From 93a7d87fc66aabd3554dca2c320d942789d634a9 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Mon, 7 Apr 2014 15:24:17 +0200
Subject: [PATCH] Bugfix: pillars support material crashed when no overhangs
 were detected

---
 lib/Slic3r/Print/SupportMaterial.pm | 5 ++++-
 xs/src/BoundingBox.cpp              | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/Slic3r/Print/SupportMaterial.pm b/lib/Slic3r/Print/SupportMaterial.pm
index 864d2682..724ecc92 100644
--- a/lib/Slic3r/Print/SupportMaterial.pm
+++ b/lib/Slic3r/Print/SupportMaterial.pm
@@ -647,6 +647,9 @@ sub generate_toolpaths {
 sub generate_pillars_shape {
     my ($self, $contact, $support_z, $shape) = @_;
     
+    # this prevents supplying an empty point set to BoundingBox constructor
+    return if !%$contact;
+    
     my $pillar_size     = scale PILLAR_SIZE;
     my $pillar_spacing  = scale PILLAR_SPACING;
     
@@ -658,7 +661,7 @@ sub generate_pillars_shape {
             [$pillar_size, $pillar_size],
             [0, $pillar_size],
         );
-    
+        
         my @pillars = ();
         my $bb = Slic3r::Geometry::BoundingBox->new_from_points([ map @$_, map @$_, values %$contact ]);
         for (my $x = $bb->x_min; $x <= $bb->x_max-$pillar_size; $x += $pillar_spacing) {
diff --git a/xs/src/BoundingBox.cpp b/xs/src/BoundingBox.cpp
index 70d688e5..44641411 100644
--- a/xs/src/BoundingBox.cpp
+++ b/xs/src/BoundingBox.cpp
@@ -6,6 +6,7 @@ namespace Slic3r {
 template <class PointClass>
 BoundingBoxBase<PointClass>::BoundingBoxBase(const std::vector<PointClass> &points)
 {
+    if (points.empty()) CONFESS("Empty point set supplied to BoundingBoxBase constructor");
     typename std::vector<PointClass>::const_iterator it = points.begin();
     this->min.x = this->max.x = it->x;
     this->min.y = this->max.y = it->y;
@@ -22,6 +23,7 @@ template <class PointClass>
 BoundingBox3Base<PointClass>::BoundingBox3Base(const std::vector<PointClass> &points)
     : BoundingBoxBase<PointClass>(points)
 {
+    if (points.empty()) CONFESS("Empty point set supplied to BoundingBox3Base constructor");
     typename std::vector<PointClass>::const_iterator it = points.begin();
     this->min.z = this->max.z = it->z;
     for (++it; it != points.end(); ++it) {