VTK 8.2.0 + Qt 5.12.2 weird event queue processing

Support
1

Dear all!

I installed VTK 8.2.0 + Qt 5.12.2 and noticed a weird behavior:
all my Qt programs that previously was working now crash at the moment of vtkRenderer creation if I build them in -DCMAKE_BUILD_TYPE=Release.

If I build them with -DCMAKE_BUILD_TYPE=Debug, they work, but all events like mouse interactions seems to be delivered only when the next event occurs.
The same problem exists with VTK 8.1.1 and Qt 5.12.2, but it doesn’t crash in Release in VTK 8.1.1.

Then I tried an example (VTK 8.2.0 + Qt 5.12.2):
https://lorensen.github.io/VTKExamples/site/Cxx/Qt/SideBySideRenderWindowsQt/.
It doesn’t crash at all, but this weird thing with events processing still here.

Here is how it looks like https://imgur.com/a/8vDeJhi. (Can’t attach it here, because of restrictions for the new users)
I make a minimal rotation of the mouse wheel on the right pane, but nothing happens. Only when I start interacting with the left pane, the previous event is dispatched to the right pane.

Is it a known problem with Qt or VTK? How it can be fixed in my code?

2

In our lab we use a VTK8.2/Qt5 based application on about 15 computers but only observed this delayed update (you need to move the mouse or move to another window to get the widget updated) on only one of them. It happens not just for the VTK render window but for other standard Qt widgets, too. If I restart the computer then usually the problem goes away.

What computer do you have this problem on? Is it a laptop/desktop? What is the operating system and graphics card? Can you reproduce it on another computer, too?

3

It is laptop. Video card: Intel Corporation HD Graphics 620. Os: Arch Linux (with latest Qt 5.12.2 from repo), VTK from sources (https://vtk.org/download/).

Reboot doesn’t help at all, problem never disappear.

When software rendering in opengl is enabled (LIBGL_ALWAYS_SOFTWARE=1 environment variable) this problem disappear.

I noticed this problem earlier under VM (virtualbox/vmware) when forgot to enable 3d graphics acceleration under Ubuntu 18 / Centos 7.

4

I just checked and found that

  • under the vmware player even with 3d graphics acceleration enabled
  • with the latest Centos 7.6.1810
  • with Qt 5.9.2 from centos repo
  • with VTK 8.2.0 built from source
    problem can be reproduced each time on the mentioned above example
5

I have the same graphics card (Intel Corporation HD Graphics 620) in the computer that has this problem. I use Windows 10. Restarting the computer may be related because after using the computer for long time, rendering slows down and the issue is only perceivable when rendering takes significant time.

I’ve now found another computer with Intel HD 620 and it has the same issue.

6

I opened the issue here: https://gitlab.kitware.com/vtk/vtk/issues/17572