prusa3d#13420 Separate XYZ compound moves into separate XY, Z moves f…

…or Snapmaker 2.0

src/libslic3r/GCode/GCodeWriter.cpp

@@ -335,7 +335,24 @@ std::string GCodeWriter::travel_to_xyz(const Vec3d& from, const Vec3d &to, const
         return this->travel_to_xy(to.head<2>(), comment);
     } else {
         m_pos = to;
-        return this->get_travel_to_xyz_gcode(from, to, comment);
+        // This is needed by Snapmaker 2.0
+        // This is a PROOF OF CONCEPT fix only.
+        bool separate_z = true;
+        if (separate_z) {
+            std::string result;
+            if (to.z() > from.z()) {
+                // Move up first
+                result += this->travel_to_z(to.z(), comment);
+                result += this->travel_to_xy(to.head<2>(), comment);
+            } else {
+                // Move down last
+                result += this->travel_to_xy(to.head<2>(), comment);
+                result += this->travel_to_z(to.z(), comment);
+            }
+            return result;
+        } else {
+            return this->get_travel_to_xyz_gcode(from, to, comment);
+        }
     }
 }