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ImathVecAlgo.h
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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 #include "ImathNamespace.h"
53 
55 
56 
57 //-----------------------------------------------------------------
58 // Find the projection of vector t onto vector s (Vec2, Vec3, Vec4)
59 //-----------------------------------------------------------------
60 
61 template <class Vec> Vec project (const Vec &s, const Vec &t);
62 
63 
64 //------------------------------------------------
65 // Find a vector that is perpendicular to s and
66 // in the same plane as s and t (Vec2, Vec3, Vec4)
67 //------------------------------------------------
68 
69 template <class Vec> Vec orthogonal (const Vec &s, const Vec &t);
70 
71 
72 //-----------------------------------------------
73 // Find the direction of a ray s after reflection
74 // off a plane with normal t (Vec2, Vec3, Vec4)
75 //-----------------------------------------------
76 
77 template <class Vec> Vec reflect (const Vec &s, const Vec &t);
78 
79 
80 //--------------------------------------------------------------------
81 // Find the vertex of triangle (v0, v1, v2) that is closest to point p
82 // (Vec2, Vec3, Vec4)
83 //--------------------------------------------------------------------
84 
85 template <class Vec> Vec closestVertex (const Vec &v0,
86  const Vec &v1,
87  const Vec &v2,
88  const Vec &p);
89 
90 //---------------
91 // Implementation
92 //---------------
93 
94 template <class Vec>
95 Vec
96 project (const Vec &s, const Vec &t)
97 {
98  Vec sNormalized = s.normalized();
99  return sNormalized * (sNormalized ^ t);
100 }
101 
102 template <class Vec>
103 Vec
104 orthogonal (const Vec &s, const Vec &t)
105 {
106  return t - project (s, t);
107 }
108 
109 template <class Vec>
110 Vec
111 reflect (const Vec &s, const Vec &t)
112 {
113  return s - typename Vec::BaseType(2) * (s - project(t, s));
114 }
115 
116 template <class Vec>
117 Vec
118 closestVertex(const Vec &v0,
119  const Vec &v1,
120  const Vec &v2,
121  const Vec &p)
122 {
123  Vec nearest = v0;
124  typename Vec::BaseType neardot = (v0 - p).length2();
125  typename Vec::BaseType tmp = (v1 - p).length2();
126 
127  if (tmp < neardot)
128  {
129  neardot = tmp;
130  nearest = v1;
131  }
132 
133  tmp = (v2 - p).length2();
134 
135  if (tmp < neardot)
136  {
137  neardot = tmp;
138  nearest = v2;
139  }
140 
141  return nearest;
142 }
143 
144 
146 
147 #endif // INCLUDED_IMATHVECALGO_H
#define IMATH_INTERNAL_NAMESPACE_HEADER_EXIT
#define IMATH_INTERNAL_NAMESPACE_HEADER_ENTER
Vec orthogonal(const Vec &s, const Vec &t)
Definition: ImathVecAlgo.h:104
GLfloat GLfloat GLfloat v2
Definition: glcorearb.h:817
Vec reflect(const Vec &s, const Vec &t)
Definition: ImathVecAlgo.h:111
GLfloat v0
Definition: glcorearb.h:815
GLfloat GLfloat v1
Definition: glcorearb.h:816
IMATH_INTERNAL_NAMESPACE_HEADER_ENTER Vec project(const Vec &s, const Vec &t)
Definition: ImathVecAlgo.h:96
Vec closestVertex(const Vec &v0, const Vec &v1, const Vec &v2, const Vec &p)
Definition: ImathVecAlgo.h:118