integrate method

Quaternion integrate(
  1. Vector3 angularVelocity,
  2. double dt,
  3. Vector3 angularFactor, [
  4. Quaternion? target,
])

Rotate an absolute orientation quaternion given an angular velocity and a time step.

Implementation

Quaternion integrate(Vector3 angularVelocity,double dt,Vector3 angularFactor, [Quaternion? target]){
  target ??= Quaternion(0,0,0,1);
  final ax = angularVelocity.x * angularFactor.x,
    ay = angularVelocity.y * angularFactor.y,
    az = angularVelocity.z * angularFactor.z,
    bx = x,
    by = y,
    bz = z,
    bw = w;

  final halfDt = dt * 0.5;

  target.x += halfDt * (ax * bw + ay * bz - az * by);
  target.y += halfDt * (ay * bw + az * bx - ax * bz);
  target.z += halfDt * (az * bw + ax * by - ay * bx);
  target.w += halfDt * (-ax * bx - ay * by - az * bz);

  return target;
}