[chimerax-users] OpenGL error running ChimeraX under VNC on CentOS 7

[Tom Goddard]

Hi Alexis,

  ChimeraX is crashing in the OpenGL graphics driver (libGL.so.1) when the Qt window toolkit is trying to use it.  This is certainly an OpenGL graphics problem with your VNC setup.  Sometimes VNC is run mirroring an actual display connected to the server computer you are connecting to, and sometimes it displays a virtual desktop, for example, when connecting to a server that has no physical display.  ChimeraX will very likely work if VNC is mirroring an actual display on the server, but will almost surely fail if it is using a virtual desktop on the server.  This is because OpenGL rendering only works to a physical display directly connected to the computer running the app (ChimeraX).  I think there have been efforts to send the OpenGL commands to another computer and have that client computer's graphics card render, but that is a very obscure capability, and I have only heard of it failing, never saw it work.

	Tom

> On Mar 14, 2019, at 10:40 AM, Alexis Rohou wrote:
> 
> Hi Tom,
> 
> I am attempting to get ChimeraX running on a CentOS7 workstation with a
> nice discrete GPU card for running ISOLDE. Unfortunately, I am having no
> luck so far. Tristan Croll, who is helping me get started with ISOLDE,
> suggested I send you directly this report and ask for guidance.
> 
> Some details:
> - I installed the daily CentOS7 RPM from yesterday (13-March-2019)
> - I am connecting to this workstation using a VNC server/client. I do
> not have physical access to the workstation, at least not any time soon
> - Starting the binary under gdb gives the error & stack trace copied below
> - it could be that this is just related to OpenGL over VNC not working
> properly. If you suspect this is true, could you suggest some test I
> could run to confirm this is the case?
> 
> Any other hints would be most welcome!
> 
> Thanks,
> Alexis
> 
> 
>> WARNING: QOpenGLShader::compile(Vertex): failed
>> WARNING: QOpenGLShader::compile(Fragment): failed
>> WARNING: Could not link shader program:
>>  ""
>> 
>> Program received signal SIGSEGV, Segmentation fault.
>> 0x00007fffe6e6a013 in ?? () from /usr/lib64/nvidia/libGL.so.1
>> Missing separate debuginfos, use: debuginfo-install
>> ucsf-chimerax-daily-2019.03.13-1.el7.x86_64
>> (gdb) bt
>> #0  0x00007fffe6e6a013 in  () at /usr/lib64/nvidia/libGL.so.1
>> #1  0x00007fffe54e268a in  () at
>> /usr/lib64/nvidia/libnvidia-glcore.so.340.107
>> #2  0x00007fffe6eac1a0 in  () at /usr/lib64/nvidia/libGL.so.1
>> #3  0x00007fffe0e4fc6f in  () at
>> /opt/UCSF/ChimeraX-daily/lib/python3.7/site-packages/PyQt5/Qt/lib/libQt5Gui.so.5
>> #4  0x00007fffe0df1842 in  () at
>> /opt/UCSF/ChimeraX-daily/lib/python3.7/site-packages/PyQt5/Qt/lib/libQt5Gui.so.5
>> #5  0x00007fffe0df2143 in
>> QPlatformBackingStore::composeAndFlush(QWindow*, QRegion const&,
>> QPoint const&, QPlatformTextureList*, QOpenGLContext*, bool) () at
>> /opt/UCSF/ChimeraX-daily/lib/python3.7/site-packages/PyQt5/Qt/lib/libQt5Gui.so.5
> 
> 
>