/*
   math/axis.h
   This file is part of the Osirion project and is distributed under
   the terms of the GNU General Public License version 2
*/

#ifndef __INCLUDED_MATH_AXIS_H__
#define __INCLUDED_MATH_AXIS_H__

#include <iostream>

#include "math/vector3f.h"

namespace math
{

/// a local coordinates system
class Axis
{
public:
	Axis();
	Axis(const Axis & other);
	
	void clear();
	
	void assign(const Axis & other);
	
	/// global coordinates of the X-axis in the local coordinates system
	inline const Vector3f & forward() const {
		return axis_vector[0];
	}
	
	/// global coordinates of the Y-axis in the local coordinates system
	inline const Vector3f & left() const {
		return axis_vector[1];
	}
	
	/// global coordinates of the Z-axis in the local coordinates system
	inline const Vector3f & up() const {
		return axis_vector[2];
	}
	
	inline Vector3f & operator[](size_t index) {
		return axis_vector[index];
	}
	
	inline const Vector3f & operator[](size_t index) const {
		return axis_vector[index];
	}
	
	Axis & operator=(const Axis & other);

	const Axis operator*(const Axis &other) const;
	
	/// change direction, rotate around up vector (positive is left)
	void change_direction(const float angle);
	
	/// change pitch, rotate around left vector (positive is up)
	void change_pitch(const float angle);
	
	/// change roll, rotate around forward vector (positive is left)
	void change_roll(const float angle);
	
	/// rotation about an arbitrary axis
	void rotate(const Vector3f & normal, const float angle);
	
	/// return the transpose of this matrix
	const Axis transpose() const;
	
private:
	Vector3f		axis_vector[3];
};

/// write an axis to a std::ostream
std::ostream &operator<<(std::ostream & os, const Axis & axis);

/// read an axis from a std::istream
std::istream &operator>>(std::istream & is, Axis & axis);

/// local-to-global coordinates
Vector3f operator*(const Axis &axis, const Vector3f &vector);

}

#endif // __INCLUDED_MATH_AXIS_H__