SteamVR Plugin 2.xでVIVEトラッカーの役割設定からトラッカー位置を取得するサンプル(肘と膝を含む)

actions.json

{
  "actions": [
    {
      "name": "/actions/default/in/Pose",
      "type": "pose"
    },
    {
      "name": "/actions/default/in/SkeletonLeftHand",
      "type": "skeleton",
      "skeleton": "/skeleton/hand/left"
    },
    {
      "name": "/actions/default/in/SkeletonRightHand",
      "type": "skeleton",
      "skeleton": "/skeleton/hand/right"
    },
    {
      "name": "/actions/default/in/SelectButton",
      "type": "boolean"
    },
    {
      "name": "/actions/default/in/CancelButton",
      "type": "boolean"
    },
    {
      "name": "/actions/default/in/StickButton",
      "type": "boolean"
    },
    {
      "name": "/actions/default/in/MenuButton",
      "type": "boolean"
    },
    {
      "name": "/actions/default/in/TriggerButton",
      "type": "boolean"
    },
    {
      "name": "/actions/default/in/GripButton",
      "type": "boolean"
    },
    {
      "name": "/actions/default/in/StickAxis",
      "type": "vector2"
    },
    {
      "name": "/actions/default/out/Haptic",
      "type": "vibration"
    }
  ],
  "action_sets": [
    {
      "name": "/actions/default",
      "usage": "single"
    }
  ],
  "default_bindings": [
    {
      "controller_type": "vive_controller",
      "binding_url": "bindings_vive_controller.json"
    },
    {
      "controller_type": "oculus_touch",
      "binding_url": "bindings_oculus_touch.json"
    },
    {
      "controller_type": "knuckles",
      "binding_url": "bindings_knuckles.json"
    },
    {
      "controller_type": "holographic_controller",
      "binding_url": "bindings_holographic_controller.json"
    },
    {
      "controller_type": "vive_cosmos_controller",
      "binding_url": "bindings_vive_cosmos_controller.json"
    },
    {
      "controller_type": "vive_cosmos",
      "binding_url": "binding_vive_cosmos.json"
    },
    {
      "controller_type": "vive",
      "binding_url": "binding_vive.json"
    },
    {
      "controller_type": "indexhmd",
      "binding_url": "binding_index_hmd.json"
    },
    {
      "controller_type": "vive_pro",
      "binding_url": "binding_vive_pro.json"
    },
    {
      "controller_type": "rift",
      "binding_url": "binding_rift.json"
    },
    {
      "controller_type": "holographic_hmd",
      "binding_url": "binding_holographic_hmd.json"
    },
    {
      "controller_type": "vive_tracker_camera",
      "binding_url": "binding_vive_tracker_camera.json"
    },
    {
      "controller_type": "vive_tracker_chest",
      "binding_url": "binding_vive_tracker_chest.json"
    },
    {
      "controller_type": "vive_tracker_head",
      "binding_url": "binding_vive_tracker_head.json"
    },
    {
      "controller_type": "vive_tracker_left_elbow",
      "binding_url": "binding_vive_tracker_left_elbow.json"
    },
    {
      "controller_type": "vive_tracker_left_foot",
      "binding_url": "binding_vive_tracker_left_foot.json"
    },
    {
      "controller_type": "vive_tracker_left_hand",
      "binding_url": "binding_vive_tracker_left_hand.json"
    },
    {
      "controller_type": "vive_tracker_left_knee",
      "binding_url": "binding_vive_tracker_left_knee.json"
    },
    {
      "controller_type": "vive_tracker_left_shoulder",
      "binding_url": "binding_vive_tracker_left_shoulder.json"
    },
    {
      "controller_type": "vive_tracker_right_elbow",
      "binding_url": "binding_vive_tracker_right_elbow.json"
    },
    {
      "controller_type": "vive_tracker_right_foot",
      "binding_url": "binding_vive_tracker_right_foot.json"
    },
    {
      "controller_type": "vive_tracker_right_hand",
      "binding_url": "binding_vive_tracker_right_hand.json"
    },
    {
      "controller_type": "vive_tracker_right_knee",
      "binding_url": "binding_vive_tracker_right_knee.json"
    },
    {
      "controller_type": "vive_tracker_right_shoulder",
      "binding_url": "binding_vive_tracker_right_shoulder.json"
    },
    {
      "controller_type": "vive_tracker_waist",
      "binding_url": "binding_vive_tracker_waist.json"
    }
  ],
  "localization": [
    {
      "language_tag": "en_US",
      "/actions/default/in/Pose": "Pose",
      "/actions/default/in/SkeletonLeftHand": "Skeleton (Left)",
      "/actions/default/in/SkeletonRightHand": "Skeleton (Right)",
      "/actions/default/out/Haptic": "Haptic"
    }
  ]
}

binding_vive_tracker_chest.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/chest/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_chest",
   "description" : "",
   "name" : "Chest",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_head.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/head/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_head",
   "description" : "",
   "name" : "Head",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_left_elbow.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/elbow/left/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_left_elbow",
   "description" : "",
   "name" : "LeftElbow",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_left_foot.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/foot/left/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_left_foot",
   "description" : "",
   "name" : "LeftFoot",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_left_hand.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/hand/left/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_left_hand",
   "description" : "",
   "name" : "LeftHand",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_left_knee.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/knee/left/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_left_knee",
   "description" : "",
   "name" : "LeftKnee",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_left_shoulder.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/shoulder/left/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_left_shoulder",
   "description" : "",
   "name" : "LeftShoulder",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_right_elbow.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/elbow/right/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_right_elbow",
   "description" : "",
   "name" : "RightElbow",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_right_foot.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/foot/right/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_right_foot",
   "description" : "",
   "name" : "RightFoot",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_right_hand.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/hand/right/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_right_hand",
   "description" : "",
   "name" : "RightHand",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_right_knee.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/knee/right/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_right_knee",
   "description" : "",
   "name" : "RightKnee",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_right_shoulder.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/shoulder/right/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_right_shoulder",
   "description" : "",
   "name" : "RightShoulder",
   "options" : {},
   "simulated_actions" : []
}

binding_vive_tracker_waist.json

{
   "alias_info" : {},
   "bindings" : {
      "/actions/default" : {
         "poses" : [
            {
               "output" : "/actions/default/in/pose",
               "path" : "/user/waist/pose/raw"
            }
         ]
      }
   },
   "controller_type" : "vive_tracker_waist",
   "description" : "",
   "name" : "Waist",
   "options" : {},
   "simulated_actions" : []
}

SteamVRTracker.cs

// SteamVR 2.x Tracker Role Pose Example
// MIT License
// Copyright (c) 2021 sh_akira

using System;
using System.Runtime.InteropServices;
using UnityEngine;
using Valve.VR;

namespace akr.Avatar.Tracking
{
    public class SteamVRTracker : MonoBehaviour
    {

        //外部からTransformを指定されたときはそちらをそのまま使用する。無い場合は自動で作成して割り当てる
        public TrackerTarget[] TrackerTargets = new TrackerTarget[]
        {
            new TrackerTarget { TrackerPosition = TrackerPositions.Head },
            new TrackerTarget { TrackerPosition = TrackerPositions.LeftHand },
            new TrackerTarget { TrackerPosition = TrackerPositions.RightHand },
            new TrackerTarget { TrackerPosition = TrackerPositions.Waist },
            new TrackerTarget { TrackerPosition = TrackerPositions.LeftFoot },
            new TrackerTarget { TrackerPosition = TrackerPositions.RightFoot },
            new TrackerTarget { TrackerPosition = TrackerPositions.LeftElbow },
            new TrackerTarget { TrackerPosition = TrackerPositions.RightElbow },
            new TrackerTarget { TrackerPosition = TrackerPositions.LeftKnee },
            new TrackerTarget { TrackerPosition = TrackerPositions.RightKnee },
        };

        // "/actions/default/in/Pose"
        public SteamVR_Action_Pose PoseAction = SteamVR_Input.GetAction<SteamVR_Action_Pose>("Pose");

        private static float framesAhead = 2;
        private ETrackingUniverseOrigin universeOrigin = ETrackingUniverseOrigin.TrackingUniverseRawAndUncalibrated;
        private uint poseActionData_size = 0;
        private ulong actionHandle = 0;

        // enum TrackerPositionsとstring InputSourcePathとの対応表
        private readonly string[] TrackerPositionsToPath = new string[]
        {
            "/unrestricted",
            OpenVR.k_pchPathUserHandLeft,
            OpenVR.k_pchPathUserHandRight,
            OpenVR.k_pchPathUserFootLeft,
            OpenVR.k_pchPathUserFootRight,
            OpenVR.k_pchPathUserShoulderLeft,
            OpenVR.k_pchPathUserShoulderRight,
            OpenVR.k_pchPathUserWaist,
            OpenVR.k_pchPathUserChest,
            OpenVR.k_pchPathUserHead,
            OpenVR.k_pchPathUserGamepad,
            OpenVR.k_pchPathUserCamera,
            OpenVR.k_pchPathUserKeyboard,
            OpenVR.k_pchPathUserTreadmill,
            OpenVR.k_pchPathUserElbowLeft,
            OpenVR.k_pchPathUserElbowRight,
            OpenVR.k_pchPathUserKneeLeft,
            OpenVR.k_pchPathUserKneeRight,
            OpenVR.k_pchPathUserStylus,
        };

        /// <summary>
        /// ActionのフルパスからHandle取得
        /// </summary>
        /// <param name="fullPath"></param>
        /// <returns></returns>
        private ulong GetActionHandle(string fullPath)
        {
            ulong newHandle = 0;
            EVRInputError err = OpenVR.Input.GetActionHandle(fullPath.ToLowerInvariant(), ref newHandle);
            if (err != EVRInputError.None)
                Debug.LogError("GetActionHandle (" + fullPath.ToLowerInvariant() + ") error: " + err.ToString());
            return newHandle;
        }

        /// <summary>
        /// 指定したTrackerPositionsのInputSourceHandleを取得
        /// </summary>
        /// <param name="trackerPosition"></param>
        /// <returns></returns>
        private ulong GetTrackerInputSourceHandle(TrackerPositions trackerPosition)
            => GetTrackerInputSourceHandle(TrackerPositionsToPath[(int)trackerPosition]);

        /// <summary>
        /// 指定したInputSourcePathのInputSourceHandleを取得
        /// </summary>
        /// <param name="path"></param>
        /// <returns></returns>
        private ulong GetTrackerInputSourceHandle(string path)
        {

            ulong handle = 0;
            EVRInputError err = OpenVR.Input.GetInputSourceHandle(path, ref handle);

            if (err != EVRInputError.None)
                Debug.LogError("GetInputSourceHandle (" + path + ") error: " + err.ToString());

            return handle;
        }

        /// <summary>
        /// 指定したInputSourceHandleからトラッカーのPoseを取得
        /// </summary>
        /// <param name="inputSourceHandle"></param>
        /// <returns></returns>
        private InputPoseActionData_t GetPoseByHandle(ulong inputSourceHandle)
        {
            var poseActionData = new InputPoseActionData_t();
            EVRInputError err = OpenVR.Input.GetPoseActionDataRelativeToNow(actionHandle, universeOrigin, framesAhead * (Time.timeScale / SteamVR.instance.hmd_DisplayFrequency), ref poseActionData, poseActionData_size, inputSourceHandle);

            if (err != EVRInputError.None)
            {
                Debug.LogError("GetPoseActionDataRelativeToNow error: " + err.ToString() + " ActionHandle: " + actionHandle.ToString() + ". Input source: " + inputSourceHandle.ToString());
            }
            return poseActionData;
        }

        private void Awake()
        {
            universeOrigin = SteamVR_Settings.instance.trackingSpace;
            poseActionData_size = (uint)Marshal.SizeOf(typeof(InputPoseActionData_t));
        }

        private void Start()
        {
            actionHandle = GetActionHandle(PoseAction.fullPath);

            foreach(var trackerTarget in TrackerTargets)
            {
                if (trackerTarget.TargetTransform == null)
                {
                    var newTarget = new GameObject(trackerTarget.TrackerPosition.ToString());
                    newTarget.transform.SetParent(transform, false);
                    trackerTarget.TargetTransform = newTarget.transform;
                }

                trackerTarget.InputSourceHandle = GetTrackerInputSourceHandle(trackerTarget.TrackerPosition);
            }
        }

        private void Update()
        {
            foreach (var trackerTarget in TrackerTargets)
            {
                var poseActionData = GetPoseByHandle(trackerTarget.InputSourceHandle);

                if (poseActionData.bActive)
                {
                    trackerTarget.TargetTransform.localPosition = poseActionData.pose.mDeviceToAbsoluteTracking.GetPosition();
                    trackerTarget.TargetTransform.localRotation = poseActionData.pose.mDeviceToAbsoluteTracking.GetRotation();
                }
            }
        }

    }

    [Serializable]
    public class TrackerTarget
    {
        public TrackerPositions TrackerPosition;
        public Transform TargetTransform;
        [NonSerialized]
        public ulong InputSourceHandle;
    }

    /// <summary>
    /// SteamVRで割り当て可能なトラッカー位置(拡張SteamVR_Input_Sources)
    /// </summary>
    public enum TrackerPositions
    {
        Any,
        LeftHand,
        RightHand,
        LeftFoot,
        RightFoot,
        LeftShoulder,
        RightShoulder,
        Waist,
        Chest,
        Head,
        Gameoad,
        Camera,
        Keyboard,
        Treadmill,
        LeftElbow,
        RightElbow,
        LeftKnee,
        RightKnee,
        Stylus,
    }
}

最低限InのActionにPoseが追加されている必要があります。

SteamVRの設定にはLeft KneeやRight Elbow設定が可能にもかかわらず、SteamVR Pluginに定義が存在しない為、拡張SteamVR_Input_Sourcesを自前で持っています。SteamVR Pluginには定義がないが、OpenVRの定義には存在しているので直接k_pchPathUserKneeLeft等を使用しています。