VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Tue Oct 03 2006 - 14:27:52 CDT

Hi,
  No, GLSL is not required in order to use the VolumeSlice representation
or the Volume coloring method. GLSL is just an optional rendering mode that
invokes an alternative shading/rendering path that generates images that look
nicer, but should otherwise contain the same data that the normal non-GLSL
rendering mode does.

VolumeSlice and the Volume coloring method both require 3-D texturing.
The Intel video chipsets have had various problems with 3-D texturing in
the past. As I recall, the symptom of the problem I've heard reported before
is that the Intel drivers claim 128x128x128 3-D texture support, but when
VMD actually tries to use it, they revert to 128x128x1, causing the
checkerboard pattern you're seeing (which is VMD's way of indicating
that it was not possible to display the 3-D texture at all...)

Since you've got the latest Intel drivers, the next thing to do is
file a bug report with them so they know that their customers want
working 3-D texturing. I know someone who works at Intel on their
graphics software, so I'll send them a note as well, but the more people
that raise the issue, the more likely it is to get fixed.

  John Stone
  vmd_at_ks.uiuc.edu

On Mon, Oct 02, 2006 at 08:26:24PM -0400, Robin L Hayes wrote:
> Hello,
>
> Based on the other archived posts, I suspect I have a video card
> problem. Like many others, I want to color an isosurface or VolumeSlice
> using the "Volume" option under the "Coloring Method" in the "Graphical
> Representations" window. For simplicity, I used the water example (7.1)
> given on Axel's CPMD VMD tutorial page:
> (http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/cpmd-vmd/part5.html#chap7).
>
> Everything, including the VolumeSlice without the Volume coloring
> option, works fine except for the Volume coloring method for the
> isosurface. I get a characteristic checkerboard pattern. However,
> according to the initial VMD system information (given below), my video
> card should be able to handle 3D arrays up to 128x128x128, while the
> volume array is only 40x40x40. Does the volume coloring option require
> GLSL rendering? If so, that is probably the problem. I looked in the
> manual, but the volume option doesn't appear (Table on page 67 in the
> current pdf manual). It is not clear to me exactly what features won't
> work if GLSL is not enabled.
>
> I'm using an HP Pavilion dv1000 laptop [Intel(R) Pentium(R) M, 1.256 GB
> RAM] running Windows XP home edition. I updated my video card driver today.
>
> Info> VMD for WIN32, version 1.8.5 (August 25, 2006)
> ...
> Info> OpenGL renderer: Intel 855GM
> Info> Features: STENCIL MDE CVA MTX PP
> Info> GLSL rendering mode is NOT available.
> Info> Textures: 2-D (2048x2048), 3-D (128x128x128), Multitexture (4)
> Info> Spaceball driver not installed. Spaceball interface disabled.
> Info> No joysticks found. Joystick interface disabled.
> Warning> Rejecting plugin with incorrect ABI version: C:/Program
> Files/University of Illinois/VMD/plugins/WIN32/molfile/mrcplugin.so
> Found 57 plugins or data handlers in directory
> 'C:/Program Files/University of
> Illinois/VMD/plugins/WIN32/molfile/'.
>
> Any suggestions beyond find a different computer to run on?
>
> Thanks,
>
> Robin 

-- 
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