I need to get the direction of the front facing camera excluding the devices orientation (landscape/portrait). I tried to represent this using Core Motion and accessing device attitude. Here I tried to access the Euler angles and exclude the yaw, however this doesn't seem to work as when rotating the device more that one Euler angle value changes. I am also considering using the orientation quaternion but I don't have experience using them. I need this information in a serialisable manner as I would later need to determine if a different device has it's camera pointed in the same direction ( this device may be either iOS or Android).
To reiterate: if a user is pointing his phone camera (main camera not selfie one) towards the statue of liberty, what would be the best way to encode this information regardless if the user is holding the phone in portrait or landscape, such that if another user is in the same location he would know the direction in which to point his camera?
