bool MyObject::buildHalfEdges(THalfEdgeList& lst)
{
int pli, i;
TPointPairHash m_pntmap;
m_pntmap.reserve(150);
// the pointer is the half edge already between these points
for(pli = 0; pli < nPolys; ++pli)
{
MyPolygon *pol = poly[pli];
HalfEdge *he = nullptr, *lasthe = nullptr;
for(i = 3; i >= 0; --i)
{
//he = new HalfEdge(pol, pol->vtx[i], he);
HalfEdge *prevhe = he;
he = m_alloc->m_hePool.allocate();
he->init(pol, pol->vtx[i], prevhe);
lst.push_back(he);
if (lasthe == nullptr)
lasthe = he;
if (pol->vtx[i]->he == nullptr)
pol->vtx[i]->he = he;
}
lasthe->next = he;
pol->he = he;
for(i = 3; i >= 0; --i)
{
PointPair pp(he->point, he->next->point);
TPointPairHash::iterator it = m_pntmap.find(pp);
if (it == m_pntmap.end()) // its not there, add it
m_pntmap.insert(make_pair(pp, he));
else
{
HalfEdge *she = it->second;
M_ASSERT((she->next->point == he->point) && (he->next->point == she->point));
he->pair = she;
she->pair = he;
m_pntmap.erase(it); // no longer needed in the map
}
he = he->next;
}
// maximum size of m_pntmap is 134
}
M_ASSERT(m_pntmap.empty());
return true;
}
