[Feature] Enabled gap fill algorithm for all solid fill types (#3412)

* ENH: Enabled gap fill algorithm for all solid fill types

* Made gap fill an option & refactored code into its own method

* Code comment updates

* Converted gap fill to enum and control filter out gap fill in the UI

* Update label for consistency

* Spelling mistake

src/libslic3r/Fill/FillBase.cpp

@@ -67,7 +67,8 @@ Fill* Fill::new_from_type(const InfillPattern type)
     // BBS: for internal solid infill only
     case ipConcentricInternal:  return new FillConcentricInternal();
     // BBS: for bottom and top surface only
-    case ipMonotonicLine:       return new FillMonotonicLineWGapFill();
+    // Orca: Replace BBS implementation with Prusa implementation
+    case ipMonotonicLine:       return new FillMonotonicLines();
     default: throw Slic3r::InvalidArgument("unknown type");
     }
 }
@@ -173,6 +174,66 @@ void Fill::fill_surface_extrusion(const Surface* surface, const FillParams& para
             for (size_t i = idx; i < eec->entities.size(); i++)
                 eec->entities[i]->set_reverse();
         }
+        
+        // Orca: run gap fill
+        this->_create_gap_fill(surface, params, eec);
+    }
+}
+
+// Orca: Dedicated function to calculate gap fill lines for the provided surface, according to the print object parameters
+// and append them to the out ExtrusionEntityCollection.
+void Fill::_create_gap_fill(const Surface* surface, const FillParams& params, ExtrusionEntityCollection* out){
+    
+    //Orca: just to be safe, check against null pointer for the print object config and if NULL return.
+    if (this->print_object_config == nullptr) return;
+    
+    // Orca: Enable gap fill as per the user preference. Return early if gap fill is to not be applied.
+    if ((this->print_object_config->gap_fill_target.value == gftNowhere) ||
+        (surface->surface_type == stInternalSolid && this->print_object_config->gap_fill_target.value != gftEverywhere))
+        return;
+    
+    Flow new_flow = params.flow;
+    ExPolygons unextruded_areas;
+    unextruded_areas = diff_ex(this->no_overlap_expolygons, union_ex(out->polygons_covered_by_spacing(10)));
+    ExPolygons gapfill_areas = union_ex(unextruded_areas);
+    if (!this->no_overlap_expolygons.empty())
+        gapfill_areas = intersection_ex(gapfill_areas, this->no_overlap_expolygons);
+    
+    if (gapfill_areas.size() > 0 && params.density >= 1) {
+        double min = 0.2 * new_flow.scaled_spacing() * (1 - INSET_OVERLAP_TOLERANCE);
+        double max = 2. * new_flow.scaled_spacing();
+        ExPolygons gaps_ex = diff_ex(
+                                     opening_ex(gapfill_areas, float(min / 2.)),
+                                     offset2_ex(gapfill_areas, -float(max / 2.), float(max / 2. + ClipperSafetyOffset)));
+        //BBS: sort the gap_ex to avoid mess travel
+        Points ordering_points;
+        ordering_points.reserve(gaps_ex.size());
+        ExPolygons gaps_ex_sorted;
+        gaps_ex_sorted.reserve(gaps_ex.size());
+        for (const ExPolygon &ex : gaps_ex)
+            ordering_points.push_back(ex.contour.first_point());
+        std::vector<Points::size_type> order2 = chain_points(ordering_points);
+        for (size_t i : order2)
+            gaps_ex_sorted.emplace_back(std::move(gaps_ex[i]));
+        
+        ThickPolylines polylines;
+        for (ExPolygon& ex : gaps_ex_sorted) {
+            //BBS: Use DP simplify to avoid duplicated points and accelerate medial-axis calculation as well.
+            ex.douglas_peucker(SCALED_RESOLUTION * 0.1);
+            ex.medial_axis(min, max, &polylines);
+        }
+        
+        if (!polylines.empty() && !is_bridge(params.extrusion_role)) {
+            polylines.erase(std::remove_if(polylines.begin(), polylines.end(),
+                                           [&](const ThickPolyline& p) {
+                return p.length() < scale_(params.config->filter_out_gap_fill.value);
+            }), polylines.end());
+            
+            ExtrusionEntityCollection gap_fill;
+            variable_width(polylines, erGapFill, params.flow, gap_fill.entities);
+            auto gap = std::move(gap_fill.entities);
+            out->append(gap);
+        }
     }
 }
 

src/libslic3r/Fill/FillBase.hpp

@@ -19,6 +19,7 @@
 #include "../Flow.hpp"
 #include "../ExtrusionEntity.hpp"
 #include "../ExtrusionEntityCollection.hpp"
+#include "../ShortestPath.hpp"
 
 namespace Slic3r {
 
@@ -106,6 +107,7 @@ public:
     FillAdaptive::Octree* adapt_fill_octree = nullptr;
 
     // PrintConfig and PrintObjectConfig are used by infills that use Arachne (Concentric and FillEnsuring).
+    // Orca: also used by gap fill function.
     const PrintConfig       *print_config        = nullptr;
     const PrintObjectConfig *print_object_config = nullptr;
 
@@ -173,6 +175,10 @@ protected:
 
     virtual std::pair<float, Point> _infill_direction(const Surface *surface) const;
     
+    // Orca: Dedicated function to calculate gap fill lines for the provided surface, according to the print object parameters
+    // and append them to the out ExtrusionEntityCollection.
+    void _create_gap_fill(const Surface* surface, const FillParams& params, ExtrusionEntityCollection* out);
+
 public:
     static void connect_infill(Polylines &&infill_ordered, const ExPolygon &boundary, Polylines &polylines_out, const double spacing, const FillParams &params);
     static void connect_infill(Polylines &&infill_ordered, const Polygons &boundary, const BoundingBox& bbox, Polylines &polylines_out, const double spacing, const FillParams &params);

src/libslic3r/Fill/FillRectilinear.cpp

@@ -3099,7 +3099,22 @@ Points sample_grid_pattern(const Polygons& polygons, coord_t spacing, const Boun
     return sample_grid_pattern(union_ex(polygons), spacing, global_bounding_box);
 }
 
-void FillMonotonicLineWGapFill::fill_surface_extrusion(const Surface* surface, const FillParams& params, ExtrusionEntitiesPtr& out)
+// Orca: Introduced FillMonotonicLines from Prusa slicer, inhereting from FillRectilinear
+// This replaces the FillMonotonicLineWGapFill from BBS
+Polylines FillMonotonicLines::fill_surface(const Surface *surface, const FillParams &params)
+{
+    FillParams params2 = params;
+    params2.monotonic = true;
+    params2.anchor_length_max = 0.0f;
+    Polylines polylines_out;
+    if (! fill_surface_by_lines(surface, params2, 0.f, 0.f, polylines_out))
+        BOOST_LOG_TRIVIAL(error) << "FillMonotonicLines::fill_surface() failed to fill a region.";
+    return polylines_out;
+}
+    
+// Orca: Replaced with FillMonotonicLines from Prusa slicer. Moved gap fill algorithm to
+// FillBase to perform gap fill for all fill types.
+/*void FillMonotonicLineWGapFill::fill_surface_extrusion(const Surface* surface, const FillParams& params, ExtrusionEntitiesPtr& out)
 {
     ExtrusionEntityCollection *coll_nosort = new ExtrusionEntityCollection();
     coll_nosort->no_sort = this->no_sort();
@@ -3274,7 +3289,7 @@ void FillMonotonicLineWGapFill::fill_surface_by_lines(const Surface* surface, co
         //assert(! it->has_duplicate_points());
         it->remove_duplicate_points();
     }
-}
+}*/
 
 
 } // namespace Slic3r

src/libslic3r/Fill/FillRectilinear.hpp

@@ -119,7 +119,19 @@ protected:
     float _layer_angle(size_t idx) const override { return 0.f; }
 };
 
-class FillMonotonicLineWGapFill : public Fill
+// Orca: Introduced FillMonotonicLines from Prusa slicer, inhereting from FillRectilinear
+// This replaces the FillMonotonicLineWGapFill from BBS
+class FillMonotonicLines : public FillRectilinear
+{
+public:
+    Fill* clone() const override { return new FillMonotonicLines(*this); }
+    ~FillMonotonicLines() override = default;
+    Polylines fill_surface(const Surface *surface, const FillParams &params) override;
+    bool no_sort() const override { return true; }
+};
+
+//Orca: Replaced with FillMonotonicLines, inheriting from FillRectilinear
+/*class FillMonotonicLineWGapFill : public Fill
 {
 public:
     ~FillMonotonicLineWGapFill() override = default;
@@ -131,7 +143,7 @@ protected:
 
 private:
     void fill_surface_by_lines(const Surface* surface, const FillParams& params, Polylines& polylines_out);
-};
+};*/
 
 Points sample_grid_pattern(const ExPolygon& expolygon, coord_t spacing, const BoundingBox& global_bounding_box);
 Points sample_grid_pattern(const ExPolygons& expolygons, coord_t spacing, const BoundingBox& global_bounding_box);

src/libslic3r/Preset.cpp

@@ -771,7 +771,7 @@ static std::vector<std::string> s_Preset_print_options {
     "extra_perimeters_on_overhangs", "ensure_vertical_shell_thickness","reduce_wall_solid_infill", "reduce_crossing_wall", "detect_thin_wall", "detect_overhang_wall", "overhang_reverse", "overhang_reverse_threshold","overhang_reverse_internal_only",
     "seam_position", "staggered_inner_seams", "wall_sequence", "is_infill_first", "sparse_infill_density", "sparse_infill_pattern", "top_surface_pattern", "bottom_surface_pattern",
     "infill_direction",
-    "minimum_sparse_infill_area", "reduce_infill_retraction","internal_solid_infill_pattern",
+    "minimum_sparse_infill_area", "reduce_infill_retraction","internal_solid_infill_pattern","gap_fill_target",
     "ironing_type", "ironing_pattern", "ironing_flow", "ironing_speed", "ironing_spacing", "ironing_angle",
     "max_travel_detour_distance",
     "fuzzy_skin", "fuzzy_skin_thickness", "fuzzy_skin_point_distance", "fuzzy_skin_first_layer",

src/libslic3r/PrintConfig.cpp

@@ -248,6 +248,7 @@ static t_config_enum_values s_keys_map_SeamPosition {
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(SeamPosition)
 
+// Orca
 static t_config_enum_values s_keys_map_InternalBridgeFilter {
     { "disabled",        ibfDisabled },
     { "limited",        ibfLimited },
@@ -255,6 +256,14 @@ static t_config_enum_values s_keys_map_InternalBridgeFilter {
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(InternalBridgeFilter)
 
+// Orca
+static t_config_enum_values s_keys_map_GapFillTarget {
+    { "everywhere",        gftEverywhere },
+    { "topbottom",        gftTopBottom },
+    { "nowhere",           gftNowhere },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(GapFillTarget)
+
 static const t_config_enum_values s_keys_map_SLADisplayOrientation = {
     { "landscape",      sladoLandscape},
     { "portrait",       sladoPortrait}
@@ -753,6 +762,26 @@ void PrintConfigDef::init_fff_params()
     def->min = 0;
     def->set_default_value(new ConfigOptionFloat(0.));
     
+    def = this->add("gap_fill_target", coEnum);
+    def->label = L("Apply gap fill");
+    def->category = L("Strength");
+    def->tooltip = L("Enables gap fill for the selected surfaces. The minimum gap length that will be filled can be controlled "
+                     "from the filter out tiny gaps option below.\n\n"
+                     "Options:\n"
+                     "1. Everywhere: Applies gap fill to top, bottom and internal solid surfaces\n"
+                     "2. Top and Bottom surfaces: Applies gap fill to top and bottom surfaces only\n"
+                     "3. Nowhere: Disables gap fill\n");
+    def->enum_keys_map = &ConfigOptionEnum<GapFillTarget>::get_enum_values();
+    def->enum_values.push_back("everywhere");
+    def->enum_values.push_back("topbottom");
+    def->enum_values.push_back("nowhere");
+    def->enum_labels.push_back(L("Everywhere"));
+    def->enum_labels.push_back(L("Top and bottom surfaces"));
+    def->enum_labels.push_back(L("Nowhere"));
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum<GapFillTarget>(gftEverywhere));
+    
+
     def = this->add("enable_overhang_bridge_fan", coBools);
     def->label = L("Force cooling for overhang and bridge");
     def->tooltip = L("Enable this option to optimize part cooling fan speed for overhang and bridge to get better cooling");

src/libslic3r/PrintConfig.hpp

@@ -152,10 +152,17 @@ enum SeamPosition {
     spNearest, spAligned, spRear, spRandom
 };
 
+//Orca
 enum InternalBridgeFilter {
     ibfDisabled, ibfLimited, ibfNofilter
 };
 
+//Orca
+enum GapFillTarget {
+     gftEverywhere, gftTopBottom, gftNowhere
+ };
+
+
 enum LiftType {
     NormalLift,
     SpiralLift,
@@ -789,6 +796,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionPercent,            tree_support_top_rate))
     ((ConfigOptionFloat,              tree_support_branch_diameter_organic))
     ((ConfigOptionFloat,              tree_support_branch_angle_organic))
+    ((ConfigOptionEnum<GapFillTarget>,gap_fill_target))
     ((ConfigOptionFloat,              min_length_factor))
 
     // Move all acceleration and jerk settings to object

src/slic3r/GUI/ConfigManipulation.cpp

@@ -510,6 +510,10 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, co
         apply(config, &new_conf);
     }
     
+    // Orca: Hide the filter out tiny gaps field when gap fill target is nowhere as no gap fill will be applied.
+    bool have_gap_fill = config->opt_enum<GapFillTarget>("gap_fill_target") != gftNowhere;
+    toggle_line("filter_out_gap_fill", have_gap_fill);
+
     bool have_ensure_vertical_thickness = config->opt_bool("ensure_vertical_shell_thickness");
     if(have_ensure_vertical_thickness) {
         DynamicPrintConfig new_conf = *config;

src/slic3r/GUI/Tab.cpp

@@ -2009,6 +2009,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("infill_anchor");
         optgroup->append_single_option_line("infill_anchor_max");
         optgroup->append_single_option_line("internal_solid_infill_pattern");
+        optgroup->append_single_option_line("gap_fill_target");
         optgroup->append_single_option_line("filter_out_gap_fill");
 
         optgroup = page->new_optgroup(L("Advanced"), L"param_advanced");