Accessing VR Controller GameObject references in MRTK 2?

Question

I'm currently working on an application where I need to stick some objects on the user's motion controllers but I can't seem to find a way to obtain the references.

Coming from VRTK which had GameObjects exposed outside of run time, this is proving to be a bit of a challenge for me. Is there a better way of doing this on MRTK?

Answer 1

To get the "proxy" game object for a controller, you can use the code down below (see the first part of it, which uses the visualizer's proxy game object).

It's also possible to get pointer's game object (note that a given controller may have many pointers)

If some of this terminology is confusing, I would also recommend having a read of this: https://microsoft.github.io/MixedRealityToolkit-Unity/Documentation/Architecture/InputSystem/Terminology.html

Which explains some of the terms being used and how they relate to each other.

using Microsoft.MixedReality.Toolkit;
using Microsoft.MixedReality.Toolkit.Input;
using UnityEngine;

public class ControllerPointers : MonoBehaviour
{
   private IMixedRealityInputSystem inputSystem = null;

   /// <summary>
   /// The active instance of the input system.
   /// </summary>
   protected IMixedRealityInputSystem InputSystem
   {
       get
       {
           if (inputSystem == null)
           {
               MixedRealityServiceRegistry.TryGetService<IMixedRealityInputSystem>(out inputSystem);
           }
           return inputSystem;
       }
   }

   // Update is called once per frame
   void Update()
   {
       // Log something every 60 frames.
       if (Time.frameCount % 60 == 0)
       {
           foreach (IMixedRealityController controller in InputSystem.DetectedControllers)
           {
               if (controller.Visualizer?.GameObjectProxy != null)
               {
                   Debug.Log("Visualizer Game Object: " + controller.Visualizer.GameObjectProxy);
               }
               else
               {
                   Debug.Log("Controller has no visualizer!");
               }


               foreach (IMixedRealityPointer pointer in controller.InputSource.Pointers)
               {
                   if (pointer is MonoBehaviour)
                   {
                       var monoBehavior = pointer as MonoBehaviour;
                       Debug.Log("Found pointer game object: " + (monoBehavior.gameObject));
                   }
               }
           }
       }
   }
}

Lastly, you could also always grab the position/rotation/velocity properties off of the pointer interfaces themselves (i.e. in the code above, use the pointer position: https://microsoft.github.io/MixedRealityToolkit-Unity/api/Microsoft.MixedReality.Toolkit.Input.IMixedRealityPointer.html#Microsoft_MixedReality_Toolkit_Input_IMixedRealityPointer_Position)