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26 // 26 //
27 // G4TessellatedGeometryAlgorithms implementat << 27 //
>> 28 // $Id: G4TessellatedGeometryAlgorithms.cc,v 1.6 2008/12/18 12:57:36 gunter Exp $
>> 29 // GEANT4 tag $Name: geant4-09-02-patch-03 $
>> 30 //
>> 31 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>> 32 //
>> 33 // MODULE: G4TessellatedGeometryAlgorithms.cc
>> 34 //
>> 35 // Date: 07/08/2005
>> 36 // Author: Rickard Holmberg & Pete Truscott
>> 37 // Organisation: QinetiQ Ltd, UK (PT)
>> 38 // Customer: ESA-ESTEC / TEC-EES
>> 39 // Contract:
>> 40 //
>> 41 // %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>> 42 //
>> 43 // CHANGE HISTORY
>> 44 // --------------
28 // 45 //
29 // 07 August 2007, P R Truscott, QinetiQ Ltd, 46 // 07 August 2007, P R Truscott, QinetiQ Ltd, UK - Created, with member
30 // functions based on the work 47 // functions based on the work of Rickard Holmberg.
31 // 12 October 2012, M Gayer, CERN, - Reviewed << 48 //
32 // ------------------------------------------- << 49 // 26 September 2007
>> 50 // P R Truscott, qinetiQ Ltd, UK
>> 51 // Updated to assign values of location array, not update
>> 52 // just the pointer.
>> 53 //
>> 54 ///////////////////////////////////////////////////////////////////////////////
33 55
34 #include "G4TessellatedGeometryAlgorithms.hh" 56 #include "G4TessellatedGeometryAlgorithms.hh"
>> 57 ///////////////////////////////////////////////////////////////////////////////
>> 58 //
>> 59 // Pointer to single instance of class.
>> 60 //
>> 61 G4TessellatedGeometryAlgorithms* G4TessellatedGeometryAlgorithms::fInstance = 0;
35 62
36 #include <cfloat> << 63 ///////////////////////////////////////////////////////////////////////////////
>> 64 //
>> 65 // G4TessellatedGeometryAlgorithms
>> 66 //
>> 67 // Constructor doesn't need to do anything since this class just allows access
>> 68 // to the geometric algorithms contained in member functions.
>> 69 //
>> 70 G4TessellatedGeometryAlgorithms::G4TessellatedGeometryAlgorithms ()
>> 71 {
>> 72 }
>> 73
>> 74 ///////////////////////////////////////////////////////////////////////////////
>> 75 //
>> 76 // GetInstance
>> 77 //
>> 78 // This is the access point for this singleton.
>> 79 //
>> 80 G4TessellatedGeometryAlgorithms* G4TessellatedGeometryAlgorithms::GetInstance()
>> 81 {
>> 82 static G4TessellatedGeometryAlgorithms worldStdGeom;
>> 83 if (!fInstance)
>> 84 {
>> 85 fInstance = &worldStdGeom;
>> 86 }
>> 87 return fInstance;
>> 88 }
37 89
38 ////////////////////////////////////////////// 90 ///////////////////////////////////////////////////////////////////////////////
39 // 91 //
40 // IntersectLineAndTriangle2D 92 // IntersectLineAndTriangle2D
41 // 93 //
42 // Determines whether there is an intersection 94 // Determines whether there is an intersection between a line defined
43 // by r = p + s.v and a triangle defined by ve << 95 // by r = p + s.v and a triangle defined by verticies P0, P0+E0 and P0+E1.
44 // 96 //
45 // Here: 97 // Here:
46 // p = 2D vector 98 // p = 2D vector
47 // s = scaler on [0,infinity) 99 // s = scaler on [0,infinity)
48 // v = 2D vector 100 // v = 2D vector
49 // p0, e0 and e1 are 2D vectors << 101 // P0, E0 and E1 are 2D vectors
50 // Information about where the intersection oc 102 // Information about where the intersection occurs is returned in the
51 // variable location. 103 // variable location.
52 // 104 //
53 // This is based on the work of Rickard Holmbe 105 // This is based on the work of Rickard Holmberg.
54 // 106 //
55 G4bool G4TessellatedGeometryAlgorithms::Inters 107 G4bool G4TessellatedGeometryAlgorithms::IntersectLineAndTriangle2D (
56 const G4TwoVector& p, const G4TwoVector& v, << 108 const G4TwoVector p, const G4TwoVector v,
57 const G4TwoVector& p0, const G4TwoVector& e0 << 109 const G4TwoVector P0, const G4TwoVector E0, const G4TwoVector E1,
58 G4TwoVector location[2]) 110 G4TwoVector location[2])
59 { 111 {
60 G4TwoVector loc0[2]; 112 G4TwoVector loc0[2];
61 G4int e0i = IntersectLineAndLineSegment2D (p << 113 G4int e0i = IntersectLineAndLineSegment2D (p,v,P0,E0,loc0);
62 if (e0i == 2) 114 if (e0i == 2)
63 { 115 {
64 location[0] = loc0[0]; 116 location[0] = loc0[0];
65 location[1] = loc0[1]; 117 location[1] = loc0[1];
66 return true; 118 return true;
67 } 119 }
68 << 120
69 G4TwoVector loc1[2]; 121 G4TwoVector loc1[2];
70 G4int e1i = IntersectLineAndLineSegment2D (p << 122 G4int e1i = IntersectLineAndLineSegment2D (p,v,P0,E1,loc1);
71 if (e1i == 2) 123 if (e1i == 2)
72 { 124 {
73 location[0] = loc1[0]; 125 location[0] = loc1[0];
74 location[1] = loc1[1]; 126 location[1] = loc1[1];
75 return true; 127 return true;
76 } 128 }
77 << 129
78 if ((e0i == 1) && (e1i == 1)) 130 if ((e0i == 1) && (e1i == 1))
79 { 131 {
80 if ((loc0[0]-p).mag2() < (loc1[0]-p).mag2( 132 if ((loc0[0]-p).mag2() < (loc1[0]-p).mag2())
81 { 133 {
82 location[0] = loc0[0]; 134 location[0] = loc0[0];
83 location[1] = loc1[0]; 135 location[1] = loc1[0];
84 } 136 }
85 else 137 else
86 { 138 {
87 location[0] = loc1[0]; 139 location[0] = loc1[0];
88 location[1] = loc0[0]; 140 location[1] = loc0[0];
89 } 141 }
90 return true; 142 return true;
91 } 143 }
92 << 144
93 G4TwoVector p1 = p0 + e0; << 145 G4TwoVector P1 = P0 + E0;
94 G4TwoVector DE = e1 - e0; << 146 G4TwoVector DE = E1 - E0;
95 G4TwoVector loc2[2]; 147 G4TwoVector loc2[2];
96 G4int e2i = IntersectLineAndLineSegment2D (p << 148 G4int e2i = IntersectLineAndLineSegment2D (p,v,P1,DE,loc2);
97 if (e2i == 2) 149 if (e2i == 2)
98 { 150 {
99 location[0] = loc2[0]; 151 location[0] = loc2[0];
100 location[1] = loc2[1]; 152 location[1] = loc2[1];
101 return true; 153 return true;
102 } 154 }
103 155
104 if ((e0i == 0) && (e1i == 0) && (e2i == 0)) << 156 if ((e0i == 0) && (e1i == 0) && (e2i == 0)) { return false; }
105 157
106 if ((e0i == 1) && (e2i == 1)) 158 if ((e0i == 1) && (e2i == 1))
107 { 159 {
108 if ((loc0[0]-p).mag2() < (loc2[0]-p).mag2( 160 if ((loc0[0]-p).mag2() < (loc2[0]-p).mag2())
109 { 161 {
110 location[0] = loc0[0]; 162 location[0] = loc0[0];
111 location[1] = loc2[0]; 163 location[1] = loc2[0];
112 } 164 }
113 else 165 else
114 { 166 {
115 location[0] = loc2[0]; 167 location[0] = loc2[0];
116 location[1] = loc0[0]; 168 location[1] = loc0[0];
117 } 169 }
118 return true; 170 return true;
119 } 171 }
120 172
121 if ((e1i == 1) && (e2i == 1)) 173 if ((e1i == 1) && (e2i == 1))
122 { 174 {
123 if ((loc1[0]-p).mag2() < (loc2[0]-p).mag2( 175 if ((loc1[0]-p).mag2() < (loc2[0]-p).mag2())
124 { 176 {
125 location[0] = loc1[0]; 177 location[0] = loc1[0];
126 location[1] = loc2[0]; 178 location[1] = loc2[0];
127 } 179 }
128 else 180 else
129 { 181 {
130 location[0] = loc2[0]; 182 location[0] = loc2[0];
131 location[1] = loc1[0]; 183 location[1] = loc1[0];
132 } 184 }
133 return true; 185 return true;
134 } 186 }
135 187
136 return false; 188 return false;
137 } 189 }
138 190
139 ////////////////////////////////////////////// 191 ///////////////////////////////////////////////////////////////////////////////
140 // 192 //
141 // IntersectLineAndLineSegment2D 193 // IntersectLineAndLineSegment2D
142 // 194 //
143 // Determines whether there is an intersection 195 // Determines whether there is an intersection between a line defined
144 // by r = p0 + s.d0 and a line-segment with en << 196 // by r = P0 + s.D0 and a line-segment with endpoints P1 and P1+D1.
145 // Here: 197 // Here:
146 // p0 = 2D vector << 198 // P0 = 2D vector
147 // s = scaler on [0,infinity) 199 // s = scaler on [0,infinity)
148 // d0 = 2D vector << 200 // D0 = 2D vector
149 // p1 and d1 are 2D vectors << 201 // P1 and D1 are 2D vectors
150 // 202 //
151 // This function returns: 203 // This function returns:
152 // 0 - if there is no intersection; 204 // 0 - if there is no intersection;
153 // 1 - if there is a unique intersection; 205 // 1 - if there is a unique intersection;
154 // 2 - if the line and line-segments overlap, 206 // 2 - if the line and line-segments overlap, and the intersection is a
155 // segment itself. 207 // segment itself.
156 // Information about where the intersection oc 208 // Information about where the intersection occurs is returned in the
157 // as ??. 209 // as ??.
158 // 210 //
159 // This is based on the work of Rickard Holmbe 211 // This is based on the work of Rickard Holmberg as well as material published
160 // by Philip J Schneider and David H Eberly, " 212 // by Philip J Schneider and David H Eberly, "Geometric Tools for Computer
161 // Graphics," ISBN 1-55860-694-0, pp 244-245, 213 // Graphics," ISBN 1-55860-694-0, pp 244-245, 2003.
162 // 214 //
163 G4int G4TessellatedGeometryAlgorithms::Interse 215 G4int G4TessellatedGeometryAlgorithms::IntersectLineAndLineSegment2D (
164 const G4TwoVector& p0, const G4TwoVector& d0 << 216 const G4TwoVector P0, const G4TwoVector D0,
165 const G4TwoVector& p1, const G4TwoVector& d1 << 217 const G4TwoVector P1, const G4TwoVector D1,
>> 218 G4TwoVector location[2])
166 { 219 {
167 G4TwoVector e = p1 - p0; << 220 G4TwoVector E = P1 - P0;
168 G4double kross = cross(d0,d1); << 221 G4double kross = cross(D0,D1);
169 G4double sqrKross = kross * kross; 222 G4double sqrKross = kross * kross;
170 G4double sqrLen0 = d0.mag2(); << 223 G4double sqrLen0 = D0.mag2();
171 G4double sqrLen1 = d1.mag2(); << 224 G4double sqrLen1 = D1.mag2();
172 location[0] = G4TwoVector(0.0,0.0); 225 location[0] = G4TwoVector(0.0,0.0);
173 location[1] = G4TwoVector(0.0,0.0); 226 location[1] = G4TwoVector(0.0,0.0);
174 227
175 if (sqrKross > DBL_EPSILON * DBL_EPSILON * s 228 if (sqrKross > DBL_EPSILON * DBL_EPSILON * sqrLen0 * sqrLen1)
176 { 229 {
177 // << 230 //
178 // The line and line segment are not paral << 231 //
179 // is in positive s where r=p0 + s*d0, and << 232 // The line and line segment are not parallel. Determine if the intersection
180 // << 233 // is in positive s where r = P0 + s*D0, and for 0<=t<=1 where r = p1 + t*D1.
181 G4double ss = cross(e,d1)/kross; << 234 //
182 if (ss < 0) return 0; // Intersect << 235 G4double s = cross(E,D1)/kross;
183 G4double t = cross(e,d0)/kross; << 236 if (s < 0) return 0; // Intersection does not occur for positive s.
184 if (t < 0 || t > 1) return 0; // Intersect << 237 G4double t = cross(E,D0)/kross;
185 // << 238 if (t < 0 || t > 1) return 0; // Intersection does not occur on line-segment.
186 // Intersection of lines is a single point << 239 //
187 // defined by r=p0 + ss*d0, and the line s << 240 //
188 // << 241 // Intersection of lines is a single point on the forward-propagating line
189 location[0] = p0 + ss*d0; << 242 // defined by r = P0 + s*D0, and the line segment defined by r = p1 + t*D1.
>> 243 //
>> 244 location[0] = P0 + s*D0;
190 return 1; 245 return 1;
191 } 246 }
192 // << 247 //
193 // Line and line segment are parallel. Deter << 248 //
194 // << 249 // Line and line segment are parallel. Determine whether they overlap or not.
195 G4double sqrLenE = e.mag2(); << 250 //
196 kross = cross(e,d0); << 251 G4double sqrLenE = E.mag2();
>> 252 kross = cross(E,D0);
197 sqrKross = kross * kross; 253 sqrKross = kross * kross;
198 if (sqrKross > DBL_EPSILON * DBL_EPSILON * s 254 if (sqrKross > DBL_EPSILON * DBL_EPSILON * sqrLen0 * sqrLenE)
199 { 255 {
200 return 0; //Lines are different. 256 return 0; //Lines are different.
201 } 257 }
202 // << 258 //
203 // Lines are the same. Test for overlap. << 259 //
204 // << 260 // Lines are the same. Test for overlap.
205 G4double s0 = d0.dot(e)/sqrLen0; << 261 //
206 G4double s1 = s0 + d0.dot(d1)/sqrLen0; << 262 G4double s0 = D0.dot(E)/sqrLen0;
>> 263 G4double s1 = s0 + D0.dot(D1)/sqrLen0;
207 G4double smin = 0.0; 264 G4double smin = 0.0;
208 G4double smax = 0.0; 265 G4double smax = 0.0;
209 266
210 if (s0 < s1) {smin = s0; smax = s1;} 267 if (s0 < s1) {smin = s0; smax = s1;}
211 else {smin = s1; smax = s0;} 268 else {smin = s1; smax = s0;}
212 269
213 if (smax < 0.0) return 0; 270 if (smax < 0.0) return 0;
214 else if (smin < 0.0) 271 else if (smin < 0.0)
215 { 272 {
216 location[0] = p0; << 273 location[0] = P0;
217 location[1] = p0 + smax*d0; << 274 location[1] = P0 + smax*D0;
218 return 2; 275 return 2;
219 } 276 }
220 else 277 else
221 { 278 {
222 location[0] = p0 + smin*d0; << 279 location[0] = P0 + smin*D0;
223 location[1] = p0 + smax*d0; << 280 location[1] = P0 + smax*D0;
224 return 2; 281 return 2;
225 } 282 }
226 } <<
227 <<
228 ////////////////////////////////////////////// <<
229 // <<
230 // CrossProduct <<
231 // <<
232 // This is just a ficticious "cross-product" f <<
233 // "ficticious" because such an operation is n <<
234 // with 3D space. <<
235 // <<
236 G4double G4TessellatedGeometryAlgorithms::cros <<
237 <<
238 { <<
239 return v1.x()*v2.y() - v1.y()*v2.x(); <<
240 } 283 }
241 284