VTK version supported

[drouin-simon]

Guys, we have, unofficially, dropped support for VTK < 7 by using VTK_OVERRIDE in the classes of IO. We can either define VTK_OVERRIDE to nothing when VTK < 7 or officially decide not to support VTK < 7 and pop an error in CMake when trying to build with an older VTK.

What do you want to do?

[adamrankin]

Support VTK7. No reason not to if it's a simple #def

[drouin-simon]

Do you mean we should support VTK < 7 (e.g. 6.3, which I'm using)?

Version 7 and above is no problem because VTK_OVERRIDE is defined by VTK itself ( defined as "override" if your c++ version > 201103L and "" otherwise ). If you use 6.3, VTK_OVERRIDE is not defined and there is a compiler error everywhere VTK_OVERRIDE is used.

[adamrankin]

Oh, sorry, I misunderstood. I have no objections to dropping VTK < 7.

[lassoan]

VTK8 is needed for good OpenGL2, Qt5, Python3, and VR support, so we will not use VTK7 in any of our projects. Slicer master has already dropped VTK7 support.

Of course we don't mind if there are some extra #defines for a while for backward compatibility with VTK7 or older.

[drouin-simon]

Again, VTK 7 is not the problem. Anything below 7 is a problem.

I still use 6.3 in Ibis but I will upgrade now. It shouldn't be a problem. I only have a problem with the OpenGL2 backend which dropped some multitexturing functionality that I'm using in Ibis but I might have found a workaround. Until I fix it, I will use the old OpenGL backend, but I don't think it makes a difference for OpenIGTLinkIO.

Plus Toolkit is still using VTK 7 by default, no? I guess this is going to change in the next release?

[adamrankin]

I was just thinking we should increment our default to 8.

[lassoan]

By default Plus uses same ITK/VTK/Qt version as Slicer. Slicer will switch to VTK8/Qt5/OpenGL2 within a few days, so it would make sense for Plus to switch, too.

[drouin-simon]

I moved my code to 7.1.1. Will probably move to 8 soon. I am a little puzzled by the fact that Kitware didn't systematically resolve the inconsistent-missing-override*** warnings before releasing vtk 7.1.1. Most classes have the VTK_OVERRIDE macros in proper places, but not all of them, including important ones like vtkInteractorObserver. Am I missing something?

*** ex: warning: 'RequestInformation' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]