await until input system is valid

Author: StephenHodgson

Assets/MixedRealityToolkit-SDK/Features/Input/GazeProvider.cs

@@ -1,16 +1,17 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
-using Microsoft.MixedReality.Toolkit.InputSystem.Pointers;
-using Microsoft.MixedReality.Toolkit.InputSystem.Sources;
 using Microsoft.MixedReality.Toolkit.Core.Definitions.InputSystem;
 using Microsoft.MixedReality.Toolkit.Core.Definitions.Utilities;
 using Microsoft.MixedReality.Toolkit.Core.EventDatum.Input;
 using Microsoft.MixedReality.Toolkit.Core.Interfaces.Devices;
 using Microsoft.MixedReality.Toolkit.Core.Interfaces.InputSystem;
 using Microsoft.MixedReality.Toolkit.Core.Interfaces.InputSystem.Handlers;
 using Microsoft.MixedReality.Toolkit.Core.Utilities;
+using Microsoft.MixedReality.Toolkit.Core.Utilities.Async;
 using Microsoft.MixedReality.Toolkit.Core.Utilities.Physics;
+using Microsoft.MixedReality.Toolkit.InputSystem.Pointers;
+using Microsoft.MixedReality.Toolkit.InputSystem.Sources;
 using UnityEngine;
 
 namespace Microsoft.MixedReality.Toolkit.SDK.Input
@@ -337,7 +338,7 @@ protected override void OnDisable()
         {
             base.OnDisable();
             GazePointer.BaseCursor?.SetVisibility(false);
-            InputSystem.RaiseSourceLost(GazeInputSource);
+            InputSystem?.RaiseSourceLost(GazeInputSource);
         }
 
         #endregion MonoBehaviour Implementation
@@ -387,8 +388,9 @@ private IMixedRealityPointer InitializeGazePointer()
             return gazePointer = new InternalGazePointer(this, "Gaze Pointer", null, raycastLayerMasks, maxGazeCollisionDistance, gazeTransform, stabilizer);
         }
 
-        private void RaiseSourceDetected()
+        private async void RaiseSourceDetected()
         {
+            await WaitUntilInputSystemValid;
             InputSystem.RaiseSourceDetected(GazeInputSource);
             GazePointer.BaseCursor?.SetVisibility(true);
         }

Assets/MixedRealityToolkit-SDK/Features/Input/InputSystemGlobalListener.cs

@@ -3,6 +3,7 @@
 
 using Microsoft.MixedReality.Toolkit.Core.Interfaces.InputSystem;
 using Microsoft.MixedReality.Toolkit.Core.Managers;
+using Microsoft.MixedReality.Toolkit.Core.Utilities.Async;
 using UnityEngine;
 
 namespace Microsoft.MixedReality.Toolkit.SDK.Input
@@ -17,30 +18,21 @@ public class InputSystemGlobalListener : MonoBehaviour
 
         private bool lateInitialize = true;
 
+        protected readonly WaitUntil WaitUntilInputSystemValid = new WaitUntil(() => InputSystem != null);
+
         protected virtual void OnEnable()
         {
-            if (!MixedRealityManager.IsInitialized)
-            {
-                Debug.LogError("Missing Mixed Reality Manager!");
-                return;
-            }
-
-            if (InputSystem != null && !lateInitialize)
+            if (MixedRealityManager.IsInitialized && InputSystem != null && !lateInitialize)
             {
                 InputSystem.Register(gameObject);
             }
         }
 
-        protected virtual void Start()
+        protected virtual async void Start()
         {
             if (lateInitialize)
             {
-                if (InputSystem == null)
-                {
-                    Debug.LogError("Unable to find Input System!");
-                    return;
-                }
-
+                await WaitUntilInputSystemValid;
                 lateInitialize = false;
                 InputSystem.Register(gameObject);
             }