Fixed a few things with the new camera rig

XRTK-Core/Packages/com.xrtk.core/Services/CameraSystem/DefaultCameraRig.cs

@@ -33,6 +33,11 @@ public Transform PlayspaceTransform
                     return playspaceTransform;
                 }
 
+                if (MixedRealityToolkit.IsApplicationQuitting)
+                {
+                    return null;
+                }
+
                 var playspaceTransformLookup = GameObject.Find(playspaceName);
 
                 playspaceTransform = playspaceTransformLookup == null
@@ -60,7 +65,7 @@ public Transform PlayspaceTransform
         }
 
         /// <inheritdoc />
-        public Transform CameraTransform => PlayerCamera.transform;
+        public Transform CameraTransform => PlayerCamera == null ? null : playerCamera.transform;
 
         [SerializeField]
         private Camera playerCamera = null;
@@ -75,6 +80,11 @@ public Camera PlayerCamera
                     return playerCamera;
                 }
 
+                if (MixedRealityToolkit.IsApplicationQuitting)
+                {
+                    return null;
+                }
+
                 // Currently the XRTK only supports a single player/user
                 // So for now we will always reference the tagged MainCamera.
                 if (playerCamera == null)
@@ -122,6 +132,11 @@ public TrackedPoseDriver CameraPoseDriver
                     return cameraPoseDriver;
                 }
 
+                if (MixedRealityToolkit.IsApplicationQuitting)
+                {
+                    return null;
+                }
+
                 cameraPoseDriver = PlayerCamera.gameObject.EnsureComponent<TrackedPoseDriver>();
                 cameraPoseDriver.UseRelativeTransform = true;
                 return cameraPoseDriver;
@@ -139,6 +154,16 @@ public Transform BodyTransform
         {
             get
             {
+                if (bodyTransform != null)
+                {
+                    return bodyTransform;
+                }
+
+                if (MixedRealityToolkit.IsApplicationQuitting)
+                {
+                    return null;
+                }
+
                 if (bodyTransform == null)
                 {
                     bodyTransform = PlayspaceTransform.Find(playerBodyName);

XRTK-Core/Packages/com.xrtk.core/Services/CameraSystem/MixedRealityCameraSystem.cs

@@ -170,13 +170,15 @@ public override void Disable()
         {
             base.Disable();
 
-            if (CameraRig == null) { return; }
+            var camera = CameraCache.Main;
 
-            if (CameraRig.CameraTransform != null)
+            if (camera != null)
             {
-                CameraRig.CameraTransform.SetParent(null);
+                camera.transform.SetParent(null);
             }
 
+            if (CameraRig == null) { return; }
+
             if (CameraRig.PlayspaceTransform != null)
             {
                 if (Application.isPlaying)
@@ -189,7 +191,8 @@ public override void Disable()
                 }
             }
 
-            if (CameraRig is Component component)
+            if (CameraRig is Component component &&
+                component is IMixedRealityCameraRig)
             {
                 if (Application.isPlaying)
                 {

XRTK-Core/Packages/com.xrtk.core/Utilities/CameraCache.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 using UnityEngine;
+using XRTK.Services;
 
 namespace XRTK.Utilities
 {
@@ -24,6 +25,11 @@ public static Camera Main
 
                 if (mainCamera == null)
                 {
+                    if (MixedRealityToolkit.IsApplicationQuitting)
+                    {
+                        return null;
+                    }
+
                     mainCamera = new GameObject("Main Camera", typeof(Camera), typeof(AudioListener)) { tag = "MainCamera" }.GetComponent<Camera>();
                 }