VMD-L Mailing List

From: Vani Vemparala (vanivemparala_at_gmail.com)
Date: Sat Oct 12 2013 - 22:43:02 CDT

Dear John,

Thank you so much! this commenting of the IF statement in vmd.frag fixed
the GLSL rendering problem I have been having.

-Vani

On Fri, Oct 11, 2013 at 6:41 PM, John Stone <johns_at_ks.uiuc.edu> wrote:

> Vani,
> Thanks, that's very helpful. It definitely seems that your OpenGL
> driver is broken with respect to proper handling of gl_FrontFacing...
>
> In your VMD installation, try editing the GLSL shader code.
> It is found inside the "shaders" folder within the VMD installation.
> /path/to/VMD/folder/vmd/shaders/vmd.frag
>
> On a Mac, you will need to go inside the VMD.app directory:
> cd "VMD 1.9.1.app/Contents/vmd/shaders"
> edit vmd.frag
>
> Look for "gl_FrontFacing" in the code:
> // determined by polygon winding order provided by OpenGL.
> vec3 N = normalize(oglnormal);
> if (!gl_FrontFacing) {
> N = -N;
> }
>
> Comment out that 'if' statement entirely:
> // determined by polygon winding order provided by OpenGL.
> vec3 N = normalize(oglnormal);
> // XXX disable gl_FrontFacing test on broken Mac Intel OpenGL video
> driver
> // if (!gl_FrontFacing) {
> // N = -N;
> // }
>
> Let us know if that has a positive impact on your problem or not...
> Disabling that test will mean that the renderings of low-resolution
> surfaces or cartoon representations won't look as good as they would
> otherwise, but they should look much better than the results you're
> getting currently.
>
> Cheers,
> John
>
> On Fri, Oct 11, 2013 at 03:54:09PM +0530, Vani Vemparala wrote:
> > John,
> >
> > The VDW/Licorice representations with GLSL off and on are here:
> > http://www.imsc.res.in/~vani/vmd/GLSL-ON-OFF-protein-VDW-licorice.jpg
> >
> > The same protein with 'NewCartoon' representation here:
> > http://www.imsc.res.in/~vani/vmd/GLSL-ON-OFF-protein.jpg
> >
> > -Thank You
> > Vani
> >
> > On Mon, Oct 7, 2013 at 10:37 PM, John Stone <johns_at_ks.uiuc.edu>
> wrote:
> >
> > Hi,
> > I have to concur with Axel, something appears to be quite broken
> with
> > the
> > OpenGL driver on your Mac. I have heard that a number of other Mac
> > users with
> > Intel chips have had intermittent issues with various driver
> versions.
> > I don't know if it's possible to roll back a driver update on
> MacOS, or
> > whether you might be able to install a newer driver, but either
> way, the
> > driver you have is clearly not working correctly. Since the screen
> is
> > nearly
> > all black, my guess is that they have a bug in the implementation of
> > gl_FrontFacing, or something similar. There's a tiny sliver of blue
> > from the
> > curved portion of the "D" in VMD, which makes me think that this
> may be
> > a
> > bug with surface normal handling, likely specifically with
> > gl_FrontFracing.
> > What happens if you load a molecule and set the representation to
> VDW or
> > CPK, or Licorice? Do you still see mostly black, or do any of the
> > spheres
> > show up? They are rendered with a different shader that doesn't
> depend
> > on
> > gl_FrontFacing, so that's why I ask. Another thing to try: disable
> > cueing
> > and see if that has any effect.
> >
> > Cheers,
> > John Stone
> > vmd_at_ks.uiuc.edu
> > On Fri, Oct 04, 2013 at 07:33:13AM +0200, Axel Kohlmeyer wrote:
> > > On Fri, Oct 4, 2013 at 6:30 AM, Vani Vemparala
> > <vanivemparala_at_gmail.com> wrote:
> > > > Hello all,
> > > >
> > > > I recently purchased a MAC mini with the following
> specifications:
> > > >
> > > > MAC OSX version 10.8.5
> > > > Graphics Intel HD Graphics 4000 512 MB
> > > > MAC mini specifications: 2.3 GHz Intel Core i7
> > > > Memory 4 GB 1600 MHZ DDR3
> > > >
> > > > I installed VMD 1.9.1 (I tried both CUDA and NO-CUDA versions of
> > VMD) and
> > > > have been having problems with GLSL rendering. The VMD start up
> > message is
> > > > below and a figure comparing the VMD GUI window with and without
> > GLSL
> > > > rendering is located at:
> > > > http://www.imsc.res.in/~vani/vmd/GLSL.jpg
> > > >
> > > > Any suggestions in this regard would be really helpful.
> > >
> > > looks like a broken OpenGL driver. happens a lot with intel
> chipset
> > graphics.
> > > the linux version of the intel driver had been very broken for
> OpenGL
> > > with GLSL for the last 3-4 years or so and is behaving decently
> only
> > > since about a couple of months ago .
> > >
> > > axel.
> > >
> > > >
> > > > -Thanks
> > > > Vani
> > > > ------------------------------
> > > >
> >
> -----------------------------------------------------------------------------
> > > > /Users/vani $ vmd
> > > > Info) VMD for MACOSXX86, version 1.9.1 (February 4, 2012)
> > > > 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, 8 CPUs detected.
> > > > Info) OpenGL renderer: Intel HD Graphics 4000 OpenGL Engine
> > > > Info) Features: STENCIL MDE MTX NPOT PP PS GLSL(OVF)
> > > > Info) Full GLSL rendering mode is available.
> > > > Info) Textures: 2-D (16384x16384), 3-D (2048x2048x2048),
> > Multitexture (8)
> > > > Info) Dynamically loaded 2 plugins in directory:
> > > > Info)
> > /Applications/VMD1.9.1.app/Contents/vmd/plugins/MACOSXX86/molfile
> > > > vmd > Info) VMD for MACOSXX86, version 1.9.1 (February 4, 2012)
> > > >
> >
> --------------------------------------------------------------------------------------------------------------
> > >
> > >
> > >
> > > --
> > > Dr. Axel Kohlmeyer akohlmey_at_gmail.com http://goo.gl/1wk0
> > > International Centre for Theoretical Physics, Trieste. Italy.
> >
> > --
> > NIH Center for Macromolecular Modeling and Bioinformatics
> > Beckman Institute for Advanced Science and Technology
> > University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> > http://www.ks.uiuc.edu/~johns/ Phone: 217-244-3349
> > http://www.ks.uiuc.edu/Research/vmd/
>
> --
> NIH Center for Macromolecular Modeling and Bioinformatics
> Beckman Institute for Advanced Science and Technology
> University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
> http://www.ks.uiuc.edu/~johns/ Phone: 217-244-3349
> http://www.ks.uiuc.edu/Research/vmd/
>