From 2ea90b74671356bf1d2aa4bb4a14a66a84423933 Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Mon, 13 Sep 2021 22:23:20 -0400
Subject: [PATCH] add fix for duplicate points in polygon_triangulation

---
 geometry.scad | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/geometry.scad b/geometry.scad
index ae70d06..cdcd4f0 100644
--- a/geometry.scad
+++ b/geometry.scad
@@ -1455,8 +1455,9 @@ function point_in_polygon(point, poly, nonzero=false, eps=EPSILON) =
 //   are considered as vertices of the polygon.
 //   .
 //   The function may issue an error if it finds that the polygon is not simple
-//   (self-intersecting) or its vertices are collinear. An error may also be issued
-//   for 3d non planar polygons.
+//   (self-intersecting) or its vertices are collinear.  It can work for 3d non-planar polygons
+//   if they are close enough to planar but may otherwise issue an error for this case.
+//   .
 //   For 2d polygons, the output triangles will have the same winding (CW or CCW) of
 //   the input polygon. For 3d polygons, the triangle windings will induce a normal
 //   vector with the same direction of the polygon normal.
@@ -1485,7 +1486,7 @@ function polygon_triangulation(poly, ind, eps=EPSILON) =
     assert(is_undef(ind) 
            || (is_vector(ind) && min(ind)>=0 && max(ind)<len(poly) ),
            "Improper or out of bounds list of indices")
-    let( ind = is_undef(ind) ? count(len(poly)) : ind )
+    let( ind = deduplicate_indexed(poly,is_undef(ind) ? count(len(poly)) : ind) )
     len(poly[ind[0]]) == 3 
       ? // represents the polygon projection on its plane as a 2d polygon 
         let( 
@@ -1502,7 +1503,7 @@ function polygon_triangulation(poly, ind, eps=EPSILON) =
             prpts = pts*transpose([v1,v2])
         )
         [for(tri=_triangulate(prpts, count(len(ind)), eps)) select(ind,tri) ]
-      : let( cw = polygon_is_clockwise(select(poly, ind)) )
+      : let( cw = is_polygon_clockwise(select(poly, ind)) )
         cw 
           ? [for(tri=_triangulate( poly, reverse(ind), eps )) reverse(tri) ]
           : _triangulate( poly, ind, eps );