### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 7, 2024, 9:04pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/1 "2024-08-07T21:04:20Z")
I’m running VTK-9.3.1 on ubuntu-22.04
My application instantiates a vtkGenericOpenGLRenderWindow and invokes vtkOpenGLRenderWindow::OpenGLInitState():
```auto
renderWindow_ =
vtkSmartPointer::New();
renderWindow_->OpenGLInitState();
```
But renderWindow\_-\>OpenGLInitState() segfaults somewhere in this call stack at Rendering/OpenGL2/vtkOpenGLRenderWindow.cxx:631
`this->GetState()->Initialize(this)`
What’s the proper way to initialize vtkGenericOpenGLRenderWindow?
Thanks!
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 7, 2024, 9:06pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/2 "2024-08-07T21:06:15Z")
Segfaults most likely because the opengl function pointers are all null. Have you tried calling `renderWindow_->vtkOpenGLRenderWindow::OpenGLInit()` instead?
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 7, 2024, 9:11pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/3 "2024-08-07T21:11:34Z")
Thanks. Yes, renderWindow\_-\>vtkOpenGLRenderWindow::OpenGLInit() also segfaults.
---
### Author:  [@Jens\_Munk\_Hansen](https://discourse.vtk.org/u/Jens_Munk_Hansen)
#### Post date: [August 7, 2024, 9:16pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/4 "2024-08-07T21:16:40Z")
Have you checked that OpenGL is working on your platform. `glxinfo | grep "OpenGL version"`
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 7, 2024, 9:20pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/5 "2024-08-07T21:20:42Z")
Yes, other OpenGL apps are working on my platform. And
```auto
glxinfo | grep "OpenGL version"
OpenGL version string: 4.6 (Compatibility Profile) Mesa 23.0.4-0ubuntu1~22.04.1
```
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 7, 2024, 9:28pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/6 "2024-08-07T21:28:46Z")
Do you really need to use a `vtkGenericOpenGLRenderWindow`? That class is generally used by applications that have already setup a win32/x/cocoa window. Did you do that?
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 7, 2024, 9:32pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/7 "2024-08-07T21:32:35Z")
My app uses vtk to render a surface within Qt, in a QQuickItem. The app was written several years ago, worked with Qt5 and VTK-9.2 using vtkGenericOpenGLRenderWindow, I assume because Qt sets up OpenGL beforehand… Now segfaults with Qt6 and VTK-9.3.
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 7, 2024, 9:45pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/8 "2024-08-07T21:45:23Z")
The code from [https://gitlab.kitware.com/vtk/vtk/-/blob/master/GUISupport/QtQuick/QQuickVTKRenderWindow.cxx#L91](https://gitlab.kitware.com/vtk/vtk/-/blob/master/GUISupport/QtQuick/QQuickVTKRenderWindow.cxx#L91) can guide you on how to do it correctly. Something may have changed since 9.2
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 7, 2024, 10:09pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/9 "2024-08-07T22:09:06Z")
Thanks for that link!
Do you know of an example that uses QQuickVTKItem and QQuickVTKRenderer?
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 7, 2024, 10:46pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/10 "2024-08-07T22:46:26Z")
I couldn’t find QtQuick applications on the VTK examples website. VTK’s QtQuick [unit tests](https://gitlab.kitware.com/vtk/vtk/-/tree/master/GUISupport/QtQuick/Testing/Cxx?ref_type=heads) should help.
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 7, 2024, 11:02pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/11 "2024-08-07T23:02:49Z")
Great, I will take a look. Thanks!
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 9, 2024, 1:52am UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/13 "2024-08-09T01:52:25Z")
Gosh I cannot for the life of me figure out how to use QQuickVTKItem from the unit tests.
[Documentation for QQuickVTKRenderItem](https://vtk.org/doc/nightly/html/classQQuickVTKRenderItem.html#details) has a nice clear example - yet when I try to build that simple app the compiler gives `warning: ‘QQuickVTKRenderWindow’ is deprecated: Use QQuickVTKItem instead`
But [documentation for QQuickVTKItem](https://vtk.org/doc/nightly/html//classQQuickVTKItem.html#details) has no such example - and I’m afraid I’m just not grokking the unit tests. Any clues appreciated!
Thanks!
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 9, 2024, 1:48pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/14 "2024-08-09T13:48:33Z")
You can build the unit tests with the cmake flag `-DVTK_BUILD_TESTING=WANT` and run them from the build directory with `ctest`. You can run `ctest -N -VV` to actually see the full path to test executables and arguments passed to them. `ctest -R NameOfTest` is another way to run a specific unit test. Have you seen [https://gitlab.kitware.com/vtk/vtk/-/blob/master/GUISupport/QtQuick/Testing/Cxx/TestQQuickVTKItem\_2.cxx](https://gitlab.kitware.com/vtk/vtk/-/blob/master/GUISupport/QtQuick/Testing/Cxx/TestQQuickVTKItem_2.cxx)?
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 12, 2024, 8:28pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/15 "2024-08-12T20:28:23Z")
Thanks! I built the VTK-9.3.1 tests, but when I try to run TestQQuickVTKItem\_1 I get an error:
```auto
$ ctest -R VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1
Test project /home/oreilly/VTK-9.3.1/build
Start 502: VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1
1/1 Test #502: VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1 ...***Failed Error regular expression found in output. Regex=[ERR\|] 4.25 sec
```
I get similar errors for TestQQuickVTKItem\_2 and TestQQuickVTKItem\_3.
I’m a ctest newbie - am I making an obvious error?
Thanks!
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 12, 2024, 8:39pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/16 "2024-08-12T20:39:51Z")
Can you increase the verbosity by running it with `-VV`?
Try `ctest -R VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1 -VV`
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 12, 2024, 8:49pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/17 "2024-08-12T20:49:29Z")
Here it is:
```auto
% ctest -R VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1 -VV
UpdateCTestConfiguration from :/home/oreilly/VTK-9.3.1/build/DartConfiguration.
tcl
Parse Config file:/home/oreilly/VTK-9.3.1/build/DartConfiguration.tcl
Add coverage exclude regular expressions.
Add coverage exclude: vtk[^\.]+(Java|Python).cxx
Add coverage exclude: .*Testing.Cxx.*cxx
Add coverage exclude: .*Testing.Cxx.*h
Add coverage exclude: .*moc_.*cxx
Add coverage exclude: .*/Utilities/.*
Add coverage exclude: .*/ThirdParty/.*
UpdateCTestConfiguration from :/home/oreilly/VTK-9.3.1/build/DartConfiguration.tcl
Parse Config file:/home/oreilly/VTK-9.3.1/build/DartConfiguration.tcl
Test project /home/oreilly/VTK-9.3.1/build
Constructing a list of tests
Done constructing a list of tests
Updating test list for fixtures
Added 0 tests to meet fixture requirements
Checking test dependency graph...
Checking test dependency graph end
test 502
Start 502: VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1
502: Test command: /home/oreilly/VTK-9.3.1/build/bin/vtkGUISupportQtQuickCxxTests "TestQQuickVTKItem_1" "-D" "/home/oreilly/VTK-9.3.1/build/ExternalData/Testing" "-T" "/home/oreilly/VTK-9.3.1/build/Testing/Temporary" "-V" "/home/oreilly/VTK-9.3.1/build/ExternalData/GUISupport/QtQuick/Testing/Data/Baseline/TestQQuickVTKItem_1.png"
502: Working Directory: /home/oreilly/VTK-9.3.1/build/GUISupport/QtQuick/Testing/Cxx
502: Test timeout computed to be: 1500
502: CTEST_FULL_OUTPUT (Avoid ctest truncation of output)
502: ESC[0mESC[31m( 1.898s) [main thread]vtkOpenGLRenderWindow.c:701 ERR| vtkGenericOpenGLRenderWindow (0x55d34121fff0): GLEW could not be initialized: Unknown errorESC[0m
502: ESC[0mESC[31m( 1.902s) [main thread]vtkOpenGLRenderWindow.c:701 ERR| vtkGenericOpenGLRenderWindow (0x55d34121fff0): GLEW could not be initialized: Unknown errorESC[0m
502: 0Standard
1/1 Test #502: VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1 ...***Failed Error regular expression found in output. Regex=[ERR\|] 3.07 sec
0% tests passed, 1 tests failed out of 1
Label Time Summary:
VTK::GUISupportQtQuick = 3.07 sec*proc (1 test)
Total Test time (real) = 3.23 sec
The following tests FAILED:
502 - VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1 (Failed)
Errors while running CTest
Output from these tests are in: /home/oreilly/VTK-9.3.1/build/Testing/Temporary/LastTest.log
```
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 12, 2024, 8:54pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/18 "2024-08-12T20:54:41Z")
> [@Tomasso](#):
>
> `ERR| vtkGenericOpenGLRenderWindow (0x55d34121fff0): GLEW could not be initialized: Unknown error`
Check if you’ve all the dependencies on ubuntu or their equivalent in your distro [docs.vtk.org#creating-the-build-environment](https://docs.vtk.org/en/latest/build_instructions/index.html#creating-the-build-environment)
---
### Author:  [@Tomasso](https://discourse.vtk.org/u/Tomasso)
#### Post date: [August 12, 2024, 9:26pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/19 "2024-08-12T21:26:19Z")
Apparently [this error is generated by a known Wayland problem](https://gitlab.kitware.com/vtk/vtk/-/issues/19357). Does this mean that QQuickVTKItem and related will not work on ubuntu 22.04 running Wayland for the time being?
I’ve disabled Wayland - running x11 - and now the unit test passes - Hurray!
```auto
$ ctest -R VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1
Test project /home/oreilly/VTK-9.3.1/build
Start 502: VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1
1/1 Test #502: VTK::GUISupportQtQuickCxx-TestQQuickVTKItem_1 ... Passed 1.35 sec
100% tests passed, 0 tests failed out of 1
Label Time Summary:
VTK::GUISupportQtQuick = 1.35 sec*proc (1 test)
vtkGUISupportQtQuick = 1.35 sec*proc (1 test)
```
But I do not see a graphical output from the test, in this case a cone. Shouldn’t I?
Thanks!
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 12, 2024, 9:31pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/20 "2024-08-12T21:31:52Z")
Ah, if you don’t want to run on X11, it might work with EGL. For the moment, you may turn off X in VTK and turn on EGL.
`cmake -DVTK_USE_X=OFF -DVTK_OPENGL_HAS_EGL=ON`
---
### Author:  [@jaswantp](https://discourse.vtk.org/u/jaswantp)
#### Post date: [August 12, 2024, 9:33pm UTC](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366/21 "2024-08-12T21:33:58Z")
> [@Tomasso](#):
>
> But I do not see a graphical output from the test, in this case a cone. Shouldn’t I?
The test exits immediately, so you might not see anything. Instead, you can run the unit test interactively with the “-I” flag. This flag is parsed by the C++ test, it is not a `ctest` option.
```auto
/home/oreilly/VTK-9.3.1/build/bin/vtkGUISupportQtQuickCxxTests "TestQQuickVTKItem_1" "-I"
```
[Next page](https://discourse.vtk.org/t/segfault-in-vtkopenglrenderwindow-openglinitstate/14366.md?page=2)