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[modules/shaper.git] / src / GeomAlgoAPI / GeomAlgoAPI_SketchBuilder.cpp
1 // File:        GeomAlgoAPI_SketchBuilder.cpp
2 // Created:     02 Jun 2014
3 // Author:      Artem ZHIDKOV
4
5 #include <GeomAlgoAPI_SketchBuilder.h>
6
7 #include <set>
8
9 #include <gp_Dir.hxx>
10 #include <gp_Pln.hxx>
11
12 #include <BOPAlgo_Builder.hxx>
13 #include <BOPAlgo_Operation.hxx>
14 #include <BOPAlgo_PaveFiller.hxx>
15 #include <BOPTools.hxx>
16 #include <BRep_Builder.hxx>
17 #include <BRep_Curve3D.hxx>
18 #include <BRep_TEdge.hxx>
19 #include <BRep_TVertex.hxx>
20 #include <BRepAlgoAPI_Cut.hxx>
21 #include <BRepBuilderAPI_MakeFace.hxx>
22 #include <BRepClass_FaceClassifier.hxx>
23 #include <Geom_Curve.hxx>
24 #include <Geom_Plane.hxx>
25 #include <TopExp.hxx>
26 #include <TopExp_Explorer.hxx>
27 #include <TopoDS_Edge.hxx>
28 #include <TopoDS_Face.hxx>
29 #include <TopoDS_Vertex.hxx>
30 #include <TopoDS_Wire.hxx>
31
32 #include <Precision.hxx>
33
34 #ifndef DBL_MAX
35 #define DBL_MAX 1.7976931348623158e+308 
36 #endif
37
38
39 const double tolerance = Precision::Confusion();
40 // This value helps to find direction on the boundaries of curve.
41 // It is not significant for lines, but is used for circles to avoid 
42 // wrong directions of movement (when two edges are tangent on the certain vertex)
43 const double shift     = acos(1.0 - 2.0 * tolerance);
44
45 /// \brief Search first vertex - the vertex with lowest x coordinate, which is used in 2 edges at least
46 static const TopoDS_Shape& findStartVertex(
47           const BOPCol_IndexedDataMapOfShapeListOfShape& theMapVE,
48           const gp_Dir& theDirX, const gp_Dir& theDirY);
49
50 /// \brief Search the vertex on the sketch candidate to be the next one in the loop
51 static void findNextVertex(
52           const TopoDS_Shape&                            theStartVertex, 
53           const BOPCol_IndexedDataMapOfShapeListOfShape& theVertexEdgeMap,
54           const gp_Dir&                                  theStartDir,
55           const gp_Dir&                                  theNormal,
56                 TopoDS_Shape&                            theNextVertex,
57                 TopoDS_Shape&                            theNextEdge,
58                 gp_Dir&                                  theNextDir);
59
60 /// \brief Create planar face using the edges surrounding it
61 static void createFace(const TopoDS_Shape&                      theStartVertex,
62                        const std::list<TopoDS_Shape>::iterator& theStartEdge,
63                        const std::list<TopoDS_Shape>::iterator& theEndOfEdges,
64                        const gp_Pln&                            thePlane,
65                              TopoDS_Face&                       theResFace);
66
67 /// \bief Create planar wire
68 static void createWireList(const TopoDS_Shape&                      theStartVertex,
69                            const std::list<TopoDS_Shape>::iterator& theStartEdge,
70                            const std::list<TopoDS_Shape>::iterator& theEndOfEdges,
71                            const std::set<Handle(TopoDS_TShape)>&   theEdgesInLoops,
72                                  std::list<TopoDS_Wire>&            theResWires);
73
74 /// \brief Calculate outer tengency on the edge in specified vertex
75 static gp_Dir getOuterEdgeDirection(const TopoDS_Shape& theEdge,
76                                     const TopoDS_Shape& theVertex);
77
78 /// \brief Unnecessary edges will be removed from the map.
79 ///        Positions of iterator will be updated
80 static void removeWasteEdges(
81                 std::list<TopoDS_Shape>::iterator&  theStartVertex,
82                 std::list<TopoDS_Shape>::iterator&  theStartEdge,
83           const std::list<TopoDS_Shape>::iterator&  theEndOfVertexes,
84           const std::list<TopoDS_Shape>::iterator&  theEndOfEdges,
85           BOPCol_IndexedDataMapOfShapeListOfShape&  theMapVE);
86
87
88
89
90 void GeomAlgoAPI_SketchBuilder::createFaces(
91           const boost::shared_ptr<GeomAPI_Pnt>&                theOrigin,
92           const boost::shared_ptr<GeomAPI_Dir>&                theDirX,
93           const boost::shared_ptr<GeomAPI_Dir>&                theDirY,
94           const boost::shared_ptr<GeomAPI_Dir>&                theNorm,
95           const std::list< boost::shared_ptr<GeomAPI_Shape> >& theFeatures,
96                 std::list< boost::shared_ptr<GeomAPI_Shape> >& theResultFaces,
97                 std::list< boost::shared_ptr<GeomAPI_Shape> >& theResultWires)
98 {
99   if (theFeatures.empty())
100     return ;
101
102   // Create the list of edges with shared vertexes
103   BOPAlgo_Builder aBuilder;
104   BOPAlgo_PaveFiller aPF;
105   TopoDS_Shape aFeaturesCompound;
106
107   if (theFeatures.size() == 1)
108   { // If there is only one feature, BOPAlgo_Builder will decline to work. Need to process it anyway
109     aFeaturesCompound = theFeatures.front()->impl<TopoDS_Shape>();
110   }
111   else
112   {
113     std::list< boost::shared_ptr<GeomAPI_Shape> >::const_iterator anIt = theFeatures.begin();
114     for (; anIt != theFeatures.end(); anIt++)
115     {
116       boost::shared_ptr<GeomAPI_Shape> aPreview(*anIt);
117       aBuilder.AddArgument(aPreview->impl<TopoDS_Edge>());
118     }
119     aPF.SetArguments(aBuilder.Arguments());
120     aPF.Perform();
121     int aErr = aPF.ErrorStatus();
122     if (aErr) return ;
123     aBuilder.PerformWithFiller(aPF);
124     aErr = aBuilder.ErrorStatus();
125     if (aErr) return ;
126     aFeaturesCompound = aBuilder.Shape();
127   }
128
129   BOPCol_IndexedDataMapOfShapeListOfShape aMapVE; // map between vertexes and edges
130   BOPTools::MapShapesAndAncestors(aFeaturesCompound, TopAbs_VERTEX, TopAbs_EDGE, aMapVE);
131   if (aMapVE.IsEmpty()) // in case of not-initialized circle
132     return;
133
134   gp_Dir aDirX = theDirX->impl<gp_Dir>();
135   gp_Dir aDirY = theDirY->impl<gp_Dir>();
136   gp_Dir aNorm = theNorm->impl<gp_Dir>();
137
138   gp_Pln aPlane(theOrigin->impl<gp_Pnt>(), aNorm);
139
140   // Set of edges used in loops
141   std::set<Handle(TopoDS_TShape)> anEdgesInLoops;
142   // Lists for processed vertexes and edges
143   std::list<TopoDS_Shape> aProcVertexes;
144   std::list<TopoDS_Shape> aProcEdges;
145
146   // Search the start vertex
147   TopoDS_Shape aStartVertex = findStartVertex(aMapVE, aDirX, aDirY);
148   aProcVertexes.push_back(aStartVertex);
149
150   TopoDS_Shape aCurVertex = aStartVertex;
151   gp_Dir aCurDir = aDirY.Reversed();
152   gp_Dir aCurNorm = aNorm.Reversed();
153
154   // Go through the edges and find loops
155   TopoDS_Shape aNextVertex;
156   TopoDS_Shape aBindingEdge;
157   gp_Dir aNextDir;
158   while (aMapVE.Extent() > 0)
159   {
160     findNextVertex(aCurVertex, aMapVE, aCurDir, aCurNorm, aNextVertex, aBindingEdge, aNextDir);
161     aCurNorm = aNorm;
162
163     // Try to find next vertex in the list of already processed
164     std::list<TopoDS_Shape>::iterator          aVertIter = aProcVertexes.begin();
165     std::list<TopoDS_Shape>::iterator          anEdgeIter = aProcEdges.begin();
166     for ( ; aVertIter != aProcVertexes.end(); aVertIter++)
167     {
168       if (aVertIter->TShape() == aNextVertex.TShape())
169         break;
170       if (anEdgeIter != aProcEdges.end())
171         anEdgeIter++;
172     }
173
174     aProcVertexes.push_back(aNextVertex);
175     aProcEdges.push_back(aBindingEdge);
176
177     // The loop was found
178     if (aVertIter != aProcVertexes.end())
179     {
180       // If the binding edge is a full circle, then the list may be empty before addition. Need to update edge iterator
181       if (aProcEdges.size() == 1)
182         anEdgeIter = aProcEdges.begin();
183
184       if (aVertIter != aProcVertexes.begin())
185       {
186         // Check the orientation of the loop
187         gp_Dir aCN = getOuterEdgeDirection(*anEdgeIter, *aVertIter);
188         gp_Dir aCP = getOuterEdgeDirection(aProcEdges.back(), *aVertIter);
189         aCN.Reverse();
190         aCP.Reverse();
191         if (aCN.DotCross(aCP, aNorm) < -tolerance)
192         {
193           // The found loop has wrong orientation and may contain sub-loops.
194           // Need to check it onle again with another initial direction.
195           aCurVertex = *aVertIter;
196           do {
197             aProcVertexes.pop_back();
198             aProcEdges.pop_back();
199           } while (aCurVertex != aProcVertexes.back());
200           aCurDir = getOuterEdgeDirection(aProcEdges.back(), aCurVertex);
201           aCurNorm = aNorm.Reversed();
202           continue;
203         }
204       }
205
206       // When the orientation is correct or the edges looped through
207       // the first element, create new face and remove unnecessary edges.
208       TopoDS_Face aPatch;
209       createFace(*aVertIter, anEdgeIter, aProcEdges.end(), aPlane, aPatch);
210       if (!aPatch.IsNull())
211       {
212         boost::shared_ptr<GeomAPI_Shape> aFace(new GeomAPI_Shape);
213         aFace->setImpl(new TopoDS_Shape(aPatch));
214         theResultFaces.push_back(aFace);
215       }
216       // push the edges used in the loop to the map
217       std::list<TopoDS_Shape>::iterator anIter;
218       for (anIter = anEdgeIter; anIter != aProcEdges.end(); anIter++)
219         anEdgesInLoops.insert(anIter->TShape());
220       // remove unnecessary edges
221       std::list<TopoDS_Shape>::iterator aCopyVLoop = aVertIter;
222       std::list<TopoDS_Shape>::iterator aCopyELoop = anEdgeIter;
223       removeWasteEdges(aVertIter, anEdgeIter, aProcVertexes.end(), aProcEdges.end(), aMapVE);
224
225       // revert the list of remaining edges
226       std::list<TopoDS_Shape> aRemainVertexes;
227       for ( ; aVertIter != aProcVertexes.end(); aVertIter++)
228         aRemainVertexes.push_front(*aVertIter);
229       std::list<TopoDS_Shape> aRemainEdges;
230       for ( ; anEdgeIter != aProcEdges.end(); anEdgeIter++)
231         aRemainEdges.push_front(*anEdgeIter);
232       // remove edges and vertexes used in the loop and add remaining ones
233       aProcVertexes.erase(aCopyVLoop, aProcVertexes.end());
234       aProcVertexes.insert(aProcVertexes.end(), aRemainVertexes.begin(), aRemainVertexes.end());
235       aProcEdges.erase(aCopyELoop, aProcEdges.end());
236       aProcEdges.insert(aProcEdges.end(), aRemainEdges.begin(), aRemainEdges.end());
237
238       // Recalculate current vertex and current direction
239       if (!aProcVertexes.empty())
240       {
241         aNextVertex = aProcVertexes.back();
242         if (!aProcEdges.empty())
243           aNextDir = getOuterEdgeDirection(aProcEdges.back(), aNextVertex);
244         else aNextDir = aDirY;
245       }
246     }
247
248     // if next vertex connected only to alone edge, this is a part of wire (not a closed loop),
249     // we need to go back through the list of already checked edges to find a branching vertex
250     if (!aMapVE.IsEmpty() && aMapVE.Contains(aNextVertex) && 
251         aMapVE.FindFromKey(aNextVertex).Size() == 1)
252     {
253       std::list<TopoDS_Shape>::reverse_iterator aVRIter = aProcVertexes.rbegin();
254       std::list<TopoDS_Shape>::reverse_iterator aERIter = aProcEdges.rbegin();
255       for (++aERIter, ++aVRIter; aERIter != aProcEdges.rend(); aERIter++, aVRIter++)
256         if (aMapVE.FindFromKey(*aVRIter).Size() > 2)
257           break;
258       if (aERIter != aProcEdges.rend() || aMapVE.FindFromKey(*aVRIter).Size() == 1)
259       { // the branching vertex was found or current list of edges is a wire without branches
260         std::list<TopoDS_Shape>::iterator aEIter;
261         TopoDS_Shape aCurEdge;
262         if (aERIter != aProcEdges.rend())
263         {
264           aEIter = aERIter.base();
265           aCurEdge = *aERIter;
266         }
267         else
268           aEIter = aProcEdges.begin();
269         std::list<TopoDS_Wire> aTail;
270         createWireList(*aVRIter, aEIter, aProcEdges.end(), anEdgesInLoops, aTail);
271         std::list<TopoDS_Wire>::const_iterator aTailIter = aTail.begin();
272         for ( ; aTailIter != aTail.end(); aTailIter++)
273           if (!aTailIter->IsNull())
274           {
275             boost::shared_ptr<GeomAPI_Shape> aWire(new GeomAPI_Shape);
276             aWire->setImpl(new TopoDS_Shape(*aTailIter));
277             theResultWires.push_back(aWire);
278           }
279         std::list<TopoDS_Shape>::iterator aVIter = aVRIter.base();
280         std::list<TopoDS_Shape>::iterator aEItCopy = aEIter;
281         removeWasteEdges(--aVIter, aEItCopy, aProcVertexes.end(), aProcEdges.end(), aMapVE);
282
283         aProcEdges.erase(aEIter, aProcEdges.end());
284         aVIter = aVRIter.base();
285         aProcVertexes.erase(aVIter, aProcVertexes.end());
286
287         if (!aProcVertexes.empty())
288         {
289           aNextVertex = aProcVertexes.back();
290           if (!aCurEdge.IsNull())
291             aNextDir = getOuterEdgeDirection(aCurEdge, aNextVertex);
292         }
293       }
294       else
295       { // there is no branching vertex in the list of proceeded,
296         // so we should revert the list and go the opposite way
297         aProcVertexes.reverse();
298         aProcEdges.reverse();
299         aNextVertex = aProcVertexes.back();
300         aNextDir = getOuterEdgeDirection(aProcEdges.back(), aNextVertex);
301       }
302     }
303
304     // When all edges of current component of connectivity are processed,
305     // we should repeat procedure for finding initial vertex in the remaining
306     if (!aMapVE.IsEmpty() && !aMapVE.Contains(aNextVertex))
307     {
308       aProcVertexes.clear();
309       aProcEdges.clear();
310
311       TopoDS_Shape aStartEdge;
312       aStartVertex = findStartVertex(aMapVE, aDirX, aDirY);
313       aProcVertexes.push_back(aStartVertex);
314       aNextVertex = aStartVertex;
315       aNextDir = aDirY.Reversed();
316       aCurNorm = aNorm.Reversed();
317     }
318
319     aCurVertex = aNextVertex;
320     aCurDir = aNextDir;
321   }
322
323   if (theResultFaces.size() > 1)
324     fixIntersections(theResultFaces);
325 }
326
327 void GeomAlgoAPI_SketchBuilder::fixIntersections(
328           std::list< boost::shared_ptr<GeomAPI_Shape> >& theFaces)
329 {
330   BRepClass_FaceClassifier aClassifier;
331
332   std::list< boost::shared_ptr<GeomAPI_Shape> >::iterator anIter1 = theFaces.begin();
333   std::list< boost::shared_ptr<GeomAPI_Shape> >::iterator anIter2;
334   for ( ; anIter1 != theFaces.end(); anIter1++)
335   {
336     anIter2 = anIter1;
337     for (++anIter2; anIter2 != theFaces.end(); anIter2++)
338     {
339       const TopoDS_Face& aF1 = (*anIter1)->impl<TopoDS_Face>();
340       TopExp_Explorer aVert2((*anIter2)->impl<TopoDS_Shape>(), TopAbs_VERTEX);
341       for ( ; aVert2.More(); aVert2.Next())
342       {
343         Handle(BRep_TVertex) aV = Handle(BRep_TVertex)::DownCast(aVert2.Current().TShape());
344         aClassifier.Perform(aF1, aV->Pnt(), tolerance);
345         if (aClassifier.State() != TopAbs_IN)
346           break;
347       }
348       if (aVert2.More())
349       { // second shape is not inside first, change the shapes order and repeat comparision
350         const TopoDS_Face& aF2 = (*anIter2)->impl<TopoDS_Face>();
351         TopExp_Explorer aVert1((*anIter1)->impl<TopoDS_Shape>(), TopAbs_VERTEX);
352         for ( ; aVert1.More(); aVert1.Next())
353         {
354           Handle(BRep_TVertex) aV = Handle(BRep_TVertex)::DownCast(aVert1.Current().TShape());
355           aClassifier.Perform(aF2, aV->Pnt(), tolerance);
356           if (aClassifier.State() != TopAbs_IN)
357             break;
358         }
359         if (!aVert1.More())
360         { // first shape should be cut from the second
361           BRepAlgoAPI_Cut aCut((*anIter2)->impl<TopoDS_Shape>(),
362                                (*anIter1)->impl<TopoDS_Shape>());
363           (*anIter2)->setImpl(new TopoDS_Shape(aCut.Shape()));
364         }
365       }
366       else
367       { // second shape should be cut from the first
368         BRepAlgoAPI_Cut aCut((*anIter1)->impl<TopoDS_Shape>(),
369                              (*anIter2)->impl<TopoDS_Shape>());
370         (*anIter1)->setImpl(new TopoDS_Shape(aCut.Shape()));
371       }
372     }
373   }
374 }
375
376
377 // =================== Auxiliary functions ====================================
378 const TopoDS_Shape& findStartVertex(
379           const BOPCol_IndexedDataMapOfShapeListOfShape& theMapVE,
380           const gp_Dir& theDirX, const gp_Dir& theDirY)
381 {
382   int aStartVertexInd = 1;
383   double aMaxX = -DBL_MAX;
384   double aMaxY = -DBL_MAX;
385   int aNbVert = theMapVE.Extent();
386   for (int i = 1; i <= aNbVert; i++)
387   {
388     const TopoDS_Vertex& aV = (const TopoDS_Vertex&)theMapVE.FindKey(i);
389     const Handle(BRep_TVertex)& aVert = (const Handle(BRep_TVertex)&)aV.TShape();
390     const gp_Pnt& aVertPnt = aVert->Pnt();
391
392     double aX = aVertPnt.XYZ().Dot(theDirX.XYZ());
393     double aY = aVertPnt.XYZ().Dot(theDirY.XYZ());
394     if ((aX > aMaxX || (fabs(aX - aMaxX) < tolerance && aY > aMaxY)) && 
395         theMapVE.FindFromIndex(i).Extent() > 1)
396     {
397       aMaxX = aX;
398       aMaxY = aY;
399       aStartVertexInd = i;
400     }
401   }
402   return theMapVE.FindKey(aStartVertexInd);
403 }
404
405 void findNextVertex(
406           const TopoDS_Shape&                            theStartVertex,
407           const BOPCol_IndexedDataMapOfShapeListOfShape& theVertexEdgeMap,
408           const gp_Dir&                                  theStartDir,
409           const gp_Dir&                                  theNormal,
410                 TopoDS_Shape&                            theNextVertex,
411                 TopoDS_Shape&                            theNextEdge,
412                 gp_Dir&                                  theNextDir)
413 {
414   const BOPCol_ListOfShape& anEdgesList = theVertexEdgeMap.FindFromKey(theStartVertex);
415   BOPCol_ListOfShape::Iterator aEdIter(anEdgesList);
416   double aBestEdgeProj = DBL_MAX;
417   for ( ; aEdIter.More(); aEdIter.Next())
418   {
419     gp_Dir aTang = getOuterEdgeDirection(aEdIter.Value(), theStartVertex);
420     aTang.Reverse();
421
422     // The projection is normalized in segment (-1, 1),
423     // where (-1, 0] corresponds to the angles (pi/2, 0] between theStartDir and aTang
424     // and [0, 1) corresponds to the angles [0, -pi/2)
425     double aProj = (aTang.Dot(theStartDir) - 1.0) * 0.5;
426     if (fabs(fabs(aProj) - 1) < tolerance)
427       continue;
428     if (theStartDir.DotCross(aTang, theNormal) < tolerance)
429       aProj *= -1.0;
430
431     if (aProj < aBestEdgeProj)
432     {
433       aBestEdgeProj = aProj;
434       theNextEdge = aEdIter.Value();
435       TopExp_Explorer aVertExp(theNextEdge, TopAbs_VERTEX);
436       for ( ; aVertExp.More(); aVertExp.Next())
437         if (aVertExp.Current().TShape() != theStartVertex.TShape())
438         {
439           theNextVertex = aVertExp.Current();
440           theNextDir = getOuterEdgeDirection(aEdIter.Value(), theNextVertex);
441           break;
442         }
443       if (!aVertExp.More())
444       { // This edge is a full circle
445         TopoDS_Vertex aV1, aV2;
446         TopExp::Vertices(*(const TopoDS_Edge*)(&theNextEdge), aV1, aV2);
447         if (aV1.Orientation() == theStartVertex.Orientation())
448           theNextVertex = aV2;
449         else
450           theNextVertex = aV1;
451         theNextDir = getOuterEdgeDirection(aEdIter.Value(), theNextVertex);
452       }
453     }
454   }
455 }
456
457 static void addEdgeToWire(const TopoDS_Edge&  theEdge,
458                           const BRep_Builder& theBuilder,
459                                 TopoDS_Shape& theSpliceVertex,
460                                 TopoDS_Wire&  theWire)
461 {
462   TopoDS_Edge anEdge = theEdge;
463   bool isCurVertChanged = false;
464   TopoDS_Shape aCurVertChanged;
465
466   TopExp_Explorer aVertExp(theEdge, TopAbs_VERTEX);
467   for ( ; aVertExp.More(); aVertExp.Next())
468   {
469     const TopoDS_Shape& aVertex = aVertExp.Current();
470     if (aVertex.TShape() == theSpliceVertex.TShape() && 
471         aVertex.Orientation() != theEdge.Orientation())
472     { // Current vertex is the last for the edge, so its orientation is wrong, need to revert the edge
473       anEdge.Reverse();
474       break;
475     }
476     if (aVertex.TShape() != theSpliceVertex.TShape())
477     {
478       aCurVertChanged = aVertex;
479       isCurVertChanged = true;
480     }
481   }
482   theSpliceVertex = isCurVertChanged ? aCurVertChanged : aVertExp.Current();
483
484   theBuilder.Add(theWire, anEdge);
485 }
486
487 void createFace(const TopoDS_Shape&                      theStartVertex,
488                 const std::list<TopoDS_Shape>::iterator& theStartEdge,
489                 const std::list<TopoDS_Shape>::iterator& theEndOfEdges,
490                 const gp_Pln&                            thePlane,
491                       TopoDS_Face&                       theResFace)
492 {
493   TopoDS_Wire aResWire;
494   BRep_Builder aBuilder;
495   aBuilder.MakeWire(aResWire);
496
497   TopoDS_Shape aCurVertex = theStartVertex;
498   std::list<TopoDS_Shape>::const_iterator anEdgeIter = theStartEdge;
499   for ( ; anEdgeIter != theEndOfEdges; anEdgeIter++)
500   {
501     TopoDS_Edge anEdge = *((TopoDS_Edge*)(&(*anEdgeIter)));
502     addEdgeToWire(anEdge, aBuilder, aCurVertex, aResWire);
503   }
504
505   BRepBuilderAPI_MakeFace aFaceBuilder(thePlane, aResWire);
506   if (aFaceBuilder.Error() == BRepBuilderAPI_FaceDone)
507     theResFace = aFaceBuilder.Face();
508 }
509
510 void createWireList(const TopoDS_Shape&                      theStartVertex,
511                     const std::list<TopoDS_Shape>::iterator& theStartEdge,
512                     const std::list<TopoDS_Shape>::iterator& theEndOfEdges,
513                     const std::set<Handle(TopoDS_TShape)>&   theEdgesInLoops,
514                           std::list<TopoDS_Wire>&            theResWires)
515 {
516   BRep_Builder aBuilder;
517   bool needNewWire = true;
518   TopoDS_Shape aCurVertex = theStartVertex;
519
520   std::list<TopoDS_Shape>::iterator anIter = theStartEdge;
521   while (anIter != theEndOfEdges)
522   {
523     while (anIter != theEndOfEdges && needNewWire && 
524            theEdgesInLoops.count(anIter->TShape()) != 0)
525     {
526       TopExp_Explorer aVertExp(*anIter, TopAbs_VERTEX);
527       for ( ; aVertExp.More(); aVertExp.Next())
528         if (aVertExp.Current().TShape() != aCurVertex.TShape())
529         {
530           aCurVertex = aVertExp.Current();
531           break;
532         }
533       anIter++;
534     }
535     if (anIter == theEndOfEdges)
536       break;
537
538     if (needNewWire)
539     { // The new wire should be created
540       TopoDS_Wire aWire;
541       aBuilder.MakeWire(aWire);
542       theResWires.push_back(aWire);
543       needNewWire = false;
544     }
545     else if (theEdgesInLoops.count(anIter->TShape()) != 0)
546     { // There was found the edge already used in loop.
547       // Current wire should be released and new one should started
548       needNewWire = true;
549       continue;
550     }
551
552     TopoDS_Edge anEdge = *((TopoDS_Edge*)(&(*anIter)));
553     addEdgeToWire(anEdge, aBuilder, aCurVertex, theResWires.back());
554     anIter++;
555   }
556 }
557
558
559 gp_Dir getOuterEdgeDirection(const TopoDS_Shape& theEdge,
560                              const TopoDS_Shape& theVertex)
561 {
562   const Handle(BRep_TVertex)& aVertex = (const Handle(BRep_TVertex)&)theVertex.TShape();
563   gp_Pnt aVertexPnt = aVertex->Pnt();
564
565   const Handle(BRep_TEdge)& anEdge = (const Handle(BRep_TEdge)&)theEdge.TShape();
566
567   // Convert the edge to the curve to calculate the tangency.
568   // There should be only one curve in the edge.
569   Handle(BRep_Curve3D) aEdCurve = 
570     Handle(BRep_Curve3D)::DownCast(anEdge->Curves().First());
571   double aFirst, aLast;
572   aEdCurve->Range(aFirst, aLast);
573   Handle(Geom_Curve) aCurve = aEdCurve->Curve3D();
574
575   gp_Pnt aPnt;
576   gp_Vec aTang;
577   aCurve->D1(aFirst + shift, aPnt, aTang);
578   aCurve->D0(aFirst, aPnt);
579   if (aVertexPnt.IsEqual(aPnt, tolerance))
580     return gp_Dir(aTang.Reversed());
581
582   aCurve->D1(aLast - shift, aPnt, aTang);
583   return gp_Dir(aTang);
584 }
585
586 void removeWasteEdges(
587                 std::list<TopoDS_Shape>::iterator&  theStartVertex,
588                 std::list<TopoDS_Shape>::iterator&  theStartEdge,
589           const std::list<TopoDS_Shape>::iterator&  theEndOfVertexes,
590           const std::list<TopoDS_Shape>::iterator&  theEndOfEdges,
591           BOPCol_IndexedDataMapOfShapeListOfShape&  theMapVE)
592 {
593   bool isVertStep = true;
594   while (theStartVertex != theEndOfVertexes && theStartEdge != theEndOfEdges)
595   {
596     BOPCol_ListOfShape& aBunch = theMapVE.ChangeFromKey(*theStartVertex);
597     BOPCol_ListOfShape::Iterator anApprEdge(aBunch);
598     for ( ; anApprEdge.More(); anApprEdge.Next())
599       if (anApprEdge.Value() == *theStartEdge)
600         break;
601     if (anApprEdge.More())
602       aBunch.Remove(anApprEdge);
603
604     if (isVertStep)
605       theStartVertex++;
606     else
607     {
608       theStartEdge++;
609       // check current vertex to be a branching point
610       // if so, it will be a new starting point to find a loop
611       if (aBunch.Size() > 1)
612         break;
613     }
614     isVertStep = !isVertStep;
615   }
616
617   // The map of vertex-edges may be changed
618   BOPCol_IndexedDataMapOfShapeListOfShape aMapVECopy;
619   BOPCol_IndexedDataMapOfShapeListOfShape::Iterator aMapIter(theMapVE);
620   for (int ind = 1; aMapIter.More(); aMapIter.Next(), ind++)
621     if (!aMapIter.Value().IsEmpty())
622       aMapVECopy.Add(theMapVE.FindKey(ind), aMapIter.Value());
623   theMapVE.Clear();
624   theMapVE.Exchange(aMapVECopy);
625 }
626