From f7967414e01da19597fdfe938bbfce770f1dee4b Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Sun, 7 Jul 2013 12:54:20 +0200
Subject: [PATCH] Store layer slices and region slices as XS data to save
 memory and make them shared across threads

---
 lib/Slic3r/ExPolygon.pm    | 3 +++
 lib/Slic3r/Layer.pm        | 4 +++-
 lib/Slic3r/Layer/Region.pm | 2 +-
 lib/Slic3r/Print/Object.pm | 4 ++--
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/lib/Slic3r/ExPolygon.pm b/lib/Slic3r/ExPolygon.pm
index c58af979f..85a31faef 100644
--- a/lib/Slic3r/ExPolygon.pm
+++ b/lib/Slic3r/ExPolygon.pm
@@ -299,6 +299,9 @@ sub medial_axis {
     return @result;
 }
 
+package Slic3r::ExPolygon::XS;
+use base 'Slic3r::ExPolygon';
+
 package Slic3r::ExPolygon::Collection;
 use Moo;
 use Slic3r::Geometry qw(X1 Y1);
diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index 77dd4ad90..8fcf87c02 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -78,7 +78,9 @@ sub region {
 # merge all regions' slices to get islands
 sub make_slices {
     my $self = shift;
-    $self->slices(union_ex([ map $_->p, map @{$_->slices}, @{$self->regions} ]));
+    
+    my $slices = union_ex([ map $_->p, map @{$_->slices}, @{$self->regions} ]);
+    $self->slices([ map Slic3r::ExPolygon::XS->new(@$_), @$slices ]);
 }
 
 sub make_perimeters {
diff --git a/lib/Slic3r/Layer/Region.pm b/lib/Slic3r/Layer/Region.pm
index 6d1d4745e..b10adc60c 100644
--- a/lib/Slic3r/Layer/Region.pm
+++ b/lib/Slic3r/Layer/Region.pm
@@ -147,7 +147,7 @@ sub _merge_loops {
     Slic3r::debugf "  %d surface(s) having %d holes detected from %d polylines\n",
         scalar(@$expolygons), scalar(map $_->holes, @$expolygons), scalar(@$loops);
     
-    return map Slic3r::Surface->new(expolygon => $_, surface_type => S_TYPE_INTERNAL), @$expolygons;
+    return map Slic3r::Surface->new(expolygon => Slic3r::ExPolygon::XS->new(@$_), surface_type => S_TYPE_INTERNAL), @$expolygons;
 }
 
 sub make_perimeters {
diff --git a/lib/Slic3r/Print/Object.pm b/lib/Slic3r/Print/Object.pm
index ae7228ff3..d40350bc4 100644
--- a/lib/Slic3r/Print/Object.pm
+++ b/lib/Slic3r/Print/Object.pm
@@ -292,8 +292,8 @@ sub make_perimeters {
                         # of our slice
                         $extra_perimeters++;
                         my $hypothetical_perimeter = diff(
-                            [ offset($slice->expolygon, -($perimeter_spacing * ($Slic3r::Config->perimeters + $extra_perimeters-1))) ],
-                            [ offset($slice->expolygon, -($perimeter_spacing * ($Slic3r::Config->perimeters + $extra_perimeters))) ],
+                            [ offset($slice->expolygon->arrayref, -($perimeter_spacing * ($Slic3r::Config->perimeters + $extra_perimeters-1))) ],
+                            [ offset($slice->expolygon->arrayref, -($perimeter_spacing * ($Slic3r::Config->perimeters + $extra_perimeters))) ],
                         );
                         last CYCLE if !@$hypothetical_perimeter;  # no extra perimeter is possible