C++ Triangle::GetNeighbor方法代码示例

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;
}

void SweepContext::MapTriangleToNodes(Triangle& t)
{
  for (int i = 0; i < 3; i++) {
    if (!t.GetNeighbor(i)) {
      Node* n = front_->LocatePoint(t.PointCW(*t.GetPoint(i)));
      if (n)
        n->triangle = &t;
    }
  }
}

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;
}

void SweepContext::MeshClean(Triangle& triangle)
{
  std::vector<Triangle *> triangles;
  triangles.push_back(&triangle);

  while(!triangles.empty()){
	Triangle *t = triangles.back();
	triangles.pop_back();

    if (t != NULL && !t->IsInterior()) {
      t->IsInterior(true);
      triangles_.push_back(t);
      for (int i = 0; i < 3; i++) {
        if (!t->constrained_edge[i])
          triangles.push_back(t->GetNeighbor(i));
      }
    }
  }
}