SteamVR_Controller.GetDeviceIndex C# (CSharp) Method

    public static int GetDeviceIndex(DeviceRelation relation,
		TrackedDeviceClass deviceClass = TrackedDeviceClass.Controller,
		int relativeTo = (int)OpenVR.k_unTrackedDeviceIndex_Hmd)
    {
        var invXform = ((uint)relativeTo < OpenVR.k_unMaxTrackedDeviceCount) ?
            Input(relativeTo).transform.GetInverse() : SteamVR_Utils.RigidTransform.identity;

        var vr = SteamVR.instance;
        var result = -1;
        var best = -float.MaxValue;
        for (int i = 0; i < OpenVR.k_unMaxTrackedDeviceCount; i++)
        {
            if (i == relativeTo || vr.hmd.GetTrackedDeviceClass((uint)i) != deviceClass)
                continue;

            var device = Input(i);
            if (!device.connected)
                continue;

            if (relation == DeviceRelation.First)
                return i;

            float score;

            var pos = invXform * device.transform.pos;
            if (relation == DeviceRelation.FarthestRight)
            {
                score = pos.x;
            }
            else if (relation == DeviceRelation.FarthestLeft)
            {
                score = -pos.x;
            }
            else
            {
                var dir = new Vector3(pos.x, 0.0f, pos.z).normalized;
                var dot = Vector3.Dot(dir, Vector3.forward);
                var cross = Vector3.Cross(dir, Vector3.forward);
                if (relation == DeviceRelation.Leftmost)
                {
                    score = (cross.y > 0.0f) ? 2.0f - dot : dot;
                }
                else
                {
                    score = (cross.y < 0.0f) ? 2.0f - dot : dot;
                }
            }

            if (score > best)
            {
                result = i;
                best = score;
            }
        }

        return result;
    }

 private static bool OpenVRRightGrip()
 {
     return(SteamVR_Controller.Input(SteamVR_Controller.GetDeviceIndex(SteamVR_Controller.DeviceRelation.Rightmost)).GetPress(Valve.VR.EVRButtonId.k_EButton_Grip));
 }