ENH: enable arachne for concentric pattern

Enable arachne for concentric pattern by
referring to PrusaSlicer

Also remove useless pattern we added.

Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: Ie2574f7fc4751ebdf1caab4de52013f3101e104f

src/libslic3r/Fill/FillConcentric.cpp

@@ -1,6 +1,8 @@
 #include "../ClipperUtils.hpp"
 #include "../ExPolygon.hpp"
 #include "../Surface.hpp"
+#include "../VariableWidth.hpp"
+#include "Arachne/WallToolPaths.hpp"
 
 #include "FillConcentric.hpp"
 
@@ -61,4 +63,84 @@ void FillConcentric::_fill_surface_single(
     // We want the loops to be split inside the G-code generator to get optimum path planning.
 }
 
+void FillConcentric::_fill_surface_single(const FillParams& params,
+    unsigned int                   thickness_layers,
+    const std::pair<float, Point>& direction,
+    ExPolygon                      expolygon,
+    ThickPolylines& thick_polylines_out)
+{
+    assert(params.use_arachne);
+    assert(this->print_config != nullptr && this->print_object_config != nullptr);
+
+    // no rotation is supported for this infill pattern
+    Point   bbox_size = expolygon.contour.bounding_box().size();
+    coord_t min_spacing = scaled<coord_t>(this->spacing);
+
+    if (params.density > 0.9999f && !params.dont_adjust) {
+        coord_t                loops_count = std::max(bbox_size.x(), bbox_size.y()) / min_spacing + 1;
+        Polygons               polygons = offset(expolygon, float(min_spacing) / 2.f);
+
+        double min_nozzle_diameter = *std::min_element(print_config->nozzle_diameter.values.begin(), print_config->nozzle_diameter.values.end());
+        Arachne::WallToolPathsParams input_params;
+        input_params.min_bead_width = 0.85 * min_nozzle_diameter;
+        input_params.min_feature_size = 0.1;
+        input_params.wall_transition_length = 1.0 * min_nozzle_diameter;
+        input_params.wall_transition_angle = 10;
+        input_params.wall_transition_filter_deviation = 0.25 * min_nozzle_diameter;
+        input_params.wall_distribution_count = 1;
+        input_params.wall_add_middle_threshold = 0.75;
+        input_params.wall_split_middle_threshold = 0.5;
+
+        Arachne::WallToolPaths wallToolPaths(polygons, min_spacing, min_spacing, loops_count, 0, input_params);
+
+        std::vector<Arachne::VariableWidthLines>    loops = wallToolPaths.getToolPaths();
+        std::vector<const Arachne::ExtrusionLine*> all_extrusions;
+        for (Arachne::VariableWidthLines& loop : loops) {
+            if (loop.empty())
+                continue;
+            for (const Arachne::ExtrusionLine& wall : loop)
+                all_extrusions.emplace_back(&wall);
+        }
+
+        // Split paths using a nearest neighbor search.
+        size_t firts_poly_idx = thick_polylines_out.size();
+        Point  last_pos(0, 0);
+        for (const Arachne::ExtrusionLine* extrusion : all_extrusions) {
+            if (extrusion->empty())
+                continue;
+
+            ThickPolyline thick_polyline = Arachne::to_thick_polyline(*extrusion);
+            if (extrusion->is_closed && thick_polyline.points.front() == thick_polyline.points.back() && thick_polyline.width.front() == thick_polyline.width.back()) {
+                thick_polyline.points.pop_back();
+                assert(thick_polyline.points.size() * 2 == thick_polyline.width.size());
+                int nearest_idx = last_pos.nearest_point_index(thick_polyline.points);
+                std::rotate(thick_polyline.points.begin(), thick_polyline.points.begin() + nearest_idx, thick_polyline.points.end());
+                std::rotate(thick_polyline.width.begin(), thick_polyline.width.begin() + 2 * nearest_idx, thick_polyline.width.end());
+                thick_polyline.points.emplace_back(thick_polyline.points.front());
+            }
+            thick_polylines_out.emplace_back(std::move(thick_polyline));
+            last_pos = thick_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 = firts_poly_idx;
+        for (size_t i = firts_poly_idx; i < thick_polylines_out.size(); ++i) {
+            thick_polylines_out[i].clip_end(this->loop_clipping);
+            if (thick_polylines_out[i].is_valid()) {
+                if (j < i)
+                    thick_polylines_out[j] = std::move(thick_polylines_out[i]);
+                ++j;
+            }
+        }
+        if (j < thick_polylines_out.size())
+            thick_polylines_out.erase(thick_polylines_out.begin() + int(j), thick_polylines_out.end());
+    }
+    else {
+        Polylines polylines;
+        this->_fill_surface_single(params, thickness_layers, direction, expolygon, polylines);
+        append(thick_polylines_out, to_thick_polylines(std::move(polylines), min_spacing));
+    }
+}
+
 } // namespace Slic3r