problem with DEC Alpha, OpenGL, and threads

problem with DEC Alpha, OpenGL, and threads

Post by Christopher Ge » Tue, 08 Jun 1999 04:00:00

Hello -

I was wondering if anyone had any experience with using DEC Alpha,
Motif, OpenGl, and threads.  I haven't found a lot of resources about
threads and OpenGL in a unix environment.

I'm having a problem with a Motif based application that uses DEC UNIX
4.0D, OpenGL 1.1, and pthreads.  My application has three threads (2 for
dealing with socket communication and 1 for the GUI interface,
XtAppMainLoop, OpenGL stuff).

My system is a DEC (guess it's Compaq now) Personal Workstation 500au,
Powerstorm 4D50T video card, running Digital Unix 4.0D, OpenGL 1.1 (DEC
refers to their implementation as Open3D v4.9), CDE, Motif 1.2.  I've
been using DEC's C++ compiler / linker and gnu c++ compiler / linker.

The problem occurs during initialization of the class that I've wrapped
the OpenGL in (when the class is being created).  Running the
application through DEC's Ladebug de* reveals that the application
is sitting and waiting on an XGetVisualInfo function call.  It also
appears that the GUI thread that is going through this initialization
already got a mutex lock and is trying to acquire another one.  The
application will eventually start after three or four tries.  Once the
application starts, everything runs fine.

I make the usual calls (XInitThreads and XtToolkitThreadInitialize) to
make sure thread safe X, Xt libraries are linked in.  There is little in
the documentation of Open3D about the safety in threads or in a threaded

This has been a mind boggling problem.  Thanks.

Christopher Gee


1. DEC Alpha asks: Lightwave's OpenGL?

Hey Folks,

I'm in the Commodity Graphics group at DECWest (a stone's throw from
Microsoft.)  My job, and the focus of our group, is to make commodity
graphics cards (like Matrox) go really fast on Windows NT Alpha.  Currently
we are working on OpenGL, and we will probably be working on Direct3D in
the future.

What do you think of Lightwave's new OpenGL support?  Is it a good feature?
 Does it help your work a lot, or is it not that relevant?  How's the speed
of OpenGL on the platform you're using?

Brandon J. Van Every       |  Free3d: old code never dies!  :-)
                           |  Starter code for GNU Copyleft projects.
DEC Graphics & Multimedia  |

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