QuadEdge& IncrementalDelaunayTriangulator::insertSite(const Vertex &v) { /** * This code is based on Guibas and Stolfi (1985), with minor modifications * and a bug fix from Dani Lischinski (Graphic Gems 1993). (The modification * I believe is the test for the inserted site falling exactly on an * existing edge. Without this test zero-width triangles have been observed * to be created) */ QuadEdge *e = subdiv->locate(v); if(!e) { throw LocateFailureException(""); } if (subdiv->isVertexOfEdge(*e, v)) { // point is already in subdivision. return *e; } else if (subdiv->isOnEdge(*e, v.getCoordinate())) { // the point lies exactly on an edge, so delete the edge // (it will be replaced by a pair of edges which have the point as a vertex) e = &e->oPrev(); subdiv->remove(e->oNext()); } /** * Connect the new point to the vertices of the containing triangle * (or quadrilateral, if the new point fell on an existing edge.) */ QuadEdge* base = &subdiv->makeEdge(e->orig(), v); QuadEdge::splice(*base, *e); QuadEdge *startEdge = base; do { base = &subdiv->connect(*e, base->sym()); e = &base->oPrev(); } while (&e->lNext() != startEdge); // Examine suspect edges to ensure that the Delaunay condition // is satisfied. do { QuadEdge* t = &e->oPrev(); if (t->dest().rightOf(*e) && v.isInCircle(e->orig(), t->dest(), e->dest())) { QuadEdge::swap(*e); e = &e->oPrev(); } else if (&e->oNext() == startEdge) { return *base; // no more suspect edges. } else { e = &e->oNext().lPrev(); } } while (true); }
void QuadEdge::splice(QuadEdge &a, QuadEdge &b) { QuadEdge &alpha = a.oNext().rot(); QuadEdge &beta = b.oNext().rot(); QuadEdge &t1 = b.oNext(); QuadEdge &t2 = a.oNext(); QuadEdge &t3 = beta.oNext(); QuadEdge &t4 = alpha.oNext(); a.setNext(&t1); b.setNext(&t2); alpha.setNext(&t3); beta.setNext(&t4); }
bool QuadEdge::testEqualQuadEdge(const QuadEdge& qe2) { /* if(&qe1 == NULL && &qe2 == NULL) { return 1; } else if((&qe1==NULL && &qe2!=NULL) || (&qe1!=NULL && &qe2==NULL)) { return 0; } */ //when both of them are not null: if((*_rot).testEqualQuadEdge(qe2.rot()) && (*next).testEqualQuadEdge(qe2.oNext()) //&& (*data == *(qe2.data)) && (isAlive == qe2.isAlive) /*&& orig()==qe2.orig()*/) return 1; else return 0; }