// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-

// Copyright 2012 Andrew Tridgell, all rights reserved.

//	This library is free software; you can redistribute it and / or
//	modify it under the terms of the GNU Lesser General Public
//	License as published by the Free Software Foundation; either
//	version 2.1 of the License, or (at your option) any later version.

#ifndef QUATERNION_H
#define QUATERNION_H

#include <math.h>

class Quaternion
{
public:
    float        q1, q2, q3, q4;

    // constructor creates a quaternion equivalent
    // to roll=0, pitch=0, yaw=0
    Quaternion() {
        q1 = 1; q2 = q3 = q4 = 0;
    }

    // setting constructor
    Quaternion(const float _q1, const float _q2, const float _q3, const float _q4) :
        q1(_q1), q2(_q2), q3(_q3), q4(_q4) {
    }

    // function call operator
    void operator        ()(const float _q1, const float _q2, const float _q3, const float _q4)
    {
        q1 = _q1; q2 = _q2; q3 = _q3; q4 = _q4;
    }

    // check if any elements are NAN
    bool        is_nan(void)
    {
        return isnan(q1) || isnan(q2) || isnan(q3) || isnan(q4);
    }

    // return the rotation matrix equivalent for this quaternion
    void        rotation_matrix(Matrix3f &m);

    // convert a vector from earth to body frame
    void        earth_to_body(Vector3f &v);

    // create a quaternion from Euler angles
    void        from_euler(float roll, float pitch, float yaw);

    // create eulers from a quaternion
    void        to_euler(float *roll, float *pitch, float *yaw);
};
#endif // QUATERNION_H