Cleanup and bug fixes

Moved needs_bridge_over_infill() to LayerRegion and fixed two bugs I introduced when I extracted it from my local tree.

src/libslic3r/Layer.hpp

@@ -61,6 +61,8 @@ class LayerRegion
     void    make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces);
     void    process_external_surfaces(const Layer *lower_layer, const Polygons *lower_layer_covered);
     double  infill_area_threshold() const;
+    // True if infill voids (computed from infill_density) are larger than bridge_infill_threshold.
+    bool    needs_bridge_over_infill() const;
     // Trim surfaces by trimming polygons. Used by the elephant foot compensation at the 1st layer.
     void    trim_surfaces(const Polygons &trimming_polygons);
     // Single elephant foot compensation step, used by the elephant foor compensation at the 1st layer.

src/libslic3r/LayerRegion.cpp

@@ -397,6 +397,17 @@ double LayerRegion::infill_area_threshold() const
     return ss*ss;
 }
 
+bool LayerRegion::needs_bridge_over_infill() const
+{
+    auto region_config = region()->config();
+    if (region_config.fill_density <= 0)
+        return true;
+    const double infill_extrusion_width = flow(frInfill).width;
+    // Compute the unsupported area assuming a grid, which is pragmatically good enough for all infill types.
+    const double bridging_area = pow<double>(2.0 * 100.0 * infill_extrusion_width / region_config.fill_density - infill_extrusion_width, 2);
+    return bridging_area > region_config.bridge_infill_threshold;
+}
+
 void LayerRegion::trim_surfaces(const Polygons &trimming_polygons)
 {
 #ifndef NDEBUG

src/libslic3r/Print.hpp

@@ -74,8 +74,6 @@ class PrintRegion
     coordf_t                    nozzle_dmr_avg(const PrintConfig &print_config) const;
     // Average diameter of nozzles participating on extruding this region.
     coordf_t                    bridging_height_avg(const PrintConfig &print_config) const;
-    // True if infill voids (computed from infill_density) are larger than bridge_infill_threshold.
-    bool                        needs_bridge_over_infill() const;
 
     // Collect 0-based extruder indices used to print this region's object.
 	void                        collect_object_printing_extruders(std::vector<unsigned int> &object_extruders) const;

src/libslic3r/PrintObject.cpp

@@ -1459,7 +1459,7 @@ void PrintObject::bridge_over_infill()
                     for (LayerRegion* lower_layerm : lower_layer->m_regions) {
                         auto surfaces = lower_layerm->fill_surfaces.surfaces;
                         for (Surfaces::iterator surface = surfaces.begin(); surface != surfaces.end(); ++surface) {
-                            if (surface->surface_type == stInternal && layerm->region()->needs_bridge_over_infill()) {
+                            if (surface->surface_type == stInternal && layerm->needs_bridge_over_infill()) {
                                 Polygons pp = surface->expolygon;
                                 lower_internal.insert(lower_internal.end(), pp.begin(), pp.end());
                             }

src/libslic3r/PrintRegion.cpp

@@ -66,17 +66,6 @@ coordf_t PrintRegion::bridging_height_avg(const PrintConfig &print_config) const
     return this->nozzle_dmr_avg(print_config) * sqrt(m_config.bridge_flow_ratio.value);
 }
 
-bool PrintRegion::needs_bridge_over_infill() const
-{
-    if (config().fill_density <= 0)
-        return false;
-    const double infill_extrusion_width = Flow::new_from_config_width(frInfill, m_config.infill_extrusion_width,
-        m_print->config().nozzle_diameter.get_at(extruder(frInfill) - 1), 0.2f, 0.f).width;
-    // Compute the unsupported area assuming a grid, which is pragmatically good enough for all infill types.
-    const double bridging_area = pow<double>(2.0 * 100.0 * infill_extrusion_width / config().fill_density - infill_extrusion_width, 2);
-    return bridging_area > config().bridge_infill_threshold;
-}
-
 void PrintRegion::collect_object_printing_extruders(const PrintConfig &print_config, const PrintRegionConfig &region_config, std::vector<unsigned int> &object_extruders)
 {
     // These checks reflect the same logic used in the GUI for enabling/disabling extruder selection fields.