From 869ae0247ebe69e51df4a794825f286fea42a9ae Mon Sep 17 00:00:00 2001
From: tamasmeszaros <meszaros.q@gmail.com>
Date: Wed, 2 Dec 2020 17:53:22 +0100
Subject: [PATCH] Use smarter object function in partial arrangement with empty
 bed.

---
 .../include/libnest2d/placers/nfpplacer.hpp   |  8 ++++++++
 src/libslic3r/Arrange.cpp                     | 20 +++++++++++--------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/libnest2d/include/libnest2d/placers/nfpplacer.hpp b/src/libnest2d/include/libnest2d/placers/nfpplacer.hpp
index 35e7e160d..83f7bd246 100644
--- a/src/libnest2d/include/libnest2d/placers/nfpplacer.hpp
+++ b/src/libnest2d/include/libnest2d/placers/nfpplacer.hpp
@@ -167,6 +167,8 @@ struct NfpPConfig {
                        const ItemGroup&              // remaining items
                        )> before_packing;
 
+    std::function<void(const ItemGroup &, NfpPConfig &config)> on_preload;
+
     NfpPConfig(): rotations({0.0, Pi/2.0, Pi, 3*Pi/2}),
         alignment(Alignment::CENTER), starting_point(Alignment::CENTER) {}
 };
@@ -577,6 +579,12 @@ public:
         Base::clearItems();
     }
 
+    void preload(const ItemGroup& packeditems) {
+        Base::preload(packeditems);
+        if (config_.on_preload)
+            config_.on_preload(packeditems, config_);
+    }
+
 private:
 
     using Shapes = TMultiShape<RawShape>;
diff --git a/src/libslic3r/Arrange.cpp b/src/libslic3r/Arrange.cpp
index 705e213e3..eaa9726dd 100644
--- a/src/libslic3r/Arrange.cpp
+++ b/src/libslic3r/Arrange.cpp
@@ -109,6 +109,7 @@ void fill_config(PConf& pcfg, const ArrangeParams &params) {
 
 // Apply penalty to object function result. This is used only when alignment
 // after arrange is explicitly disabled (PConfig::Alignment::DONT_ALIGN)
+// Also, this will only work well for Box shaped beds.
 static double fixed_overfit(const std::tuple<double, Box>& result, const Box &binbb)
 {
     double score = std::get<0>(result);
@@ -348,6 +349,17 @@ public:
         
         m_pconf.object_function = get_objfn();
 
+        m_pconf.on_preload = [this](const ItemGroup &items, PConfig &cfg) {
+            if (items.empty()) return;
+
+            cfg.alignment = PConfig::Alignment::DONT_ALIGN;
+            auto bb = sl::boundingBox(m_bin);
+            auto bbcenter = bb.center();
+            cfg.object_function = [this, bb, bbcenter](const Item &item) {
+                return fixed_overfit(objfunc(item, bbcenter), bb);
+            };
+        };
+
         auto on_packed = params.on_packed;
         
         if (progressind || on_packed)
@@ -384,13 +396,6 @@ public:
     const PConfig& config() const { return m_pconf; }
     
     inline void preload(std::vector<Item>& fixeditems) {
-        m_pconf.alignment = PConfig::Alignment::DONT_ALIGN;
-        auto bb = sl::boundingBox(m_bin);
-        auto bbcenter = bb.center();
-        m_pconf.object_function = [this, bb, bbcenter](const Item &item) {
-            return fixed_overfit(objfunc(item, bbcenter), bb);
-        };
-
         // Build the rtree for queries to work
         
         for(unsigned idx = 0; idx < fixeditems.size(); ++idx) {
@@ -398,7 +403,6 @@ public:
             itm.markAsFixedInBin(itm.binId());
         }
 
-        m_pck.configure(m_pconf);
         m_item_count += fixeditems.size();
     }
 };