Hey,
I just updated my iPad Mini 2 to iOS 10 for testing and found that my VR applications head tracking is completly messed up when reading from CMMotionManager. I expect it to work simularrly to iOS 8/9, but what i'm seeing doesn't make sense.
If I turn on the magnetometer, the tracking becomes very unstable and jittery. Also looking up and down is not working, it seems to have some sort of gimble issue.
self.motionManager.magnetometerUpdateInterval = 1.0f / 60;
self.motionManager.showsDeviceMovementDisplay = YES;
If I don't use the magnetometer, its not jittery, but the behavior is different. When i use startDeviceMotionUpdatesUsingReferenceFrame: CMAttitudeReferenceFrameXArbitraryZVertical I expect the frame to be centered with the device. And If I stop and again, the frame shall recenter itself. Now it starts pointing north, and if I stop and start, its still pointing north.
My motion tracker code can be found here:
https://github.com/mgatelabs/SCN-VR/blob/master/scn-vr/CoreMotionTracker.m