VMD-L Mailing List
From: John Stone (johns_at_ks.uiuc.edu)
Date: Wed Apr 09 2014 - 11:47:56 CDT
One of the reasons I think they may have "overoptimized" the graphics
driver is that it is unusual for an applcation to swap the buffer, then
swap it back, like we do for the VMD "snapshot" rendering mode.
I would be curious if you can cause "snapshot" to malfunction more generally
by rendering a frame, then doing "rotate y by 90" and then doing another
snapshot. Given what you observe with the movie maker, it may be that
the driver misbehaves for snapshot renderings in general, or at least
when operated in a loop in much the same way that the movie maker does.
If you are able to try any experiments there to see if this driver
is breaking snapshot in general, or only causes trouble with the movie
maker, that would be good to know.
On Wed, Apr 09, 2014 at 12:41:42PM -0400, Carlos Simmerling wrote:
> thanks. and to clarify, it works fine when not in moviemaker.
> On Wed, Apr 9, 2014 at 12:39 PM, John Stone <johns_at_ks.uiuc.edu> wrote:
> 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.
> John Stone
> 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
> > and no updates are available.
> > Is the buffer swap between consecutive frames, or should it be as I
> > alternating the initial frame with the one that is supposed to be
> > If it's buffer swap, then it seems to draw frame 1, then 2, then 1,
> > 3, then 1 and so on, so that toward the end the structures that
> > are completely different...
> > thanks!
> > carlos
> > On Wed, Apr 9, 2014 at 11:48 AM, John Stone <johns_at_ks.uiuc.edu>
> > Carlos,
> > The "jiggling" you see during movie rendering is normal and is
> > caused by VMD swapping the "front" and "back" OpenGL color
> > when it takes the snapshot. The outcome you described however
> > that you may have a broken graphics driver, as you should
> > be getting the expected output in the files on disk. What NVIDIA
> > driver version is this machine running? I haven't seen this
> > on Linux and we have a Quadro 5800 in our lab as well, so this
> > be a windows-specific driver issue for that card, or an issue
> > that particular driver version. If you can tell me more about
> > 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
> > > 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
> > 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
> > 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
> > 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
> > identical,
> > > and are all the original view. When I'm not making the movie
> > work
> > > fine and the dynamics are shown fine. It's only in the movie
> > 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
-- 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/