WebXR support

[oscarlorentzon]

The library should support WebVR. Continuation of the discussion in the issue posted here: mapillary/mapillary_issues#1829.

Features to discuss and handle:

• Pan and tilt in perspective images. Avoid showing void.
• Movement/navigation. Should movement be completely free or restricted in any way.

[gyllen]

Restricted in what sense?

[oscarlorentzon]

The movement/navigation in its current form is restricted to discrete points in space where there are camera centers (with continuous transitions between those points). The question/discussion point was really - Should the navigation/movement be the same as in the general viewer or is it desired that it is more free. If so we need to solve that. Keeping it as is would be simplest for the first version.

The other point regarding pan and tilt is more important though because that is the essence of VR. Pan and tilt need to be handled for all types of images in a good way.

[gyllen]

Agree for pan, tilt. I think for first version we should keep to discrete points.

However in the future it would be interesting to see fi we can have "free positioning" in very densly covered areas.