/*
===========================================================================

Return to Castle Wolfenstein single player GPL Source Code
Copyright (C) 1999-2010 id Software LLC, a ZeniMax Media company. 

This file is part of the Return to Castle Wolfenstein single player GPL Source Code (RTCW SP Source Code).  

RTCW SP Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

RTCW SP Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with RTCW SP Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the RTCW SP Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the RTCW SP Source Code.  If not, please request a copy in writing from id Software at the address below.

If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.

===========================================================================
*/

#ifndef __MATH_QUATERNION_H__
#define __MATH_QUATERNION_H__

#include <assert.h>
#include <math.h>

class idVec3_t;
class angles_t;
class mat3_t;

class quat_t {
public:
float x;
float y;
float z;
float w;

quat_t();
quat_t( float x, float y, float z, float w );

friend void     toQuat( idVec3_t &src, quat_t &dst );
friend void     toQuat( angles_t &src, quat_t &dst );
friend void     toQuat( mat3_t &src, quat_t &dst );

float           *vec4( void );

float operator[]( int index ) const;
float           &operator[]( int index );

void            set( float x, float y, float z, float w );

void operator=( quat_t a );

friend quat_t operator+( quat_t a, quat_t b );
quat_t          &operator+=( quat_t a );

friend quat_t operator-( quat_t a, quat_t b );
quat_t          &operator-=( quat_t a );

friend quat_t operator*( quat_t a, float b );
friend quat_t operator*( float a, quat_t b );
quat_t          &operator*=( float a );

friend int operator==( quat_t a, quat_t b );
friend int operator!=( quat_t a, quat_t b );

float           Length( void );
quat_t          &Normalize( void );

quat_t operator-();
};

inline quat_t::quat_t() {
}

inline quat_t::quat_t( float x, float y, float z, float w ) {
	this->x = x;
	this->y = y;
	this->z = z;
	this->w = w;
}

inline float *quat_t::vec4( void ) {
	return &x;
}

inline float quat_t::operator[]( int index ) const {
	assert( ( index >= 0 ) && ( index < 4 ) );
	return ( &x )[ index ];
}

inline float& quat_t::operator[]( int index ) {
	assert( ( index >= 0 ) && ( index < 4 ) );
	return ( &x )[ index ];
}

inline void quat_t::set( float x, float y, float z, float w ) {
	this->x = x;
	this->y = y;
	this->z = z;
	this->w = w;
}

inline void quat_t::operator=( quat_t a ) {
	x = a.x;
	y = a.y;
	z = a.z;
	w = a.w;
}

inline quat_t operator+( quat_t a, quat_t b ) {
	return quat_t( a.x + b.x, a.y + b.y, a.z + b.z, a.w + b.w );
}

inline quat_t& quat_t::operator+=( quat_t a ) {
	x += a.x;
	y += a.y;
	z += a.z;
	w += a.w;

	return *this;
}

inline quat_t operator-( quat_t a, quat_t b ) {
	return quat_t( a.x - b.x, a.y - b.y, a.z - b.z, a.w - b.w );
}

inline quat_t& quat_t::operator-=( quat_t a ) {
	x -= a.x;
	y -= a.y;
	z -= a.z;
	w -= a.w;

	return *this;
}

inline quat_t operator*( quat_t a, float b ) {
	return quat_t( a.x * b, a.y * b, a.z * b, a.w * b );
}

inline quat_t operator*( float a, quat_t b ) {
	return b * a;
}

inline quat_t& quat_t::operator*=( float a ) {
	x *= a;
	y *= a;
	z *= a;
	w *= a;

	return *this;
}

inline int operator==( quat_t a, quat_t b ) {
	return ( ( a.x == b.x ) && ( a.y == b.y ) && ( a.z == b.z ) && ( a.w == b.w ) );
}

inline int operator!=( quat_t a, quat_t b ) {
	return ( ( a.x != b.x ) || ( a.y != b.y ) || ( a.z != b.z ) && ( a.w != b.w ) );
}

inline float quat_t::Length( void ) {
	float length;

	length = x * x + y * y + z * z + w * w;
	return ( float )sqrt( length );
}

inline quat_t& quat_t::Normalize( void ) {
	float length;
	float ilength;

	length = this->Length();
	if ( length ) {
		ilength = 1 / length;
		x *= ilength;
		y *= ilength;
		z *= ilength;
		w *= ilength;
	}

	return *this;
}

inline quat_t quat_t::operator-() {
	return quat_t( -x, -y, -z, -w );
}

#endif /* !__MATH_QUATERNION_H__ */
