Fixes MRTK3's Tap to Place solver to work with any hand and interactor (#11545)

## Overview
Fixes MRTK3's `Tap to Place` solver to work with any hand and any interactor (even speech). This change, on `StartPlacement`, queries the `XRInteractionManager` for all registered interactors, and then registers for the interactors' select events.  This is an alternative to requiring the developer to specify particular actions. 

Note, this change also removes the `StatefulInteractable` requirement.  The consumer of `TapToPlace` is now required to determine when `StartPlacement` is invoked. This change is meant to provide extensibility for future scenarios which may not require or use `StatefulInteractables`.

This also adds Unit Tests to validate `TapToPlace`.

## Changes
- Fixes: #11527

Author: AMollis

UnityProjects/MRTKDevTemplate/Assets/Scenes/TapToPlaceExample.unity

@@ -257,8 +257,8 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 3986155c7a728454f8bbbabd2e274601, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  leftInteractor: {fileID: 1127029052}
-  rightInteractor: {fileID: 0}
+  leftInteractor: {fileID: 1127029054}
+  rightInteractor: {fileID: 1127029052}
   trackedTargetType: 1
   trackedHandedness: 3
   trackedHandJoint: 2
@@ -572,7 +572,20 @@ MonoBehaviour:
         m_Calls: []
   <OnClicked>k__BackingField:
     m_PersistentCalls:
-      m_Calls: []
+      m_Calls:
+      - m_Target: {fileID: 396224581}
+        m_TargetAssemblyTypeName: Microsoft.MixedReality.Toolkit.SpatialManipulation.TapToPlace,
+          Microsoft.MixedReality.Toolkit.SpatialManipulation
+        m_MethodName: StartPlacement
+        m_Mode: 1
+        m_Arguments:
+          m_ObjectArgument: {fileID: 0}
+          m_ObjectArgumentAssemblyTypeName: UnityEngine.Object, UnityEngine
+          m_IntArgument: 0
+          m_FloatArgument: 0
+          m_StringArgument: 
+          m_BoolArgument: 0
+        m_CallState: 2
   <OnEnabled>k__BackingField:
     m_PersistentCalls:
       m_Calls: []
@@ -1210,6 +1223,10 @@ PrefabInstance:
       propertyPath: m_RootOrder
       value: 3
       objectReference: {fileID: 0}
+    - target: {fileID: 8479077998186684813, guid: 4d7e2f87fefe0ba468719b15288b46e7, type: 3}
+      propertyPath: m_IsActive
+      value: 1
+      objectReference: {fileID: 0}
     m_RemovedComponents: []
   m_SourcePrefab: {fileID: 100100000, guid: 4d7e2f87fefe0ba468719b15288b46e7, type: 3}
 --- !u!4 &1127029051 stripped
@@ -1239,6 +1256,17 @@ MonoBehaviour:
   m_Script: {fileID: 11500000, guid: 83e4e6cca11330d4088d729ab4fc9d9f, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
+--- !u!114 &1127029054 stripped
+MonoBehaviour:
+  m_CorrespondingSourceObject: {fileID: 7115113329451106245, guid: 4d7e2f87fefe0ba468719b15288b46e7, type: 3}
+  m_PrefabInstance: {fileID: 1127029050}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 0}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: e85416945309f8244a5715a2ec5c254f, type: 3}
+  m_Name: 
+  m_EditorClassIdentifier: 
 --- !u!1 &1167916486
 GameObject:
   m_ObjectHideFlags: 0
@@ -2650,7 +2678,20 @@ MonoBehaviour:
         m_Calls: []
   <OnClicked>k__BackingField:
     m_PersistentCalls:
-      m_Calls: []
+      m_Calls:
+      - m_Target: {fileID: 4125495309857526231}
+        m_TargetAssemblyTypeName: Microsoft.MixedReality.Toolkit.SpatialManipulation.TapToPlace,
+          Microsoft.MixedReality.Toolkit.SpatialManipulation
+        m_MethodName: StartPlacement
+        m_Mode: 1
+        m_Arguments:
+          m_ObjectArgument: {fileID: 0}
+          m_ObjectArgumentAssemblyTypeName: UnityEngine.Object, UnityEngine
+          m_IntArgument: 0
+          m_FloatArgument: 0
+          m_StringArgument: 
+          m_BoolArgument: 0
+        m_CallState: 2
   <OnEnabled>k__BackingField:
     m_PersistentCalls:
       m_Calls: []

com.microsoft.mrtk.spatialmanipulation/Editor/Solvers/TapToPlaceEditor.cs

@@ -16,8 +16,6 @@ public class TapToPlaceEditor : UnityEditor.Editor
     {
         private TapToPlace instance;
 
-        private GUIContent placementActionContent = new GUIContent("Placement action");
-
         // Tap to Place properties
         private SerializedProperty placementAction;
         private SerializedProperty autoStart;
@@ -81,7 +79,6 @@ private void RenderCustomInspector()
         {
             serializedObject.Update();
 
-            EditorGUILayout.PropertyField(placementAction, placementActionContent);
             EditorGUILayout.PropertyField(autoStart);
             EditorGUILayout.PropertyField(defaultPlacementDistance);
             EditorGUILayout.PropertyField(maxRaycastDistance);
@@ -128,4 +125,4 @@ private void RenderAdvancedProperties()
             }
         }
     }
-}
+}

com.microsoft.mrtk.spatialmanipulation/Solvers/TapToPlace.cs

@@ -1,33 +1,22 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
+using System.Collections.Generic;
 using Unity.Profiling;
 using UnityEngine;
 using UnityEngine.Events;
 using UnityEngine.InputSystem;
+using UnityEngine.XR.Interaction.Toolkit;
 using UnityPhysics = UnityEngine.Physics;
 
 namespace Microsoft.MixedReality.Toolkit.SpatialManipulation
 {
     /// <summary>
     /// Tap to place is a far interaction component used to place objects on a surface.
     /// </summary>
-    [RequireComponent(typeof(StatefulInteractable))]
     [AddComponentMenu("MRTK/Spatial Manipulation/Solvers/Tap To Place")]
     public class TapToPlace : Solver
     {
-        [SerializeField]
-        [Tooltip("The input action which is to control placement.")]
-        private InputActionReference placementActionReference = null;
-
-        /// <summary>
-        /// The input action which is to control placement.
-        /// </summary>
-        public InputActionReference PlacementActionReference
-        {
-            get => placementActionReference;
-            set => placementActionReference = value;
-        }
 
         // todo: needed? [Space(10)]
         [SerializeField]
@@ -237,8 +226,11 @@ public UnityEvent OnPlacingStopped
         // Used to mark whether StartPlacement() is called before Start() is called.
         private bool placementRequested;
 
-        // The interactable used to pick up the obect. 
-        private StatefulInteractable interactable;
+        // Used to obtain list of known interactors
+        private XRInteractionManager interactionManager;
+
+        // Used to cache a known set of interactor
+        private List<IXRInteractor> interactorsCache;
 
         #region MonoBehaviour Implementation
 
@@ -257,9 +249,6 @@ protected override void Start()
 
             startCalled = true;
 
-            interactable = gameObject.GetComponent<StatefulInteractable>();
-            RegisterPickupAction();
-
             if (AutoStart || placementRequested)
             {
                 StartPlacement();
@@ -272,8 +261,7 @@ protected override void Start()
 
         protected override void OnDisable()
         {
-            UnregisterPlacementAction();
-            UnregisterPickupAction();
+            StopPlacement();
             base.OnDisable();
         }
 
@@ -284,13 +272,13 @@ protected override void OnDisable()
 
         /// <summary>
         /// Start the placement of a game object without the need of the OnPointerClicked event. The game object will begin to follow the 
-        /// TrackedTargetType (Head by default) at a default distance. StopPlacement() must be called after StartPlacement() to stop the 
+        /// TrackedTargetType (Head by default) at a default distance. StopPlacementViaPerformedAction() must be called after StartPlacement() to stop the 
         /// game object from following the TrackedTargetType.  The game object layer is changed to IgnoreRaycast temporarily and then
-        /// restored to its original layer in StopPlacement().
+        /// restored to its original layer in StopPlacementViaPerformedAction().
         /// </summary>
         public void StartPlacement()
         {
-            // Checking the amount of time passed between when StartPlacement or StopPlacement is called twice in
+            // Checking the amount of time passed between when StartPlacement or StopPlacementViaPerformedAction is called twice in
             // succession. If these methods are called twice very rapidly, the object will be
             // selected and then immediately unselected. If two calls occur within the
             // double click timeout, then return to prevent an immediate object state switch.
@@ -299,6 +287,7 @@ public void StartPlacement()
             {
                 return;
             }
+
             // Get the time of this click action
             LastTimeClicked = Time.time;
 
@@ -333,14 +322,30 @@ public void StartPlacement()
         }
 
         private static readonly ProfilerMarker StopPlacementPerfMarker =
-            new ProfilerMarker("[MRTK] TapToPlace.StopPlacement");
+            new ProfilerMarker("[MRTK] TapToPlace.StopPlacementViaPerformedAction");
 
         /// <summary>
-        /// Stop the placement of a game object without the need of the OnPointerClicked event. 
+        /// Stop the placement of a game object via an action's performance.
         /// </summary>
-        public void StopPlacement(InputAction.CallbackContext context)
+        private void StopPlacementViaPerformedAction(InputAction.CallbackContext context)
         {
-            // Checking the amount of time passed between when StartPlacement or StopPlacement is called twice in
+            StopPlacement();
+        }
+
+        /// <summary>
+        /// Stop the placement of a game object via an interactor's select event.
+        /// </summary>
+        private void StopPlacementViaSelect(SelectEnterEventArgs args)
+        {
+            StopPlacement();
+        }
+
+        /// <summary>
+        /// Stop the placement of a game object. 
+        /// </summary>
+        public void StopPlacement()
+        {
+            // Checking the amount of time passed between when StartPlacement or StopPlacementViaPerformedAction is called twice in
             // succession. If these methods are called twice very rapidly, the object will be
             // selected and then immediately unselected. If two calls occur within the
             // double click timeout, then return to prevent an immediate object state switch.
@@ -353,7 +358,7 @@ public void StopPlacement(InputAction.CallbackContext context)
 
             using (StopPlacementPerfMarker.Auto())
             {
-                // Added for code configurability to avoid multiple calls to StopPlacement in a row
+                // Added for code configurability to avoid multiple calls to StopPlacementViaPerformedAction in a row
                 if (IsBeingPlaced)
                 {
                     // Change the game object layer back to the game object's layer on start
@@ -467,53 +472,61 @@ protected virtual void SetRotation()
         /// </summary>
         private void RegisterPlacementAction()
         {
-            InputAction placementAction = GetInputActionFromReference(placementActionReference);
-            if (placementAction == null)
+            // Refresh the registeration if they already exist
+            UnregisterPlacementAction();
+
+            if (interactionManager == null)
             {
-                Debug.Log("Failed to register the placement action, the action reference was null or contained no action.");
-                return;
+                interactionManager = FindObjectOfType<XRInteractionManager>();
+                if (interactionManager == null)
+                {
+                    Debug.LogError("No interaction manager found in scene. Please add an interaction manager to the scene.");
+                }
             }
-            placementAction.performed += StopPlacement;
-        }
 
-        /// <summary>
-        /// Registers the event which performs pickup.
-        /// </summary>
-        private void RegisterPickupAction()
-        {
-            if (interactable == null)
+            if (interactorsCache == null)
             {
-                Debug.Log("Failed to register the pick up event. There is no StatefulInteractable set.");
-                return;
+                interactorsCache = new List<IXRInteractor>();
             }
-            interactable.OnClicked.AddListener(StartPlacement);
-        }
 
-        /// <summary>
-        /// Unregisters the input action which performs placement.
-        /// </summary>
-        private void UnregisterPlacementAction()
-        {
-            InputAction placementAction = GetInputActionFromReference(placementActionReference);
-            if (placementAction == null)
+            // Try registering for the controller's "action" so object selection isn't required for placement.
+            // If no controller, then fallback to using object selections for placement.
+            interactionManager.GetRegisteredInteractors(interactorsCache);
+            foreach (IXRInteractor interactor in interactorsCache)
             {
-                Debug.Log("Failed to unregister the placement action, the action reference was null or contained no action.");
-                return;
+                if (interactor is XRBaseControllerInteractor controllerInteractor &&
+                    controllerInteractor.xrController is ActionBasedController actionController)
+                {
+                    actionController.selectAction.action.performed += StopPlacementViaPerformedAction;
+                }
+                else if (interactor is IXRSelectInteractor selectInteractor)
+                {
+                    selectInteractor.selectEntered.AddListener(StopPlacementViaSelect);
+                }
             }
-            placementAction.performed -= StopPlacement;
         }
 
         /// <summary>
-        /// Unregisters the event which performs pickup.
+        /// Unregisters the input action which performs placement.
         /// </summary>
-        private void UnregisterPickupAction()
+        private void UnregisterPlacementAction()
         {
-            if (interactable == null)
+            if (interactorsCache != null)
             {
-                Debug.Log("Failed to unregister the pick up event. There is no StatefulInteractable set.");
-                return;
+                foreach (IXRInteractor interactor in interactorsCache)
+                {
+                    if (interactor is XRBaseControllerInteractor controllerInteractor &&
+                        controllerInteractor.xrController is ActionBasedController actionController)
+                    {
+                        actionController.selectAction.action.performed -= StopPlacementViaPerformedAction;
+                    }
+                    else if (interactor is IXRSelectInteractor selectInteractor)
+                    {
+                        selectInteractor.selectEntered.RemoveListener(StopPlacementViaSelect);
+                    }
+                }
+                interactorsCache.Clear();
             }
-            interactable.OnClicked.RemoveListener(StartPlacement);
         }
 
         /// <summary>