Perform additional checks before merging solid surfaces (i.e. take flow and fill pattern into account)

xs/src/Surface.cpp

@@ -16,6 +16,13 @@ Surface::is_solid() const
         || this->surface_type == stInternalSolid;
 }
 
+bool
+Surface::is_external() const
+{
+    return this->surface_type == stTop
+        || this->surface_type == stBottom;
+}
+
 bool
 Surface::is_bridge() const
 {

xs/src/Surface.hpp

@@ -18,6 +18,7 @@ class Surface
     unsigned short  extra_perimeters;
     double area() const;
     bool is_solid() const;
+    bool is_external() const;
     bool is_bridge() const;
     
     #ifdef SLIC3RXS

xs/src/SurfaceCollection.cpp

@@ -21,14 +21,14 @@ SurfaceCollection::simplify(double tolerance)
 
 /* group surfaces by common properties */
 void
-SurfaceCollection::group(std::vector<SurfacesPtr> *retval, bool merge_solid)
+SurfaceCollection::group(std::vector<SurfacesPtr> *retval)
 {
     for (Surfaces::iterator it = this->surfaces.begin(); it != this->surfaces.end(); ++it) {
         // find a group with the same properties
         SurfacesPtr* group = NULL;
         for (std::vector<SurfacesPtr>::iterator git = retval->begin(); git != retval->end(); ++git) {
             Surface* gkey = git->front();
-            if ((gkey->surface_type == it->surface_type || (merge_solid && gkey->is_solid() && it->is_solid()))
+            if (   gkey->surface_type      == it->surface_type
                 && gkey->thickness         == it->thickness
                 && gkey->thickness_layers  == it->thickness_layers
                 && gkey->bridge_angle      == it->bridge_angle) {

xs/src/SurfaceCollection.hpp

@@ -11,7 +11,7 @@ class SurfaceCollection
     public:
     Surfaces surfaces;
     void simplify(double tolerance);
-    void group(std::vector<SurfacesPtr> *retval, bool merge_solid = false);
+    void group(std::vector<SurfacesPtr> *retval);
 };
 
 }