public override VROverlayError SetOverlayTransformTrackedDeviceRelative(ulong ulOverlayHandle,uint unTrackedDevice,ref HmdMatrix34_t pmatTrackedDeviceToOverlayTransform)
 {
     CheckIfUsable();
     VROverlayError result = VRNativeEntrypoints.VR_IVROverlay_SetOverlayTransformTrackedDeviceRelative(m_pVROverlay,ulOverlayHandle,unTrackedDevice,ref pmatTrackedDeviceToOverlayTransform);
     return result;
 }

 public abstract bool GetWorkingStandingZeroPoseToRawTrackingPose(ref HmdMatrix34_t pmatStandingZeroPoseToRawTrackingPose);

 public override EVROverlayError GetTransformForOverlayCoordinates(ulong ulOverlayHandle,ETrackingUniverseOrigin eTrackingOrigin,HmdVector2_t coordinatesInOverlay,ref HmdMatrix34_t pmatTransform)
 {
     CheckIfUsable();
     EVROverlayError result = VRNativeEntrypoints.VR_IVROverlay_GetTransformForOverlayCoordinates(m_pVROverlay,ulOverlayHandle,eTrackingOrigin,coordinatesInOverlay,ref pmatTransform);
     return result;
 }

 public override VROverlayError SetOverlayTransformAbsolute(ulong ulOverlayHandle,TrackingUniverseOrigin eTrackingOrigin,ref HmdMatrix34_t pmatTrackingOriginToOverlayTransform)
 {
     CheckIfUsable();
     VROverlayError result = VRNativeEntrypoints.VR_IVROverlay_SetOverlayTransformAbsolute(m_pVROverlay,ulOverlayHandle,eTrackingOrigin,ref pmatTrackingOriginToOverlayTransform);
     return result;
 }

 public static extern bool GetLastTrackerFromHeadPose(System.IntPtr pHmd, ref HmdMatrix34_t pmPose);

 public abstract void SetKeyboardTransformAbsolute(ETrackingUniverseOrigin eTrackingOrigin,ref HmdMatrix34_t pmatTrackingOriginToKeyboardTransform);

 public abstract void SetWorkingStandingZeroPoseToRawTrackingPose(ref HmdMatrix34_t pMatStandingZeroPoseToRawTrackingPose);

 public abstract bool GetLiveSeatedZeroPoseToRawTrackingPose(ref HmdMatrix34_t pmatSeatedZeroPoseToRawTrackingPose);

 public override void ApplyTransform(ref TrackedDevicePose_t pOutputPose,ref TrackedDevicePose_t pTrackedDevicePose,ref HmdMatrix34_t pTransform)
 {
     CheckIfUsable();
     VRNativeEntrypoints.VR_IVRSystem_ApplyTransform(m_pVRSystem,ref pOutputPose,ref pTrackedDevicePose,ref pTransform);
 }

 public abstract bool GetWorkingTagPoseByName(string pchTagName,ref HmdMatrix34_t pmatTagPose,ref float pflScale);

 public abstract bool GetWorkingTagPoses(out HmdMatrix34_t [] pTagPosesBuffer);

 public static extern bool GetTrackerFromHeadPose(System.IntPtr pHmd, float fPredictedSecondsFromNow, ref HmdMatrix34_t pmPose, ref HmdTrackingResult peResult);