| Geant4 Cross Reference |
1 // 1 //
2 // ******************************************* 2 // ********************************************************************
3 // * License and Disclaimer 3 // * License and Disclaimer *
4 // * 4 // * *
5 // * The Geant4 software is copyright of th 5 // * The Geant4 software is copyright of the Copyright Holders of *
6 // * the Geant4 Collaboration. It is provided 6 // * the Geant4 Collaboration. It is provided under the terms and *
7 // * conditions of the Geant4 Software License 7 // * conditions of the Geant4 Software License, included in the file *
8 // * LICENSE and available at http://cern.ch/ 8 // * LICENSE and available at http://cern.ch/geant4/license . These *
9 // * include a list of copyright holders. 9 // * include a list of copyright holders. *
10 // * 10 // * *
11 // * Neither the authors of this software syst 11 // * Neither the authors of this software system, nor their employing *
12 // * institutes,nor the agencies providing fin 12 // * institutes,nor the agencies providing financial support for this *
13 // * work make any representation or warran 13 // * work make any representation or warranty, express or implied, *
14 // * regarding this software system or assum 14 // * regarding this software system or assume any liability for its *
15 // * use. Please see the license in the file 15 // * use. Please see the license in the file LICENSE and URL above *
16 // * for the full disclaimer and the limitatio 16 // * for the full disclaimer and the limitation of liability. *
17 // * 17 // * *
18 // * This code implementation is the result 18 // * This code implementation is the result of the scientific and *
19 // * technical work of the GEANT4 collaboratio 19 // * technical work of the GEANT4 collaboration and of QinetiQ Ltd, *
20 // * subject to DEFCON 705 IPR conditions. 20 // * subject to DEFCON 705 IPR conditions. *
21 // * By using, copying, modifying or distri 21 // * By using, copying, modifying or distributing the software (or *
22 // * any work based on the software) you ag 22 // * any work based on the software) you agree to acknowledge its *
23 // * use in resulting scientific publicati 23 // * use in resulting scientific publications, and indicate your *
24 // * acceptance of all terms of the Geant4 Sof 24 // * acceptance of all terms of the Geant4 Software license. *
25 // ******************************************* 25 // ********************************************************************
26 // 26 //
27 // G4TessellatedGeometryAlgorithms implementat 27 // G4TessellatedGeometryAlgorithms implementation
28 // 28 //
29 // 07 August 2007, P R Truscott, QinetiQ Ltd, 29 // 07 August 2007, P R Truscott, QinetiQ Ltd, UK - Created, with member
30 // functions based on the work 30 // functions based on the work of Rickard Holmberg.
31 // 12 October 2012, M Gayer, CERN, - Reviewed 31 // 12 October 2012, M Gayer, CERN, - Reviewed optimized implementation.
32 // ------------------------------------------- 32 // --------------------------------------------------------------------
33 33
34 #include "G4TessellatedGeometryAlgorithms.hh" 34 #include "G4TessellatedGeometryAlgorithms.hh"
35 35
36 #include <cfloat> 36 #include <cfloat>
37 37
38 ////////////////////////////////////////////// 38 ///////////////////////////////////////////////////////////////////////////////
39 // 39 //
40 // IntersectLineAndTriangle2D 40 // IntersectLineAndTriangle2D
41 // 41 //
42 // Determines whether there is an intersection 42 // Determines whether there is an intersection between a line defined
43 // by r = p + s.v and a triangle defined by ve 43 // by r = p + s.v and a triangle defined by verticies p0, p0+e0 and p0+e1.
44 // 44 //
45 // Here: 45 // Here:
46 // p = 2D vector 46 // p = 2D vector
47 // s = scaler on [0,infinity) 47 // s = scaler on [0,infinity)
48 // v = 2D vector 48 // v = 2D vector
49 // p0, e0 and e1 are 2D vectors 49 // p0, e0 and e1 are 2D vectors
50 // Information about where the intersection oc 50 // Information about where the intersection occurs is returned in the
51 // variable location. 51 // variable location.
52 // 52 //
53 // This is based on the work of Rickard Holmbe 53 // This is based on the work of Rickard Holmberg.
54 // 54 //
55 G4bool G4TessellatedGeometryAlgorithms::Inters 55 G4bool G4TessellatedGeometryAlgorithms::IntersectLineAndTriangle2D (
56 const G4TwoVector& p, const G4TwoVector& v, 56 const G4TwoVector& p, const G4TwoVector& v,
57 const G4TwoVector& p0, const G4TwoVector& e0 57 const G4TwoVector& p0, const G4TwoVector& e0, const G4TwoVector& e1,
58 G4TwoVector location[2]) 58 G4TwoVector location[2])
59 { 59 {
60 G4TwoVector loc0[2]; 60 G4TwoVector loc0[2];
61 G4int e0i = IntersectLineAndLineSegment2D (p 61 G4int e0i = IntersectLineAndLineSegment2D (p,v,p0,e0,loc0);
62 if (e0i == 2) 62 if (e0i == 2)
63 { 63 {
64 location[0] = loc0[0]; 64 location[0] = loc0[0];
65 location[1] = loc0[1]; 65 location[1] = loc0[1];
66 return true; 66 return true;
67 } 67 }
68 68
69 G4TwoVector loc1[2]; 69 G4TwoVector loc1[2];
70 G4int e1i = IntersectLineAndLineSegment2D (p 70 G4int e1i = IntersectLineAndLineSegment2D (p,v,p0,e1,loc1);
71 if (e1i == 2) 71 if (e1i == 2)
72 { 72 {
73 location[0] = loc1[0]; 73 location[0] = loc1[0];
74 location[1] = loc1[1]; 74 location[1] = loc1[1];
75 return true; 75 return true;
76 } 76 }
77 77
78 if ((e0i == 1) && (e1i == 1)) 78 if ((e0i == 1) && (e1i == 1))
79 { 79 {
80 if ((loc0[0]-p).mag2() < (loc1[0]-p).mag2( 80 if ((loc0[0]-p).mag2() < (loc1[0]-p).mag2())
81 { 81 {
82 location[0] = loc0[0]; 82 location[0] = loc0[0];
83 location[1] = loc1[0]; 83 location[1] = loc1[0];
84 } 84 }
85 else 85 else
86 { 86 {
87 location[0] = loc1[0]; 87 location[0] = loc1[0];
88 location[1] = loc0[0]; 88 location[1] = loc0[0];
89 } 89 }
90 return true; 90 return true;
91 } 91 }
92 92
93 G4TwoVector p1 = p0 + e0; 93 G4TwoVector p1 = p0 + e0;
94 G4TwoVector DE = e1 - e0; 94 G4TwoVector DE = e1 - e0;
95 G4TwoVector loc2[2]; 95 G4TwoVector loc2[2];
96 G4int e2i = IntersectLineAndLineSegment2D (p 96 G4int e2i = IntersectLineAndLineSegment2D (p,v,p1,DE,loc2);
97 if (e2i == 2) 97 if (e2i == 2)
98 { 98 {
99 location[0] = loc2[0]; 99 location[0] = loc2[0];
100 location[1] = loc2[1]; 100 location[1] = loc2[1];
101 return true; 101 return true;
102 } 102 }
103 103
104 if ((e0i == 0) && (e1i == 0) && (e2i == 0)) 104 if ((e0i == 0) && (e1i == 0) && (e2i == 0)) return false;
105 105
106 if ((e0i == 1) && (e2i == 1)) 106 if ((e0i == 1) && (e2i == 1))
107 { 107 {
108 if ((loc0[0]-p).mag2() < (loc2[0]-p).mag2( 108 if ((loc0[0]-p).mag2() < (loc2[0]-p).mag2())
109 { 109 {
110 location[0] = loc0[0]; 110 location[0] = loc0[0];
111 location[1] = loc2[0]; 111 location[1] = loc2[0];
112 } 112 }
113 else 113 else
114 { 114 {
115 location[0] = loc2[0]; 115 location[0] = loc2[0];
116 location[1] = loc0[0]; 116 location[1] = loc0[0];
117 } 117 }
118 return true; 118 return true;
119 } 119 }
120 120
121 if ((e1i == 1) && (e2i == 1)) 121 if ((e1i == 1) && (e2i == 1))
122 { 122 {
123 if ((loc1[0]-p).mag2() < (loc2[0]-p).mag2( 123 if ((loc1[0]-p).mag2() < (loc2[0]-p).mag2())
124 { 124 {
125 location[0] = loc1[0]; 125 location[0] = loc1[0];
126 location[1] = loc2[0]; 126 location[1] = loc2[0];
127 } 127 }
128 else 128 else
129 { 129 {
130 location[0] = loc2[0]; 130 location[0] = loc2[0];
131 location[1] = loc1[0]; 131 location[1] = loc1[0];
132 } 132 }
133 return true; 133 return true;
134 } 134 }
135 135
136 return false; 136 return false;
137 } 137 }
138 138
139 ////////////////////////////////////////////// 139 ///////////////////////////////////////////////////////////////////////////////
140 // 140 //
141 // IntersectLineAndLineSegment2D 141 // IntersectLineAndLineSegment2D
142 // 142 //
143 // Determines whether there is an intersection 143 // Determines whether there is an intersection between a line defined
144 // by r = p0 + s.d0 and a line-segment with en 144 // by r = p0 + s.d0 and a line-segment with endpoints p1 and p1+d1.
145 // Here: 145 // Here:
146 // p0 = 2D vector 146 // p0 = 2D vector
147 // s = scaler on [0,infinity) 147 // s = scaler on [0,infinity)
148 // d0 = 2D vector 148 // d0 = 2D vector
149 // p1 and d1 are 2D vectors 149 // p1 and d1 are 2D vectors
150 // 150 //
151 // This function returns: 151 // This function returns:
152 // 0 - if there is no intersection; 152 // 0 - if there is no intersection;
153 // 1 - if there is a unique intersection; 153 // 1 - if there is a unique intersection;
154 // 2 - if the line and line-segments overlap, 154 // 2 - if the line and line-segments overlap, and the intersection is a
155 // segment itself. 155 // segment itself.
156 // Information about where the intersection oc 156 // Information about where the intersection occurs is returned in the
157 // as ??. 157 // as ??.
158 // 158 //
159 // This is based on the work of Rickard Holmbe 159 // This is based on the work of Rickard Holmberg as well as material published
160 // by Philip J Schneider and David H Eberly, " 160 // by Philip J Schneider and David H Eberly, "Geometric Tools for Computer
161 // Graphics," ISBN 1-55860-694-0, pp 244-245, 161 // Graphics," ISBN 1-55860-694-0, pp 244-245, 2003.
162 // 162 //
163 G4int G4TessellatedGeometryAlgorithms::Interse 163 G4int G4TessellatedGeometryAlgorithms::IntersectLineAndLineSegment2D (
164 const G4TwoVector& p0, const G4TwoVector& d0 164 const G4TwoVector& p0, const G4TwoVector& d0,
165 const G4TwoVector& p1, const G4TwoVector& d1 165 const G4TwoVector& p1, const G4TwoVector& d1, G4TwoVector location[2])
166 { 166 {
167 G4TwoVector e = p1 - p0; 167 G4TwoVector e = p1 - p0;
168 G4double kross = cross(d0,d1); 168 G4double kross = cross(d0,d1);
169 G4double sqrKross = kross * kross; 169 G4double sqrKross = kross * kross;
170 G4double sqrLen0 = d0.mag2(); 170 G4double sqrLen0 = d0.mag2();
171 G4double sqrLen1 = d1.mag2(); 171 G4double sqrLen1 = d1.mag2();
172 location[0] = G4TwoVector(0.0,0.0); 172 location[0] = G4TwoVector(0.0,0.0);
173 location[1] = G4TwoVector(0.0,0.0); 173 location[1] = G4TwoVector(0.0,0.0);
174 174
175 if (sqrKross > DBL_EPSILON * DBL_EPSILON * s 175 if (sqrKross > DBL_EPSILON * DBL_EPSILON * sqrLen0 * sqrLen1)
176 { 176 {
177 // 177 //
178 // The line and line segment are not paral 178 // The line and line segment are not parallel. Determine if the intersection
179 // is in positive s where r=p0 + s*d0, and 179 // is in positive s where r=p0 + s*d0, and for 0<=t<=1 where r=p1 + t*d1.
180 // 180 //
181 G4double ss = cross(e,d1)/kross; 181 G4double ss = cross(e,d1)/kross;
182 if (ss < 0) return 0; // Intersect 182 if (ss < 0) return 0; // Intersection does not occur for positive ss
183 G4double t = cross(e,d0)/kross; 183 G4double t = cross(e,d0)/kross;
184 if (t < 0 || t > 1) return 0; // Intersect 184 if (t < 0 || t > 1) return 0; // Intersection does not occur on line-segment
185 // 185 //
186 // Intersection of lines is a single point 186 // Intersection of lines is a single point on the forward-propagating line
187 // defined by r=p0 + ss*d0, and the line s 187 // defined by r=p0 + ss*d0, and the line segment defined by r=p1 + t*d1.
188 // 188 //
189 location[0] = p0 + ss*d0; 189 location[0] = p0 + ss*d0;
190 return 1; 190 return 1;
191 } 191 }
192 // 192 //
193 // Line and line segment are parallel. Deter 193 // Line and line segment are parallel. Determine whether they overlap or not.
194 // 194 //
195 G4double sqrLenE = e.mag2(); 195 G4double sqrLenE = e.mag2();
196 kross = cross(e,d0); 196 kross = cross(e,d0);
197 sqrKross = kross * kross; 197 sqrKross = kross * kross;
198 if (sqrKross > DBL_EPSILON * DBL_EPSILON * s 198 if (sqrKross > DBL_EPSILON * DBL_EPSILON * sqrLen0 * sqrLenE)
199 { 199 {
200 return 0; //Lines are different. 200 return 0; //Lines are different.
201 } 201 }
202 // 202 //
203 // Lines are the same. Test for overlap. 203 // Lines are the same. Test for overlap.
204 // 204 //
205 G4double s0 = d0.dot(e)/sqrLen0; 205 G4double s0 = d0.dot(e)/sqrLen0;
206 G4double s1 = s0 + d0.dot(d1)/sqrLen0; 206 G4double s1 = s0 + d0.dot(d1)/sqrLen0;
207 G4double smin = 0.0; 207 G4double smin = 0.0;
208 G4double smax = 0.0; 208 G4double smax = 0.0;
209 209
210 if (s0 < s1) {smin = s0; smax = s1;} 210 if (s0 < s1) {smin = s0; smax = s1;}
211 else {smin = s1; smax = s0;} 211 else {smin = s1; smax = s0;}
212 212
213 if (smax < 0.0) return 0; 213 if (smax < 0.0) return 0;
214 else if (smin < 0.0) 214 else if (smin < 0.0)
215 { 215 {
216 location[0] = p0; 216 location[0] = p0;
217 location[1] = p0 + smax*d0; 217 location[1] = p0 + smax*d0;
218 return 2; 218 return 2;
219 } 219 }
220 else 220 else
221 { 221 {
222 location[0] = p0 + smin*d0; 222 location[0] = p0 + smin*d0;
223 location[1] = p0 + smax*d0; 223 location[1] = p0 + smax*d0;
224 return 2; 224 return 2;
225 } 225 }
226 } 226 }
227 227
228 ////////////////////////////////////////////// 228 ///////////////////////////////////////////////////////////////////////////////
229 // 229 //
230 // CrossProduct 230 // CrossProduct
231 // 231 //
232 // This is just a ficticious "cross-product" f 232 // This is just a ficticious "cross-product" function for two 2D vectors...
233 // "ficticious" because such an operation is n 233 // "ficticious" because such an operation is not relevant to 2D space compared
234 // with 3D space. 234 // with 3D space.
235 // 235 //
236 G4double G4TessellatedGeometryAlgorithms::cros 236 G4double G4TessellatedGeometryAlgorithms::cross(const G4TwoVector& v1,
237 237 const G4TwoVector& v2)
238 { 238 {
239 return v1.x()*v2.y() - v1.y()*v2.x(); 239 return v1.x()*v2.y() - v1.y()*v2.x();
240 } 240 }
241 241