Rémi Arnaud (remi++at++intrinsic.com)
Thu, 22 Apr 1999 10:58:47 -0700
-----Original Message-----
From: Larry Peruski <peruski++at++lep.cs.gmr.com>
To: info-performer++at++sgi.com <info-performer++at++sgi.com>
Date: Thursday, April 22, 1999 6:00 AM
Subject: glXBindSwapBarrierSGIX question
>This is not a performer question but, being a multiple pipe/multiple ONYX
>question, I can't think of a better audience.
>
>I am trying to sync buffer swaps across multiple ONYX IR's as well as
multiple
>pipes within a single IR (each with it's own Xserver/keyboard). I am not
using
>Performer or any other toolkit.
>
>I did this 4 years ago on REALITY engines in GL and it seemed to work ok.
>
>According to all the documentation I can find, all you do is:
>
>1. Connect up all the swapready connectors.
>
>2. Genlock the Video signals across all pipes in the config
>
>3. Have each draw process call glXBindSwapBarrierSGIX one time.
> ( I am using all default swap groups since I have multiple Xservers.
> There is only 1 draw process per group). The actual call is:
You should also call glxJoinSwapGroupSGIX(display, win, win); to make sure
that your
window is not by accident attached to another swap group before attaching to
the Barrier
>
> glXBindSwapBarrierSGIX ( XtDisplay (widget), glXGetCurrentDrawable(),
1)
>
> where 1 is the barrier.
>
> I did call glXQueryMaxSwapBarriersSGIX() to verify it returned 1.
Yes, it returns number of SwapReady connectors on the pipe :-)
>
>4. Each draw proceess calls GLwDrawingAreaSwapBuffers at the end of it's
draw
>cycle.
>
>
>Everything seems to run fine for anywhere from 2 to 20 minutes. I can drag
>geometry across screens being drawn by different workstations and
everything
>is in perfect lockstep. Then for no apparent reason, my frame rates will
start
>decreasing something like 50 frame/sec down to 20 frame/sec down to 1
>frame/sec.
This sounds to me just like if your pipes are not genlocked. After some time
the derivation is enough such as it is not possible to synchronize the
swapready signal. Maybe you have a problem with the video format.
I think gfxinfo prints 'genlocked' when the videos are realy genlocked.
>
>Things will run this way for a few seconds then the frame rates go back up
to
>normal but all synchronization between pipes is gone. I drag geometry
across
>screens and see no synch at all.
>
>I am not connecting all the swapreadys on the machines, only the ones that
I am
>using. One question would be do you have to connect up all the swapreadys
even
>if you are not using some of them?
No, you are fine. You can have several swap group doing the right
connections for example.
>
>Before I tear my code apart, does anyone have a clue here?
I hope that helps.
>
>Thanks,
>
>Larry Peruski
>General Motors Research Labs
>Warren, Mich
>(810-986-1475)
Rémi ARNAUD
Intrinsic Graphics
remi++at++intrinsic.com
http://www.intrinsic.com
707 California Street
Mountain View, CA 95120
Tel: 650 210 9933
Fax: 650 210 9340
This archive was generated by hypermail 2.0b2 on Thu Apr 22 1999 - 11:03:59 PDT