ENH: fix empty infill layers

This is fix for github issue #216 that
sometimes the infill layer is empty.

Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: Ie3be08b75506e48f5ae9dd6aae2ae729ba666e01

src/libslic3r/Layer.cpp

@@ -190,7 +190,7 @@ void Layer::make_perimeters()
 	        
 	        if (layerms.size() == 1) {  // optimization
 	            (*layerm)->fill_surfaces.surfaces.clear();
-	            (*layerm)->make_perimeters((*layerm)->slices, &(*layerm)->fill_surfaces);
+	            (*layerm)->make_perimeters((*layerm)->slices, &(*layerm)->fill_surfaces, &(*layerm)->fill_no_overlap_expolygons);
 	            (*layerm)->fill_expolygons = to_expolygons((*layerm)->fill_surfaces.surfaces);
 	        } else {
 	            SurfaceCollection new_slices;
@@ -212,7 +212,9 @@ void Layer::make_perimeters()
 	            
 	            // make perimeters
 	            SurfaceCollection fill_surfaces;
-	            layerm_config->make_perimeters(new_slices, &fill_surfaces);
+                //BBS
+                ExPolygons fill_no_overlap;
+	            layerm_config->make_perimeters(new_slices, &fill_surfaces, &fill_no_overlap);
 
 	            // assign fill_surfaces to each layer
 	            if (!fill_surfaces.surfaces.empty()) { 
@@ -221,6 +223,8 @@ void Layer::make_perimeters()
 	                    ExPolygons expp = intersection_ex(fill_surfaces.surfaces, (*l)->slices.surfaces);
 	                    (*l)->fill_expolygons = expp;
 	                    (*l)->fill_surfaces.set(std::move(expp), fill_surfaces.surfaces.front());
+                        //BBS: Separate fill_no_overlap
+                        (*l)->fill_no_overlap_expolygons = intersection_ex((*l)->slices.surfaces, fill_no_overlap);
 	                }
 	            }
 	        }

src/libslic3r/Layer.hpp

@@ -68,7 +68,8 @@ public:
 
     void    slices_to_fill_surfaces_clipped();
     void    prepare_fill_surfaces();
-    void    make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces);
+    //BBS
+    void    make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces, ExPolygons* fill_no_overlap);
     void    process_external_surfaces(const Layer *lower_layer, const Polygons *lower_layer_covered);
     double  infill_area_threshold() const;
     // Trim surfaces by trimming polygons. Used by the elephant foot compensation at the 1st layer.

src/libslic3r/LayerRegion.cpp

@@ -63,7 +63,7 @@ void LayerRegion::slices_to_fill_surfaces_clipped()
     }
 }
 
-void LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces)
+void LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces, ExPolygons* fill_no_overlap)
 {
     this->perimeters.clear();
     this->thin_fills.clear();
@@ -90,7 +90,9 @@ void LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollec
         // output:
         &this->perimeters,
         &this->thin_fills,
-        fill_surfaces
+        fill_surfaces,
+        //BBS
+        fill_no_overlap
     );
     
     if (this->layer()->lower_layer != nullptr)
@@ -105,9 +107,6 @@ void LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollec
     g.solid_infill_flow     = this->flow(frSolidInfill);
     
     g.process();
-
-    // BBS
-    this->fill_no_overlap_expolygons = g.fill_no_overlap;
 }
 
 //#define EXTERNAL_SURFACES_OFFSET_PARAMETERS ClipperLib::jtMiter, 3.

src/libslic3r/PerimeterGenerator.cpp

@@ -763,7 +763,7 @@ void PerimeterGenerator::process()
                     double(-inset - infill_peri_overlap));
             if (!top_fills.empty())
                 polyWithoutOverlap = union_ex(polyWithoutOverlap, top_infill_exp);
-            this->fill_no_overlap.insert(this->fill_no_overlap.end(), polyWithoutOverlap.begin(), polyWithoutOverlap.end());
+            this->fill_no_overlap->insert(this->fill_no_overlap->end(), polyWithoutOverlap.begin(), polyWithoutOverlap.end());
         }
 
     } // for each island

src/libslic3r/PerimeterGenerator.hpp

@@ -29,13 +29,14 @@ public:
     ExtrusionEntityCollection   *loops;
     ExtrusionEntityCollection   *gap_fill;
     SurfaceCollection           *fill_surfaces;
+    //BBS
+    ExPolygons                  *fill_no_overlap;
 
     //BBS
     Flow                        smaller_ext_perimeter_flow;
     std::map<int, Polygons>     m_lower_polygons_series;
     std::map<int, Polygons>     m_external_lower_polygons_series;
     std::map<int, Polygons>     m_smaller_external_lower_polygons_series;
-    ExPolygons                  fill_no_overlap;
     
     PerimeterGenerator(
         // Input:
@@ -52,14 +53,16 @@ public:
         // Gaps without the thin walls
         ExtrusionEntityCollection*  gap_fill,
         // Infills without the gap fills
-        SurfaceCollection*          fill_surfaces)
+        SurfaceCollection*          fill_surfaces,
+        //BBS
+        ExPolygons*                 fill_no_overlap)
         : slices(slices), upper_slices(nullptr), lower_slices(nullptr), layer_height(layer_height),
             layer_id(-1), perimeter_flow(flow), ext_perimeter_flow(flow),
             overhang_flow(flow), solid_infill_flow(flow),
             config(config), object_config(object_config), print_config(print_config),
             m_spiral_vase(spiral_mode),
             m_scaled_resolution(scaled<double>(print_config->resolution.value > EPSILON ? print_config->resolution.value : EPSILON)),
-            loops(loops), gap_fill(gap_fill), fill_surfaces(fill_surfaces),
+            loops(loops), gap_fill(gap_fill), fill_surfaces(fill_surfaces), fill_no_overlap(fill_no_overlap),
             m_ext_mm3_per_mm(-1), m_mm3_per_mm(-1), m_mm3_per_mm_overhang(-1), m_ext_mm3_per_mm_smaller_width(-1)
         {}