well, it looks a little silly, and it takes up a lot of desk space.
But it is, as you point out, a poor man's solution to the dedicated
glove processor problem.  Whenever I'm not using the PC, someone else
can be using it to do, well, whatever it is you do with a PC.

One problem is, how do you get the glove information to the client
fast enough, i.e., the client can respond to one glove data packet
before the next packet is ready on the glove?  If you don't already 
have both the PC and workstation linked by a net, you have to rig 
some kind of cable.

Other than that, I see no problems.  I can put the sensor array on the
Sun (it fits just right :-), and have the PC sitting nearby.

>an XT or AT class machine, or for an Amiga 500 or 1000.

I use a 12 MHz "Standard" PC clone, and my Sun program can usually respond
to the glove about as fast as it responds to the Sun mouse.
--
Daniel Jimenez

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From: [email-masked] (Bob Salnick)
Date: Tue, 21 Jan 92 18:06:23 PST

> an old PC or Amiga as the "external data processor" for the PowerGlove?
Yeah - I suggested this about the time people started looking at outboard
processors...

In addition, the Amiga is a multitasking machine - it could easily handle the
addition of Sega glasses or XSpecs, and maybe do the rendering as well - it does
blitting in hardware - no CPU required.

I think the push to do everything on a pc because everyone has a pc is a little
off the mark.  Use the machine best suited for the task, and you will make
yourself a LOT less work.

Amiga 500's are now selling for <$200, new...  

bob

Bob Salnick, Spokane,WA |  USENET: oliveb!isc-br!tau-ceti!DejaVu!salnick
  Amiga 1000, WB 1.3    |  INTERNET: [email-masked]
      WA9BVE            |

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From: Dave Stampe-Psy+Eng <[email-masked]>
Date: Wed, 22 Jan 92 01:32:06 -0500

I discussed this idea about 2 months ago, then sat down and did a detailed
analysis of it.  The end result: the CPU in the A500 is FAR to slow to
do the 3D computations needed for realtime 3D, and you'd need a 1 MB/s
data link to transfer the computed poly data to the Amiga.  An A500 also
has a relatively slow memory cycle rate, which degrades the draw rate.
To top it off, you can't do polys directly with the hardware, and need
to do a series of horizontal line segments.  Programming the hardware 
takes almost all the CPUs time to do this, leaving none for the 3D
calculations, clipping, etc.

Now the good news:  the 386 renderer (first pass) is ready for posting
(by next week) and is currently doing 10+ fps on a 500 polygon database.
If you drop down to 30 or so polys, speed increases to 72 fps!  This
includes all viewport setup, clipping, cosine lighting (!) and drawing
on a fairly slow VGA card.  Still lots to be done on the rendering
end, but this thing proves the concept (and looks great, too).

- Dave Stampe