summaryrefslogtreecommitdiff
path: root/src/3rdparty/poly2tri/sweep/sweep.cpp
blob: 902c029502f247daedfd283b4a60e970b8d84103 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
/*
 * Poly2Tri Copyright (c) 2009-2010, Poly2Tri Contributors
 * http://code.google.com/p/poly2tri/
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * * Neither the name of Poly2Tri nor the names of its contributors may be
 *   used to endorse or promote products derived from this software without specific
 *   prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <stddef.h>
#include <stdexcept>
#include "sweep.h"
#include "sweep_context.h"
#include "advancing_front.h"
#include "../common/utils.h"

namespace p2t {

// Triangulate simple polygon with holes
void Sweep::Triangulate(SweepContext& tcx)
{
  tcx.InitTriangulation();
  tcx.CreateAdvancingFront(nodes_);
  // Sweep points; build mesh
  SweepPoints(tcx);
  // Clean up
  FinalizationPolygon(tcx);
}

void Sweep::SweepPoints(SweepContext& tcx)
{
  for (int i = 1; i < tcx.point_count(); i++) {
    Point& point = *tcx.GetPoint(i);
    Node* node = &PointEvent(tcx, point);
    for (unsigned int i = 0; i < point.edge_list.size(); i++) {
      EdgeEvent(tcx, point.edge_list[i], node);
    }
  }
}

void Sweep::FinalizationPolygon(SweepContext& tcx)
{
  // Get an Internal triangle to start with
  Triangle* t = tcx.front()->head()->next->triangle;
  Point* p = tcx.front()->head()->next->point;
  while (!t->GetConstrainedEdgeCW(*p)) {
    t = t->NeighborCCW(*p);
  }

  // Collect interior triangles constrained by edges
  tcx.MeshClean(*t);
}

Node& Sweep::PointEvent(SweepContext& tcx, Point& point)
{
  Node& node = tcx.LocateNode(point);
  Node& new_node = NewFrontTriangle(tcx, point, node);

  // Only need to check +epsilon since point never have smaller
  // x value than node due to how we fetch nodes from the front
  if (point.x <= node.point->x + EPSILON) {
    Fill(tcx, node);
  }

  //tcx.AddNode(new_node);

  FillAdvancingFront(tcx, new_node);
  return new_node;
}

void Sweep::EdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
{
  tcx.edge_event.constrained_edge = edge;
  tcx.edge_event.right = (edge->p->x > edge->q->x);

  if (IsEdgeSideOfTriangle(*node->triangle, *edge->p, *edge->q)) {
    return;
  }

  // For now we will do all needed filling
  // TODO: integrate with flip process might give some better performance
  //       but for now this avoid the issue with cases that needs both flips and fills
  FillEdgeEvent(tcx, edge, node);
  EdgeEvent(tcx, *edge->p, *edge->q, node->triangle, *edge->q);
}

void Sweep::EdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle* triangle, Point& point)
{
  if (IsEdgeSideOfTriangle(*triangle, ep, eq)) {
    return;
  }

  Point* p1 = triangle->PointCCW(point);
  Orientation o1 = Orient2d(eq, *p1, ep);
  if (o1 == COLLINEAR) {
    if ( triangle->Contains(&eq, p1)) {
      triangle->MarkConstrainedEdge(&eq, p1 );
      // We are modifying the constraint maybe it would be better to
      // not change the given constraint and just keep a variable for the new constraint
      tcx.edge_event.constrained_edge->q = p1;
      triangle = &triangle->NeighborAcross(point);
      EdgeEvent( tcx, ep, *p1, triangle, *p1 );
    } else {
      std::runtime_error("EdgeEvent - collinear points not supported");
      assert(0);
    }
    return;
  }

  Point* p2 = triangle->PointCW(point);
  Orientation o2 = Orient2d(eq, *p2, ep);
  if (o2 == COLLINEAR) {
    if ( triangle->Contains(&eq, p2)) {
      triangle->MarkConstrainedEdge(&eq, p2 );
      // We are modifying the constraint maybe it would be better to
      // not change the given constraint and just keep a variable for the new constraint
      tcx.edge_event.constrained_edge->q = p2;
      triangle = &triangle->NeighborAcross(point);
      EdgeEvent( tcx, ep, *p2, triangle, *p2 );
    } else {
      std::runtime_error("EdgeEvent - collinear points not supported");
      assert(0);
    }
    return;
  }

  if (o1 == o2) {
    // Need to decide if we are rotating CW or CCW to get to a triangle
    // that will cross edge
    if (o1 == CW) {
      triangle = triangle->NeighborCCW(point);
    }       else{
      triangle = triangle->NeighborCW(point);
    }
    EdgeEvent(tcx, ep, eq, triangle, point);
  } else {
    // This triangle crosses constraint so lets flippin start!
    FlipEdgeEvent(tcx, ep, eq, triangle, point);
  }
}

bool Sweep::IsEdgeSideOfTriangle(Triangle& triangle, Point& ep, Point& eq)
{
  int index = triangle.EdgeIndex(&ep, &eq);

  if (index != -1) {
    triangle.MarkConstrainedEdge(index);
    Triangle* t = triangle.GetNeighbor(index);
    if (t) {
      t->MarkConstrainedEdge(&ep, &eq);
    }
    return true;
  }
  return false;
}

Node& Sweep::NewFrontTriangle(SweepContext& tcx, Point& point, Node& node)
{
  Triangle* triangle = new Triangle(point, *node.point, *node.next->point);

  triangle->MarkNeighbor(*node.triangle);
  tcx.AddToMap(triangle);

  Node* new_node = new Node(point);
  nodes_.push_back(new_node);

  new_node->next = node.next;
  new_node->prev = &node;
  node.next->prev = new_node;
  node.next = new_node;

  if (!Legalize(tcx, *triangle)) {
    tcx.MapTriangleToNodes(*triangle);
  }

  return *new_node;
}

void Sweep::Fill(SweepContext& tcx, Node& node)
{
  Triangle* triangle = new Triangle(*node.prev->point, *node.point, *node.next->point);

  // TODO: should copy the constrained_edge value from neighbor triangles
  //       for now constrained_edge values are copied during the legalize
  triangle->MarkNeighbor(*node.prev->triangle);
  triangle->MarkNeighbor(*node.triangle);

  tcx.AddToMap(triangle);

  // Update the advancing front
  node.prev->next = node.next;
  node.next->prev = node.prev;

  // If it was legalized the triangle has already been mapped
  if (!Legalize(tcx, *triangle)) {
    tcx.MapTriangleToNodes(*triangle);
  }

}

void Sweep::FillAdvancingFront(SweepContext& tcx, Node& n)
{

  // Fill right holes
  Node* node = n.next;

  while (node->next) {
    // if HoleAngle exceeds 90 degrees then break.
    if (LargeHole_DontFill(node)) break;
    Fill(tcx, *node);
    node = node->next;
  }

  // Fill left holes
  node = n.prev;

  while (node->prev) {
    // if HoleAngle exceeds 90 degrees then break.
    if (LargeHole_DontFill(node)) break;
    Fill(tcx, *node);
    node = node->prev;
  }

  // Fill right basins
  if (n.next && n.next->next) {
    float angle = BasinAngle(n);
    if (angle < PI_3div4) {
      FillBasin(tcx, n);
    }
  }
}

// True if HoleAngle exceeds 90 degrees.
bool Sweep::LargeHole_DontFill(Node* node) {

  Node* nextNode = node->next;
  Node* prevNode = node->prev;
  if (!AngleExceeds90Degrees(node->point, nextNode->point, prevNode->point))
          return false;

  // Check additional points on front.
  Node* next2Node = nextNode->next;
  // "..Plus.." because only want angles on same side as point being added.
  if ((next2Node != NULL) && !AngleExceedsPlus90DegreesOrIsNegative(node->point, next2Node->point, prevNode->point))
          return false;

  Node* prev2Node = prevNode->prev;
  // "..Plus.." because only want angles on same side as point being added.
  if ((prev2Node != NULL) && !AngleExceedsPlus90DegreesOrIsNegative(node->point, nextNode->point, prev2Node->point))
          return false;

  return true;
}

bool Sweep::AngleExceeds90Degrees(Point* origin, Point* pa, Point* pb) {
  float angle = Angle(*origin, *pa, *pb);
  bool exceeds90Degrees = ((angle > PI_div2) || (angle < -PI_div2));
  return exceeds90Degrees;
}

bool Sweep::AngleExceedsPlus90DegreesOrIsNegative(Point* origin, Point* pa, Point* pb) {
  float angle = Angle(*origin, *pa, *pb);
  bool exceedsPlus90DegreesOrIsNegative = (angle > PI_div2) || (angle < 0);
  return exceedsPlus90DegreesOrIsNegative;
}

float Sweep::Angle(Point& origin, Point& pa, Point& pb) {
  /* Complex plane
   * ab = cosA +i*sinA
   * ab = (ax + ay*i)(bx + by*i) = (ax*bx + ay*by) + i(ax*by-ay*bx)
   * atan2(y,x) computes the principal value of the argument function
   * applied to the complex number x+iy
   * Where x = ax*bx + ay*by
   *       y = ax*by - ay*bx
   */
  float px = origin.x;
  float py = origin.y;
  float ax = pa.x- px;
  float ay = pa.y - py;
  float bx = pb.x - px;
  float by = pb.y - py;
  float x = ax * by - ay * bx;
  float y = ax * bx + ay * by;
  float angle = atan2(x, y);
  return angle;
}

float Sweep::BasinAngle(Node& node)
{
  float ax = node.point->x - node.next->next->point->x;
  float ay = node.point->y - node.next->next->point->y;
  return atan2(ay, ax);
}

float Sweep::HoleAngle(Node& node)
{
  /* Complex plane
   * ab = cosA +i*sinA
   * ab = (ax + ay*i)(bx + by*i) = (ax*bx + ay*by) + i(ax*by-ay*bx)
   * atan2(y,x) computes the principal value of the argument function
   * applied to the complex number x+iy
   * Where x = ax*bx + ay*by
   *       y = ax*by - ay*bx
   */
  float ax = node.next->point->x - node.point->x;
  float ay = node.next->point->y - node.point->y;
  float bx = node.prev->point->x - node.point->x;
  float by = node.prev->point->y - node.point->y;
  return atan2(ax * by - ay * bx, ax * bx + ay * by);
}

bool Sweep::Legalize(SweepContext& tcx, Triangle& t)
{
  // To legalize a triangle we start by finding if any of the three edges
  // violate the Delaunay condition
  for (int i = 0; i < 3; i++) {
    if (t.delaunay_edge[i])
      continue;

    Triangle* ot = t.GetNeighbor(i);

    if (ot) {
      Point* p = t.GetPoint(i);
      Point* op = ot->OppositePoint(t, *p);
      int oi = ot->Index(op);

      // If this is a Constrained Edge or a Delaunay Edge(only during recursive legalization)
      // then we should not try to legalize
      if (ot->constrained_edge[oi] || ot->delaunay_edge[oi]) {
        t.constrained_edge[i] = ot->constrained_edge[oi];
        continue;
      }

      bool inside = Incircle(*p, *t.PointCCW(*p), *t.PointCW(*p), *op);

      if (inside) {
        // Lets mark this shared edge as Delaunay
        t.delaunay_edge[i] = true;
        ot->delaunay_edge[oi] = true;

        // Lets rotate shared edge one vertex CW to legalize it
        RotateTrianglePair(t, *p, *ot, *op);

        // We now got one valid Delaunay Edge shared by two triangles
        // This gives us 4 new edges to check for Delaunay

        // Make sure that triangle to node mapping is done only one time for a specific triangle
        bool not_legalized = !Legalize(tcx, t);
        if (not_legalized) {
          tcx.MapTriangleToNodes(t);
        }

        not_legalized = !Legalize(tcx, *ot);
        if (not_legalized)
          tcx.MapTriangleToNodes(*ot);

        // Reset the Delaunay edges, since they only are valid Delaunay edges
        // until we add a new triangle or point.
        // XXX: need to think about this. Can these edges be tried after we
        //      return to previous recursive level?
        t.delaunay_edge[i] = false;
        ot->delaunay_edge[oi] = false;

        // If triangle have been legalized no need to check the other edges since
        // the recursive legalization will handles those so we can end here.
        return true;
      }
    }
  }
  return false;
}

bool Sweep::Incircle(Point& pa, Point& pb, Point& pc, Point& pd)
{
  float adx = pa.x - pd.x;
  float ady = pa.y - pd.y;
  float bdx = pb.x - pd.x;
  float bdy = pb.y - pd.y;

  float adxbdy = adx * bdy;
  float bdxady = bdx * ady;
  float oabd = adxbdy - bdxady;

  if (oabd <= 0)
    return false;

  float cdx = pc.x - pd.x;
  float cdy = pc.y - pd.y;

  float cdxady = cdx * ady;
  float adxcdy = adx * cdy;
  float ocad = cdxady - adxcdy;

  if (ocad <= 0)
    return false;

  float bdxcdy = bdx * cdy;
  float cdxbdy = cdx * bdy;

  float alift = adx * adx + ady * ady;
  float blift = bdx * bdx + bdy * bdy;
  float clift = cdx * cdx + cdy * cdy;

  float det = alift * (bdxcdy - cdxbdy) + blift * ocad + clift * oabd;

  return det > 0;
}

void Sweep::RotateTrianglePair(Triangle& t, Point& p, Triangle& ot, Point& op)
{
  Triangle* n1, *n2, *n3, *n4;
  n1 = t.NeighborCCW(p);
  n2 = t.NeighborCW(p);
  n3 = ot.NeighborCCW(op);
  n4 = ot.NeighborCW(op);

  bool ce1, ce2, ce3, ce4;
  ce1 = t.GetConstrainedEdgeCCW(p);
  ce2 = t.GetConstrainedEdgeCW(p);
  ce3 = ot.GetConstrainedEdgeCCW(op);
  ce4 = ot.GetConstrainedEdgeCW(op);

  bool de1, de2, de3, de4;
  de1 = t.GetDelunayEdgeCCW(p);
  de2 = t.GetDelunayEdgeCW(p);
  de3 = ot.GetDelunayEdgeCCW(op);
  de4 = ot.GetDelunayEdgeCW(op);

  t.Legalize(p, op);
  ot.Legalize(op, p);

  // Remap delaunay_edge
  ot.SetDelunayEdgeCCW(p, de1);
  t.SetDelunayEdgeCW(p, de2);
  t.SetDelunayEdgeCCW(op, de3);
  ot.SetDelunayEdgeCW(op, de4);

  // Remap constrained_edge
  ot.SetConstrainedEdgeCCW(p, ce1);
  t.SetConstrainedEdgeCW(p, ce2);
  t.SetConstrainedEdgeCCW(op, ce3);
  ot.SetConstrainedEdgeCW(op, ce4);

  // Remap neighbors
  // XXX: might optimize the markNeighbor by keeping track of
  //      what side should be assigned to what neighbor after the
  //      rotation. Now mark neighbor does lots of testing to find
  //      the right side.
  t.ClearNeighbors();
  ot.ClearNeighbors();
  if (n1) ot.MarkNeighbor(*n1);
  if (n2) t.MarkNeighbor(*n2);
  if (n3) t.MarkNeighbor(*n3);
  if (n4) ot.MarkNeighbor(*n4);
  t.MarkNeighbor(ot);
}

void Sweep::FillBasin(SweepContext& tcx, Node& node)
{
  if (Orient2d(*node.point, *node.next->point, *node.next->next->point) == CCW) {
    tcx.basin.left_node = node.next->next;
  } else {
    tcx.basin.left_node = node.next;
  }

  // Find the bottom and right node
  tcx.basin.bottom_node = tcx.basin.left_node;
  while (tcx.basin.bottom_node->next
         && tcx.basin.bottom_node->point->y >= tcx.basin.bottom_node->next->point->y) {
    tcx.basin.bottom_node = tcx.basin.bottom_node->next;
  }
  if (tcx.basin.bottom_node == tcx.basin.left_node) {
    // No valid basin
    return;
  }

  tcx.basin.right_node = tcx.basin.bottom_node;
  while (tcx.basin.right_node->next
         && tcx.basin.right_node->point->y < tcx.basin.right_node->next->point->y) {
    tcx.basin.right_node = tcx.basin.right_node->next;
  }
  if (tcx.basin.right_node == tcx.basin.bottom_node) {
    // No valid basins
    return;
  }

  tcx.basin.width = tcx.basin.right_node->point->x - tcx.basin.left_node->point->x;
  tcx.basin.left_highest = tcx.basin.left_node->point->y > tcx.basin.right_node->point->y;

  FillBasinReq(tcx, tcx.basin.bottom_node);
}

void Sweep::FillBasinReq(SweepContext& tcx, Node* node)
{
  // if shallow stop filling
  if (IsShallow(tcx, *node)) {
    return;
  }

  Fill(tcx, *node);

  if (node->prev == tcx.basin.left_node && node->next == tcx.basin.right_node) {
    return;
  } else if (node->prev == tcx.basin.left_node) {
    Orientation o = Orient2d(*node->point, *node->next->point, *node->next->next->point);
    if (o == CW) {
      return;
    }
    node = node->next;
  } else if (node->next == tcx.basin.right_node) {
    Orientation o = Orient2d(*node->point, *node->prev->point, *node->prev->prev->point);
    if (o == CCW) {
      return;
    }
    node = node->prev;
  } else {
    // Continue with the neighbor node with lowest Y value
    if (node->prev->point->y < node->next->point->y) {
      node = node->prev;
    } else {
      node = node->next;
    }
  }

  FillBasinReq(tcx, node);
}

bool Sweep::IsShallow(SweepContext& tcx, Node& node)
{
  float height;

  if (tcx.basin.left_highest) {
    height = tcx.basin.left_node->point->y - node.point->y;
  } else {
    height = tcx.basin.right_node->point->y - node.point->y;
  }

  // if shallow stop filling
  if (tcx.basin.width > height) {
    return true;
  }
  return false;
}

void Sweep::FillEdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
{
  if (tcx.edge_event.right) {
    FillRightAboveEdgeEvent(tcx, edge, node);
  } else {
    FillLeftAboveEdgeEvent(tcx, edge, node);
  }
}

void Sweep::FillRightAboveEdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
{
  while (node->next->point->x < edge->p->x) {
    // Check if next node is below the edge
    if (Orient2d(*edge->q, *node->next->point, *edge->p) == CCW) {
      FillRightBelowEdgeEvent(tcx, edge, *node);
    } else {
      node = node->next;
    }
  }
}

void Sweep::FillRightBelowEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
{
  if (node.point->x < edge->p->x) {
    if (Orient2d(*node.point, *node.next->point, *node.next->next->point) == CCW) {
      // Concave
      FillRightConcaveEdgeEvent(tcx, edge, node);
    } else{
      // Convex
      FillRightConvexEdgeEvent(tcx, edge, node);
      // Retry this one
      FillRightBelowEdgeEvent(tcx, edge, node);
    }
  }
}

void Sweep::FillRightConcaveEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
{
  Fill(tcx, *node.next);
  if (node.next->point != edge->p) {
    // Next above or below edge?
    if (Orient2d(*edge->q, *node.next->point, *edge->p) == CCW) {
      // Below
      if (Orient2d(*node.point, *node.next->point, *node.next->next->point) == CCW) {
        // Next is concave
        FillRightConcaveEdgeEvent(tcx, edge, node);
      } else {
        // Next is convex
      }
    }
  }

}

void Sweep::FillRightConvexEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
{
  // Next concave or convex?
  if (Orient2d(*node.next->point, *node.next->next->point, *node.next->next->next->point) == CCW) {
    // Concave
    FillRightConcaveEdgeEvent(tcx, edge, *node.next);
  } else{
    // Convex
    // Next above or below edge?
    if (Orient2d(*edge->q, *node.next->next->point, *edge->p) == CCW) {
      // Below
      FillRightConvexEdgeEvent(tcx, edge, *node.next);
    } else{
      // Above
    }
  }
}

void Sweep::FillLeftAboveEdgeEvent(SweepContext& tcx, Edge* edge, Node* node)
{
  while (node->prev->point->x > edge->p->x) {
    // Check if next node is below the edge
    if (Orient2d(*edge->q, *node->prev->point, *edge->p) == CW) {
      FillLeftBelowEdgeEvent(tcx, edge, *node);
    } else {
      node = node->prev;
    }
  }
}

void Sweep::FillLeftBelowEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
{
  if (node.point->x > edge->p->x) {
    if (Orient2d(*node.point, *node.prev->point, *node.prev->prev->point) == CW) {
      // Concave
      FillLeftConcaveEdgeEvent(tcx, edge, node);
    } else {
      // Convex
      FillLeftConvexEdgeEvent(tcx, edge, node);
      // Retry this one
      FillLeftBelowEdgeEvent(tcx, edge, node);
    }
  }
}

void Sweep::FillLeftConvexEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
{
  // Next concave or convex?
  if (Orient2d(*node.prev->point, *node.prev->prev->point, *node.prev->prev->prev->point) == CW) {
    // Concave
    FillLeftConcaveEdgeEvent(tcx, edge, *node.prev);
  } else{
    // Convex
    // Next above or below edge?
    if (Orient2d(*edge->q, *node.prev->prev->point, *edge->p) == CW) {
      // Below
      FillLeftConvexEdgeEvent(tcx, edge, *node.prev);
    } else{
      // Above
    }
  }
}

void Sweep::FillLeftConcaveEdgeEvent(SweepContext& tcx, Edge* edge, Node& node)
{
  Fill(tcx, *node.prev);
  if (node.prev->point != edge->p) {
    // Next above or below edge?
    if (Orient2d(*edge->q, *node.prev->point, *edge->p) == CW) {
      // Below
      if (Orient2d(*node.point, *node.prev->point, *node.prev->prev->point) == CW) {
        // Next is concave
        FillLeftConcaveEdgeEvent(tcx, edge, node);
      } else{
        // Next is convex
      }
    }
  }

}

void Sweep::FlipEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle* t, Point& p)
{
  Triangle& ot = t->NeighborAcross(p);
  Point& op = *ot.OppositePoint(*t, p);

  if (&ot == NULL) {
    // If we want to integrate the fillEdgeEvent do it here
    // With current implementation we should never get here
    //throw new RuntimeException( "[BUG:FIXME] FLIP failed due to missing triangle");
    assert(0);
  }

  if (InScanArea(p, *t->PointCCW(p), *t->PointCW(p), op)) {
    // Lets rotate shared edge one vertex CW
    RotateTrianglePair(*t, p, ot, op);
    tcx.MapTriangleToNodes(*t);
    tcx.MapTriangleToNodes(ot);

    if (p == eq && op == ep) {
      if (eq == *tcx.edge_event.constrained_edge->q && ep == *tcx.edge_event.constrained_edge->p) {
        t->MarkConstrainedEdge(&ep, &eq);
        ot.MarkConstrainedEdge(&ep, &eq);
        Legalize(tcx, *t);
        Legalize(tcx, ot);
      } else {
        // XXX: I think one of the triangles should be legalized here?
      }
    } else {
      Orientation o = Orient2d(eq, op, ep);
      t = &NextFlipTriangle(tcx, (int)o, *t, ot, p, op);
      FlipEdgeEvent(tcx, ep, eq, t, p);
    }
  } else {
    Point& newP = NextFlipPoint(ep, eq, ot, op);
    FlipScanEdgeEvent(tcx, ep, eq, *t, ot, newP);
    EdgeEvent(tcx, ep, eq, t, p);
  }
}

Triangle& Sweep::NextFlipTriangle(SweepContext& tcx, int o, Triangle& t, Triangle& ot, Point& p, Point& op)
{
  if (o == CCW) {
    // ot is not crossing edge after flip
    int edge_index = ot.EdgeIndex(&p, &op);
    ot.delaunay_edge[edge_index] = true;
    Legalize(tcx, ot);
    ot.ClearDelunayEdges();
    return t;
  }

  // t is not crossing edge after flip
  int edge_index = t.EdgeIndex(&p, &op);

  t.delaunay_edge[edge_index] = true;
  Legalize(tcx, t);
  t.ClearDelunayEdges();
  return ot;
}

Point& Sweep::NextFlipPoint(Point& ep, Point& eq, Triangle& ot, Point& op)
{
  Orientation o2d = Orient2d(eq, op, ep);
  if (o2d == CW) {
    // Right
    return *ot.PointCCW(op);
  } else if (o2d == CCW) {
    // Left
    return *ot.PointCW(op);
  } else{
    //throw new RuntimeException("[Unsupported] Opposing point on constrained edge");
    assert(0);
  }
}

void Sweep::FlipScanEdgeEvent(SweepContext& tcx, Point& ep, Point& eq, Triangle& flip_triangle,
                              Triangle& t, Point& p)
{
  Triangle& ot = t.NeighborAcross(p);
  Point& op = *ot.OppositePoint(t, p);

  if (&t.NeighborAcross(p) == NULL) {
    // If we want to integrate the fillEdgeEvent do it here
    // With current implementation we should never get here
    //throw new RuntimeException( "[BUG:FIXME] FLIP failed due to missing triangle");
    assert(0);
  }

  if (InScanArea(eq, *flip_triangle.PointCCW(eq), *flip_triangle.PointCW(eq), op)) {
    // flip with new edge op->eq
    FlipEdgeEvent(tcx, eq, op, &ot, op);
    // TODO: Actually I just figured out that it should be possible to
    //       improve this by getting the next ot and op before the above
    //       flip and continue the flipScanEdgeEvent here
    // set new ot and op here and loop back to inScanArea test
    // also need to set a new flip_triangle first
    // Turns out at first glance that this is somewhat complicated
    // so it will have to wait.
  } else{
    Point& newP = NextFlipPoint(ep, eq, ot, op);
    FlipScanEdgeEvent(tcx, ep, eq, flip_triangle, ot, newP);
  }
}

Sweep::~Sweep() {

    // Clean up memory
    for (size_t i = 0; i < nodes_.size(); i++) {
        delete nodes_[i];
    }

}

}