/src/FreeImage/Source/OpenEXR/Imath/ImathVecAlgo.h

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  2//
  3// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
  4// Digital Ltd. LLC
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 33///////////////////////////////////////////////////////////////////////////
 34
 35
 36
 37#ifndef INCLUDED_IMATHVECALGO_H
 38#define INCLUDED_IMATHVECALGO_H
 39
 40//-------------------------------------------------------------------------
 41//
 42//      This file contains algorithms applied to or in conjunction
 43//      with points (Imath::Vec2 and Imath::Vec3).
 44//      The assumption made is that these functions are called much
 45//      less often than the basic point functions or these functions
 46//      require more support classes.
 47//
 48//-------------------------------------------------------------------------
 49
 50#include "ImathVec.h"
 51#include "ImathLimits.h"
 52
 53namespace Imath {
 54
 55
 56//-----------------------------------------------------------------
 57// Find the projection of vector t onto vector s (Vec2, Vec3, Vec4)
 58//-----------------------------------------------------------------
 59
 60template <class Vec> Vec        project (const Vec &s, const Vec &t);
 61
 62
 63//------------------------------------------------
 64// Find a vector that is perpendicular to s and
 65// in the same plane as s and t (Vec2, Vec3, Vec4)
 66//------------------------------------------------
 67
 68template <class Vec> Vec        orthogonal (const Vec &s, const Vec &t);
 69
 70
 71//-----------------------------------------------
 72// Find the direction of a ray s after reflection
 73// off a plane with normal t (Vec2, Vec3, Vec4)
 74//-----------------------------------------------
 75
 76template <class Vec> Vec        reflect (const Vec &s, const Vec &t);
 77
 78
 79//--------------------------------------------------------------------
 80// Find the vertex of triangle (v0, v1, v2) that is closest to point p
 81// (Vec2, Vec3, Vec4)
 82//--------------------------------------------------------------------
 83
 84template <class Vec> Vec        closestVertex (const Vec &v0,
 85                                               const Vec &v1,
 86                                               const Vec &v2, 
 87                                               const Vec &p);
 88
 89//---------------
 90// Implementation
 91//---------------
 92
 93template <class Vec>
 94Vec
 95project (const Vec &s, const Vec &t)
 96{
 97    Vec sNormalized = s.normalized();
 98    return sNormalized * (sNormalized ^ t);
 99}
100
101template <class Vec>
102Vec
103orthogonal (const Vec &s, const Vec &t)
104{
105    return t - project (s, t);
106}
107
108template <class Vec>
109Vec
110reflect (const Vec &s, const Vec &t)
111{
112    return s - typename Vec::BaseType(2) * (s - project(t, s));
113}
114
115template <class Vec>
116Vec
117closestVertex(const Vec &v0,
118              const Vec &v1,
119              const Vec &v2, 
120              const Vec &p)
121{
122    Vec nearest = v0;
123    typename Vec::BaseType neardot = (v0 - p).length2();
124    typename Vec::BaseType tmp     = (v1 - p).length2();
125
126    if (tmp < neardot)
127    {
128        neardot = tmp;
129        nearest = v1;
130    }
131
132    tmp = (v2 - p).length2();
133
134    if (tmp < neardot)
135    {
136        neardot = tmp;
137        nearest = v2;
138    }
139
140    return nearest;
141}
142
143
144} // namespace Imath
145
146#endif