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34 
35 
36 
37 #ifndef INCLUDED_IMATHLINE_H
38 #define INCLUDED_IMATHLINE_H
39 
40 //-------------------------------------
41 //
42 //	A 3D line class template
43 //
44 //-------------------------------------
45 
46 #include "ImathVec.h"
47 #include "ImathLimits.h"
48 #include "ImathMatrix.h"
49 
50 namespace Imath {
51 
52 
53 template <class T>
54 class Line3
55 {
56   public:
57 
58     Vec3<T>			pos;
59     Vec3<T>			dir;
60 
61     //-------------------------------------------------------------
62     //	Constructors - default is normalized units along direction
63     //-------------------------------------------------------------
64 
Line3()65     Line3() {}
66     Line3(const Vec3<T>& point1, const Vec3<T>& point2);
67 
68     //------------------
69     //	State Query/Set
70     //------------------
71 
72     void			set(const Vec3<T>& point1,
73                     const Vec3<T>& point2);
74 
75     //-------
76     //	F(t)
77     //-------
78 
79     Vec3<T>			operator() (T parameter) const;
80 
81     //---------
82     //	Query
83     //---------
84 
85     T				distanceTo(const Vec3<T>& point) const;
86     T				distanceTo(const Line3<T>& line) const;
87     Vec3<T>			closestPointTo(const Vec3<T>& point) const;
88     Vec3<T>			closestPointTo(const Line3<T>& line) const;
89 };
90 
91 
92 //--------------------
93 // Convenient typedefs
94 //--------------------
95 
96 typedef Line3<float> Line3f;
97 typedef Line3<double> Line3d;
98 
99 
100 //---------------
101 // Implementation
102 //---------------
103 
104 template <class T>
Line3(const Vec3<T> & p0,const Vec3<T> & p1)105 inline Line3<T>::Line3(const Vec3<T> &p0, const Vec3<T> &p1)
106 {
107     set(p0,p1);
108 }
109 
110 template <class T>
set(const Vec3<T> & p0,const Vec3<T> & p1)111 inline void Line3<T>::set(const Vec3<T> &p0, const Vec3<T> &p1)
112 {
113     pos = p0; dir = p1-p0;
114     dir.normalize();
115 }
116 
117 template <class T>
operator()118 inline Vec3<T> Line3<T>::operator()(T parameter) const
119 {
120     return pos + dir * parameter;
121 }
122 
123 template <class T>
distanceTo(const Vec3<T> & point)124 inline T Line3<T>::distanceTo(const Vec3<T>& point) const
125 {
126     return (closestPointTo(point)-point).length();
127 }
128 
129 template <class T>
closestPointTo(const Vec3<T> & point)130 inline Vec3<T> Line3<T>::closestPointTo(const Vec3<T>& point) const
131 {
132     return ((point - pos) ^ dir) * dir + pos;
133 }
134 
135 template <class T>
distanceTo(const Line3<T> & line)136 inline T Line3<T>::distanceTo(const Line3<T>& line) const
137 {
138     T d = (dir % line.dir) ^ (line.pos - pos);
139     return (d >= 0)? d: -d;
140 }
141 
142 template <class T>
143 inline Vec3<T>
closestPointTo(const Line3<T> & line)144 Line3<T>::closestPointTo(const Line3<T>& line) const
145 {
146     // Assumes the lines are normalized
147 
148     Vec3<T> posLpos = pos - line.pos ;
149     T c = dir ^ posLpos;
150     T a = line.dir ^ dir;
151     T f = line.dir ^ posLpos ;
152     T num = c - a * f;
153 
154     T denom = a*a - 1;
155 
156     T absDenom = ((denom >= 0)? denom: -denom);
157 
158     if (absDenom < 1)
159     {
160     T absNum = ((num >= 0)? num: -num);
161 
162     if (absNum >= absDenom * limits<T>::max())
163         return pos;
164     }
165 
166     return pos + dir * (num / denom);
167 }
168 
169 template<class T>
170 std::ostream& operator<< (std::ostream &o, const Line3<T> &line)
171 {
172     return o << "(" << line.pos << ", " << line.dir << ")";
173 }
174 
175 template<class S, class T>
176 inline Line3<S> operator * (const Line3<S> &line, const Matrix44<T> &M)
177 {
178     return Line3<S>( line.pos * M, (line.pos + line.dir) * M );
179 }
180 
181 
182 } // namespace Imath
183 
184 #endif
185