Detection of optimal infill direction for bridges. Includes many fixes and improvements.

1 files changed, 239 insertions, 23 deletions

diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index 2f25706d3..448927142 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -2,8 +2,11 @@ package Slic3r::Layer;
 use Moo;
 
 use Math::Clipper ':all';
+use Math::ConvexHull qw(convex_hull);
 use XXX;
 
+use constant PI => 4 * atan2(1, 1);
+
 # a sequential number of layer, starting at 0
 has 'id' => (
     is          => 'ro',
@@ -26,17 +29,31 @@ has 'surfaces' => (
     default => sub { [] },
 );
 
+# collection of surfaces representing bridges
+has 'bridges' => (
+    is      => 'rw',
+    #isa     => 'ArrayRef[Slic3r::Surface::Bridge]',
+    default => sub { [] },
+);
+
+# collection of surfaces to make perimeters for
+has 'perimeter_surfaces' => (
+    is      => 'rw',
+    #isa     => 'ArrayRef[Slic3r::Surface]',
+    default => sub { [] },
+);
+
 # ordered collection of extrusion paths to build all perimeters
 has 'perimeters' => (
     is      => 'rw',
-    #isa     => 'ArrayRef[Slic3r::ExtrusionPath]',
+    #isa     => 'ArrayRef[Slic3r::ExtrusionLoop]',
     default => sub { [] },
 );
 
 # ordered collection of extrusion paths to build skirt loops
 has 'skirts' => (
     is      => 'rw',
-    #isa     => 'ArrayRef[Slic3r::ExtrusionPath]',
+    #isa     => 'ArrayRef[Slic3r::ExtrusionLoop]',
     default => sub { [] },
 );
 
@@ -44,7 +61,7 @@ has 'skirts' => (
 # they represent boundaries of areas to fill
 has 'fill_surfaces' => (
     is      => 'rw',
-    #isa     => 'ArrayRef[Slic3r::Surface]',
+    #isa     => 'ArrayRef[Slic3r::Surface::Collection]',
     default => sub { [] },
 );
 
@@ -101,18 +118,34 @@ sub remove_surface {
 }
 
 # build polylines of lines which do not already belong to a surface
+# okay, this code is a mess.  will need some refactoring.  sorry.
 sub make_polylines {
     my $self = shift;
     
     # remove line duplicates
-    {
+    if (0) {
+        # this removes any couple of coinciding Slic3r::Line::FacetEdge
+        my %lines_map = ();
+        foreach my $line (grep $_->isa('Slic3r::Line::FacetEdge'), @{ $self->lines }) {
+            my $ordered_id = $line->ordered_id;
+            if (exists $lines_map{$ordered_id}) {
+                delete $lines_map{$ordered_id};
+                next;
+            }
+            $lines_map{$ordered_id} = $line;
+        }
+        
+        @{ $self->lines } = (values(%lines_map), grep !$_->isa('Slic3r::Line::FacetEdge'), @{ $self->lines });
+    }
+    if (1) {
+        # this removes any duplicate, leaving one
         my %lines_map = map { join(',', sort map $_->id, @{$_->points} ) => "$_" } @{ $self->lines };
         %lines_map = reverse %lines_map;
         @{ $self->lines } = grep $lines_map{"$_"}, @{ $self->lines };
     }
     
     # now remove lines that are already part of a surface
-    {
+    if (1) {
         my @lines = @{ $self->lines };
         @{ $self->lines } = ();
         LINE: foreach my $line (@lines) {
@@ -130,26 +163,31 @@ sub make_polylines {
     }
     
     # make a cache of line endpoints
-    my %pointmap = ();
+    my (%pointmap) = ();
     foreach my $line (@{ $self->lines }) {
         for my $point (@{ $line->points }) {
             $pointmap{$point->id} ||= [];
             push @{ $pointmap{$point->id} }, $line;
         }
     }
-    
-    # defensive programming
-    #die "No point should be endpoint of less or more than 2 lines!"
-    #    if grep @$_ != 2, values %pointmap;
+    foreach my $point_id (keys %pointmap) {
+        $pointmap{$point_id} = [
+            sort { $a->isa('Slic3r::Line::FacetEdge') <=> $b->isa('Slic3r::Line::FacetEdge') } 
+                @{$pointmap{$point_id}} ];
+    }
     
     if (0) {
         # defensive programming
         for (keys %pointmap) {
             next if @{$pointmap{$_}} == 2;
             
-            #use Slic3r::SVG;
-            #Slic3r::SVG::output_points($main::print, "points.svg", [ map [split /,/], keys %pointmap ], [ [split /,/, $_ ] ]);
-            #Slic3r::SVG::output_lines($main::print, "lines.svg", [ map $_->p, @{$self->lines} ]);
+            use Slic3r::SVG;
+            Slic3r::SVG::output(undef, "lines_and_points.svg",
+                lines       => [ map $_->p, grep !$_->isa('Slic3r::Line::FacetEdge'), @{$self->lines} ],
+                red_lines   => [ map $_->p, grep $_->isa('Slic3r::Line::FacetEdge'), @{$self->lines} ],
+                points      => [ map [split /,/], keys %pointmap ],
+                red_points  => [ [split /,/, $_ ] ],
+            );
             
             YYY $pointmap{$_};
             
@@ -198,6 +236,11 @@ sub make_polylines {
         # remove last point as it coincides with first one
         pop @$points;
         
+        if (@$points == 1 && $first_line->isa('Slic3r::Line::FacetEdge')) {
+            Slic3r::debugf "Skipping spare facet edge";
+            next;
+        }
+        
         die sprintf "Invalid polyline with only %d points\n", scalar(@$points) if @$points < 3;
         
         Slic3r::debugf "Discovered polyline of %d points (%s)\n", scalar @$points,
@@ -336,6 +379,21 @@ sub merge_contiguous_surfaces {
         $resulting_surfaces{$type} = $result2;
     }
     
+    # remove overlapping surfaces
+    # (remove anything that is not internal from areas covered by internal surfaces)
+    # this may happen because of rounding of Z coordinates: the model could have
+    # features smaller than our layer height, so we'd get more things on a single
+    # layer
+    if (0) {  # not proven to be necessary until now
+        my $clipper = Math::Clipper->new;
+        foreach my $type (qw(bottom top)) {
+            $clipper->clear;
+            $clipper->add_subject_polygons([ map { $_->{outer}, @{$_->{holes}} } @{$resulting_surfaces{$type}} ]);
+            $clipper->add_clip_polygons([ map { $_->{outer}, @{$_->{holes}} } @{$resulting_surfaces{internal}} ]);
+            $resulting_surfaces{$type} = $clipper->ex_execute(CT_DIFFERENCE, PFT_NONZERO, PFT_NONZERO);
+        }
+    }
+    
     # save surfaces
     @{ $self->surfaces } = ();
     foreach my $type (keys %resulting_surfaces) {
@@ -357,23 +415,181 @@ sub merge_contiguous_surfaces {
     }
 }
 
-sub remove_small_features {
+sub remove_small_surfaces {
     my $self = shift;
+    my @good_surfaces = ();
     
-    # for each perimeter, try to get an inwards offset
-    # for a distance equal to half of the extrusion width;
-    # if no offset is possible, then feature is not printable
-    my @good_perimeters = ();
-    foreach my $loop (@{$self->perimeters}) {
-        my $p = $loop->p;
-        @$p = reverse @$p if !is_counter_clockwise($p);
-        my $offsets = offset([$p], -($Slic3r::flow_width / 2 / $Slic3r::resolution), $Slic3r::resolution * 100000, JT_MITER, 2);
-        push @good_perimeters, $loop if @$offsets;
+    foreach my $surface (@{$self->surfaces}) {
+        next if !$surface->contour->is_printable;
+        @{$surface->holes} = grep $_->is_printable, @{$surface->holes};
+        push @good_surfaces, $surface;
     }
+    
+    @{$self->surfaces} = @good_surfaces;
+}
+
+sub remove_small_perimeters {
+    my $self = shift;
+    my @good_perimeters = grep $_->is_printable, @{$self->perimeters};
     Slic3r::debugf "removed %d unprintable perimeters\n", (@{$self->perimeters} - @good_perimeters) 
         if @good_perimeters != @{$self->perimeters};
     
     @{$self->perimeters} = @good_perimeters;
 }
 
+# make bridges printable
+sub process_bridges {
+    my $self = shift;
+    return if $self->id == 0;
+    
+    # a bottom surface on a layer > 0 is either a bridge or a overhang 
+    # or a combination of both
+    
+    my @bottom_surfaces     = grep $_->surface_type eq 'bottom',   @{$self->surfaces} or return;
+    my @supporting_surfaces = grep $_->surface_type =~ /internal/, @{$self->surfaces};
+    
+    SURFACE: foreach my $surface (@bottom_surfaces) {
+        # since we can't print concave bridges, we transform the surface
+        # in a convex polygon; this will print thin membranes eventually
+        my $surface_p = convex_hull($surface->contour->p);
+        
+        # find all supported edges (as polylines, thus keeping notion of 
+        # consecutive supported edges)
+        my @supported_polylines = ();
+        {
+            my @current_polyline = ();
+            EDGE: foreach my $edge (Slic3r::Geometry::polygon_lines($surface_p)) {
+                for (@supporting_surfaces) {
+                    local $Slic3r::Geometry::epsilon = 1E+7;
+                    if (Slic3r::Geometry::polygon_has_subsegment($_->contour->p, $edge)) {
+                        push @current_polyline, $edge;
+                        next EDGE;
+                    }
+                }
+                if (@current_polyline) {
+                    push @supported_polylines, [@current_polyline];
+                    @current_polyline = ();
+                }
+            }
+            push @supported_polylines, [@current_polyline] if @current_polyline;
+        }
+        
+        # defensive programming, this shouldn't happen
+        if (@supported_polylines == 0) {
+            Slic3r::debugf "Found bridge/overhang with no supports on layer %d; ignoring\n", $self->id;
+            next SURFACE;
+        }
+        
+        if (@supported_polylines == 1) {
+            Slic3r::debugf "Found bridge/overhang with only one support on layer %d; ignoring\n", $self->id;
+            next SURFACE;
+        }
+        
+        # now connect the first point to the last of each polyline
+        @supported_polylines = map [ $_->[0]->[0], $_->[-1]->[-1] ], @supported_polylines;
+        
+        # if we got more than two supports, get the longest two
+        if (@supported_polylines > 2) {
+            my %lengths = map { "$_" => Slic3r::Geometry::line_length($_) }, @supported_polylines;
+            @supported_polylines = sort { $lengths{"$a"} <=> $lengths{"$b"} } @supported_polylines;
+            @supported_polylines = @supported_polylines[0,1];
+        }
+        
+        # connect the midpoints, that will give the the optimal infill direction
+        my @midpoints = map Slic3r::Geometry::midpoint($_), @supported_polylines;
+        my $bridge_angle = -Slic3r::Geometry::rad2deg(Slic3r::Geometry::line_atan(\@midpoints) + PI/2);
+        Slic3r::debugf "Optimal infill angle of bridge on layer %d is %d degrees\n", $self->id, $bridge_angle;
+        
+        # detect which neighbor surfaces are now supporting our bridge
+        my @supporting_neighbor_surfaces = ();
+        foreach my $supporting_surface (@supporting_surfaces) {
+            local $Slic3r::Geometry::epsilon = 1E+7;
+            push @supporting_neighbor_surfaces, $supporting_surface 
+                if grep Slic3r::Geometry::polygon_has_vertex($supporting_surface->contour->p, $_), 
+                    map $_->[0], @supported_polylines;
+        }
+        
+        # defensive programming, this shouldn't happen
+        if (@supporting_neighbor_surfaces == 0) {
+            Slic3r::debugf "Couldn't find supporting surfaces on layer %d; ignoring\n", $self->id;
+            next SURFACE;
+        }
+        
+        # now, extend our bridge by taking a portion of supporting surfaces
+        {
+            # offset the bridge by 5mm
+            my $bridge_offset = ${ offset([$surface_p], 5 / $Slic3r::resolution, $Slic3r::resolution * 100, JT_MITER, 2) }[0];
+            
+            # calculate the new bridge
+            my $clipper = Math::Clipper->new;
+            $clipper->add_subject_polygon($surface_p);
+            $clipper->add_subject_polygons([ map $_->p, @supporting_neighbor_surfaces ]);
+            $clipper->add_clip_polygon($bridge_offset);
+            my $intersection = $clipper->execute(CT_INTERSECTION, PFT_NONZERO, PFT_NONZERO);
+            
+            push @{$self->bridges}, map Slic3r::Surface::Bridge->cast_from_polygon($_,
+                surface_type => 'bottom',
+                bridge_angle => $bridge_angle,
+            ), @$intersection;
+        }
+    }
+}
+
+# generates a set of surfaces that will be used to make perimeters
+# thus, we need to merge internal surfaces and bridges
+sub detect_perimeter_surfaces {
+    my $self = shift;
+    
+    # little optimization: skip the Clipper UNION if we have no bridges
+    if (!@{$self->bridges}) {
+        push @{$self->perimeter_surfaces}, @{$self->surfaces};
+    } else {
+        my $clipper = Math::Clipper->new;
+        $clipper->add_subject_polygons([ map $_->p, grep $_->surface_type =~ /internal/, @{$self->surfaces} ]);
+        $clipper->add_clip_polygons([ map $_->p, @{$self->bridges} ]);
+        my $union = $clipper->ex_execute(CT_UNION, PFT_NONZERO, PFT_NONZERO);
+        
+        push @{$self->perimeter_surfaces}, 
+            map Slic3r::Surface->cast_from_expolygon($_, surface_type => 'internal'), 
+            @$union;
+        
+        push @{$self->perimeter_surfaces}, 
+            grep $_->surface_type !~ /internal/ && ($_->surface_type ne 'bottom' || $self->id == 0), 
+            @{$self->surfaces};
+    }
+}
+
+# splits fill_surfaces in internal and bridge surfaces
+sub split_bridges_fills {
+    my $self = shift;
+    
+    my $clipper = Math::Clipper->new;
+    foreach my $surf_coll (@{$self->fill_surfaces}) {
+        my @surfaces = @{$surf_coll->surfaces};
+        @{$surf_coll->surfaces} = ();
+        
+        # intersect fill_surfaces with bridges to get actual bridges
+        foreach my $bridge (@{$self->bridges}) {
+            $clipper->clear;
+            $clipper->add_subject_polygons([ map $_->p, @surfaces ]);
+            $clipper->add_clip_polygon($bridge->contour->p);
+            my $intersection = $clipper->ex_execute(CT_INTERSECTION, PFT_NONZERO, PFT_NONZERO);
+            push @{$surf_coll->surfaces}, map Slic3r::Surface::Bridge->cast_from_expolygon($_,
+                surface_type => 'bottom',
+                bridge_angle => $bridge->bridge_angle,
+            ), @$intersection;
+        }
+        
+        # difference between fill_surfaces and bridges are the other surfaces
+        foreach my $surface (@surfaces) {
+            $clipper->clear;
+            $clipper->add_subject_polygons([ $surface->p ]);
+            $clipper->add_clip_polygons([ map $_->contour->p, @{$self->bridges} ]);
+            my $difference = $clipper->ex_execute(CT_DIFFERENCE, PFT_NONZERO, PFT_NONZERO);
+            push @{$surf_coll->surfaces}, map Slic3r::Surface->cast_from_expolygon($_,
+                surface_type => $surface->surface_type), @$difference;
+        }
+    }
+}
+
 1;