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26 //
27 // G4QuadrangularFacet class implementation.
28 //
29 // 31 October 2004 P R Truscott, QinetiQ Ltd, UK - Created.
30 // 12 October 2012 M Gayer, CERN
31 // New implementation reducing memory requirements by 50%,
32 // and considerable CPU speedup together with the new
33 // implementation of G4TessellatedSolid.
34 // 29 February 2016 E Tcherniaev, CERN
35 // Added exhaustive tests to catch various problems with a
36 // quadrangular facet: collinear vertices, non planar surface,
37 // degenerate, concave or self intersecting quadrilateral.
38 // --------------------------------------------------------------------
39
40 #include "G4QuadrangularFacet.hh"
41 #include "geomdefs.hh"
42 #include "Randomize.hh"
43
44 using namespace std;
45
46 ///////////////////////////////////////////////////////////////////////////////
47 //
48 // Constructing two adjacent G4TriangularFacet
49 // Not efficient, but practical...
50 //
51 G4QuadrangularFacet::G4QuadrangularFacet (const G4ThreeVector& vt0,
52 const G4ThreeVector& vt1,
53 const G4ThreeVector& vt2,
54 const G4ThreeVector& vt3,
55 G4FacetVertexType vertexType)
56 {
57 G4double delta = 1.0 * kCarTolerance; // dimension tolerance
58 G4double epsilon = 0.01 * kCarTolerance; // planarity tolerance
59
60 G4ThreeVector e1, e2, e3;
61 SetVertex(0, vt0);
62 if (vertexType == ABSOLUTE)
63 {
64 SetVertex(1, vt1);
65 SetVertex(2, vt2);
66 SetVertex(3, vt3);
67
68 e1 = vt1 - vt0;
69 e2 = vt2 - vt0;
70 e3 = vt3 - vt0;
71 }
72 else
73 {
74 SetVertex(1, vt0 + vt1);
75 SetVertex(2, vt0 + vt2);
76 SetVertex(3, vt0 + vt3);
77
78 e1 = vt1;
79 e2 = vt2;
80 e3 = vt3;
81 }
82
83 // Check length of sides and diagonals
84 //
85 G4double leng1 = e1.mag();
86 G4double leng2 = (e2-e1).mag();
87 G4double leng3 = (e3-e2).mag();
88 G4double leng4 = e3.mag();
89
90 G4double diag1 = e2.mag();
91 G4double diag2 = (e3-e1).mag();
92
93 if (leng1 <= delta || leng2 <= delta || leng3 <= delta || leng4 <= delta ||
94 diag1 <= delta || diag2 <= delta)
95 {
96 ostringstream message;
97 message << "Sides/diagonals of facet are too small." << G4endl
98 << "P0 = " << GetVertex(0) << G4endl
99 << "P1 = " << GetVertex(1) << G4endl
100 << "P2 = " << GetVertex(2) << G4endl
101 << "P3 = " << GetVertex(3) << G4endl
102 << "Side1 length (P0->P1) = " << leng1 << G4endl
103 << "Side2 length (P1->P2) = " << leng2 << G4endl
104 << "Side3 length (P2->P3) = " << leng3 << G4endl
105 << "Side4 length (P3->P0) = " << leng4 << G4endl
106 << "Diagonal1 length (P0->P2) = " << diag1 << G4endl
107 << "Diagonal2 length (P1->P3) = " << diag2;
108 G4Exception("G4QuadrangularFacet::G4QuadrangularFacet()",
109 "GeomSolids1001", JustWarning, message);
110 return;
111 }
112
113 // Check that vertices are not collinear
114 //
115 G4double s1 = (e1.cross(e2)).mag()*0.5;
116 G4double s2 = ((e2-e1).cross(e3-e2)).mag()*0.5;
117 G4double s3 = (e2.cross(e3)).mag()*0.5;
118 G4double s4 = (e1.cross(e3)).mag()*0.5;
119
120 G4double h1 = 2.*s1 / std::max(std::max(leng1,leng2),diag1);
121 G4double h2 = 2.*s2 / std::max(std::max(leng2,leng3),diag2);
122 G4double h3 = 2.*s3 / std::max(std::max(leng3,leng4),diag1);
123 G4double h4 = 2.*s4 / std::max(std::max(leng4,leng1),diag2);
124
125 if (h1 <= delta || h2 <= delta || h3 <= delta || h4 <= delta )
126 {
127 ostringstream message;
128 message << "Facet has three or more collinear vertices." << G4endl
129 << "P0 = " << GetVertex(0) << G4endl
130 << "P1 = " << GetVertex(1) << G4endl
131 << "P2 = " << GetVertex(2) << G4endl
132 << "P3 = " << GetVertex(3) << G4endl
133 << "Smallest heights:" << G4endl
134 << " in triangle P0-P1-P2 = " << h1 << G4endl
135 << " in triangle P1-P2-P3 = " << h2 << G4endl
136 << " in triangle P2-P3-P0 = " << h3 << G4endl
137 << " in triangle P3-P0-P1 = " << h4;
138 G4Exception("G4QuadrangularFacet::G4QuadrangularFacet()",
139 "GeomSolids1001", JustWarning, message);
140 return;
141 }
142
143 // Check that vertices are coplanar by computing minimal
144 // height of tetrahedron comprising of vertices
145 //
146 G4double smax = std::max( std::max(s1,s2), std::max(s3,s4) );
147 G4double hmin = 0.5 * std::fabs( e1.dot(e2.cross(e3)) ) / smax;
148 if (hmin >= epsilon)
149 {
150 ostringstream message;
151 message << "Facet is not planar." << G4endl
152 << "Disrepancy = " << hmin << G4endl
153 << "P0 = " << GetVertex(0) << G4endl
154 << "P1 = " << GetVertex(1) << G4endl
155 << "P2 = " << GetVertex(2) << G4endl
156 << "P3 = " << GetVertex(3);
157 G4Exception("G4QuadrangularFacet::G4QuadrangularFacet()",
158 "GeomSolids1001", JustWarning, message);
159 return;
160 }
161
162 // Check that facet is convex by computing crosspoint
163 // of diagonals
164 //
165 G4ThreeVector normal = e2.cross(e3-e1);
166 G4double s = kInfinity, t = kInfinity, magnitude2 = normal.mag2();
167 if (magnitude2 > delta*delta) // check: magnitude2 != 0.
168 {
169 s = normal.dot(e1.cross(e3-e1)) / magnitude2;
170 t = normal.dot(e1.cross(e2)) / magnitude2;
171 }
172 if (s <= 0. || s >= 1. || t <= 0. || t >= 1.)
173 {
174 ostringstream message;
175 message << "Facet is not convex." << G4endl
176 << "Parameters of crosspoint of diagonals: "
177 << s << " and " << t << G4endl
178 << "should both be within (0,1) range" << G4endl
179 << "P0 = " << GetVertex(0) << G4endl
180 << "P1 = " << GetVertex(1) << G4endl
181 << "P2 = " << GetVertex(2) << G4endl
182 << "P3 = " << GetVertex(3);
183 G4Exception("G4QuadrangularFacet::G4QuadrangularFacet()",
184 "GeomSolids1001", JustWarning, message);
185 return;
186 }
187
188 // Define facet
189 //
190 fFacet1 = G4TriangularFacet(GetVertex(0),GetVertex(1),GetVertex(2),ABSOLUTE);
191 fFacet2 = G4TriangularFacet(GetVertex(0),GetVertex(2),GetVertex(3),ABSOLUTE);
192
193 normal = normal.unit();
194 fFacet1.SetSurfaceNormal(normal);
195 fFacet2.SetSurfaceNormal(normal);
196
197 G4ThreeVector vtmp = 0.5 * (e1 + e2);
198 fCircumcentre = GetVertex(0) + vtmp;
199 G4double radiusSqr = vtmp.mag2();
200 fRadius = std::sqrt(radiusSqr);
201 // 29.02.2016 Remark by E.Tcherniaev: computation
202 // of fCircumcenter and fRadius is wrong, however
203 // it did not create any problem till now.
204 // Bizarre! Need to investigate!
205 }
206
207 ///////////////////////////////////////////////////////////////////////////////
208 //
209 G4QuadrangularFacet::~G4QuadrangularFacet () = default;
210
211 ///////////////////////////////////////////////////////////////////////////////
212 //
213 G4QuadrangularFacet::G4QuadrangularFacet (const G4QuadrangularFacet& rhs)
214 : G4VFacet(rhs)
215 {
216 fFacet1 = rhs.fFacet1;
217 fFacet2 = rhs.fFacet2;
218 fRadius = 0.0;
219 }
220
221 ///////////////////////////////////////////////////////////////////////////////
222 //
223 G4QuadrangularFacet &
224 G4QuadrangularFacet::operator=(const G4QuadrangularFacet& rhs)
225 {
226 if (this == &rhs) return *this;
227
228 fFacet1 = rhs.fFacet1;
229 fFacet2 = rhs.fFacet2;
230 fRadius = 0.0;
231
232 return *this;
233 }
234
235 ///////////////////////////////////////////////////////////////////////////////
236 //
237 G4VFacet* G4QuadrangularFacet::GetClone ()
238 {
239 auto c = new G4QuadrangularFacet (GetVertex(0), GetVertex(1),
240 GetVertex(2), GetVertex(3), ABSOLUTE);
241 return c;
242 }
243
244 ///////////////////////////////////////////////////////////////////////////////
245 //
246 G4ThreeVector G4QuadrangularFacet::Distance (const G4ThreeVector& p)
247 {
248 G4ThreeVector v1 = fFacet1.Distance(p);
249 G4ThreeVector v2 = fFacet2.Distance(p);
250
251 if (v1.mag2() < v2.mag2()) return v1;
252 else return v2;
253 }
254
255 ///////////////////////////////////////////////////////////////////////////////
256 //
257 G4double G4QuadrangularFacet::Distance (const G4ThreeVector& p,
258 G4double)
259 {
260 G4double dist = Distance(p).mag();
261 return dist;
262 }
263
264 ///////////////////////////////////////////////////////////////////////////////
265 //
266 G4double G4QuadrangularFacet::Distance (const G4ThreeVector& p, G4double,
267 const G4bool outgoing)
268 {
269 G4double dist;
270
271 G4ThreeVector v = Distance(p);
272 G4double dir = v.dot(GetSurfaceNormal());
273 if ( ((dir > dirTolerance) && (!outgoing))
274 || ((dir < -dirTolerance) && outgoing))
275 dist = kInfinity;
276 else
277 dist = v.mag();
278 return dist;
279 }
280
281 ///////////////////////////////////////////////////////////////////////////////
282 //
283 G4double G4QuadrangularFacet::Extent (const G4ThreeVector axis)
284 {
285 G4double ss = 0;
286
287 for (G4int i = 0; i <= 3; ++i)
288 {
289 G4double sp = GetVertex(i).dot(axis);
290 if (sp > ss) ss = sp;
291 }
292 return ss;
293 }
294
295 ///////////////////////////////////////////////////////////////////////////////
296 //
297 G4bool G4QuadrangularFacet::Intersect (const G4ThreeVector& p,
298 const G4ThreeVector& v,
299 G4bool outgoing,
300 G4double& distance,
301 G4double& distFromSurface,
302 G4ThreeVector& normal)
303 {
304 G4bool intersect =
305 fFacet1.Intersect(p,v,outgoing,distance,distFromSurface,normal);
306 if (!intersect) intersect =
307 fFacet2.Intersect(p,v,outgoing,distance,distFromSurface,normal);
308 if (!intersect)
309 {
310 distance = distFromSurface = kInfinity;
311 normal.set(0,0,0);
312 }
313 return intersect;
314 }
315
316 ///////////////////////////////////////////////////////////////////////////////
317 //
318 // Auxiliary method to get a uniform random point on the facet
319 //
320 G4ThreeVector G4QuadrangularFacet::GetPointOnFace() const
321 {
322 G4double s1 = fFacet1.GetArea();
323 G4double s2 = fFacet2.GetArea();
324 return ((s1+s2)*G4UniformRand() < s1) ?
325 fFacet1.GetPointOnFace() : fFacet2.GetPointOnFace();
326 }
327
328 ///////////////////////////////////////////////////////////////////////////////
329 //
330 // Auxiliary method for returning the surface area
331 //
332 G4double G4QuadrangularFacet::GetArea() const
333 {
334 G4double area = fFacet1.GetArea() + fFacet2.GetArea();
335 return area;
336 }
337
338 ///////////////////////////////////////////////////////////////////////////////
339 //
340 G4String G4QuadrangularFacet::GetEntityType () const
341 {
342 return "G4QuadrangularFacet";
343 }
344
345 ///////////////////////////////////////////////////////////////////////////////
346 //
347 G4ThreeVector G4QuadrangularFacet::GetSurfaceNormal () const
348 {
349 return fFacet1.GetSurfaceNormal();
350 }
351