concentric infill with gap fill : push the new code in a new option.

xs/src/libslic3r/Fill/FillBase.cpp

@@ -22,6 +22,7 @@ Fill* Fill::new_from_type(const InfillPattern type)
 {
     switch (type) {
     case ipConcentric:          return new FillConcentric();
+    case ipConcentricGapFill:   return new FillConcentricWGapFill();
     case ipHoneycomb:           return new FillHoneycomb();
     case ip3DHoneycomb:         return new Fill3DHoneycomb();
     case ipGyroid:              return new FillGyroid();

xs/src/libslic3r/Fill/FillConcentric.cpp

@@ -7,8 +7,64 @@
 #include "FillConcentric.hpp"
 
 namespace Slic3r {
+    
 
-void FillConcentric::fill_surface_extrusion(const Surface *surface, const FillParams &params,
+void FillConcentric::_fill_surface_single(
+    const FillParams                &params, 
+    unsigned int                     thickness_layers,
+    const std::pair<float, Point>   &direction, 
+    ExPolygon                       &expolygon, 
+    Polylines                       &polylines_out)
+{
+    // no rotation is supported for this infill pattern
+    BoundingBox bounding_box = expolygon.contour.bounding_box();
+    
+    coord_t min_spacing = scale_(this->spacing);
+    coord_t distance = coord_t(min_spacing / params.density);
+    
+    if (params.density > 0.9999f && !params.dont_adjust) {
+        distance = this->_adjust_solid_spacing(bounding_box.size().x, distance);
+        this->spacing = unscale(distance);
+    }
+
+    Polygons loops = (Polygons)expolygon;
+    Polygons last  = loops;
+    while (! last.empty()) {
+        last = offset2(last, -(distance + min_spacing/2), +min_spacing/2);
+        loops.insert(loops.end(), last.begin(), last.end());
+    }
+
+    // generate paths from the outermost to the innermost, to avoid
+    // adhesion problems of the first central tiny loops
+    loops = union_pt_chained(loops, false);
+    
+    // split paths using a nearest neighbor search
+    size_t iPathFirst = polylines_out.size();
+    Point last_pos(0, 0);
+    for (const Polygon &loop : loops) {
+        polylines_out.push_back(loop.split_at_index(last_pos.nearest_point_index(loop)));
+        last_pos = polylines_out.back().last_point();
+    }
+
+    // clip the paths to prevent the extruder from getting exactly on the first point of the loop
+    // Keep valid paths only.
+    size_t j = iPathFirst;
+    for (size_t i = iPathFirst; i < polylines_out.size(); ++ i) {
+        polylines_out[i].clip_end(this->loop_clipping);
+        if (polylines_out[i].is_valid()) {
+            if (j < i)
+                polylines_out[j] = std::move(polylines_out[i]);
+            ++ j;
+        }
+    }
+    if (j < polylines_out.size())
+        polylines_out.erase(polylines_out.begin() + j, polylines_out.end());
+    //TODO: return ExtrusionLoop objects to get better chained paths,
+    // otherwise the outermost loop starts at the closest point to (0, 0).
+    // We want the loops to be split inside the G-code generator to get optimum path planning.
+}
+
+void FillConcentricWGapFill::fill_surface_extrusion(const Surface *surface, const FillParams &params,
     const Flow &flow, const ExtrusionRole &role, ExtrusionEntitiesPtr &out) {
 
     // Perform offset.

xs/src/libslic3r/Fill/FillConcentric.hpp

@@ -12,10 +12,27 @@ public:
 
 protected:
     virtual Fill* clone() const { return new FillConcentric(*this); };
+    virtual void _fill_surface_single(
+        const FillParams                &params,
+        unsigned int                     thickness_layers,
+        const std::pair<float, Point>   &direction,
+        ExPolygon                       &expolygon,
+        Polylines                       &polylines_out);
+
+	virtual bool no_sort() const { return true; }
+};
+
+
+class FillConcentricWGapFill : public Fill {
+public:
+    virtual ~FillConcentricWGapFill() {}
+
+protected:
+    virtual Fill* clone() const { return new FillConcentricWGapFill(*this); };
     virtual void fill_surface_extrusion(const Surface *surface, const FillParams &params,
         const Flow &flow, const ExtrusionRole &role, ExtrusionEntitiesPtr &out);
 
-	virtual bool no_sort() const { return true; }
+    virtual bool no_sort() const { return true; }
 };
 
 } // namespace Slic3r

xs/src/libslic3r/PrintConfig.cpp

@@ -316,6 +316,7 @@ PrintConfigDef::PrintConfigDef()
     def->enum_keys_map = &ConfigOptionEnum<InfillPattern>::get_enum_values();
     def->enum_values.push_back("rectilinear");
     def->enum_values.push_back("concentric");
+    def->enum_values.push_back("concentricgapfill");
     def->enum_values.push_back("hilbertcurve");
     def->enum_values.push_back("archimedeanchords");
     def->enum_values.push_back("octagramspiral");
@@ -324,12 +325,13 @@ PrintConfigDef::PrintConfigDef()
     def->enum_values.push_back("smoothhilbert");
     def->enum_labels.push_back(L("Rectilinear"));
     def->enum_labels.push_back(L("Concentric"));
+    def->enum_labels.push_back(L("Concentric (filled)"));
     def->enum_labels.push_back(L("Hilbert Curve"));
     def->enum_labels.push_back(L("Archimedean Chords"));
     def->enum_labels.push_back(L("Octagram Spiral"));
-    def->enum_labels.push_back("Ironing");
-    def->enum_labels.push_back("Ironing (triple)");
-    def->enum_labels.push_back("Ironing (hilbert)");
+    def->enum_labels.push_back(L("Ironing"));
+    def->enum_labels.push_back(L("Ironing (triple)"));
+    def->enum_labels.push_back(L("Ironing (hilbert)"));
     // solid_fill_pattern is an obsolete equivalent to top_fill_pattern/bottom_fill_pattern.
     def->aliases = { "solid_fill_pattern" };
     def->default_value = new ConfigOptionEnum<InfillPattern>(ipRectilinear);
@@ -342,14 +344,16 @@ PrintConfigDef::PrintConfigDef()
     def->enum_keys_map = &ConfigOptionEnum<InfillPattern>::get_enum_values();
     def->enum_values.push_back("rectilinear");
     def->enum_values.push_back("concentric");
+    def->enum_values.push_back("concentricgapfill");
     def->enum_values.push_back("hilbertcurve");
     def->enum_values.push_back("archimedeanchords");
     def->enum_values.push_back("octagramspiral");
-    def->enum_labels.push_back("Rectilinear");
-    def->enum_labels.push_back("Concentric");
-    def->enum_labels.push_back("Hilbert Curve");
-    def->enum_labels.push_back("Archimedean Chords");
-    def->enum_labels.push_back("Octagram Spiral");
+    def->enum_labels.push_back(L("Rectilinear"));
+    def->enum_labels.push_back(L("Concentric"));
+    def->enum_labels.push_back(L("Concentric (filled)"));
+    def->enum_labels.push_back(L("Hilbert Curve"));
+    def->enum_labels.push_back(L("Archimedean Chords"));
+    def->enum_labels.push_back(L("Octagram Spiral"));
     def->default_value = new ConfigOptionEnum<InfillPattern>(ipRectilinear);
 
     def = this->add("enforce_full_fill_volume", coBool);
@@ -790,6 +794,7 @@ PrintConfigDef::PrintConfigDef()
     def->enum_values.push_back("cubic");
     def->enum_values.push_back("line");
     def->enum_values.push_back("concentric");
+    def->enum_values.push_back("concentricgapfill");
     def->enum_values.push_back("honeycomb");
     def->enum_values.push_back("3dhoneycomb");
     def->enum_values.push_back("gyroid");
@@ -803,6 +808,7 @@ PrintConfigDef::PrintConfigDef()
     def->enum_labels.push_back(L("Cubic"));
     def->enum_labels.push_back(L("Line"));
     def->enum_labels.push_back(L("Concentric"));
+    def->enum_labels.push_back(L("Concentric (filled)"));
     def->enum_labels.push_back(L("Honeycomb"));
     def->enum_labels.push_back(L("3D Honeycomb"));
     def->enum_labels.push_back(L("Gyroid"));

xs/src/libslic3r/PrintConfig.hpp

@@ -34,7 +34,7 @@ enum PrintHostType {
 enum InfillPattern {
     ipRectilinear, ipGrid, ipTriangles, ipStars, ipCubic, ipLine, ipConcentric, ipHoneycomb, ip3DHoneycomb,
     ipGyroid, ipHilbertCurve, ipArchimedeanChords, ipOctagramSpiral, ipSmooth, ipSmoothHilbert, ipSmoothTriple,
-    ipRectiWithPerimeter,
+    ipRectiWithPerimeter, ipConcentricGapFill
 };
 
 enum SupportMaterialPattern {
@@ -89,6 +89,7 @@ template<> inline t_config_enum_values& ConfigOptionEnum<InfillPattern>::get_enu
         keys_map["cubic"]               = ipCubic;
         keys_map["line"]                = ipLine;
         keys_map["concentric"]          = ipConcentric;
+        keys_map["concentricgapfill"]   = ipConcentricGapFill;
         keys_map["honeycomb"]           = ipHoneycomb;
         keys_map["3dhoneycomb"]         = ip3DHoneycomb;
         keys_map["gyroid"]              = ipGyroid;

xs/src/libslic3r/SupportMaterial.cpp

@@ -3098,7 +3098,7 @@ void PrintObjectSupportMaterial::generate_toolpaths(
         size_t idx_layer_top_contact      = size_t(-1);
         size_t idx_layer_intermediate     = size_t(-1);
         size_t idx_layer_inteface         = size_t(-1);
-        std::unique_ptr<Fill> filler_interface = std::unique_ptr<Fill>(Fill::new_from_type(m_slicing_params.soluble_interface ? ipConcentric : ipRectilinear));
+        std::unique_ptr<Fill> filler_interface = std::unique_ptr<Fill>(Fill::new_from_type(m_slicing_params.soluble_interface ? ipConcentricGapFill : ipRectilinear));
         std::unique_ptr<Fill> filler_support = std::unique_ptr<Fill>(Fill::new_from_type(infill_pattern));
         std::unique_ptr<Fill> filler_solid = std::unique_ptr<Fill>(Fill::new_from_type(ipRectiWithPerimeter));
         filler_interface->set_bounding_box(bbox_object);