Determine the direction of "gaze" of the device in any orientation

CMDeviceMotion.swift

extension CMDeviceMotion {
    
    func gaze(atOrientation orientation: UIInterfaceOrientation) -> SCNVector4 {
        
        let attitude = self.attitude.quaternion
        let aq = GLKQuaternionMake(Float(attitude.x), Float(attitude.y), Float(attitude.z), Float(attitude.w))
        
        let final: SCNVector4
        
        switch orientation {
            
        case .landscapeRight:
            
            let cq = GLKQuaternionMakeWithAngleAndAxis(Float.pi / 2, 0, 1, 0)
            let q = GLKQuaternionMultiply(cq, aq)
            
            final = SCNVector4(x: -q.y, y: q.x, z: q.z, w: q.w)
            
        case .landscapeLeft:
            
            let cq = GLKQuaternionMakeWithAngleAndAxis(-Float.pi / 2, 0, 1, 0)
            let q = GLKQuaternionMultiply(cq, aq)
            
            final = SCNVector4(x: q.y, y: -q.x, z: q.z, w: q.w)
            
        case .portraitUpsideDown:
            
            let cq = GLKQuaternionMakeWithAngleAndAxis(Float.pi / 2, 1, 0, 0)
            let q = GLKQuaternionMultiply(cq, aq)
            
            final = SCNVector4(x: -q.x, y: -q.y, z: q.z, w: q.w)
            
        case .unknown:
            
            fallthrough
            
        case .portrait:
            
            fallthrough
            
        @unknown default:
            
            let cq = GLKQuaternionMakeWithAngleAndAxis(-Float.pi / 2, 1, 0, 0)
            let q = GLKQuaternionMultiply(cq, aq)
            
            final = SCNVector4(x: q.x, y: q.y, z: q.z, w: q.w)
        }
        
        return final
    }
}

You saved my life. Thank you so much for this.
I will post the magic this class will help em create.

Thank you again.

@99centbrains.

Thanks so much for this! One thing to point out: it looks like you should be switching on the orientation parameter passed into the function, not UIApplication.sharedApplication().statusBarOrientation

This is awesome, thanks!!

Thank you Travis! This is super helpful!!

Great extension! My camera however is not updating. I can drag the view with my finger and it changes apporpriatly. But I want to be able to 'look around' the picture when the device moves.

Thank you for this.

Thanks for the code. It solved my problem, which I was facing for more than 3 months.

Thanks for your code, it solved my 3D game camera motion control perfectly.
Here is the StackOverflow raw problem.
And I think u can update it to Swift4 version :P

@travisnewby My math is very bad, could you please explain more detailed? Hopefully you can introduce the codes line by line, please forgive my foolishness.
Thank you very much!

And I think u can update it to Swift4 version :P

Done!

@travisnewby My math is very bad, could you please explain more detailed? Hopefully you can introduce the codes line by line, please forgive my foolishness.

@evanxlh The math is nothing more than applying a rotation – based on the orientation of your phone – to a vector. I can't explain the math as clearly as many of the youtube videos talking about quaternions for game developers. That's your best bet for understanding.

thank you for your "magic" extension.

@ostholz you’re welcome.

Thank you very much for this! Saves a lot of headaches!