VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Tue Jun 17 2003 - 15:32:29 CDT

Hi,
  Interesting. We haven't seen this behavior for a while, though I
am familiar with what you're talking about. When I experienced that
behavior it seemed to be combination of the Window manager and XFree86
driver that made it occur.

I also saw the exact same problem when I used ImageMagick to view
large images on the same machine(s), with the same window manager.
Try loading a large image with ImageMagick and tell me if you encounter
the same problem. ImageMagick isn't even using OpenGL, its just doing
simple X calls to display bitmaps, so it should be somewhat
independent of the NVidia OpenGL drivers, though it will obviously still
exercise the video card substantially.

The images I loaded that gave trouble were VMD pictures I rendered with
Tachyon at 4096x4096 resolution for journal covers people were doing.
I experienced exactly the same problems you describe, and on the same
machine both VMD and ImageMagick triggered the issue.
Naturally, out of curiosity I compared the X event
processing code in VMD and in ImageMagick, but they have very little
in common, so I didn't see anything that they'd be doing similarly that
would explain the odd behavior I experienced on Linux.

For what its worth, I've NEVER seen this behavior on any of the
commercial Unix systems, even when using the same window managers on them
as I used on Linux. I suspect its an interaction between XFree86 and
the window manager(s) in question.

We made some changes in the way VMD does event processing so that
resize events aren't nearly as "agressive" as they used to be, but
perhaps we need to take another look at this. Do you observe this
behavior on any other machines besides yours?

Thanks,
  John Stone
  vmd_at_ks.uiuc.edu

On Tue, Jun 17, 2003 at 11:01:44AM +0300, Mikko Huhtala wrote:
>
> There was some discussion of performance dropping when the Opengl
> window is enlarged to the point that it exhausts the memory on the
> graphics card. My problem is that VMD actually hangs upon resizing the
> Opengl window, even at small window sizes and when there are no
> coordinates loaded and the window is only showing the 'VMD' logo. The
> problem seems to depend on the exact size of the window: when the
> window is resized in a wireframe mode (non-opaque resize; no updates
> during resize), it sometimes works just fine and sometimes hangs (just
> happens to hit a 'bad' size?). Unfortunately I am now using Gnome on
> RH9 and the Metacity wm only does opaque resizes. Windows are updated
> constantly during resize, and resizing the VMD Opengl window hangs
> every time.
>
> I'm running the 1.0-3123 version of the NVidia drivers. The card
> (Geforce 3 by Creative) and the motherboard chipset are an unfortunate
> combination that do not work with newer driver versions. However,
> other Opengl graphics software do work on the system and I've had the
> resize problem with many window managers, driver/Linux kernel versions
> and VMD versions 1.7 - 1.8.1, so it seems like the bug is in
> FLTK/VMD's interaction with Opengl.
>
> Mikko 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu                 Phone: 217-244-3349              
  WWW: http://www.ks.uiuc.edu/~johns/      Fax: 217-244-6078