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34 
35 
36 
37 #ifndef INCLUDED_IMATHPLANE_H
38 #define INCLUDED_IMATHPLANE_H
39 
40 //----------------------------------------------------------------------
41 //
42 //	template class Plane3
43 //
44 //	The Imath::Plane3<> class represents a half space, so the
45 //	normal may point either towards or away from origin.  The
46 //	plane P can be represented by Imath::Plane3 as either p or -p
47 //	corresponding to the two half-spaces on either side of the
48 //	plane. Any function which computes a distance will return
49 //	either negative or positive values for the distance indicating
50 //	which half-space the point is in. Note that reflection, and
51 //	intersection functions will operate as expected.
52 //
53 //----------------------------------------------------------------------
54 
55 #include "ImathVec.h"
56 #include "ImathLine.h"
57 #include "ImathNamespace.h"
58 
59 IMATH_INTERNAL_NAMESPACE_HEADER_ENTER
60 
61 
62 template <class T>
63 class Plane3
64 {
65   public:
66 
67     Vec3<T>			normal;
68     T				distance;
69 
Plane3()70     Plane3() {}
71     Plane3(const Vec3<T> &normal, T distance);
72     Plane3(const Vec3<T> &point, const Vec3<T> &normal);
73     Plane3(const Vec3<T> &point1,
74 	   const Vec3<T> &point2,
75 	   const Vec3<T> &point3);
76 
77     //----------------------
78     //	Various set methods
79     //----------------------
80 
81     void                        set(const Vec3<T> &normal,
82 				    T distance);
83 
84     void                        set(const Vec3<T> &point,
85 				    const Vec3<T> &normal);
86 
87     void                        set(const Vec3<T> &point1,
88 				    const Vec3<T> &point2,
89 				    const Vec3<T> &point3 );
90 
91     //----------------------
92     //	Utilities
93     //----------------------
94 
95     bool                        intersect(const Line3<T> &line,
96                                           Vec3<T> &intersection) const;
97 
98     bool                        intersectT(const Line3<T> &line,
99 					   T &parameter) const;
100 
101     T				distanceTo(const Vec3<T> &) const;
102 
103     Vec3<T>                     reflectPoint(const Vec3<T> &) const;
104     Vec3<T>                     reflectVector(const Vec3<T> &) const;
105 };
106 
107 
108 //--------------------
109 // Convenient typedefs
110 //--------------------
111 
112 typedef Plane3<float> Plane3f;
113 typedef Plane3<double> Plane3d;
114 
115 
116 //---------------
117 // Implementation
118 //---------------
119 
120 template <class T>
Plane3(const Vec3<T> & p0,const Vec3<T> & p1,const Vec3<T> & p2)121 inline Plane3<T>::Plane3(const Vec3<T> &p0,
122 			 const Vec3<T> &p1,
123 			 const Vec3<T> &p2)
124 {
125     set(p0,p1,p2);
126 }
127 
128 template <class T>
Plane3(const Vec3<T> & n,T d)129 inline Plane3<T>::Plane3(const Vec3<T> &n, T d)
130 {
131     set(n, d);
132 }
133 
134 template <class T>
Plane3(const Vec3<T> & p,const Vec3<T> & n)135 inline Plane3<T>::Plane3(const Vec3<T> &p, const Vec3<T> &n)
136 {
137     set(p, n);
138 }
139 
140 template <class T>
set(const Vec3<T> & point1,const Vec3<T> & point2,const Vec3<T> & point3)141 inline void Plane3<T>::set(const Vec3<T>& point1,
142 			   const Vec3<T>& point2,
143 			   const Vec3<T>& point3)
144 {
145     normal = (point2 - point1) % (point3 - point1);
146     normal.normalize();
147     distance = normal ^ point1;
148 }
149 
150 template <class T>
set(const Vec3<T> & point,const Vec3<T> & n)151 inline void Plane3<T>::set(const Vec3<T>& point, const Vec3<T>& n)
152 {
153     normal = n;
154     normal.normalize();
155     distance = normal ^ point;
156 }
157 
158 template <class T>
set(const Vec3<T> & n,T d)159 inline void Plane3<T>::set(const Vec3<T>& n, T d)
160 {
161     normal = n;
162     normal.normalize();
163     distance = d;
164 }
165 
166 template <class T>
distanceTo(const Vec3<T> & point)167 inline T Plane3<T>::distanceTo(const Vec3<T> &point) const
168 {
169     return (point ^ normal) - distance;
170 }
171 
172 template <class T>
reflectPoint(const Vec3<T> & point)173 inline Vec3<T> Plane3<T>::reflectPoint(const Vec3<T> &point) const
174 {
175     return normal * distanceTo(point) * -2.0 + point;
176 }
177 
178 
179 template <class T>
reflectVector(const Vec3<T> & v)180 inline Vec3<T> Plane3<T>::reflectVector(const Vec3<T> &v) const
181 {
182     return normal * (normal ^ v)  * 2.0 - v;
183 }
184 
185 
186 template <class T>
intersect(const Line3<T> & line,Vec3<T> & point)187 inline bool Plane3<T>::intersect(const Line3<T>& line, Vec3<T>& point) const
188 {
189     T d = normal ^ line.dir;
190     if ( d == 0.0 ) return false;
191     T t = - ((normal ^ line.pos) - distance) /  d;
192     point = line(t);
193     return true;
194 }
195 
196 template <class T>
intersectT(const Line3<T> & line,T & t)197 inline bool Plane3<T>::intersectT(const Line3<T>& line, T &t) const
198 {
199     T d = normal ^ line.dir;
200     if ( d == 0.0 ) return false;
201     t = - ((normal ^ line.pos) - distance) /  d;
202     return true;
203 }
204 
205 template<class T>
206 std::ostream &operator<< (std::ostream &o, const Plane3<T> &plane)
207 {
208     return o << "(" << plane.normal << ", " << plane.distance
209 	     << ")";
210 }
211 
212 template<class T>
213 Plane3<T> operator* (const Plane3<T> &plane, const Matrix44<T> &M)
214 {
215     //                        T
216     //	                    -1
217     //	Could also compute M    but that would suck.
218     //
219 
220     Vec3<T> dir1   = Vec3<T> (1, 0, 0) % plane.normal;
221     T dir1Len      = dir1 ^ dir1;
222 
223     Vec3<T> tmp    = Vec3<T> (0, 1, 0) % plane.normal;
224     T tmpLen       = tmp ^ tmp;
225 
226     if (tmpLen > dir1Len)
227     {
228 	dir1      = tmp;
229 	dir1Len   = tmpLen;
230     }
231 
232     tmp            = Vec3<T> (0, 0, 1) % plane.normal;
233     tmpLen         = tmp ^ tmp;
234 
235     if (tmpLen > dir1Len)
236     {
237 	dir1      = tmp;
238     }
239 
240     Vec3<T> dir2   = dir1 % plane.normal;
241     Vec3<T> point  = plane.distance * plane.normal;
242 
243     return Plane3<T> ( point         * M,
244 		      (point + dir2) * M,
245 		      (point + dir1) * M );
246 }
247 
248 template<class T>
249 Plane3<T> operator- (const Plane3<T> &plane)
250 {
251     return Plane3<T>(-plane.normal,-plane.distance);
252 }
253 
254 
255 IMATH_INTERNAL_NAMESPACE_HEADER_EXIT
256 
257 #endif // INCLUDED_IMATHPLANE_H
258