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2 //
3 // Copyright (c) 2002-2012, 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 #include "ImathNamespace.h"
53
54 IMATH_INTERNAL_NAMESPACE_HEADER_ENTER
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
project(const Vec & s,const Vec & t)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
orthogonal(const Vec & s,const Vec & t)104 orthogonal (const Vec &s, const Vec &t)
105 {
106 return t - project (s, t);
107 }
108
109 template <class Vec>
110 Vec
reflect(const Vec & s,const Vec & t)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
closestVertex(const Vec & v0,const Vec & v1,const Vec & v2,const Vec & p)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
145 IMATH_INTERNAL_NAMESPACE_HEADER_EXIT
146
147 #endif // INCLUDED_IMATHVECALGO_H
148