VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Wed Aug 22 2007 - 22:55:06 CDT

Mario,
  The "wobbling" is an effect of the way current generation shading
languages perform interpolation of parameters to fragment shaders,
and is nothing to do with the video driver. This will go away when
they enable a non-perspective-corrected interpolation mode in GLSL,
which should be available soon if I recall correctly. The programs
that don't do perspective projected spheres won't exhibit this
effect. Most of the other programs are using "billboard" spheres
rather than proxy geometry like VMD uses, so there's a totally
different rendering approach in each case.

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu

On Thu, Aug 23, 2007 at 05:45:02AM +0200, Mario Valle wrote:
> I spoke too fast...
> From a distance the atom spheres are normal, but if you zoom, you see
> strange wobbling on the surface (see attached). Seems like there are two
> compenetrating surfaces.
> Another tool (Molekel), that provides an extensive set of shaders, after
> the upgrade reported no similar problem. Today I'll try to investigate
> further.
> Thanks for the help!
> mario
>
> John Stone wrote:
> >Mario,
> > Thanks, it's good to see that working for you!
> >I'm CCing VMD-L in case any other Quadro 4500 users are still
> >using the old drivers and would benefit from knowing what version
> >you're using successfully.
> >
> >Cheers,
> > John Stone
> > vmd_at_ks.uiuc.edu
> >
> >
> >On Wed, Aug 22, 2007 at 03:13:03PM +0200, Mario Valle wrote:
> >
> >>Ciao John!
> >>Just to close an old thread (GLSL rendering problems - Apr 2007).
> >>On our HP SVA cluster (LINUX AMD 64bits) we have upgraded the nvidia
> >>drivers to 100.14.09
> >>and now VMD 1.8.6 works flawlessly also using full GLSL!
> >>
> >>Info) VMD for LINUXAMD64, version 1.8.6 (April 6, 2007)
> >>Info) http://www.ks.uiuc.edu/Research/vmd/
> >>Info) Email questions and bug reports to vmd_at_ks.uiuc.edu
> >>Info) Please include this reference in published work using VMD:
> >>Info) Humphrey, W., Dalke, A. and Schulten, K., `VMD - Visual
> >>Info) Molecular Dynamics', J. Molec. Graphics 1996, 14.1, 33-38.
> >>Info) -------------------------------------------------------------
> >>Info) Multithreading available, 2 CPUs detected.
> >>Info) Free system memory: 3774MB (95%)
> >>Info) OpenGL renderer: Quadro FX 4500/PCI/SSE2
> >>Info) Features: STENCIL MSAA(16) MDE CVA MTX NPOT PP PS GLSL(OVF)
> >>Info) Full GLSL rendering mode is available.
> >>Info) Textures: 2-D (4096x4096), 3-D (512x512x512), Multitexture (4)
> >>
> >>Only four months to upgrade the drivers...
> >>
> >>Ciao!
> >> mario
> >>
> >>--
> >>Ing. Mario Valle
> >>Visualization Group |
> >>http://www.cscs.ch/~mvalle
> >>Swiss National Supercomputing Centre (CSCS) | Tel: +41 (91)
> >>610.82.60
> >>v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax: +41 (91)
> >>610.82.82
> >>
> >
> >
>
>
> --
> Ing. Mario Valle
> Visualization Group |
> http://www.cscs.ch/~mvalle
> Swiss National Supercomputing Centre (CSCS) | Tel: +41 (91) 610.82.60
> v. Cantonale Galleria 2, 6928 Manno, Switzerland | Fax: +41 (91) 610.82.82
> 

-- 
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