Audio3D head tracking

Cookbook/Cookbook/Info.plist

@@ -26,6 +26,8 @@
 	<true/>
 	<key>NSMicrophoneUsageDescription</key>
 	<string>We use the microphone to demonstrate processing input.</string>
+	<key>NSMotionUsageDescription</key>
+	<string>We use the headphone motion tracker if available during the Audio3D demo to pan the audio.</string>
 	<key>UIApplicationSceneManifest</key>
 	<dict>
 		<key>UIApplicationSupportsMultipleScenes</key>

Cookbook/CookbookCommon/Sources/CookbookCommon/Recipes/MiniApps/Audio3D.swift

@@ -8,14 +8,41 @@ import SoundpipeAudioKit
 import Tonic
 import SceneKit
 import AVFoundation
-
+import CoreMotion
+
+extension CMQuaternion {
+    var angle: Double {
+        return acos(w) * 2
+    }
+
+    var axis: SCNVector3 {
+        let length = sqrt(1 - w * w)
+        if length < 0.001 {
+            return SCNVector3(1, 0, 0)
+        }
+        return SCNVector3(x / length, y / length, z / length)
+    }
+}
 final class AudioKit3DVM: ObservableObject {
 	@Published var conductor = AudioEngine3DConductor()
 	@Published var coordinator = SceneCoordinator()
+    private let headphoneMotionManager = CMHeadphoneMotionManager()
 
 	init() {
 		coordinator.updateAudioSourceNodeDelegate = conductor
+        headphoneMotionManager.delegate = coordinator
 	}
+    func startHeadTracking() {
+        if let updateDeviceMotion = coordinator.updateDeviceMotion,
+            headphoneMotionManager.isDeviceMotionAvailable && !headphoneMotionManager.isDeviceMotionActive {
+            headphoneMotionManager.startDeviceMotionUpdates(to: .main,
+                                                            withHandler: updateDeviceMotion)
+        }
+    }
+    func stopHeadTracking() {
+        headphoneMotionManager.stopDeviceMotionUpdates()
+        coordinator.motionData = nil
+    }
 }
 
 protocol UpdateAudioSourceNodeDelegate: AnyObject {
@@ -82,12 +109,14 @@ class AudioEngine3DConductor: ObservableObject, ProcessesPlayerInput, UpdateAudi
 	}
 }
 
-class SceneCoordinator: NSObject, SCNSceneRendererDelegate, ObservableObject {
+class SceneCoordinator: NSObject, SCNSceneRendererDelegate, ObservableObject, CMHeadphoneMotionManagerDelegate {
 
 	var showsStatistics: Bool = false
 	var debugOptions: SCNDebugOptions = []
 
 	weak var updateAudioSourceNodeDelegate: UpdateAudioSourceNodeDelegate?
+    var updateDeviceMotion: CMHeadphoneMotionManager.DeviceMotionHandler?
+    var motionData: CMDeviceMotion?
 
 	lazy var theScene: SCNScene = {
 		// create a new scene
@@ -102,12 +131,30 @@ class SceneCoordinator: NSObject, SCNSceneRendererDelegate, ObservableObject {
 		return cameraNode
 	}
 
+    override init() {
+        super.init()
+        updateDeviceMotion = { motionData, error in
+            if let motionData = motionData {
+                self.motionData = motionData
+            } else if let error = error {
+                print(error.localizedDescription)
+            } else {
+                print("No motion data to process")
+            }
+        }
+    }
 	func moveRight() {
 
 	}
 
 	func renderer(_ renderer: SCNSceneRenderer, updateAtTime time: TimeInterval) {
 
+        if let motionData = motionData, let pointOfView = renderer.pointOfView {
+            pointOfView.rotation.w = Float(motionData.attitude.quaternion.angle)
+            pointOfView.rotation.x = Float(motionData.attitude.quaternion.axis.x)
+            pointOfView.rotation.y = Float(motionData.attitude.quaternion.axis.z)
+            pointOfView.rotation.z = -1.0 * Float(motionData.attitude.quaternion.axis.y)
+        }
 		if let pointOfView = renderer.pointOfView,
 		   let soundSource = renderer.scene?.rootNode.childNode(withName: "soundSource", recursively: true) {
 
@@ -137,6 +184,13 @@ class SceneCoordinator: NSObject, SCNSceneRendererDelegate, ObservableObject {
 		renderer.showsStatistics = self.showsStatistics
 		renderer.debugOptions = self.debugOptions
 	}
+    func headphoneMotionManagerDidConnect(_ manager: CMHeadphoneMotionManager) {
+        print("Headphones Connected")
+    }
+    func headphoneMotionManagerDidDisconnect(_ manager: CMHeadphoneMotionManager) {
+        print("Headphones Disconnected")
+        motionData = nil
+    }
 }
 
 struct AudioKit3DView: View {
@@ -174,9 +228,11 @@ struct AudioKit3DView: View {
 		}.cookbookNavBarTitle("Audio 3D")
 			.onAppear {
 				viewModel.conductor.start()
+                viewModel.startHeadTracking()
 			}
 			.onDisappear {
 				viewModel.conductor.stop()
+                viewModel.stopHeadTracking()
 			}
 	}
 }