DOOM-3-BFG/neo/idlib/math/Complex.h

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

Doom 3 BFG Edition GPL Source Code
Copyright (C) 1993-2012 id Software LLC, a ZeniMax Media company. 

This file is part of the Doom 3 BFG Edition GPL Source Code ("Doom 3 BFG Edition Source Code").  

Doom 3 BFG Edition 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.

Doom 3 BFG Edition 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 Doom 3 BFG Edition Source Code.  If not, see <http://www.gnu.org/licenses/>.

In addition, the Doom 3 BFG Edition 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 Doom 3 BFG Edition 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_COMPLEX_H__
#define __MATH_COMPLEX_H__

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

  Complex number

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

class idComplex {
public:
	float				r;		// real part
	float				i;		// imaginary part

						idComplex();
						idComplex( const float r, const float i );

	void 				Set( const float r, const float i );
	void				Zero();

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

	idComplex			operator-() const;
	idComplex &			operator=( const idComplex &a );

	idComplex			operator*( const idComplex &a ) const;
	idComplex			operator/( const idComplex &a ) const;
	idComplex			operator+( const idComplex &a ) const;
	idComplex			operator-( const idComplex &a ) const;

	idComplex &			operator*=( const idComplex &a );
	idComplex &			operator/=( const idComplex &a );
	idComplex &			operator+=( const idComplex &a );
	idComplex &			operator-=( const idComplex &a );

	idComplex			operator*( const float a ) const;
	idComplex			operator/( const float a ) const;
	idComplex			operator+( const float a ) const;
	idComplex			operator-( const float a ) const;

	idComplex &			operator*=( const float a );
	idComplex &			operator/=( const float a );
	idComplex &			operator+=( const float a );
	idComplex &			operator-=( const float a );

	friend idComplex	operator*( const float a, const idComplex &b );
	friend idComplex	operator/( const float a, const idComplex &b );
	friend idComplex	operator+( const float a, const idComplex &b );
	friend idComplex	operator-( const float a, const idComplex &b );

	bool				Compare( const idComplex &a ) const;						// exact compare, no epsilon
	bool				Compare( const idComplex &a, const float epsilon ) const;	// compare with epsilon
	bool				operator==(	const idComplex &a ) const;						// exact compare, no epsilon
	bool				operator!=(	const idComplex &a ) const;						// exact compare, no epsilon

	idComplex			Reciprocal() const;
	idComplex			Sqrt() const;
	float				Abs() const;

	int					GetDimension() const;

	const float *		ToFloatPtr() const;
	float *				ToFloatPtr();
	const char *		ToString( int precision = 2 ) const;
};

extern idComplex complex_origin;
#define complex_zero complex_origin

ID_INLINE idComplex::idComplex() {
}

ID_INLINE idComplex::idComplex( const float r, const float i ) {
	this->r = r;
	this->i = i;
}

ID_INLINE void idComplex::Set( const float r, const float i ) {
	this->r = r;
	this->i = i;
}

ID_INLINE void idComplex::Zero() {
	r = i = 0.0f;
}

ID_INLINE float idComplex::operator[]( int index ) const {
	assert( index >= 0 && index < 2 );
	return ( &r )[ index ];
}

ID_INLINE float& idComplex::operator[]( int index ) {
	assert( index >= 0 && index < 2 );
	return ( &r )[ index ];
}

ID_INLINE idComplex idComplex::operator-() const {
	return idComplex( -r, -i );
}

ID_INLINE idComplex &idComplex::operator=( const idComplex &a ) {
	r = a.r;
	i = a.i;
	return *this;
}

ID_INLINE idComplex idComplex::operator*( const idComplex &a ) const {
	return idComplex( r * a.r - i * a.i, i * a.r + r * a.i );
}

ID_INLINE idComplex idComplex::operator/( const idComplex &a ) const {
	float s, t;
	if ( idMath::Fabs( a.r ) >= idMath::Fabs( a.i ) ) {
		s = a.i / a.r;
		t = 1.0f / ( a.r + s * a.i );
		return idComplex( ( r + s * i ) * t, ( i - s * r ) * t );
	} else {
		s = a.r / a.i;
		t = 1.0f / ( s * a.r + a.i );
		return idComplex( ( r * s + i ) * t, ( i * s - r ) * t );
	}
}

ID_INLINE idComplex idComplex::operator+( const idComplex &a ) const {
	return idComplex( r + a.r, i + a.i );
}

ID_INLINE idComplex idComplex::operator-( const idComplex &a ) const {
	return idComplex( r - a.r, i - a.i );
}

ID_INLINE idComplex &idComplex::operator*=( const idComplex &a ) {
	*this = idComplex( r * a.r - i * a.i, i * a.r + r * a.i );
	return *this;
}

ID_INLINE idComplex &idComplex::operator/=( const idComplex &a ) {
	float s, t;
	if ( idMath::Fabs( a.r ) >= idMath::Fabs( a.i ) ) {
		s = a.i / a.r;
		t = 1.0f / ( a.r + s * a.i );
		*this = idComplex( ( r + s * i ) * t, ( i - s * r ) * t );
	} else {
		s = a.r / a.i;
		t = 1.0f / ( s * a.r + a.i );
		*this = idComplex( ( r * s + i ) * t, ( i * s - r ) * t );
	}
	return *this;
}

ID_INLINE idComplex &idComplex::operator+=( const idComplex &a ) {
	r += a.r;
	i += a.i;
	return *this;
}

ID_INLINE idComplex &idComplex::operator-=( const idComplex &a ) {
	r -= a.r;
	i -= a.i;
	return *this;
}

ID_INLINE idComplex idComplex::operator*( const float a ) const {
	return idComplex( r * a, i * a );
}

ID_INLINE idComplex idComplex::operator/( const float a ) const {
	float s = 1.0f / a;
	return idComplex( r * s, i * s );
}

ID_INLINE idComplex idComplex::operator+( const float a ) const {
	return idComplex( r + a, i );
}

ID_INLINE idComplex idComplex::operator-( const float a ) const {
	return idComplex( r - a, i );
}

ID_INLINE idComplex &idComplex::operator*=( const float a ) {
	r *= a;
	i *= a;
	return *this;
}

ID_INLINE idComplex &idComplex::operator/=( const float a ) {
	float s = 1.0f / a;
	r *= s;
	i *= s;
	return *this;
}

ID_INLINE idComplex &idComplex::operator+=( const float a ) {
	r += a;
	return *this;
}

ID_INLINE idComplex &idComplex::operator-=( const float a ) {
	r -= a;
	return *this;
}

ID_INLINE idComplex operator*( const float a, const idComplex &b ) {
	return idComplex( a * b.r, a * b.i );
}

ID_INLINE idComplex operator/( const float a, const idComplex &b ) {
	float s, t;
	if ( idMath::Fabs( b.r ) >= idMath::Fabs( b.i ) ) {
		s = b.i / b.r;
		t = a / ( b.r + s * b.i );
		return idComplex( t, - s * t );
	} else {
		s = b.r / b.i;
		t = a / ( s * b.r + b.i );
		return idComplex( s * t, - t );
	}
}

ID_INLINE idComplex operator+( const float a, const idComplex &b ) {
	return idComplex( a + b.r, b.i );
}

ID_INLINE idComplex operator-( const float a, const idComplex &b ) {
	return idComplex( a - b.r, -b.i );
}

ID_INLINE idComplex idComplex::Reciprocal() const {
	float s, t;
	if ( idMath::Fabs( r ) >= idMath::Fabs( i ) ) {
		s = i / r;
		t = 1.0f / ( r + s * i );
		return idComplex( t, - s * t );
	} else {
		s = r / i;
		t = 1.0f / ( s * r + i );
		return idComplex( s * t, - t );
	}
}

ID_INLINE idComplex idComplex::Sqrt() const {
	float x, y, w;

	if ( r == 0.0f && i == 0.0f ) {
		return idComplex( 0.0f, 0.0f );
	}
	x = idMath::Fabs( r );
	y = idMath::Fabs( i );
	if ( x >= y ) {
		w = y / x;
		w = idMath::Sqrt( x ) * idMath::Sqrt( 0.5f * ( 1.0f + idMath::Sqrt( 1.0f + w * w ) ) );
	} else {
		w = x / y;
		w = idMath::Sqrt( y ) * idMath::Sqrt( 0.5f * ( w + idMath::Sqrt( 1.0f + w * w ) ) );
	}
	if ( w == 0.0f ) {
		return idComplex( 0.0f, 0.0f );
	}
	if ( r >= 0.0f ) {
		return idComplex( w, 0.5f * i / w );
	} else {
		return idComplex( 0.5f * y / w, ( i >= 0.0f ) ? w : -w );
	}
}

ID_INLINE float idComplex::Abs() const {
	float x, y, t;
	x = idMath::Fabs( r );
	y = idMath::Fabs( i );
	if ( x == 0.0f ) {
		return y;
	} else if ( y == 0.0f ) {
		return x;
	} else if ( x > y ) {
		t = y / x;
		return x * idMath::Sqrt( 1.0f + t * t );
	} else {
		t = x / y;
		return y * idMath::Sqrt( 1.0f + t * t );
	}
}

ID_INLINE bool idComplex::Compare( const idComplex &a ) const {
	return ( ( r == a.r ) && ( i == a.i ) );
}

ID_INLINE bool idComplex::Compare( const idComplex &a, const float epsilon ) const {
	if ( idMath::Fabs( r - a.r ) > epsilon ) {
		return false;
	}
	if ( idMath::Fabs( i - a.i ) > epsilon ) {
		return false;
	}
	return true;
}

ID_INLINE bool idComplex::operator==( const idComplex &a ) const {
	return Compare( a );
}

ID_INLINE bool idComplex::operator!=( const idComplex &a ) const {
	return !Compare( a );
}

ID_INLINE int idComplex::GetDimension() const {
	return 2;
}

ID_INLINE const float *idComplex::ToFloatPtr() const {
	return &r;
}

ID_INLINE float *idComplex::ToFloatPtr() {
	return &r;
}

#endif /* !__MATH_COMPLEX_H__ */