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From: sweetmr@SCT60A.SUNYCT.EDU (michael sweet)
Newsgroups: comp.sys.sgi
Subject: Re: interrupting long draw cycles
Message-ID: <13816.on.Tue,.12.Mar.91.07:57:23.EST.@sct60a.sunyct.edu>
Date: 12 Mar 91 12:57:23 GMT
Sender: usenet@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 31


(other stuff deleted...)

> This will entail the gl calls being interrupted and aborted at any step..

> My experiments with this code have.....

I assume that you want to jump out of this when a user says 'no, try this
view'?  Well, one way would be to use the qgetfd() function to get a
file descriptor for the event queue, and then start a separate process that
would monitor the queue.  When something becomes available on the queue,
the process could send a SIGIO (or whatever) signal to its parent telling
it to stop drawing and get the new viewing parameters.  You'd probably want
to disable 'noisy' devices (i.e. MOUSEX, MOUSEY).  The signal catching routine
in the primary (drawing) process could set a flag which the drawing function
could check periodically.

I *think* 3.3 and later also allow multi-process access to the same window,
so you might not have to get the file descriptor....




 -Mike Sweet

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