Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!ufqtp!sutherla
From: sutherla@qtp.ufl.edu (scott sutherland)
Newsgroups: comp.sys.amiga
Subject: X-Specs and Interlace
Keywords: X-Specs
Message-ID: <563@orange6.qtp.ufl.edu>
Date: 26 May 89 00:15:22 GMT
Reply-To: sutherla@orange6 (scott sutherland)
Distribution: na
Organization: University of Florida Quantum Theory Project
Lines: 33


	I have a question concerning the "compatability" of the double-
buffering used in the X-specs 3D glasses (and others, like the SEGA 3D
glasses) and an interlaced screen. My reason for asking this question is
simple. I recently received my Turbo Silver SV upgrade, where the SV stands
for stereo vision (or something equivalent). Now I can render my favorite
animations in stereo. I also purchased the SV adaptor for use with X-Specs
and/or SEGA glasses. (I haven't gotten my 3D glasses yet, as the best price
I can find for the SEGA glasses is $50) However, I render most of my 
animations in interlace so that I can record them to VHS tape at a later
date (when I get my encoder or genlock, another of the many things on my
wish list). So my question is as follows:

	I believe that the stereo is accomplished by double buffering two
"copies" of the images being viewed. Each buffer is one of the two stereo
images. I believe that the "switching rate" is ~30Hz. So each of the two
stereo images is on the screen 1/60th of a second. Now the apparent problem.
An interlaced screen takes 1/30th of a second to be totally displayed. So
the "standard" 30 Hz rate won't work. So what happens? Does the hardware/
software combination compensate and slow down to 15Hz? I would think that
this would be an unacceptable rate, since the flicker in the X-Specs 
glasses is only somewhat tolerable at 30 Hz. (I have tried Space Spuds and
the molecular modelling stuff with X-Specs, and the flicker of everything 
but the screen is most annoying) 

	So, does anyone out there on the 'net know what happens in this
situation? Does X-Specs and its software even support interlace? The answer
to these and many other questions will help me in my quest for "fantastic"
stereo ray-traced animations!! 

						Thanks,

						Scott Sutherland