From b2070342e55c4a3361a7a77ad11d0a020bdb2649 Mon Sep 17 00:00:00 2001
From: supermerill <merill@free.fr>
Date: Fri, 29 Dec 2023 00:12:34 +0100
Subject: [PATCH] fix monotonic supermerill/SuperSlicer#3770

---
 src/libslic3r/Fill/FillBase.cpp        | 7 +++++--
 src/libslic3r/Fill/FillRectilinear.cpp | 3 ++-
 src/libslic3r/Fill/FillRectilinear.hpp | 6 ++++++
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/libslic3r/Fill/FillBase.cpp b/src/libslic3r/Fill/FillBase.cpp
index a6fff4aae49..08daf3c2222 100644
--- a/src/libslic3r/Fill/FillBase.cpp
+++ b/src/libslic3r/Fill/FillBase.cpp
@@ -211,7 +211,7 @@ void Fill::fill_surface_extrusion(const Surface *surface, const FillParams &para
                     good_role,
                     used_flow,
                     used_flow.scaled_width() / 8,
-                    true);
+                    !params.monotonic);
                 // compute the path of the nozzle -> extruded volume
                 for (const ExtrusionEntity* entity : entities) {
                     extruded_volume += entity->total_volume();
@@ -219,6 +219,8 @@ void Fill::fill_surface_extrusion(const Surface *surface, const FillParams &para
                 //append (move so the pointers are reused, and won't need to be deleted)
                 all_new_paths->append(std::move(entities));
             }
+            if(params.monotonic)
+                all_new_paths->set_can_sort_reverse(false, false);
             thick_polylines.clear();
 
 
@@ -305,7 +307,8 @@ void Fill::fill_surface_extrusion(const Surface *surface, const FillParams &para
                 good_role,
                 params.flow.mm3_per_mm()* params.flow_mult * mult_flow,
                 (float)(params.flow.width()* params.flow_mult * mult_flow),
-                (float)params.flow.height());
+                (float)params.flow.height(),
+                !params.monotonic);
         }
     } catch (InfillFailedException&) {
     }
diff --git a/src/libslic3r/Fill/FillRectilinear.cpp b/src/libslic3r/Fill/FillRectilinear.cpp
index 74e74a70fe5..b171db95122 100644
--- a/src/libslic3r/Fill/FillRectilinear.cpp
+++ b/src/libslic3r/Fill/FillRectilinear.cpp
@@ -3532,7 +3532,8 @@ FillRectilinearWGapFill::fill_surface_extrusion(const Surface *surface, const Fi
             good_role,
             params.flow.mm3_per_mm() * params.flow_mult * flow_mult_exact_volume,
             params.flow.width() * params.flow_mult * float(flow_mult_exact_volume),
-            params.flow.height());
+            params.flow.height(),
+            !is_monotonic());
 
         coll_nosort->append(ExtrusionEntitiesPtr{ eec });
 
diff --git a/src/libslic3r/Fill/FillRectilinear.hpp b/src/libslic3r/Fill/FillRectilinear.hpp
index d9151dab8b0..dae36dc6ca7 100644
--- a/src/libslic3r/Fill/FillRectilinear.hpp
+++ b/src/libslic3r/Fill/FillRectilinear.hpp
@@ -50,6 +50,12 @@ class FillMonotonic : public FillRectilinear
 public:
     Fill* clone() const override { return new FillMonotonic(*this); }
     ~FillMonotonic() override = default;
+    //apply monotonic
+    void fill_surface_extrusion(const Surface *surface, const FillParams &params, ExtrusionEntitiesPtr &out) const override {
+        FillParams monotonic_params = params;
+        monotonic_params.monotonic = true;
+        FillRectilinear::fill_surface_extrusion(surface, monotonic_params, out);
+    }
     Polylines fill_surface(const Surface* surface, const FillParams& params) const override;
     bool no_sort() const override { return true; }
 };