[comp.graphics] SGI NTSC Mode

bouma@cs.purdue.EDU (William J. Bouma) (10/11/90)

Help, can someone tell me how to throw a personal iris into NTSC
monitor mode?  There is a function called "setmonitor" which is
supposed to do this, but it either core dumps or gives an error
whenever I call it.  What the crap is "immediate mode" on an iris
anyway?  The manuals with this machine are junk! Thanks.
-- 
Bill <bouma@cs.purdue.edu>      Just ask the Axis   He knows everything

thant@horus.esd.sgi.com (Thant Tessman) (10/11/90)

In article <12000@medusa.cs.purdue.edu>, bouma@cs.purdue.EDU (William J.
Bouma) writes:
> Help, can someone tell me how to throw a personal iris into NTSC
> monitor mode?  There is a function called "setmonitor" which is
> supposed to do this, but it either core dumps or gives an error
> whenever I call it.  What the crap is "immediate mode" on an iris
> anyway?  The manuals with this machine are junk! Thanks.


Immediate mode means not within a display list.  (See 'makeobj,' etc.)
Historically, people are used to thinking about computer graphics
in terms of display lists.  Hence the note about "immediate mode."

This is just a guess, but:

Most graphics commands need the graphics initialized.  The way to
initialize graphics is to open a graphics window with the 'winopen'
command.  If you want to use gl commands without actually opening
a window, for example to change monitor modes or the colormap, 
precede the 'winopen' with a 'noport.'

Hope this helps,

thant

cook@sgi.com (Doug Cook) (10/11/90)

In article <12000@medusa.cs.purdue.edu> bouma@cs.purdue.EDU (William J. Bouma) writes:
>Help, can someone tell me how to throw a personal iris into NTSC
>monitor mode?  There is a function called "setmonitor" which is
>supposed to do this, but it either core dumps or gives an error
>whenever I call it.  What the crap is "immediate mode" on an iris
>anyway?  The manuals with this machine are junk! Thanks.

1) In order to get the setmonitor() call to work, you must first initialize
graphics; this is done with
	noport();
	winopen();

2) If all you want to do is switch to NTSC timing, you can blow off using
setmonitor() and use an existing program to do the job:
	/etc/gl/setmon -n ntsc

Make sure you have the -n flag there. Otherwise ntsc will become the default
mode for your machine.

3) Caveat: Does your PI *have* NTSC hardware? I can't say for
sure about the PI, but most of the other SGI machines (those with GT, GTX,
or VGX graphics subsystems) require an extra board or daughtercard to deliver 
NTSC video instead of the default (60HZ noninterlaced) video. Just because the 
system call is there doesn't necessarily mean that you will get meaningful 
video out when you switch to NTSC timing.

	-Doug

Doug Cook				|" ...hello honey... i hope i didn't
Video Group, Advanced Systems Division	| wake you up, but i had to hear your
Silicon Graphics, Inc.			| voice... i'm standing in another 
Mountain View, CA			| phone booth... somewhere on the 
					| moon..."	-Adrian Belew