Backported a fix from Clipper 6.4.2 for the issue that Clipper Z coordinated has incorrect value because ZFillFunction wasn't called in all cases (https://sourceforge.net/p/polyclipping/bugs/160/). Also, this issue led to duplicity vertices with the same XY coordinates but differ in Z coordinates.lh_clipper_fix

1 files changed, 9 insertions, 0 deletions

diff --git a/src/clipper/clipper.cpp b/src/clipper/clipper.cpp
index 84d68b1e6..84109398a 100644
--- a/src/clipper/clipper.cpp
+++ b/src/clipper/clipper.cpp
@@ -2290,6 +2290,12 @@ void Clipper::ProcessHorizontal(TEdge *horzEdge)
 
     if (horzEdge->OutIdx >= 0 && !IsOpen)  //note: may be done multiple times
 		{
+#ifdef CLIPPERLIB_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)
@@ -2614,6 +2620,9 @@ void Clipper::ProcessEdgesAtTopOfScanbeam(const cInt topY)
       {
         e->Curr.x() = TopX( *e, topY );
         e->Curr.y() = topY;
+#ifdef CLIPPERLIB_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