Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!timbuk!shamash!awm
From: awm@shamash.cdc.com (Allan Magnuson)
Newsgroups: comp.sys.sgi
Subject: Motif & GL
Message-ID: <29333@shamash.cdc.com>
Date: 17 Dec 90 17:43:30 GMT
Organization: Control Data, Arden Hills, MN
Lines: 35

Let me describe my problem and see if anyone can offer me a solution (I'm sure
that some of you may have the same one).

I work on a large CAD/CAM suite of programs that runs with GL.  We have a user
interface in GL.  It doesn't look great and isn't portable, but it is fast
because we can put it in the overdraw planes to avoid a REDRAW token being
placed in the window with the users geometry.

Users have *very* large parts (those cars can get pretty big), so
a REDRAW in the main window every time something pops up, down or resizes can
be an extreme problem, even with bounding box clipping (or bounding sphere
clipping, or whatnot), just because of the size of the parts. It actually
isn't real bad, the GL is *very* fast, but users will, naturally, create
parts as big as the machine can handle so they can get their work done faster.

Now the problem: We would very much like an interface in something that is
X based, like MOTIF.  We know that right now, MOTIF and GL windows cannot
co-exist, but in the future they will be allowed to.  This is great, our
development of a nice, portable, interface will probably take until the
4.0 release comes out.  But we can't sell the idea to anyone unless we can
solve this REDRAW problem.  We can't have an interface that causes redrawing
of all the users geometry. We thought about saving the bit image off the
screen when you pop something in MOTIF up, asking the pipeline what is on
the screen, and a number of other things, but nothing seems to be safe
or clean.  What we would really like to do is be able to pop up our interface
in a completely different set of bitplanes, as to avoid a REDRAW token.

Maybe this isn't even the best idea, any suggestions?  Am I missing something
obvious?

By the way, the SGI workstations are really nice pieces of work.

Eric Swildens
Control Data Corporation
awm@shamash.cdc.com (using Al's account temporarily :-) )