mathematics.h

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/*
-------------------------------------------------------------------------------
libfob - C++ interface to Ascension Technology Corporation's
         Flock of Birds position and orientation measurement system.
Copyright (C) 2002 Nathan Cournia

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.

This library 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
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-------------------------------------------------------------------------------
*/

//FILE:         mathematics.h
//AUTHOR:       Nathan Cournia <nathan@cournia.com>
#ifndef COURNIA_MATHEMATICS_H
#define COURNIA_MATHEMATICS_H 1 

typedef float real_t;

#include <cstdlib>
#include <cmath>

//#define MATH_EPSILON 1.19209290e-07f
#define MATH_EPSILON 0.00001

namespace math {

inline double
rand01( void ) 
{
    return (rand( ) / (double)RAND_MAX);
}


inline double
to_degrees( double x )
{
    return (x * 180.0 / M_PI);
}


inline double
to_radians( double x )
{
    return (x * M_PI / 180.0);
}


inline bool
equals( double x, double y ) 
{
    return (std::fabs( x - y ) < MATH_EPSILON);
}


template <class T>
inline void
swap( T& x, T& y )
{
    T z = x;
    x = y;
    y = z;
}


inline double
sign( double x )
{
    if( x < 0.0 ) {
        return -1.0;
    } else {
        return 1.0;
    }
}


inline bool
same_sign( double x, double y )
{
    if( x * y >= 0.0 ) {
        return true;
    } else {
        return false;
    }
}


inline bool
negative( double x )
{
    if( x < 0.0 ) {
        return true;
    } else {
        return false;
    }
}


inline bool
positive( double x )
{
    if( x < 0.0 ) {
        return false;
    } else {
        return true;
    }
}

//Ripped from Quake 3 Mod SDK code/game/q_math.c.
//Seems to be pretty common on the net, so this can probably be considered
//public domain code.
inline float
angle_normalize_360( float angle )
{
    return (360.0 / 65536) * ((int)(angle * (65536 / 360.0)) & 65535);
}

inline float
angle_normalize_180( float angle )
{
    angle = angle_normalize_360( angle );
    if( angle > 180.0 ) {
        angle -= 360.0;
    }
    return angle;
}

inline float
angle_subtract( float a, float b )
{
    return angle_normalize_180( a - b );
}


/*
\param value The value to clamp.
\param min The smallest allowable value.
\param max The largest allowable value.
\return The clamped value.
*/
template <class T>
inline T 
clamp( T value, T min, T max )
{
    if( value < min ) {
        //value less, clamp
        return min;
    }

    if( value > max ) {
        //value greater, clamp
        return max;
    }

    //value ok
    return value;
}

} //end of namespace math

#endif

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