Location based compass orientation is incorrect. It always says North is direction when starting up.

[beachgrub]

Bug. There are similar issue but all marked as closed, incorrectly.

What is the current behavior?
Currently on iOS (Safari and Chrome tested) the simple location examples will always point the north cube in the direction the phone is facing after any interaction or started.
If the current behavior is a bug, please provide the steps to reproduce.
Load the basic example
https://github.com/AR-js-org/AR.js/blob/master/aframe/examples/new-location-based/basic-js/index.html
On iOS at startup there will always be several permissions popups. After hitting them all you will see the Red cube (North) in the direction of whatever you started. If you tap the cube or any cube, you will get a popup and then the orientation will reset so that direction is North and the Red Cube is there.

It is always happening with the included example. I put a copy on website at www.pasotours.com/location2

Please mention other relevant information such as the browser version, Operating System and Device Name
iOS (Chrome and Safari) it works correctly on android.
What is the expected behavior?

If this is a feature request, what is motivation or use case for changing the behavior?

[beachgrub]

It looks to me like iOS no longer supports the compass deviceorientationabsolute event. It only supports the deviceorientation event and that seems to reset with the context in some way. In the basic example when you tap on a cube when it returns the device orientation resets with alpha = 0 regardless of the direction facing.
I believe on ios you now need to support the webkitcompassheading event to know which way the phone is facing absolutely.
https://developer.apple.com/documentation/webkitjs/deviceorientationevent/1804777-webkitcompassheading

[beachgrub]

It appears that this is know. There was a MR that was not merged that seems to help but enabling the webkitcompassheading. #466

[nickw1]

We really need developers who have an iOS device, this will help progress the iOS issues and allow the merging of #466.

Also see #278 and #603.

[nickw1]

For additional context: this appears to be a known problem in some Android devices, so much so that the DeviceOrientationControls object has been removed from the offical three.js repository. Unfortunately it seems that for certain Android phones it may not be possible to obtain reliable North via the Web device orientation API. Hopefully this is only a minority of devices, though.

See: mrdoob/three.js#22613 and mrdoob/three.js#22654

[nickw1]

Just an update on this: there is now a separate project for location-based AR (only) within AR.js where any future work to resolve, or find workarounds for at least (as they may be an inherent problem with the device), these kinds of bugs will be done:

https://github.com/AR-js-org/locar.js

[garthhenning]

I've been fighting this, too. I've been seeing the webkit compass swing around, which has made this tricky for me. The initial compass reading might be right, then it later drifts out of calibration. Or it is initially our of calibration and then comes into calibration. Its hard to know if the value is getting better or worse over time. Also, I can recalibrate an iPhone by waving it in a figure 8 pattern and then it comes back into calibration. I can see this calibration effect not in ar.js but actually just with the iPhone's native compass app.

I'm a Java developer driving ar.js and three.js from transpiled Java code (see: GWT), so I might not be the best to help with the Javascript code, but I am actively working the calibration issue and would love to contribute back on this.

[nickw1]

@garthhenning does using LocAR.js help? There have been a few iOS fixes over there recently. (Just use the version on master, also available via npm as version 0.0.12).