VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Wed Apr 09 2014 - 11:39:55 CDT

Carlos,
  Normally the buffer swap jiggles back and forth between the last frame
and the next frame. The fact that you're only seeing the first frame
there may indicate that someone has overoptimized the graphics driver and it
is breaking the normal OpenGL buffer swap behavior. I'm traveling for
the next two days and away from the office, but I'll revisit the code
when I get a chance. You might consider downgrading to an older
video driver and see if that cures the problem in the mean time.

Cheers,
  John Stone
  vmd_at_ks.uiuc.edu

On Wed, Apr 09, 2014 at 12:16:53PM -0400, Carlos Simmerling wrote:
> Hi John,
> thanks for the reply. My nvidia control panel says I have driver 332.50,
> and no updates are available.
> Is the buffer swap between consecutive frames, or should it be as I see,
> alternating the initial frame with the one that is supposed to be written?
> If it's buffer swap, then it seems to draw frame 1, then 2, then 1, then
> 3, then 1 and so on, so that toward the end the structures that alternate
> are completely different...
> thanks!
> carlos
>
> On Wed, Apr 9, 2014 at 11:48 AM, John Stone <johns_at_ks.uiuc.edu> wrote:
>
> Carlos,
> The "jiggling" you see during movie rendering is normal and is
> caused by VMD swapping the "front" and "back" OpenGL color buffers
> when it takes the snapshot. The outcome you described however indicates
> that you may have a broken graphics driver, as you should definitely
> be getting the expected output in the files on disk. What NVIDIA
> driver version is this machine running? I haven't seen this occur
> on Linux and we have a Quadro 5800 in our lab as well, so this may
> be a windows-specific driver issue for that card, or an issue with
> that particular driver version. If you can tell me more about the
> driver version that may be helpful.
>
> Cheers,
> John Stone
> vmd_at_ks.uiuc.edu
> On Wed, Apr 09, 2014 at 11:31:51AM -0400, Carlos Simmerling wrote:
> > hi all,
> > I'm having trouble making a movie in VMD. I've done this many times
> in the
> > past, but not since I upgraded to 1.9.1. I also upgraded some of my
> > hardware recently, so not sure which has caused this. I'm running
> windows
> > 7 home premium on a quadro fx5800.
> > The issue is that all of my visualization works fine, but when I
> try to
> > use the movie maker (snapshot mode) it runs but produces incorrect
> output.
> > it performs the operation (either rotate or traj), and appears to
> be
> > making snapshots. I can see the molecule move, but after every step
> it
> > also redraws the image like it was right when I started the movie.
> In
> > other words, it moves forward, then back to the start, then to the
> next
> > frame of the rotation or traj, then back to the start, then
> advances
> > again, and so on. The actual image files saved to disk are all
> identical,
> > and are all the original view. When I'm not making the movie things
> work
> > fine and the dynamics are shown fine. It's only in the movie where
> it
> > seems to draw the right frame, then snap back to the original one,
> which
> > gets written to disk.
> > any ideas?
> > thanks!
> > Carlos
>
> --
> 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/