[vtkusers] Offscreen rendering problems on headless Ubuntu

[Sophonet]

One more update:

First of all some correction: glxinfo of course shows the X rendering 
capabilities, not the OSMesa ones, so glxinfo is not the tool of choice.

Then: It seems that Ubuntu's mesa (16.04 update) does not ship with 
llvmpipe drivers for OSMesa, so I have built OSMesa myself, without X, 
based on Utkarsh's hints at 
https://blog.kitware.com/messing-with-mesa-for-paraview-5-0vtk-7-0/.

However, it seems that no OpenGL extensions are available (see output 
below).

Any hint how mesa needs to be compiled / what runtime variables need to 
be set in order to support OpenGL extensions in OSMesa?

Thanks,

      Sophonet


Debug output:
In [1]: import vtk
In [2]: rw = vtk.vtkRenderWindow()
In [3]: rw.SetOffScreenRendering(1)
In [4]: rw.Render()
ERROR: In 
/home/CODE1/dep14473/SW/source/VTK-8.1.0/Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx, 
line 797
vtkOSOpenGLRenderWindow (0x2ebb060): GL version 2.1 with the gpu_shader4 
extension is not supported by your graphics driver but is required for 
the new OpenGL rendering backend. Please update your OpenGL driver. If 
you are using Mesa please make sure you have version 10.6.5 or later and 
make sure your driver in Mesa supports OpenGL 3.2.

In [5]: print(rw.ReportCapabilities())
OpenGL vendor string:  VMware, Inc.
OpenGL renderer string:  llvmpipe (LLVM 5.0, 256 bits)
OpenGL version string:  3.3 (Core Profile) Mesa 17.3.1
OpenGL extensions:

---- (No OpenGL extensions are reported)


On 2018-01-04 14:35, Sophonet wrote:
> Hi list, happy new year!
> 
> I have compiled VTK 8.1.0 on a headless Ubuntu 16.04 with OSMesa
> support (flags: -D VTK_RENDERING_BACKEND="OpenGL2" -D
> VTK_OPENGL_HAS_OSMESA=True).
> 
> Using python (for example), I see an error about an unsupported OpenGL
> version (see below). However, Ubuntu comes with mesa 17.2.4 (which
> should be recent enough). Moreover, glxinfo shows "OpenGL core profile
> version string: 3.3 (Core Profile) Mesa 17.2.4.
> 
> Any clues what went wrong?
> 
> Thanks,
> 
>       Sophonet
> 
> 
> In [1]: import vtk
> In [2]: rw = vtk.vtkRenderWindow()
> In [3]: rw.SetOffScreenRendering(1)
> In [4]: rw.Render()
> ERROR: In
> /home/CODE1/dep14473/SW/source/VTK-8.1.0/Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx,
> line 797
> vtkOSOpenGLRenderWindow (0x1991250): GL version 2.1 with the
> gpu_shader4 extension is not supported by your graphics driver but is
> required for the new OpenGL rendering backend. Please update your
> OpenGL driver. If you are using Mesa please make sure you have version
> 10.6.5 or later and make sure your driver in Mesa supports OpenGL 3.2.
> 
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