From debdd164e20c89786701a8f1be452f16c049b382 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Sat, 21 Jan 2012 18:44:24 +0100
Subject: [PATCH] Bugfix: fatal error and warnings removed when cleaning some
 dirty layers

---
 lib/Slic3r/Geometry.pm     | 2 +-
 lib/Slic3r/Polygon.pm      | 1 +
 lib/Slic3r/TriangleMesh.pm | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/Slic3r/Geometry.pm b/lib/Slic3r/Geometry.pm
index 6652a49d..4166fa49 100644
--- a/lib/Slic3r/Geometry.pm
+++ b/lib/Slic3r/Geometry.pm
@@ -654,7 +654,7 @@ sub angle3points {
 sub polyline_remove_parallel_continuous_edges {
     my ($points, $isPolygon) = @_;
     
-    for (my $i = $isPolygon ? 0 : 2; $i <= $#$points; $i++) {
+    for (my $i = $isPolygon ? 0 : 2; $i <= $#$points && @$points >= 3; $i++) {
         if (Slic3r::Geometry::lines_parallel([$points->[$i-2], $points->[$i-1]], [$points->[$i-1], $points->[$i]])) {
             # we can remove $points->[$i-1]
             splice @$points, $i-1, 1;
diff --git a/lib/Slic3r/Polygon.pm b/lib/Slic3r/Polygon.pm
index 1c5d9021..b3bab44a 100644
--- a/lib/Slic3r/Polygon.pm
+++ b/lib/Slic3r/Polygon.pm
@@ -38,6 +38,7 @@ sub lines {
 sub cleanup {
     my $self = shift;
     $self->merge_continuous_lines;
+    return @$self >= 3;
 }
 
 sub merge_continuous_lines {
diff --git a/lib/Slic3r/TriangleMesh.pm b/lib/Slic3r/TriangleMesh.pm
index 1d68804a..e67c514e 100644
--- a/lib/Slic3r/TriangleMesh.pm
+++ b/lib/Slic3r/TriangleMesh.pm
@@ -166,7 +166,7 @@ sub make_loops {
             pop @points;
             Slic3r::debugf "  Discovered polygon of %d points\n", scalar(@points);
             push @polygons, Slic3r::Polygon->new(@points);
-            $polygons[-1]->cleanup;
+            pop @polygons if !$polygons[-1]->cleanup;
         }
     };