Merge branch 'master' of https://github.com/Prusa-Development/PrusaSlicerPrivate into et_transformations

src/libslic3r/ExtrusionEntity.hpp

@@ -31,6 +31,9 @@ public:
     virtual void reverse() = 0;
     virtual const Point& first_point() const = 0;
     virtual const Point& last_point() const = 0;
+    // Returns an approximately middle point of a path, loop or an extrusion collection.
+    // Used to get a sample point of an extrusion or extrusion collection, which is possibly deep inside its island.
+    virtual const Point& middle_point() const = 0;
     // Produce a list of 2D polygons covered by the extruded paths, offsetted by the extrusion width.
     // Increase the offset by scaled_epsilon to achieve an overlap, so a union will produce no gaps.
     virtual void polygons_covered_by_width(Polygons &out, const float scaled_epsilon) const = 0;
@@ -81,6 +84,7 @@ public:
     void reverse() override { this->polyline.reverse(); }
     const Point& first_point() const override { return this->polyline.points.front(); }
     const Point& last_point() const override { return this->polyline.points.back(); }
+    const Point& middle_point() const override { return this->polyline.points[this->polyline.size() / 2]; }
     size_t size() const { return this->polyline.size(); }
     bool empty() const { return this->polyline.empty(); }
     bool is_closed() const { return ! this->empty() && this->polyline.points.front() == this->polyline.points.back(); }
@@ -153,6 +157,7 @@ public:
     void reverse() override;
     const Point& first_point() const override { return this->paths.front().polyline.points.front(); }
     const Point& last_point() const override { return this->paths.back().polyline.points.back(); }
+    const Point& middle_point() const override { auto &path = this->paths[this->paths.size() / 2]; return path.polyline.points[path.polyline.size() / 2]; }
     size_t size() const { return this->paths.size(); }
     bool empty() const { return this->paths.empty(); }
     double length() const override;
@@ -204,6 +209,7 @@ public:
     void reverse() override;
     const Point& first_point() const override { return this->paths.front().polyline.points.front(); }
     const Point& last_point() const override { assert(this->first_point() == this->paths.back().polyline.points.back()); return this->first_point(); }
+    const Point& middle_point() const override { auto& path = this->paths[this->paths.size() / 2]; return path.polyline.points[path.polyline.size() / 2]; }
     Polygon polygon() const;
     double length() const override;
     bool split_at_vertex(const Point &point, const double scaled_epsilon = scaled<double>(0.001));

src/libslic3r/ExtrusionEntityCollection.hpp

@@ -102,6 +102,7 @@ public:
     void reverse() override;
     const Point& first_point() const override { return this->entities.front()->first_point(); }
     const Point& last_point() const override { return this->entities.back()->last_point(); }
+    const Point& middle_point() const override { return this->entities[this->entities.size() / 2]->middle_point(); }
     // Produce a list of 2D polygons covered by the extruded paths, offsetted by the extrusion width.
     // Increase the offset by scaled_epsilon to achieve an overlap, so a union will produce no gaps.
     void polygons_covered_by_width(Polygons &out, const float scaled_epsilon) const override;

src/libslic3r/Layer.cpp

@@ -578,7 +578,7 @@ void Layer::sort_perimeters_into_islands(
         // Take a sample deep inside its island if available. Infills are usually quite far from the island boundary.
         for (uint32_t iexpoly : fill_expolygons_ranges[islice])
             if (const ExPolygon &expoly = fill_expolygons[iexpoly]; ! expoly.empty()) {
-                sample     = expoly.contour.points.front();
+                sample     = expoly.contour.points[expoly.contour.points.size() / 2];
                 sample_set = true;
                 break;
             }
@@ -589,12 +589,12 @@ void Layer::sort_perimeters_into_islands(
                 if (ee.is_collection()) {
                     for (const ExtrusionEntity *ee2 : dynamic_cast<const ExtrusionEntityCollection&>(ee).entities)
                         if (! ee2->role().is_external()) {
-                            sample     = ee2->first_point();
+                            sample     = ee2->middle_point();
                             sample_set = true;
                             goto loop_end;
                         }
                 } else if (! ee.role().is_external()) {
-                    sample = ee.first_point();
+                    sample = ee.middle_point();
                     sample_set = true;
                     break;
                 }
@@ -603,12 +603,12 @@ void Layer::sort_perimeters_into_islands(
             if (! sample_set) {
                 if (! extrusions.second.empty()) {
                     // If there is no inner perimeter, take a sample of some gap fill extrusion.
-                    sample     = this_layer_region.thin_fills().entities[*extrusions.second.begin()]->first_point();
+                    sample     = this_layer_region.thin_fills().entities[*extrusions.second.begin()]->middle_point();
                     sample_set = true;
                 }
                 if (! sample_set && ! extrusions.first.empty()) {
                     // As a last resort, take a sample of some external perimeter.
-                    sample     = this_layer_region.perimeters().entities[*extrusions.first.begin()]->first_point();
+                    sample     = this_layer_region.perimeters().entities[*extrusions.first.begin()]->middle_point();
                     sample_set = true;
                 }
             }
@@ -835,6 +835,15 @@ void Layer::sort_perimeters_into_islands(
                     d2min = d2;
                     lslice_idx_min = lslice_idx;
                 }
+            if (lslice_idx_min == -1) {
+                // This should not happen, but Arachne seems to produce a perimeter point far outside its source contour.
+                // As a last resort, find the closest source contours to the sample point.
+                for (int lslice_idx = int(lslices_ex.size()) - 1; lslice_idx >= 0; -- lslice_idx)
+                    if (double d2 = (lslices[lslice_idx].point_projection(it_source_slice->second) - it_source_slice->second).cast<double>().squaredNorm(); d2 < d2min) {
+                        d2min = d2;
+                        lslice_idx_min = lslice_idx;
+                    }
+            }
             assert(lslice_idx_min != -1);
             insert_into_island(lslice_idx_min, it_source_slice->first);
         }