C++ QuadEdge::oNext方法代码示例

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;

}