Fixed regression introduced by the recent PerimeterGenerator refactoring causing spiral vase not to be correctly skipped on multi-loop layers. Includes regression test. #2761

xs/src/libslic3r/ExtrusionEntity.hpp

@@ -35,6 +35,9 @@ enum ExtrusionLoopRole {
 class ExtrusionEntity
 {
     public:
+    virtual bool is_collection() const {
+        return false;
+    };
     virtual bool is_loop() const {
         return false;
     };

xs/src/libslic3r/ExtrusionEntityCollection.cpp

@@ -121,6 +121,22 @@ ExtrusionEntityCollection::grow() const
     return pp;
 }
 
+/* Recursively count paths and loops contained in this collection */
+size_t
+ExtrusionEntityCollection::items_count() const
+{
+    size_t count = 0;
+    for (ExtrusionEntitiesPtr::const_iterator it = this->entities.begin(); it != this->entities.end(); ++it) {
+        if ((*it)->is_collection()) {
+            ExtrusionEntityCollection* collection = dynamic_cast<ExtrusionEntityCollection*>(*it);
+            count += collection->items_count();
+        } else {
+            ++count;
+        }
+    }
+    return count;
+}
+
 #ifdef SLIC3RXS
 // there is no ExtrusionLoop::Collection or ExtrusionEntity::Collection
 REGISTER_CLASS(ExtrusionEntityCollection, "ExtrusionPath::Collection");

xs/src/libslic3r/ExtrusionEntityCollection.hpp

@@ -16,6 +16,9 @@ class ExtrusionEntityCollection : public ExtrusionEntity
     ExtrusionEntityCollection(): no_sort(false) {};
     ExtrusionEntityCollection(const ExtrusionEntityCollection &collection);
     ExtrusionEntityCollection& operator= (const ExtrusionEntityCollection &other);
+    bool is_collection() const {
+        return true;
+    };
     bool can_reverse() const {
         return !this->no_sort;
     };
@@ -26,6 +29,7 @@ class ExtrusionEntityCollection : public ExtrusionEntity
     Point first_point() const;
     Point last_point() const;
     Polygons grow() const;
+    size_t items_count() const;
 };
 
 }

xs/src/libslic3r/Layer.hpp

@@ -47,7 +47,7 @@ class LayerRegion
     PolylineCollection unsupported_bridge_edges;
 
     // ordered collection of extrusion paths/loops to build all perimeters
-    // (this collection contains both ExtrusionPath and ExtrusionLoop objects)
+    // (this collection contains only ExtrusionEntityCollection objects)
     ExtrusionEntityCollection perimeters;
 
     // ordered collection of extrusion paths to fill surfaces

xs/xsp/ExtrusionEntityCollection.xsp

@@ -26,6 +26,8 @@
     Clone<Point> last_point();
     int count()
         %code{% RETVAL = THIS->entities.size(); %};
+    int items_count()
+        %code{% RETVAL = THIS->items_count(); %};
     bool empty()
         %code{% RETVAL = THIS->entities.empty(); %};
     std::vector<size_t> orig_indices()