VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Tue Apr 29 2003 - 13:36:00 CDT

Lubos,

On Tue, Apr 29, 2003 at 08:23:10PM +0200, Lubos Vrbka wrote:
> we'll try to play with the settings and we'll see... do you think switching
> to the mesa version will "cure" this problem?

Using the Mesa driver in XFree86 would cure the problem, but would run
20x slower, so its not the ideal way of dealing with the problem. I don't
intend to continue building statically-linked Mesa versions of VMD much longer
since all platforms support real OpenGL drivers these days, and the old
statically linked version I've been shipping doesn't work on as many Linux
distros as the "OpenGL" (dynamically linked) version. If you like you might
keep the OpenGL version of VMD on your box, and set your XFree driver to use
Mesa and see if the problem goes away for you or not.

> what surprises me that whole
> geometry is displayed correctly, problem is with the labels only. in case it
> would be graphics card problem WHOLE structure would flash, wouldn't it?

Not necessarily. Depends on the order of rendering and the size of the
structure you're drawing. I've seen many variants on this sort of behavior.
I reported a very similar bug to ATI about a month ago, but it was showing
up with the "Points" representation and not on others....

[labels in renderers...]
> i think the "label" stuff can be solved in povray. i was playing a little
> bit with this and povray is capable of doing text output in the scene...
> you're right, doing lines (especially dashed, dotted and similar types) is
> quite complicated. i'm doing povray plugin for my colleague's software and i
> still haven't solved how to do dashed line - to adjust the size of the
> "sub-lines" and scale them according to the size of the bond, or compose the
> dashed line of the corresponding number of "fixed size" parts... so i think
> i understand the problems you have here...

Yeah. I could add real Lines to Tachyon if people think this is important
enough, I've never done it in the past because I didn't think it was useful
for much except label type things like VMD uses. These lines wouldn't show
up in reflections in the scene, so they'd be "breaking a few rules" of how a
normal ray tracer works. On the plus side, they'd look just like they do in
VMD if I implemented them... I haven't had time yet, but that might be
another solution.

Thanks,
  John Stone
  vmd_at_ks.uiuc.edu 

-- 
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