Date: 	Mon, 26 Jul 1993 11:51:11 -0400
From: garym AT argos DOT rose DOT utoronto DOT ca (Gary Lawrence Murphy)
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Graphics on video

I may have been dreaming, but I thought I saw a message go by a few
days ago that told how to detect the video retrace signal from within
djgpp --- I also thought I had saved it :-(

Part of my programming task will be very well served by the XFER.S
code so graciously posted :-), but I have a further constraint I
expect is solvable and thought I'd ask in case anyone had some really
elegant solutions: I want to draw on a stereo video signal where the
cameras are switched on the input vertical retrace.  This means,
first, I need to detect the retrace so I can change the context of my
drawing (whether left or right views), and then I need to draw through
a stencil of alternating clear and opaque lines.  Since I'm drawing to
horizontal line, I expect I can modify the XFER.S to skip the opaque
lines of my 'stencil' (unless there is some faster method --- I only
have a few ms to render before the next video frame arrives.

Any and all suggestions are most welcome ;-)

Gary Lawrence Murphy ---------------- garym AT virtual DOT rose DOT utoronto DOT ca
University of Toronto, Industrial Eng Dept    fax:    (416) 978-3453
4 Taddle Creek Rd, Toronto, Ont M5S 1A4       voice:  (416) 978-3776
The true destination is always just here, now ----------------------