WIP: Moved sources int src/, separated most of the source code from Perl.

The XS was left only for the unit / integration tests, and it links
libslic3r only. No wxWidgets are allowed to be used from Perl starting
from now.

src/libslic3r/Fill/FillRectilinear.hpp

@@ -0,0 +1,79 @@
+#ifndef slic3r_FillRectilinear_hpp_
+#define slic3r_FillRectilinear_hpp_
+
+#include "../libslic3r.h"
+
+#include "FillBase.hpp"
+
+namespace Slic3r {
+
+class Surface;
+
+class FillRectilinear : public Fill
+{
+public:
+    virtual Fill* clone() const { return new FillRectilinear(*this); };
+    virtual ~FillRectilinear() {}
+
+protected:
+	virtual void _fill_surface_single(
+	    const FillParams                &params, 
+	    unsigned int                     thickness_layers,
+	    const std::pair<float, Point>   &direction, 
+	    ExPolygon                       &expolygon, 
+	    Polylines                       &polylines_out);
+
+	coord_t _min_spacing;
+	coord_t _line_spacing;
+	// distance threshold for allowing the horizontal infill lines to be connected into a continuous path
+	coord_t _diagonal_distance;
+	// only for line infill
+	coord_t _line_oscillation;
+
+	// Enabled for the grid infill, disabled for the rectilinear and line infill.
+	virtual bool _horizontal_lines() const { return false; }
+
+	virtual Line _line(int i, coord_t x, coord_t y_min, coord_t y_max) const 
+		{ return Line(Point(x, y_min), Point(x, y_max)); }
+	
+	virtual bool _can_connect(coord_t dist_X, coord_t dist_Y) {
+	    return dist_X <= this->_diagonal_distance
+	        && dist_Y <= this->_diagonal_distance;
+    }
+};
+
+class FillLine : public FillRectilinear
+{
+public:
+    virtual ~FillLine() {}
+
+protected:
+	virtual Line _line(int i, coord_t x, coord_t y_min, coord_t y_max) const {
+		coord_t osc = (i & 1) ? this->_line_oscillation : 0;
+		return Line(Point(x - osc, y_min), Point(x + osc, y_max));
+	}
+
+	virtual bool _can_connect(coord_t dist_X, coord_t dist_Y)
+	{
+	    coord_t TOLERANCE = 10 * SCALED_EPSILON;
+    	return (dist_X >= (this->_line_spacing - this->_line_oscillation) - TOLERANCE)
+        	&& (dist_X <= (this->_line_spacing + this->_line_oscillation) + TOLERANCE)
+        	&& (dist_Y <= this->_diagonal_distance);
+    }
+};
+
+class FillGrid : public FillRectilinear
+{
+public:
+    virtual ~FillGrid() {}
+
+protected:
+	// The grid fill will keep the angle constant between the layers, see the implementation of Slic3r::Fill.
+    virtual float _layer_angle(size_t idx) const { return 0.f; }
+	// Flag for Slic3r::Fill::Rectilinear to fill both directions.
+	virtual bool _horizontal_lines() const { return true; }
+};
+
+}; // namespace Slic3r
+
+#endif // slic3r_FillRectilinear_hpp_