/**

 * @file  quaternion.h

 * @brief Quaternion class

 *

 * This file is part of Pyrit Ray Tracer.

 *

 * Copyright 2007, 2008  Radek Brich

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#ifndef QUATERNION_H

#define QUATER_H

/**

 * quaternion class

 */

class Quaternion

{

public:

	union {

		struct {

			Float a,b,c,d;

		};

		struct {

			Float t,x,y,z;

		};

	};

	Quaternion(): a(0), b(0), c(0), d(0) {};

	Quaternion(const Float aa, const Float ab, const Float ac, const Float ad):

		a(aa), b(ab), c(ac), d(ad) {};

	Quaternion(const Vector& v): a(0), b(v.x), c(v.y), d(v.z) {};

	Vector toVector() { return Vector(b, c, d); };

	Quaternion normalize()

	{

		Float f = (Float)1.0f / sqrtf(a * a + b * b + c * c + d * d);

		a *= f;

		b *= f;

		c *= f;

		d *= f;

		return *this;

	};

	Float mag2() const

	{

		return (a*a + b*b + c*c + d*d);

	};

	Float mag() const

	{

		return sqrtf(mag());

	};

	friend Quaternion operator*(const Quaternion &q1, const Quaternion &q2)

	{

		return Quaternion(

			q1.a*q2.a - q1.b*q2.b - q1.c*q2.c - q1.d*q2.d,

			q1.a*q2.b + q1.b*q2.a + q1.c*q2.d - q1.d*q2.c,

			q1.a*q2.c - q1.b*q2.d + q1.c*q2.a + q1.d*q2.b,

			q1.a*q2.d + q1.b*q2.c - q1.c*q2.b + q1.d*q2.a);

	};

	friend Float dot(const Quaternion &q1, const Quaternion &q2)

	{

		return q1.a*q2.a + q1.b*q2.b + q1.c*q2.c + q1.d*q2.d;

	};

	friend Quaternion conjugate(const Quaternion &q)

	{

		return Quaternion(q.a, -q.b, -q.c, -q.d);

	};

};

#endif