Fixed regression causing some bridges not to be detected correctly. #629

lib/Slic3r/ExPolygon.pm

@@ -61,13 +61,12 @@ sub boost_polygon {
 
 sub offset {
     my $self = shift;
-    my ($distance, $scale, $joinType, $miterLimit) = @_;
-    $scale      ||= &Slic3r::SCALING_FACTOR * 1000000;
-    $joinType   = JT_MITER if !defined $joinType;
-    $miterLimit ||= 2;
-    
-    my $offsets = Math::Clipper::offset($self, $distance, $scale, $joinType, $miterLimit);
-    return @$offsets;
+    return Slic3r::Geometry::Clipper::offset($self, @_);
+}
+
+sub offset_ex {
+    my $self = shift;
+    return Slic3r::Geometry::Clipper::offset_ex($self, @_);
 }
 
 sub safety_offset {
@@ -83,14 +82,6 @@ sub safety_offset {
     );
 }
 
-sub offset_ex {
-    my $self = shift;
-    my @offsets = $self->offset(@_);
-    
-    # apply holes to the right contours
-    return @{ union_ex(\@offsets) };
-}
-
 sub encloses_point {
     my $self = shift;
     my ($point) = @_;

lib/Slic3r/Geometry/Clipper.pm

@@ -4,11 +4,11 @@ use warnings;
 
 require Exporter;
 our @ISA = qw(Exporter);
-our @EXPORT_OK = qw(explode_expolygon explode_expolygons safety_offset offset
+our @EXPORT_OK = qw(explode_expolygon explode_expolygons safety_offset offset offset_ex
     diff_ex diff union_ex intersection_ex xor_ex PFT_EVENODD JT_MITER JT_ROUND
     JT_SQUARE is_counter_clockwise);
 
-use Math::Clipper 1.09 ':all';
+use Math::Clipper 1.09 qw(:cliptypes :polyfilltypes :jointypes is_counter_clockwise area);
 use Slic3r::Geometry qw(scale);
 our $clipper = Math::Clipper->new;
 
@@ -27,6 +27,21 @@ sub safety_offset {
     return Math::Clipper::offset($polygons, $factor || (scale 1e-05), 100, JT_MITER, 2);
 }
 
+sub offset {
+    my ($polygons, $distance, $scale, $joinType, $miterLimit) = @_;
+    $scale      ||= &Slic3r::SCALING_FACTOR * 1000000;
+    $joinType   = JT_MITER if !defined $joinType;
+    $miterLimit ||= 2;
+    
+    my $offsets = Math::Clipper::offset($polygons, $distance, $scale, $joinType, $miterLimit);
+    return @$offsets;
+}
+
+sub offset_ex {
+    # offset polygons and then apply holes to the right contours
+    return @{ union_ex([ offset(@_) ]) };
+}
+
 sub diff_ex {
     my ($subject, $clip, $safety_offset) = @_;
     

lib/Slic3r/Layer.pm

@@ -358,13 +358,30 @@ sub prepare_fill_surfaces {
     if ($Slic3r::Config->fill_density == 0) {
         @surfaces = grep $_->surface_type != S_TYPE_INTERNAL, @surfaces;
     }
+    
+    # remove unprintable regions (they would slow down the infill process and also cause
+    # some weird failures during bridge neighbor detection)
+    {
+        my $distance = scale $self->infill_flow->spacing / 2;
+        @surfaces = map {
+            my $surface = $_;
+            
+            # offset inwards
+            my @offsets = $surface->expolygon->offset_ex(-$distance);
+            @offsets = @{union_ex(Math::Clipper::offset([ map @$_, @offsets ], $distance, 100, JT_MITER))};
+            map Slic3r::Surface->new(
+                expolygon => $_,
+                surface_type => $surface->surface_type,
+            ), @offsets;
+        } @surfaces;
+    }
         
     # turn too small internal regions into solid regions
     {
         my $min_area = scale scale $Slic3r::Config->solid_infill_below_area; # scaling an area requires two calls!
         my @small = grep $_->surface_type == S_TYPE_INTERNAL && $_->expolygon->contour->area <= $min_area, @surfaces;
         $_->surface_type(S_TYPE_INTERNALSOLID) for @small;
-        Slic3r::debugf "identified %d small surfaces at layer %d\n", scalar(@small), $self->id if @small > 0;
+        Slic3r::debugf "identified %d small solid surfaces at layer %d\n", scalar(@small), $self->id if @small > 0;
     }
     
     $self->fill_surfaces([@surfaces]);

lib/Slic3r/Polygon.pm

@@ -71,13 +71,7 @@ sub safety_offset {
 
 sub offset {
     my $self = shift;
-    my ($distance, $scale, $joinType, $miterLimit) = @_;
-    $scale      ||= &Slic3r::SCALING_FACTOR * 1000000;
-    $joinType   = JT_MITER if !defined $joinType;
-    $miterLimit ||= 2;
-    
-    my $offsets = Math::Clipper::offset([$self], $distance, $scale, $joinType, $miterLimit);
-    return map Slic3r::Polygon->new($_), @$offsets;
+    return map Slic3r::Polygon->new($_), Slic3r::Geometry::Clipper::offset([$self], @_);
 }
 
 # this method subdivides the polygon segments to that no one of them

lib/Slic3r/Print.pm

@@ -497,7 +497,7 @@ sub make_skirt {
     my @skirt = ();
     for (my $i = $Slic3r::Config->skirts; $i > 0; $i--) {
         my $distance = scale ($Slic3r::Config->skirt_distance + ($flow->spacing * $i));
-        my $outline = offset([$convex_hull], $distance, &Slic3r::SCALING_FACTOR * 100, JT_ROUND);
+        my $outline = Math::Clipper::offset([$convex_hull], $distance, &Slic3r::SCALING_FACTOR * 100, JT_ROUND);
         push @skirt, Slic3r::ExtrusionLoop->pack(
             polygon => Slic3r::Polygon->new(@{$outline->[0]}),
             role => EXTR_ROLE_SKIRT,