, stack_end=0x7fffffffddc8)
at ../csu/libc-start.c:291
#44 0x0000000000401f39 in _start ()
```
I checked out ParaView `v5.5.2` and cherry picked `931c779d` to fix a Qt 5.11 compilation issue.
```auto
$>cmake \
-DVTK_USE_X=ON \
-DVTK_OPENGL_HAS_OSMESA=ON \
-DCMAKE_INSTALL_PREFIX="../paraview-install" \
-DCMAKE_BUILD_TYPE:STRING="Release" \
-DPARAVIEW_ENABLE_PYTHON:BOOL=ON \
-DPARAVIEW_ENABLE_MPI:BOOL=OFF \
-DPARAVIEW_INSTALL_DEVELOPMENT_FILES:BOOL=ON \
../paraview
```
```auto
$>grep OSMESA CMakeCache.txt
OSMESA_INCLUDE_DIR:PATH=/usr/include
OSMESA_LIBRARY:FILEPATH=/usr/lib/x86_64-linux-gnu/libOSMesa.so
VTK_OPENGL_HAS_OSMESA:BOOL=ON
VTKm_ENABLE_OSMESA:BOOL=ON
//ADVANCED property for variable: OSMESA_INCLUDE_DIR
OSMESA_INCLUDE_DIR-ADVANCED:INTERNAL=1
//ADVANCED property for variable: OSMESA_LIBRARY
OSMESA_LIBRARY-ADVANCED:INTERNAL=1
//ADVANCED property for variable: VTK_OPENGL_HAS_OSMESA
VTK_OPENGL_HAS_OSMESA-ADVANCED:INTERNAL=1
//MODIFIED property for variable: VTK_OPENGL_HAS_OSMESA
VTK_OPENGL_HAS_OSMESA-MODIFIED:INTERNAL=ON
//MODIFIED property for variable: VTKm_ENABLE_OSMESA
VTKm_ENABLE_OSMESA-MODIFIED:INTERNAL=ON
```
Many thanks for your help!
Lukas
---
### Author:  [@Scott\_Wittenburg](https://discourse.paraview.org/u/Scott_Wittenburg)
#### Post date: [June 28, 2018, 3:21pm UTC](https://discourse.paraview.org/t/pvpython-offscreen-rendering-segfault/246/2 "2018-06-28T15:21:03Z")
The documentation you linked has the following line:
- If `VTK_OPENGL_HAS_EGL` or `VTK_OPENGL_HAS_OSMESA` is ON, the build supports headless rendering, otherwise `VTK_USE_X` must be ON and the build does not support headless, but can still support offscreen rendering.
According to that you can do offscreen rendering with VTK\_USE\_X=ON, but it won’t be “headless” (i.e. you’ll need a display). For headless rendering you can use either EGL or OSMESA, but then VTK\_USE\_X must be OFF. EGL allows headless rendering with an NVidia GPU (assuming recent enough drivers), while OSMESA provides software rendering (in several flavors: llvm, swr).
Hope this helps,
Scott
---
### Author:  [@Lukas](https://discourse.paraview.org/u/Lukas)
#### Post date: [June 28, 2018, 3:56pm UTC](https://discourse.paraview.org/t/pvpython-offscreen-rendering-segfault/246/3 "2018-06-28T15:56:37Z")
Hey Scott,
Many thanks for your quick reply!
I interpreted the documentation differently:
> If `VTK_OPENGL_HAS_EGL` or `VTK_OPENGL_HAS_OSMESA` is ON, the build supports headless rendering, otherwise VTK\_USE\_X must be ON and the build does not support headless, but can still support offscreen rendering.
If `VTK_OPENGL_HAS_EGL=ON` or `VTK_OPENGL_HAS_OSMESA=ON` → headless support
otherwise (`VTK_OPENGL_HAS_EGL=OFF` and `VTK_OPENGL_HAS_OSMESA=OFF`) → no headless support and `VTK_USE_X` must be turned on.
However, it does not exclude the case where `VTK_OPENGL_HAS_OSMESA=ON` and `VTK_USE_X=ON`.
Further down it is mentioned that:
> it’s possible to build ParaView with onscreen and headless support simultaneously
Is this a fault in the documentation?
Thanks again,
Lukas
---
### Author:  [@Scott\_Wittenburg](https://discourse.paraview.org/u/Scott_Wittenburg)
#### Post date: [June 28, 2018, 4:19pm UTC](https://discourse.paraview.org/t/pvpython-offscreen-rendering-segfault/246/4 "2018-06-28T16:19:46Z")
> Lukas [https://discourse.paraview.org/u/lukas](https://discourse.paraview.org/u/lukas)
> [https://discourse.paraview.org/u/lukas](https://discourse.paraview.org/u/lukas)
> June 28
>
> Hey Scott,
>
> Many thanks for your quick reply!
> I interpreted the documentation differently:
>
> If VTK\_OPENGL\_HAS\_EGL or VTK\_OPENGL\_HAS\_OSMESA is ON, the build supports
> headless rendering, otherwise VTK\_USE\_X must be ON and the build does not
> support headless, but can still support offscreen rendering.
>
> If VTK\_OPENGL\_HAS\_EGL=ON or VTK\_OPENGL\_HAS\_OSMESA=ON → headless support
> otherwise (VTK\_OPENGL\_HAS\_EGL=OFF and VTK\_OPENGL\_HAS\_OSMESA=OFF) → no
> headless support and VTK\_USE\_X must be turned on.
>
> However, it does not exclude the case where VTK\_OPENGL\_HAS\_OSMESA=ON and
> VTK\_USE\_X=ON.
I guess that’s true, and according to the documentation, that specific
combination is possible, though I don’t have any experience building that
way. In that case it says that “all the OpenGL and OSMesa variables should
point to the Mesa libraries”. I think it would help if that were more
explicit, but maybe it’s enough to get you pointed in the right direction.
FWIW: If you have an NVidia GPU with at least driver version 384, I
recommend the EGL approach to headless rendering, Here are my build
options from a recent EGL build:
cmake
-DCMAKE\_INSTALL\_PREFIX:PATH=/home/ubuntu/paraview
-DBUILD\_TESTING:BOOL=OFF
-DPARAVIEW\_BUILD\_QT\_GUI:BOOL=OFF
-DPARAVIEW\_ENABLE\_PYTHON:BOOL=ON
-DVTK\_USE\_X:BOOL=OFF
-DVTK\_OPENGL\_HAS\_EGL:BOOL=ON
-DEGL\_INCLUDE\_DIR:PATH=/tmp/egl
-DEGL\_LIBRARY:FILEPATH=/usr/lib/nvidia-384/libEGL.so
-DEGL\_opengl\_LIBRARY:FILEPATH=/usr/lib/nvidia-384/libOpenGL.so
…/src/
You have to download the EGL headers yourself probably, as described in
this older blog post about EGL:
[https://blog.kitware.com/off-screen-rendering-through-the-native-platform-interface-egl/](https://blog.kitware.com/off-screen-rendering-through-the-native-platform-interface-egl/)
Further down it is mentioned that:
> it’s possible to build ParaView with onscreen and headless support
> simultaneously
>
> Is this a fault in the documentation?
Perhaps it could be more clear, as there are lots of combinations of
options. However, I’ll leave it to someone else to chime in on that aspect.
Cheers,
Scott
---
### Author:  [@Lukas](https://discourse.paraview.org/u/Lukas)
#### Post date: [July 6, 2018, 1:02pm UTC](https://discourse.paraview.org/t/pvpython-offscreen-rendering-segfault/246/5 "2018-07-06T13:02:36Z")
Hi Scott,
Thanks for your suggestion to use EGL. Unfortunately though, I don’t have a Nvidia GPU.
I need headless support to run tests on Travis-CI. I got it working using `xvfb`.
For those who are interested; before running `pvpython` execute:
```auto
export DISPLAY=:99.0
util/xvfb-initd.sh start
```
[Here](https://github.com/BioDynaMo/biodynamo/blob/a6b19860daa0c7adee5b58df3b19d8e35dfbedcc/util/xvfb-initd.sh) the script to start the xvfb server.
Also check out [Travis’ documentation](https://docs.travis-ci.com/user/gui-and-headless-browsers/)
Thanks and all the best,
Lukas