Port Quartercubic infill pattern (#7243)

* Ported Quarter Cubic infill pattern from Cura

* Code reformat

src/libslic3r/Fill/FillBase.cpp

@@ -50,6 +50,7 @@ Fill* Fill::new_from_type(const InfillPattern type)
     case ipTriangles:           return new FillTriangles();
     case ipStars:               return new FillStars();
     case ipCubic:               return new FillCubic();
+    case ipQuarterCubic:        return new FillQuarterCubic();
     case ipArchimedeanChords:   return new FillArchimedeanChords();
     case ipHilbertCurve:        return new FillHilbertCurve();
     case ipOctagramSpiral:      return new FillOctagramSpiral();

src/libslic3r/Fill/FillRectilinear.cpp

@@ -9,6 +9,7 @@
 #include <boost/container/small_vector.hpp>
 #include <boost/log/trivial.hpp>
 #include <boost/static_assert.hpp>
+#include <boost/math/constants/constants.hpp>
 
 #include "../ClipperUtils.hpp"
 #include "../ExPolygon.hpp"
@@ -3035,6 +3036,39 @@ Polylines FillCubic::fill_surface(const Surface *surface, const FillParams &para
     return polylines_out; 
 }
 
+Polylines FillQuarterCubic::fill_surface(const Surface* surface, const FillParams& params)
+{
+    using namespace boost::math::float_constants;
+
+    Polylines polylines_out;
+
+    coord_t line_width = coord_t(scale_(this->spacing));
+    coord_t period = coord_t(scale_(this->spacing) / params.density) * 4;
+
+    // First half tetrahedral fill
+    double  pattern_z_shift = 0.0;
+    coord_t shift = coord_t(one_div_root_two * (scale_(z) + pattern_z_shift * period * 2)) % period;
+    shift = std::min(shift, period - shift); // symmetry due to the fact that we are applying the shift in both directions
+    shift = std::min(shift, period / 2 - line_width / 2); // don't put lines too close to each other
+    shift = std::max(shift, line_width / 2);              // don't put lines too close to each other
+    float dx1 = unscale_(shift);
+
+    // Second half tetrahedral fill
+    pattern_z_shift = 0.5;
+    shift = coord_t(one_div_root_two * (scale_(z) + pattern_z_shift * period * 2)) % period;
+    shift = std::min(shift, period - shift); // symmetry due to the fact that we are applying the shift in both directions
+    shift = std::min(shift, period / 2 - line_width / 2); // don't put lines too close to each other
+    shift = std::max(shift, line_width / 2);              // don't put lines too close to each other
+    float dx2 = unscale_(shift);
+    if (!this->fill_surface_by_multilines(
+            surface, params, 
+            {{0.f, dx1}, {0.f, -dx1}, {float(M_PI / 2.), dx2}, {float(M_PI / 2.), -dx2}},
+            polylines_out))
+        BOOST_LOG_TRIVIAL(error) << "FillQuarterCubic::fill_surface() failed to fill a region.";
+
+    return polylines_out;
+}
+
 Polylines FillSupportBase::fill_surface(const Surface *surface, const FillParams &params)
 {
     assert(! params.full_infill());

src/libslic3r/Fill/FillRectilinear.hpp

@@ -107,6 +107,20 @@ protected:
     float _layer_angle(size_t idx) const override { return 0.f; }
 };
 
+// Added QuarterCubic pattern from Cura
+class FillQuarterCubic : public FillRectilinear
+{
+public:
+    Fill* clone() const override { return new FillQuarterCubic(*this); }
+    ~FillQuarterCubic() override = default;
+    Polylines fill_surface(const Surface *surface, const FillParams &params) override;
+
+protected:
+	// The grid fill will keep the angle constant between the layers, see the implementation of Slic3r::Fill.
+    float _layer_angle(size_t idx) const override { return 0.f; }
+};
+
+
 class FillSupportBase : public FillRectilinear
 {
 public: