feat(SDK): add native Unity Windows Mixed Reality support

Support for the Unity Windows Mixed Reality WSA namespace to allow
for Windows Mixed Reality headsets and controllers to be used within
VRTK.

A number of reflection methods have been abstracted into the
Shared Methods class to remove errors when building on the Unity WSA
platform with the .NET scripting backend. These errors are caused
by the alternative version of .NET and differing ways of handling
reflection code.

Controller visualisation is provided by a 3rd party repository and
instructions of how to use are provided in the WindowsMR README.md
file.

A massive thanks to @tomwim for all his hard work on this and thanks
to @DDReaper for continued support along the way.

Author: thestonefox

Assets/VRTK/Documentation/API.md

@@ -44,6 +44,7 @@ For further information on getting started with the supported SDKs, please refer
  * [Simulator](/Assets/VRTK/Source/SDK/Simulator/README.md)
  * [SteamVR](/Assets/VRTK/Source/SDK/SteamVR/README.md)
  * [Oculus](/Assets/VRTK/Source/SDK/Oculus/README.md)
+ * [Windows Mixed Reality](/Assets/VRTK/Source/SDK/WindowsMR/README.md)
  * [Daydream](/Assets/VRTK/Source/SDK/Daydream/README.md)
  * [HyperealVR](/Assets/VRTK/Source/SDK/HyperealVR/README.md)
  * [Ximmerse](/Assets/VRTK/Source/SDK/Ximmerse/README.md)

Assets/VRTK/Documentation/GETTING_STARTED.md

@@ -25,6 +25,7 @@ public enum EventQuickSelect
         public bool triggerButtonEvents = true;
         public bool gripButtonEvents = true;
         public bool touchpadButtonEvents = true;
+        public bool touchpadTwoButtonEvents = true;
         public bool buttonOneButtonEvents = true;
         public bool buttonTwoButtonEvents = true;
         public bool startMenuButtonEvents = true;
@@ -80,6 +81,10 @@ private void OnEnable()
             controllerEvents.TouchpadTouchStart += DoTouchpadTouchStart;
             controllerEvents.TouchpadTouchEnd += DoTouchpadTouchEnd;
             controllerEvents.TouchpadAxisChanged += DoTouchpadAxisChanged;
+            controllerEvents.TouchpadTwoPressed += DoTouchpadTwoPressed;
+            controllerEvents.TouchpadTwoReleased += DoTouchpadTwoReleased;
+            controllerEvents.TouchpadTwoTouchStart += DoTouchpadTwoTouchStart;
+            controllerEvents.TouchpadTwoTouchEnd += DoTouchpadTwoTouchEnd;
             controllerEvents.TouchpadTwoAxisChanged += DoTouchpadTwoAxisChanged;
             controllerEvents.TouchpadSenseAxisChanged += DoTouchpadSenseAxisChanged;
 
@@ -135,6 +140,10 @@ private void OnDisable()
                 controllerEvents.TouchpadTouchStart -= DoTouchpadTouchStart;
                 controllerEvents.TouchpadTouchEnd -= DoTouchpadTouchEnd;
                 controllerEvents.TouchpadAxisChanged -= DoTouchpadAxisChanged;
+                controllerEvents.TouchpadTwoPressed -= DoTouchpadTwoPressed;
+                controllerEvents.TouchpadTwoReleased -= DoTouchpadTwoReleased;
+                controllerEvents.TouchpadTwoTouchStart -= DoTouchpadTwoTouchStart;
+                controllerEvents.TouchpadTwoTouchEnd -= DoTouchpadTwoTouchEnd;
                 controllerEvents.TouchpadTwoAxisChanged -= DoTouchpadTwoAxisChanged;
                 controllerEvents.TouchpadSenseAxisChanged -= DoTouchpadSenseAxisChanged;
 
@@ -169,6 +178,7 @@ private void LateUpdate()
                     triggerButtonEvents = false;
                     gripButtonEvents = false;
                     touchpadButtonEvents = false;
+                    touchpadTwoButtonEvents = false;
                     buttonOneButtonEvents = false;
                     buttonTwoButtonEvents = false;
                     startMenuButtonEvents = false;
@@ -188,6 +198,7 @@ private void LateUpdate()
                     triggerButtonEvents = true;
                     gripButtonEvents = true;
                     touchpadButtonEvents = true;
+                    touchpadTwoButtonEvents = true;
                     buttonOneButtonEvents = true;
                     buttonTwoButtonEvents = true;
                     startMenuButtonEvents = true;
@@ -207,6 +218,7 @@ private void LateUpdate()
                     triggerButtonEvents = true;
                     gripButtonEvents = true;
                     touchpadButtonEvents = true;
+                    touchpadTwoButtonEvents = true;
                     buttonOneButtonEvents = true;
                     buttonTwoButtonEvents = true;
                     startMenuButtonEvents = true;
@@ -226,6 +238,7 @@ private void LateUpdate()
                     triggerButtonEvents = false;
                     gripButtonEvents = false;
                     touchpadButtonEvents = false;
+                    touchpadTwoButtonEvents = false;
                     buttonOneButtonEvents = false;
                     buttonTwoButtonEvents = false;
                     startMenuButtonEvents = false;
@@ -245,6 +258,7 @@ private void LateUpdate()
                     triggerButtonEvents = false;
                     gripButtonEvents = false;
                     touchpadButtonEvents = false;
+                    touchpadTwoButtonEvents = false;
                     buttonOneButtonEvents = false;
                     buttonTwoButtonEvents = false;
                     startMenuButtonEvents = false;
@@ -462,6 +476,38 @@ private void DoTouchpadAxisChanged(object sender, ControllerInteractionEventArgs
             }
         }
 
+        private void DoTouchpadTwoPressed(object sender, ControllerInteractionEventArgs e)
+        {
+            if (touchpadTwoButtonEvents)
+            {
+                DebugLogger(VRTK_ControllerReference.GetRealIndex(e.controllerReference), "TOUCHPADTWO", "pressed down", e);
+            }
+        }
+
+        private void DoTouchpadTwoReleased(object sender, ControllerInteractionEventArgs e)
+        {
+            if (touchpadTwoButtonEvents)
+            {
+                DebugLogger(VRTK_ControllerReference.GetRealIndex(e.controllerReference), "TOUCHPADTWO", "released", e);
+            }
+        }
+
+        private void DoTouchpadTwoTouchStart(object sender, ControllerInteractionEventArgs e)
+        {
+            if (touchpadTwoButtonEvents)
+            {
+                DebugLogger(VRTK_ControllerReference.GetRealIndex(e.controllerReference), "TOUCHPADTWO", "touched", e);
+            }
+        }
+
+        private void DoTouchpadTwoTouchEnd(object sender, ControllerInteractionEventArgs e)
+        {
+            if (touchpadTwoButtonEvents)
+            {
+                DebugLogger(VRTK_ControllerReference.GetRealIndex(e.controllerReference), "TOUCHPADTWO", "untouched", e);
+            }
+        }
+
         private void DoTouchpadTwoAxisChanged(object sender, ControllerInteractionEventArgs e)
         {
             if (touchpadTwoAxisEvents)

Assets/VRTK/Examples/ExampleResources/SceneResources/[001 - Interactions] ControllerEvents/Scripts/VRTKExample_ControllerEventsDelegateListeners.cs

@@ -72,34 +72,40 @@ protected virtual void ToggleSDKVisibility()
             {
                 VRTK_ControllerReference leftController = VRTK_ControllerReference.GetControllerReference(VRTK_DeviceFinder.GetControllerLeftHand(true));
                 VRTK_ControllerReference rightController = VRTK_ControllerReference.GetControllerReference(VRTK_DeviceFinder.GetControllerRightHand(true));
-
                 switch (sdkType.name)
                 {
                     case "SteamVR":
-                        ToggleSteamVRRenderer(leftController.actual);
-                        ToggleSteamVRRenderer(rightController.actual);
+                        ToggleControllerRenderer(leftController.actual, "Model");
+                        ToggleControllerRenderer(rightController.actual, "Model");
                         break;
                     case "Oculus":
-                        ToggleOculusRenderer(leftController.model);
-                        ToggleOculusRenderer(rightController.model);
+                        ToggleControllerRenderer(leftController.model);
+                        ToggleControllerRenderer(rightController.model);
+                        break;
+                    case "WindowsMR":
+                        ToggleControllerRenderer(leftController.model, "glTFController");
+                        ToggleControllerRenderer(rightController.model, "glTFController");
                         break;
                 }
             }
         }
 
-        protected virtual void ToggleSteamVRRenderer(GameObject controller)
-        {
-            if (controller != null)
-            {
-                controller.transform.Find("Model").gameObject.SetActive(!state);
-            }
-        }
-
-        protected virtual void ToggleOculusRenderer(GameObject controller)
+        protected virtual void ToggleControllerRenderer(GameObject controller, string findPath = "")
         {
             if (controller != null)
             {
-                controller.SetActive(!state);
+                if (findPath == "")
+                {
+                    controller.SetActive(!state);
+                }
+                else
+                {
+                    Transform childModel = controller.transform.Find(findPath);
+                    if (childModel != null)
+                    {
+                        childModel.gameObject.SetActive(!state);
+                    }
+                }
             }
         }