From b0042882c9a87de6df7108823bf488a6d57b1015 Mon Sep 17 00:00:00 2001
From: Adrian Mariano <avm4@cornell.edu>
Date: Sat, 21 Jan 2023 13:36:33 -0500
Subject: [PATCH] fix vnf_vertex_array bug where zero area faces don't get
 removed

---
 skin.scad | 33 ++-------------------------------
 vnf.scad  |  5 ++---
 2 files changed, 4 insertions(+), 34 deletions(-)

diff --git a/skin.scad b/skin.scad
index 19187f5..4d9dbcf 100644
--- a/skin.scad
+++ b/skin.scad
@@ -2585,9 +2585,9 @@ function associate_vertices(polygons, split, curpoly=0) =
 //   Another serious limitation is more subtle.  In the 2D examples above, it is obvious how to connect the
 //   dots together.  But in 3D example we need to triangulate the points on a grid, and this triangulation is not unique.
 //   The `style` argument lets you specify how the points are triangulated using the styles supported by {{vnf_vertex_array()}}.
-//   In the example below we have expanded the 2D example into 3D: [[0,0,0,0],[0,1,1,0],[0,1,1,0],[0,0,0,0]], and we show the
+//   In the example below we have expanded the 2D example into 3D: `[[0,0,0,0],[0,1,1,0],[0,1,1,0],[0,0,0,0]]`, and we show the
 //   3D triangulations produced by the different styles:
-// Figure(Big, NoAxes, VPR = [39.2, 0, 13.3], VPT = [3.76242, -5.50969, 4.51854], VPD = 32.0275):
+// Figure(Big,NoAxes,VPR=[39.2,0,13.3],VPT=[3.76242,-5.50969,4.51854],VPD=32.0275):
 //   tex = [
 //          [0,0,0,0,0],
 //          [0,1,1,0,0],
@@ -3432,35 +3432,6 @@ function _textured_linear_sweep(
     ) reorient(anchor,spin,orient, vnf=final_vnf, extent=true, anchors=anchors, p=final_vnf);
 
 
-module _textured_linear_sweep(
-    path, texture, tex_size=[5,5], h,
-    inset=false, rot=false, tex_scale=1,
-    twist, scale, shift, samples, caps=true, 
-    style="min_edge", l,
-    height, length, counts,
-    anchor=CENTER, spin=0, orient=UP,
-    convexity=10
-) {
-    h = first_defined([h, l, height, length, 1]);
-    vnf = _textured_linear_sweep(
-        path, texture, h=h, caps=caps, 
-        tex_size=tex_size, counts=counts,
-        inset=inset, rot=rot, tex_scale=tex_scale,
-        twist=twist, scale=scale, shift=shift,
-        samples=samples, style=style,
-        anchor=CENTER, spin=0, orient=UP
-    );
-    cent = centroid(path);
-    anchors = [
-        named_anchor("centroid_top", point3d(cent, h/2), UP),
-        named_anchor("centroid",     point3d(cent),      UP),
-        named_anchor("centroid_bot", point3d(cent,-h/2), DOWN)
-    ];
-    attachable(anchor,spin,orient, vnf=vnf, extent=true, anchors=anchors) {
-        vnf_polyhedron(vnf, convexity=convexity);
-        children();
-    }
-}
 
 function _find_vnf_tile_edge_path(vnf, val) =
     let(
diff --git a/vnf.scad b/vnf.scad
index b4c52e8..1f34297 100644
--- a/vnf.scad
+++ b/vnf.scad
@@ -206,9 +206,8 @@ function vnf_vertex_array(
                       : [[i1,i3,i2],[i1,i4,i3]],
                    // remove degenerate faces
                    culled_faces= [for(face=faces)
-                       if (norm(verts[face[0]]-verts[face[1]])>EPSILON &&
-                           norm(verts[face[1]]-verts[face[2]])>EPSILON &&
-                           norm(verts[face[2]]-verts[face[0]])>EPSILON)
+                       if (norm(cross(verts[face[1]]-verts[face[0]],
+                                      verts[face[2]]-verts[face[0]]))>EPSILON)
                            face
                    ],
                    rfaces = reverse? [for (face=culled_faces) reverse(face)] : culled_faces