Automatically switch to rectilinear when a pattern is used that doesn't support solid infill

xs/src/libslic3r/Fill/Fill.hpp

@@ -75,6 +75,9 @@ public:
     // Do not sort the fill lines to optimize the print head path?
     virtual bool no_sort() const { return false; };
 
+    // Can this pattern be used for solid infill?
+    virtual bool can_solid() const { return false; };
+
     // Perform the fill.
     virtual Polylines fill_surface(const Surface &surface);
     

xs/src/libslic3r/Fill/FillConcentric.hpp

@@ -19,6 +19,7 @@ protected:
 	    Polylines*                      polylines_out);
 
 	virtual bool no_sort() const { return true; }
+    virtual bool can_solid() const { return true; };
 };
 
 } // namespace Slic3r

xs/src/libslic3r/Fill/FillRectilinear.hpp

@@ -12,6 +12,7 @@ class FillRectilinear : public Fill
 public:
     virtual Fill* clone() const { return new FillRectilinear(*this); };
     virtual ~FillRectilinear() {}
+    virtual bool can_solid() const { return true; };
 
 protected:
 	virtual void _fill_surface_single(
@@ -50,6 +51,7 @@ class FillAlignedRectilinear : public FillRectilinear
 public:
     virtual Fill* clone() const { return new FillAlignedRectilinear(*this); };
     virtual ~FillAlignedRectilinear() {};
+    virtual bool can_solid() const { return false; };
 
 protected:
 	// Keep the angle constant in all layers.
@@ -61,6 +63,7 @@ class FillGrid : public FillRectilinear
 public:
     virtual Fill* clone() const { return new FillGrid(*this); };
     virtual ~FillGrid() {}
+    virtual bool can_solid() const { return false; };
 
 protected:
 	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
@@ -78,6 +81,7 @@ class FillTriangles : public FillRectilinear
 public:
     virtual Fill* clone() const { return new FillTriangles(*this); };
     virtual ~FillTriangles() {}
+    virtual bool can_solid() const { return false; };
 
 protected:
 	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
@@ -95,6 +99,7 @@ class FillStars : public FillRectilinear
 public:
     virtual Fill* clone() const { return new FillStars(*this); };
     virtual ~FillStars() {}
+    virtual bool can_solid() const { return false; };
 
 protected:
 	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.
@@ -112,6 +117,7 @@ class FillCubic : public FillRectilinear
 public:
     virtual Fill* clone() const { return new FillCubic(*this); };
     virtual ~FillCubic() {}
+    virtual bool can_solid() const { return false; };
 
 protected:
 	// The grid fill will keep the angle constant between the layers,; see the implementation of Slic3r::Fill.

xs/src/libslic3r/LayerRegionFill.cpp

@@ -183,6 +183,15 @@ LayerRegion::make_fill()
         #else
             std::auto_ptr<Fill> f = std::auto_ptr<Fill>(Fill::new_from_type(fill_pattern));
         #endif
+        
+        // switch to rectilinear if this pattern doesn't support solid infill
+        if (density > 0.9999f && !f->can_solid())
+            #if SLIC3R_CPPVER >= 11
+                f = std::unique_ptr<Fill>(Fill::new_from_type(ipRectilinear));
+            #else
+                f = std::auto_ptr<Fill>(Fill::new_from_type(ipRectilinear));
+            #endif
+        
         f->bounding_box = this->layer()->object()->bounding_box();
         
         // calculate the actual flow we'll be using for this infill