Method BuildIntersectList

TheForceEngine/TFE_Polygon/clipper.cpp:2856–2902

//------------------------------------------------------------------------------

void Clipper::BuildIntersectList(const cInt topY)
{
  if ( !m_ActiveEdges ) return;

  //prepare for sorting ...
  TEdge* e = m_ActiveEdges;
  m_SortedEdges = e;
  while( e )
  {
    e->PrevInSEL = e->PrevInAEL;
    e->NextInSEL = e->NextInAEL;
    e->Curr.X = TopX( *e, topY );
    e = e->NextInAEL;
  }

  //bubblesort ...
  bool isModified;
  do
  {
    isModified = false;
    e = m_SortedEdges;
    while( e->NextInSEL )
    {
      TEdge *eNext = e->NextInSEL;
      IntPoint Pt;
      if(e->Curr.X > eNext->Curr.X)
      {
        IntersectPoint(*e, *eNext, Pt);
        if (Pt.Y < topY) Pt = IntPoint(TopX(*e, topY), topY);
        IntersectNode * newNode = new IntersectNode;
        newNode->Edge1 = e;
        newNode->Edge2 = eNext;
        newNode->Pt = Pt;
        m_IntersectList.push_back(newNode);

        SwapPositionsInSEL(e, eNext);
        isModified = true;
      }
      else
        e = eNext;
    }
    if( e->PrevInSEL ) e->PrevInSEL->NextInSEL = 0;
    else break;
  }
  while ( isModified );
  m_SortedEdges = 0; //important
}
//------------------------------------------------------------------------------