[chimerax-users] Stereo mode error

[Tom Goddard]

Hi J.C.,

  Since Chimera works in stereo and ChimeraX does not I think the problem is almost surely that ChimeraX requires a "core" OpenGL context (ie using modern OpenGL) while Chimera requires a "legacy" OpenGL context.  I assume ChimeraX is working for you not in stereo.  So it can get a core context, but apparently not a core stereo context.

  It looks like the Nvidia driver is not providing a core OpenGL stereo context.  But Nvidia has clearly stated that it does support this in their 3D Vision FAQ

	https://nvidia.custhelp.com/app/answers/detail/a_id/4845
"Without 3D Vision, will NVIDIA Quadro GPUs still support OpenGL Quad-buffered Stereo?
Absolutely YES. OpenGL Quad-buffered Stereo is not affected by changes to the 3D Vision driver."

ChimeraX is asking for quad-buffered stereo core context and "core" contexts are the standard of current OpenGL.  So if we believe Nvidia's statement then their driver will give this kind of context.  And that suggests that you have a driver configuration setting that prevents it.  It is certainly also possible that the Nvidia driver you are using is simply broken in its ability to provide core stereo contexts.  But I think it is more likely you have it configured to not give such a context, possibly your X server "Option "Stereo" "10"" setting is the cause.

  When the Nvidia driver provides a core OpenGL stereo context this does not mean your 3D Vision glasses will work.  In fact the above 3D Vision FAQ very clearly says it will not work with a current Nvidia driver unless a separate 3D Vision USB driver is installed.
"NVIDIA announced it is no longer supporting 3D Vision. What does this mean?
Hardware: NVIDIA is no longer selling the 3D Vision emitters and glasses.
Drivers: R418 graphics drivers will be the last driver to contain the 3D Vision driver package. The R418 branch will be supported until January 2020.
In addition, NVIDIA will decouple the 3D Vision USB driver from the graphics driver. NVIDIA will provide the 3D Vision USB driver package as a separate installer on NVIDIA.com moving forward - see Quadro Advance Options <https://www.nvidia.com/object/quadro-advance-options.html>. This will allow users to upgrade the graphics driver while continuing to use the standalone 3D Vision USB driver."

If this statement from Nvidia is true then the 3D Vision emitter on your computer can only work if you have installed a separate 3D Vision USB driver.  If the emitter does not work the screen will show a double image and stereo software like ChimeraX, Chimera and Coot will not complain but you will not see it in stereo through the glasses because the glasses cannot synchronize to the interleaved in time left and right eye images without the infrared emitter.  It is possible that that separate 3D Vision USB driver does not work with a core OpenGL context.

  Kenneth Satyshur has several legacy Nvidia stereo systems and may know how to make ChimeraX work in stereo with 3D Vision.

  Ultimately, you are trying to use no longer supported hardware.  Honestly Nvidia never supported 3D Vision well, and Windows is much more likely to work than Linux.  It probably can be made to work with ChimeraX if enough hours are sunk into it, and will certainly be easier if you use old graphics software such as Chimera or Coot which was written based on the legacy OpenGL that 3D Vision originally worked with.

	Tom


> On Jan 7, 2021, at 5:53 AM, Jean-Christophe HAESSIG <haessigj at igbmc.fr> wrote:
> 
> Le mardi 05 janvier 2021 à 10:31 -0800, Tom Goddard a écrit :
>> Hi Jean-Christophe,
> Hi,
> 
> That was a *very* insightful answer, thank you vey much. But at the
> same time it's a bit saddening because it sounds like there will be no
> way to use ChimeraX fully on this setup.
> 
> My tests indicate that for the time being, 3D Vision still works with
> the latest Nvidia driver on Linux. Despite nvidias decision to retire
> 3D Vision, it only means they will stop producing shutter glasses. The
> following FAQ entry makes that a little clearer :
> https://nvidia.custhelp.com/app/answers/detail/a_id/4845
> Still, that doesn't explain how standard OpenGL calls would not be
> supported on a recent driver. Maybe using 'Option "Stereo" "10"' in X
> selects an alternate code path where only legacy contexts are
> available. On the other hand, it seems this is the only way to get the
> glasses to work. In fact, I tried every single stereo mode of the
> nvidia driver, and all of them except one gave the same results : the
> programs using the legacy contexts worked and ChimeraX crashed.
> I also tried Chimera and indeed, it works as you suggested.
> 
> In mode 14 (dubbed "Generic Stereo for DP") however, I couldn't get any
> of the programs to work. Stereo is reported as disabled in nvidia-
> settings but that could simply be beacuse there is no DP screen
> attached. Anyway, it sounds more like this mode could support one of
> the more recent GL calls.
> 
> I guess I will keep the older 3D vision sets to run coot and chimera,
> and seek more recent hardware for chimeraX.
> 
> J.C. Haessig -- systems administrator, IGBMC
> 
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://plato.cgl.ucsf.edu/pipermail/chimerax-users/attachments/20210107/939d8d22/attachment.html>