// Update is called once per frame.
void Update()
{
// Access the ThalmicMyo component attached to the Myo object.
ThalmicMyo thalmicMyo = myo.GetComponent <ThalmicMyo> ();
// Update references when the pose becomes fingers spread or the q key is pressed.
bool updateReference = false;
if (thalmicMyo.pose != _lastPose)
{
_lastPose = thalmicMyo.pose;
if (thalmicMyo.pose == Pose.FingersSpread)
{
updateReference = true;
ExtendUnlockAndNotifyUserAction(thalmicMyo);
}
}
if (Input.GetKeyDown("r"))
{
updateReference = true;
}
// Update references. This anchors the joint on-screen such that it faces forward away
// from the viewer when the Myo armband is oriented the way it is when these references are taken.
if (updateReference)
{
// _antiYaw represents a rotation of the Myo armband about the Y axis (up) which aligns the forward
// vector of the rotation with Z = 1 when the wearer's arm is pointing in the reference direction.
_antiYaw = Quaternion.FromToRotation(
new Vector3(myo.transform.forward.x, 0, myo.transform.forward.z),
new Vector3(0, 0, 1)
);
// _referenceRoll represents how many degrees the Myo armband is rotated clockwise
// about its forward axis (when looking down the wearer's arm towards their hand) from the reference zero
// roll direction. This direction is calculated and explained below. When this reference is
// taken, the joint will be rotated about its forward axis such that it faces upwards when
// the roll value matches the reference.
Vector3 referenceZeroRoll = computeZeroRollVector(myo.transform.forward);
_referenceRoll = rollFromZero(referenceZeroRoll, myo.transform.forward, myo.transform.up);
}
// Current zero roll vector and roll value.
Vector3 zeroRoll = computeZeroRollVector(myo.transform.forward);
float roll = rollFromZero(zeroRoll, myo.transform.forward, myo.transform.up);
// The relative roll is simply how much the current roll has changed relative to the reference roll.
// adjustAngle simply keeps the resultant value within -180 to 180 degrees.
float relativeRoll = normalizeAngle(roll - _referenceRoll);
// antiRoll represents a rotation about the myo Armband's forward axis adjusting for reference roll.
Quaternion antiRoll = Quaternion.AngleAxis(relativeRoll, myo.transform.forward);
// Here the anti-roll and yaw rotations are applied to the myo Armband's forward direction to yield
// the orientation of the joint.
transform.rotation = _antiYaw * antiRoll * Quaternion.LookRotation(myo.transform.forward);
// The above calculations were done assuming the Myo armbands's +x direction, in its own coordinate system,
// was facing toward the wearer's elbow. If the Myo armband is worn with its +x direction facing the other way,
// the rotation needs to be updated to compensate.
if (thalmicMyo.xDirection == Thalmic.Myo.XDirection.TowardWrist)
{
// Mirror the rotation around the XZ plane in Unity's coordinate system (XY plane in Myo's coordinate
// system). This makes the rotation reflect the arm's orientation, rather than that of the Myo armband.
transform.rotation = new Quaternion(transform.localRotation.x,
-transform.localRotation.y,
transform.localRotation.z,
-transform.localRotation.w);
}
}