feat: add WebXR Helper widget

[munozco]

This adds a WebXR Helper widget to enable VtkView and VtkLocalView to be used for a WebXR session.
vue-vtk-js PR: Kitware/vue-vtk-js#9

The new VtkWebXRHelper class contains the XrSessionTypes enum that has the same values as XrSessionTypes in vtk.js.

Here's an example that uses the new VtkWebXRHelper widget in a TrameApp:

with vuetify3.VContainer(fluid=True, classes="pa-0 fill-height"):
  with vtk.VtkView() as view:
      self.xr_widget = vtk.VtkWebXRHelper(draw_controllers_ray=True, enterXR=self.ctrl.enterXR, exitXR=self.ctrl.exitXR)
      with vtk.VtkGeometryRepresentation():
          vtk.VtkAlgorithm(vtk_class="vtkConeSource")

# [...]

# start a HmdVR WebXR session
self.xr_widget.startXR(vtk.VtkWebXRHelper.XrSessionTypes.HmdVR)

# stop the session
self.xr_widget.stopXR()

[jourdain]

You need to update the version of vue-vtk-js in that PR

https://github.com/Kitware/trame-vtk/blob/master/.fetch_externals.sh

[finetjul]

I do not understand how it knows on which view the helper applies...

[munozco]

The helper has a vtkView (or a vtkLocalView) as its parent. It can get the corresponding ClientView (or LocalView) thanks to the Vue.js provide/inject mechanism. For instance, the vtkView Vue component is providing the ClientView object here

[jourdain]

It would be nice to add an example in this repo showcasing the usage of XR

[munozco]

I added an example, let me know if I need to change anything.
I'm not sure why the tests fail... I cannot reproduce this on my machine

[munozco]

@jourdain do you think tests failures are related to this change or is the CI unstable ?

[jourdain]

CI is unstable for remote rendering of volume rendering. (slow and image capture happen before the resized image is retrieved) We may have to disable that test or figure out a way to wait longer before doing image comparison of the browser.

[munozco]

Is the CI missing a apt-get update ? It failed while installing OSMesa

[jourdain]

yes that was the solution for trame-vtklocal
Kitware/trame-vtklocal@0545876

[munozco]

I can't find a way to fix the CI. @jourdain do you have any idea ?

[jourdain]

@psavery

[jourdain]

We need to update the CI to do what I recently did in trame-tauri

[psavery]

The failing CI is due to an issue with Selenium. We are switching over to Playwright soon where the issue will be resolved.

[psavery]

@munozco if you rebase on master, it should fix your CI issues.

[jourdain]

I'm not sure why the color mapping is a little bit different, but probably because of some vtk.js update/fix?

You may want to add a new baseline to the repo

Currently produced image

vs baseline

[munozco]

test_big_int.py also seems broken. The produced image is missing the local view on the left...

[jourdain]

Are the tests working for you locally?

[munozco]

No, they are not working locally. The big int test is having a TypeError: can't convert BigInt to number error. That might also be due to a vtk.js update.

Also, on my machine, 3 tests on master are failing (big int, lookup table and volume rendering) because output image doesn't match with any of the baselines. They are failing for a few pixels.

[jourdain]

Can you double check that "older" vtk.js version work and that is indeed a regression?

[munozco]

I checked with older and newer vtk.js versions, and with both versions the "BigInt" test works. So this looks like I should bump vtk.js in vue-vtk-js. What do you think ?

[jourdain]

A bump of vtk.js could indeed be good for vue-vtk-js. The strange thing is that this test was working before. So I'm not sure why changed.

[munozco]

Sorry, I mixed things up. This doesn't work using newer vtk.js versions.
The BigInt test doesn't work on my branch because I have vtk.js 32.2.0 (vue-vtk-js 3.3.0). It works with vtk.js 29.4.5 (vue-vtk-js 3.2.2), but this version of vtk.js lacks WebXR features.
So yes, this is a regression.

[jourdain]

Here is the answer

Kitware/vtk-js@2d322e5

the latest code, don't have that piece anymore.