Port of Cura's multi-material interlocking (#5775)

* Init port of Cura's MM interlocking

* Refactor a bit

* Fix crash when bottom surface is multi-color

* Fix crash when boundary avoidance is 0

* Add config

---------

Co-authored-by: SoftFever <softfeverever@gmail.com>

src/libslic3r/PrintConfig.cpp

@@ -2810,6 +2810,56 @@ void PrintConfigDef::init_fff_params()
     def->mode     = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(0.));
 
+    def           = this->add("interlocking_beam", coBool);
+    def->label    = L("Use beam interlocking");
+    def->tooltip  = L("Generate interlocking beam structure at the locations where different filaments touch. This improves the adhesion between filaments, especially models printed in different materials.");
+    def->category = L("Advanced");
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    def           = this->add("interlocking_beam_width", coFloat);
+    def->label    = L("Interlocking beam width");
+    def->tooltip  = L("The width of the interlocking structure beams.");
+    def->sidetext = L("mm");
+    def->min      = 0.01;
+    def->category = L("Advanced");
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0.8));
+
+    def           = this->add("interlocking_orientation", coFloat);
+    def->label    = L("Interlocking direction");
+    def->tooltip  = L("Orientation of interlock beams.");
+    def->sidetext = L("°");
+    def->min      = 0;
+    def->max      = 360;
+    def->category = L("Advanced");
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(22.5));
+
+    def           = this->add("interlocking_beam_layer_count", coInt);
+    def->label    = L("Interlocking beam layers");
+    def->tooltip  = L("The height of the beams of the interlocking structure, measured in number of layers. Less layers is stronger, but more prone to defects.");
+    def->min      = 1;
+    def->category = L("Advanced");
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionInt(2));
+
+    def           = this->add("interlocking_depth", coInt);
+    def->label    = L("Interlocking depth");
+    def->tooltip  = L("The distance from the boundary between filaments to generate interlocking structure, measured in cells. Too few cells will result in poor adhesion.");
+    def->min      = 1;
+    def->category = L("Advanced");
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionInt(2));
+
+    def           = this->add("interlocking_boundary_avoidance", coInt);
+    def->label    = L("Interlocking boundary avoidance");
+    def->tooltip  = L("The distance from the outside of a model where interlocking structures will not be generated, measured in cells.");
+    def->min      = 0;
+    def->category = L("Advanced");
+    def->mode     = comAdvanced;
+    def->set_default_value(new ConfigOptionInt(2));
+
     def = this->add("ironing_type", coEnum);
     def->label = L("Ironing Type");
     def->category = L("Quality");