Add new input action focus handling

Author: keveleigh

org.mixedrealitytoolkit.core/Subsystems/MRTKLifecycleManager.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using Unity.Profiling;
 using UnityEngine;
+using UnityEngine.InputSystem;
 
 namespace MixedReality.Toolkit.Subsystems
 {
@@ -18,6 +19,9 @@ public class MRTKLifecycleManager :
         MonoBehaviour,
         IDisposable
     {
+        [SerializeField, Tooltip("A set of input actions to enable/disable according to the app's focus state.")]
+        private InputActionReference[] inputActionReferences;
+
         private List<IMRTKManagedSubsystem> managedSubsystems = new List<IMRTKManagedSubsystem>();
 
         /// <summary>
@@ -176,6 +180,33 @@ private void LateUpdate()
             }
         }
 
+        /// <summary>
+        /// Sent to all GameObjects when the player gets or loses focus.
+        /// </summary>
+        /// <param name="focus"><see langword="true"/> if the GameObjects have focus, else <see langword="false"/>.</param>
+        protected void OnApplicationFocus(bool focus)
+        {
+            // We want to ensure we're focused for input, as some runtimes continue reporting "tracked" while pose updates are paused.
+            // This is allowed, per-spec, as a "should": "Runtimes should make input actions inactive while the application is unfocused,
+            // and applications should react to an inactive input action by skipping rendering of that action's input avatar
+            // (depictions of hands or other tracked objects controlled by the user)."
+
+            if (focus)
+            {
+                foreach (InputActionReference reference in inputActionReferences)
+                {
+                    reference.action.Enable();
+                }
+            }
+            else
+            {
+                foreach (InputActionReference reference in inputActionReferences)
+                {
+                    reference.action.Disable();
+                }
+            }
+        }
+
         #endregion MonoBehaviour
 
         /// <summary>

org.mixedrealitytoolkit.input/Assets/Prefabs/MRTK XR Rig.prefab

@@ -377,6 +377,9 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 1a107350295baaf4489642caa92f05de, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
+  inputActionReferences:
+  - {fileID: -7613329581162844239, guid: 18c412191cdc9274897f101c7fd5316f, type: 3}
+  - {fileID: 3239510804178183174, guid: 18c412191cdc9274897f101c7fd5316f, type: 3}
 --- !u!1 &7735890427496681069
 GameObject:
   m_ObjectHideFlags: 0