OVR::Posef head_pose = state.HeadPose.ThePose;
OVR::Matrix4f tracking_matrix(head_pose);
update_from_matrix(transpose(GL::Matrix(&tracking_matrix.M[0][0])));
OVR::Posef head_pose = state.HeadPose.ThePose;
OVR::Matrix4f tracking_matrix(head_pose);
update_from_matrix(transpose(GL::Matrix(&tracking_matrix.M[0][0])));