From a73020c10e586b35db54d52103fdbed5ce79c044 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Mon, 13 May 2013 21:22:57 +0200
Subject: [PATCH] Faster implementation of concentric infill, with loop order
 reversed so that smaller loops will be printed at the end. #898

---
 lib/Slic3r/ExtrusionPath/Collection.pm |  3 ++
 lib/Slic3r/Fill.pm                     |  1 +
 lib/Slic3r/Fill/Concentric.pm          | 54 +++++++-------------------
 3 files changed, 18 insertions(+), 40 deletions(-)

diff --git a/lib/Slic3r/ExtrusionPath/Collection.pm b/lib/Slic3r/ExtrusionPath/Collection.pm
index f523a3076..5a4af96de 100644
--- a/lib/Slic3r/ExtrusionPath/Collection.pm
+++ b/lib/Slic3r/ExtrusionPath/Collection.pm
@@ -2,6 +2,7 @@ package Slic3r::ExtrusionPath::Collection;
 use Moo;
 
 has 'paths' => (is => 'rw', default => sub { [] });
+has 'no_sort' => (is => 'rw');
 
 # no-op
 sub unpack { $_[0] }
@@ -15,6 +16,8 @@ sub chained_path {
     my $self = shift;
     my ($start_near) = @_;
     
+    return @{$self->paths} if $self->no_sort;
+    
     # make sure we pass the same path objects to the Collection constructor
     # and the ->chained_path() method because the latter will reverse the
     # paths in-place when needed and we need to return them that way
diff --git a/lib/Slic3r/Fill.pm b/lib/Slic3r/Fill.pm
index 177420055..68b677c9f 100644
--- a/lib/Slic3r/Fill.pm
+++ b/lib/Slic3r/Fill.pm
@@ -176,6 +176,7 @@ sub make_fill {
         # save into layer
         next unless @paths;
         push @fills, Slic3r::ExtrusionPath::Collection->new(
+            no_sort => $params->{no_sort},
             paths => [
                 map Slic3r::ExtrusionPath->pack(
                     polyline => Slic3r::Polyline->new(@$_),
diff --git a/lib/Slic3r/Fill/Concentric.pm b/lib/Slic3r/Fill/Concentric.pm
index 0f1cce8d8..0d8488097 100644
--- a/lib/Slic3r/Fill/Concentric.pm
+++ b/lib/Slic3r/Fill/Concentric.pm
@@ -3,8 +3,8 @@ use Moo;
 
 extends 'Slic3r::Fill::Base';
 
-use Slic3r::ExtrusionPath ':roles';
-use Slic3r::Geometry qw(scale unscale X1 Y1 X2 Y2);
+use Slic3r::Geometry qw(scale unscale X1 X2);
+use Slic3r::Geometry::Clipper qw(offset2 union_pt traverse_pt PFT_EVENODD);
 
 sub fill_surface {
     my $self = shift;
@@ -27,48 +27,22 @@ sub fill_surface {
         $flow_spacing = unscale $distance;
     }
     
-    my @contour_loops = ();
-    my @hole_loops = ();
-    my @last_offsets = ($expolygon->offset_ex($distance));
-    while (@last_offsets) {
-        my @new_offsets = ();
-        foreach my $last_expolygon (@last_offsets) {
-            my @offsets = $last_expolygon->offset_ex(-$distance);
-            foreach my $offset (@offsets) {
-                push @new_offsets, $offset;
-                push @contour_loops, $offset->contour;
-                push @hole_loops, $offset->holes;
-            }
-        }
-        @last_offsets = @new_offsets;
+    my @loops = my @last = @$expolygon;
+    while (@last) {
+        push @loops, @last = offset2(\@last, -1.5*$distance,  +0.5*$distance);
     }
     
-    my @loops = (@contour_loops, reverse @hole_loops);
+    # generate paths from the outermost to the innermost, to avoid 
+    # adhesion problems of the first central tiny loops
+    my @paths = map Slic3r::Polygon->new(@$_)->split_at_first_point,
+        reverse traverse_pt( union_pt(\@loops, PFT_EVENODD) );
     
-    # make paths
-    my @paths = ();
-    my $cur_pos = Slic3r::Point->new(
-        ($bounding_box->[X1] + $bounding_box->[X2]) / 2,
-        ($bounding_box->[Y1] + $bounding_box->[Y2]) / 2,
-    );
-    foreach my $loop (@loops) {
-        # extrude all loops ccw
-        $loop->make_counter_clockwise;
-        
-        # find the point of the loop that is closest to the current extruder position
-        my $index = $loop->nearest_point_index_to($cur_pos);
-        $cur_pos = $loop->[0];
-        
-        # split the loop at the starting point and make a path
-        my $path = $loop->split_at_index($index);
-        
-        # clip the path to avoid the extruder to get exactly on the first point of the loop
-        $path->clip_end(scale $flow_spacing * &Slic3r::LOOP_CLIPPING_LENGTH_OVER_SPACING);
-        
-        push @paths, $path if @$path;
-    }
+    # clip the paths to avoid the extruder to get exactly on the first point of the loop
+    my $clip_length = scale $flow_spacing * &Slic3r::LOOP_CLIPPING_LENGTH_OVER_SPACING;
+    $_->clip_end($clip_length) for @paths;
     
-    return { flow_spacing => $flow_spacing }, @paths;
+    # TODO: return ExtrusionLoop objects to get better chained paths
+    return { flow_spacing => $flow_spacing, no_sort => 1 }, @paths;
 }
 
 1;