void Update()
{
Vector3 axis = Vector3.down;
float angularSpeed = 1.0f;
float dt = m_timeScale * Time.fixedDeltaTime;
// render
Quaternion baseRot = Quaternion.FromToRotation(Vector3.one, Vector3.up);
DebugUtil.DrawBox(Vector3.zero, m_quatClosedForm * baseRot, Vector3.one, m_closedColor, true, DebugUtil.Style.FlatShaded);
DebugUtil.DrawBox(Vector3.zero, m_quatPower * baseRot, 1.05f * Vector3.one, m_powerColor, true, DebugUtil.Style.Wireframe);
DebugUtil.DrawBox(Vector3.zero, m_quatDerivative * baseRot, 1.1f * Vector3.one, m_derivativeColor, true, DebugUtil.Style.Wireframe);
// integrate
Quaternion v = QuaternionUtil.AxisAngle(axis, angularSpeed);
Vector3 o = angularSpeed * axis;
m_quatClosedForm = QuaternionUtil.Normalize(QuaternionUtil.AxisAngle(axis, (m_angle += angularSpeed * dt)));
m_quatPower = QuaternionUtil.Normalize(QuaternionUtil.Integrate(m_quatPower, v, dt));
m_quatDerivative = QuaternionUtil.Normalize(QuaternionUtil.Integrate(m_quatDerivative, o, dt));
if (Input.GetKey(KeyCode.Space))
{
Reset();
}
}