Update clipper code to 6.4.2 from upstream

tools/vectorosm-tilecreator/clipper/clipper.cpp

 /*******************************************************************************
 *                                                                              *
 * Author    :  Angus Johnson                                                   *
-* Version   :  6.4.0                                                           *
-* Date      :  2 July 2015                                                     *
+* Version   :  6.4.2                                                           *
+* Date      :  27 February 2017                                                *
 * Website   :  http://www.angusj.com                                           *
-* Copyright :  Angus Johnson 2010-2015                                         *
+* Copyright :  Angus Johnson 2010-2017                                         *
 *                                                                              *
 * License:                                                                     *
 * Use, modification & distribution is subject to Boost Software License Ver 1. *
@@ -14,7 +14,7 @@
 * The code in this library is an extension of Bala Vatti's clipping algorithm: *
 * "A generic solution to polygon clipping"                                     *
 * Communications of the ACM, Vol 35, Issue 7 (July 1992) pp 56-63.             *
-*     https://dl.acm.org/citation.cfm?id=129906                                *
+* https://portal.acm.org/citation.cfm?id=129906                                *
 *                                                                              *
 * Computer graphics and geometric modeling: implementation and algorithms      *
 * By Max K. Agoston                                                            *
@@ -27,7 +27,7 @@
 * ASME 2005 International Design Engineering Technical Conferences             *
 * and Computers and Information in Engineering Conference (IDETC/CIE2005)      *
 * September 24-28, 2005 , Long Beach, California, USA                          *
-* https://mcmains.me.berkeley.edu/pubs/DAC05OffsetPolygon.pdf                  *
+* https://www.me.berkeley.edu/~mcmains/pubs/DAC05OffsetPolygon.pdf             *
 *                                                                              *
 *******************************************************************************/
 
@@ -1626,7 +1626,7 @@ bool Clipper::ExecuteInternal()
 void Clipper::SetWindingCount(TEdge &edge)
 {
   TEdge *e = edge.PrevInAEL;
-  //find the edge of the same polytype that immediately precedes 'edge' in AEL
+  //find the edge of the same polytype that immediately preceeds 'edge' in AEL
   while (e  && ((e->PolyTyp != edge.PolyTyp) || (e->WindDelta == 0))) e = e->PrevInAEL;
   if (!e)
   {
@@ -1868,7 +1868,7 @@ OutPt* Clipper::AddLocalMinPoly(TEdge *e1, TEdge *e2, const IntPoint &Pt)
         prevE = e->PrevInAEL;
   }
 
-  if (prevE && prevE->OutIdx >= 0)
+  if (prevE && prevE->OutIdx >= 0 && prevE->Top.Y < Pt.Y && e->Top.Y < Pt.Y)
   {
     cInt xPrev = TopX(*prevE, Pt.Y);
     cInt xE = TopX(*e, Pt.Y);
@@ -2715,7 +2715,11 @@ void Clipper::ProcessHorizontal(TEdge *horzEdge)
 
     if (horzEdge->OutIdx >= 0 && !IsOpen)  //note: may be done multiple times
 		{
-            op1 = AddOutPt(horzEdge, e->Curr);
+#ifdef use_xyz
+			if (dir == dLeftToRight) SetZ(e->Curr, *horzEdge, *e);
+			else SetZ(e->Curr, *e, *horzEdge);
+#endif
+			op1 = AddOutPt(horzEdge, e->Curr);
 			TEdge* eNextHorz = m_SortedEdges;
 			while (eNextHorz)
 			{
@@ -3041,7 +3045,10 @@ void Clipper::ProcessEdgesAtTopOfScanbeam(const cInt topY)
       {
         e->Curr.X = TopX( *e, topY );
         e->Curr.Y = topY;
-      }
+#ifdef use_xyz
+		e->Curr.Z = topY == e->Top.Y ? e->Top.Z : (topY == e->Bot.Y ? e->Bot.Z : 0);
+#endif
+	  }
 
       //When StrictlySimple and 'e' is being touched by another edge, then
       //make sure both edges have a vertex here ...
@@ -3665,7 +3672,7 @@ void Clipper::FixupFirstLefts3(OutRec* OldOutRec, OutRec* NewOutRec)
   {
     OutRec* outRec = m_PolyOuts[i];
     OutRec* firstLeft = ParseFirstLeft(outRec->FirstLeft);
-    if (outRec->Pts && outRec->FirstLeft == OldOutRec)
+    if (outRec->Pts && firstLeft == OldOutRec)
       outRec->FirstLeft = NewOutRec;
   }
 }

tools/vectorosm-tilecreator/clipper/clipper.hpp

 /*******************************************************************************
 *                                                                              *
 * Author    :  Angus Johnson                                                   *
-* Version   :  6.4.0                                                           *
-* Date      :  2 July 2015                                                     *
+* Version   :  6.4.2                                                           *
+* Date      :  27 February 2017                                                *
 * Website   :  http://www.angusj.com                                           *
-* Copyright :  Angus Johnson 2010-2015                                         *
+* Copyright :  Angus Johnson 2010-2017                                         *
 *                                                                              *
 * License:                                                                     *
 * Use, modification & distribution is subject to Boost Software License Ver 1. *
@@ -14,7 +14,7 @@
 * The code in this library is an extension of Bala Vatti's clipping algorithm: *
 * "A generic solution to polygon clipping"                                     *
 * Communications of the ACM, Vol 35, Issue 7 (July 1992) pp 56-63.             *
-* https://dl.acm.org/citation.cfm?id=129906                                    *
+* http://portal.acm.org/citation.cfm?id=129906                                 *
 *                                                                              *
 * Computer graphics and geometric modeling: implementation and algorithms      *
 * By Max K. Agoston                                                            *
@@ -27,14 +27,14 @@
 * ASME 2005 International Design Engineering Technical Conferences             *
 * and Computers and Information in Engineering Conference (IDETC/CIE2005)      *
 * September 24-28, 2005 , Long Beach, California, USA                          *
-* https://mcmains.me.berkeley.edu/pubs/DAC05OffsetPolygon.pdf                  *
+* https://www.me.berkeley.edu/~mcmains/pubs/DAC05OffsetPolygon.pdf             *
 *                                                                              *
 *******************************************************************************/
 
 #ifndef clipper_hpp
 #define clipper_hpp
 
-#define CLIPPER_VERSION "6.2.6"
+#define CLIPPER_VERSION "6.4.2"
 
 //use_int32: When enabled 32bit ints are used instead of 64bit ints. This
 //improve performance but coordinate values are limited to the range +/- 46340