Reapply correct optimization for simplifiying fill_surfaces before performing the offset. #1325

lib/Slic3r/ExPolygon.pm

@@ -145,15 +145,21 @@ sub clip_line {
     return Boost::Geometry::Utils::polygon_multi_linestring_intersection($self, [$line]);
 }
 
-sub simplify {
+sub simplify_as_polygons {
     my $self = shift;
     my ($tolerance) = @_;
     
     # it would be nice to have a multilinestring_simplify method in B::G::U
-    my @simplified = Slic3r::Geometry::Clipper::simplify_polygons(
+    return Slic3r::Geometry::Clipper::simplify_polygons(
         [ map Boost::Geometry::Utils::linestring_simplify($_, $tolerance), @$self ],
     );
-    return @{ Slic3r::Geometry::Clipper::union_ex([ @simplified ]) };
+}
+
+sub simplify {
+    my $self = shift;
+    my ($tolerance) = @_;
+    
+    return @{ Slic3r::Geometry::Clipper::union_ex([ $self->simplify_as_polygons($tolerance) ]) };
 }
 
 sub scale {

lib/Slic3r/Geometry/Clipper.pm

@@ -150,12 +150,14 @@ sub collapse_ex {
 
 sub simplify_polygon {
     my ($polygon, $pft) = @_;
-    return @{ Math::Clipper::simplify_polygon($polygon, $pft // PFT_NONZERO) };
+    return map Slic3r::Polygon->new(@$_),
+        @{ Math::Clipper::simplify_polygon($polygon, $pft // PFT_NONZERO) };
 }
 
 sub simplify_polygons {
     my ($polygons, $pft) = @_;
-    return @{ Math::Clipper::simplify_polygons($polygons, $pft // PFT_NONZERO) };
+    return map Slic3r::Polygon->new(@$_),
+        @{ Math::Clipper::simplify_polygons($polygons, $pft // PFT_NONZERO) };
 }
 
 sub traverse_pt {

lib/Slic3r/Layer/Region.pm

@@ -209,12 +209,11 @@ sub make_perimeters {
         # and then we offset back and forth by the infill spacing to only consider the
         # non-collapsing regions
         push @{ $self->fill_surfaces },
-            map $_->simplify(&Slic3r::SCALED_RESOLUTION),
-                offset2_ex(
-                    \@last,
-                    -($perimeter_spacing/2 + $infill_spacing),
-                    +$infill_spacing,
-                );
+            offset2_ex(
+                [ map $_->simplify_as_polygons(&Slic3r::SCALED_RESOLUTION), @{union_ex(\@last)} ],
+                -($perimeter_spacing/2 + $infill_spacing),
+                +$infill_spacing,
+            );
     }
     
     $self->_fill_gaps(\@gaps);

lib/Slic3r/Polygon.pm

@@ -72,6 +72,8 @@ sub grow {
     return $self->split_at_first_point->grow(@_);
 }
 
+# NOTE that this will turn the polygon to ccw regardless of its 
+# original orientation
 sub simplify {
     my $self = shift;
     return Slic3r::Geometry::Clipper::simplify_polygon( $self->SUPER::simplify(@_) );