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108 lines
2.6 KiB
108 lines
2.6 KiB
//============================================================================
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//
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// 3-dim real vector class
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// $Id$
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// Copyright (C) 2004 Georg Drenkhahn
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//
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// This file is free software; you can redistribute it and/or modify it under
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// the terms of the GNU General Public License version 2 as published by the
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// Free Software Foundation.
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//
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//============================================================================
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#include <math.h>
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#if !defined(NAN)
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static inline double nan__()
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{
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static const unsigned int one = 1;
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static const bool BigEndian = (*((unsigned char *) &one) == 0);
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static const unsigned char be_nan_bytes[] = { 0x7f, 0xf8, 0, 0, 0, 0, 0, 0 };
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static const unsigned char le_nan_bytes[] = { 0, 0, 0, 0, 0, 0, 0xf8, 0x7f };
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return *( ( const double * )( BigEndian ? be_nan_bytes : le_nan_bytes ) );
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}
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# define NAN (::nan__())
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#endif
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#include <config.h>
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#ifdef HAVE_NUMERIC_LIMITS
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#include <limits>
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#endif
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#include <cerrno>
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#include "vec3.h"
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template<typename T>
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vec3<T>& vec3<T>::normalize()
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{
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T n = norm(*this);
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if (n != 0)
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{
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(*this) /= n;
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}
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else
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{
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errno = EDOM; // indicate domain error
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// TODO: throw an exception?
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}
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return *this;
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}
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template<typename T>
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vec3<T>& vec3<T>::rotate(const vec3<T>& r)
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{
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T phi = norm(r);
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if (phi != 0)
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{
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// part of vector which is parallel to r
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vec3<T> par(r*(*this)/(r*r) * r);
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// part of vector which is perpendicular to r
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vec3<T> perp(*this);
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std::valarray<T> &perp_ = perp;
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perp -= std::valarray<T>(par);
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// rotation direction, size of perp
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vec3<T> rotdir(norm(perp) * normalized(crossprod(r,perp)));
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*this = par + cos(phi)*perp + sin(phi)*rotdir;
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}
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return *this;
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}
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/*--- static member functions ---*/
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template<typename T>
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T vec3<T>::cos_angle(const vec3<T>& a, const vec3<T>& b)
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{
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T den = norm(a) * norm(b);
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T ret = 0;
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// if |a|=0 or |b|=0 then angle is not defined. We return NAN in this case.
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if (den != 0.0)
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{
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ret = a*b/den;
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}
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else
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{
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errno = EDOM; // indicate domain error
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#ifdef HAVE_NUMERIC_LIMITS
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// TODO test
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ret = std::numeric_limits<T>::quiet_NaN();
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#else
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ret = NAN; // return NAN from ISO C99
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#endif
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}
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return ret;
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}
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template<typename T>
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T vec3<T>::angle(const vec3<T>& a, const vec3<T>& b, const vec3<T>& c)
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{
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// if |a|=0 or |b|=0 then angle is not defined. We return NAN in this case.
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T ang = vec3<T>::angle(a,b);
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return (crossprod(a,b)*c<0) ?
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T(2.*M_PI)-ang : ang;
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}
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// explicite instantiation
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template class vec3<double>;
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