From afacf0c99d2e26b29303ef6acef8cde8505ab4d4 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Thu, 9 Mar 2017 20:40:06 +0100
Subject: [PATCH] Parallelized process_external_surfaces

---
 xs/src/libslic3r/Layer.cpp       |  7 +++++++
 xs/src/libslic3r/Layer.hpp       |  3 ++-
 xs/src/libslic3r/LayerRegion.cpp |  8 +++++---
 xs/src/libslic3r/PrintObject.cpp | 16 +++++-----------
 4 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/xs/src/libslic3r/Layer.cpp b/xs/src/libslic3r/Layer.cpp
index 77bc74892..722b539e5 100644
--- a/xs/src/libslic3r/Layer.cpp
+++ b/xs/src/libslic3r/Layer.cpp
@@ -419,4 +419,11 @@ Layer::detect_surfaces_type()
     }
 }
 
+void
+Layer::process_external_surfaces()
+{
+    for (LayerRegion* &layerm : this->regions)
+        layerm->process_external_surfaces();
+}
+
 }
diff --git a/xs/src/libslic3r/Layer.hpp b/xs/src/libslic3r/Layer.hpp
index 278927e15..29405258e 100644
--- a/xs/src/libslic3r/Layer.hpp
+++ b/xs/src/libslic3r/Layer.hpp
@@ -61,7 +61,7 @@ class LayerRegion
     void prepare_fill_surfaces();
     void make_perimeters(const SurfaceCollection &slices, SurfaceCollection* fill_surfaces);
     void make_fill();
-    void process_external_surfaces(const Layer* lower_layer);
+    void process_external_surfaces();
     double infill_area_threshold() const;
     
     private:
@@ -111,6 +111,7 @@ class Layer {
     void make_perimeters();
     void make_fills();
     void detect_surfaces_type();
+    void process_external_surfaces();
     
     protected:
     size_t _id;     // sequential number of layer, 0-based
diff --git a/xs/src/libslic3r/LayerRegion.cpp b/xs/src/libslic3r/LayerRegion.cpp
index 42809d0ae..b7d9058fe 100644
--- a/xs/src/libslic3r/LayerRegion.cpp
+++ b/xs/src/libslic3r/LayerRegion.cpp
@@ -65,8 +65,10 @@ LayerRegion::make_perimeters(const SurfaceCollection &slices, SurfaceCollection*
     g.process();
 }
 
+// This function reads lower_layer->slices and writes this->bridged and this->fill_surfaces,
+// so it's thread-safe.
 void
-LayerRegion::process_external_surfaces(const Layer* lower_layer)
+LayerRegion::process_external_surfaces()
 {
     const Surfaces &surfaces = this->fill_surfaces.surfaces;
     const double margin = scale_(EXTERNAL_INFILL_MARGIN);
@@ -82,10 +84,10 @@ LayerRegion::process_external_surfaces(const Layer* lower_layer)
             also, supply the original expolygon instead of the grown one, because in case
             of very thin (but still working) anchors, the grown expolygon would go beyond them */
         double angle = -1;
-        if (lower_layer != NULL && surface->is_bridge()) {
+        if (this->layer()->lower_layer != NULL && surface->is_bridge()) {
             BridgeDetector bd(
                 surface->expolygon,
-                lower_layer->slices,
+                this->layer()->lower_layer->slices,
                 this->flow(frInfill, true).scaled_width()
             );
             
diff --git a/xs/src/libslic3r/PrintObject.cpp b/xs/src/libslic3r/PrintObject.cpp
index be38fda0a..b8ab9cdbf 100644
--- a/xs/src/libslic3r/PrintObject.cpp
+++ b/xs/src/libslic3r/PrintObject.cpp
@@ -371,17 +371,11 @@ PrintObject::detect_surfaces_type()
 void
 PrintObject::process_external_surfaces()
 {
-    FOREACH_REGION(this->_print, region) {
-        size_t region_id = region - this->_print->regions.begin();
-        
-        FOREACH_LAYER(this, layer_it) {
-            const Layer* lower_layer = (layer_it == this->layers.begin())
-                ? NULL
-                : *(layer_it-1);
-            
-            (*layer_it)->get_region(region_id)->process_external_surfaces(lower_layer);
-        }
-    }
+    parallelize<Layer*>(
+        std::queue<Layer*>(std::deque<Layer*>(this->layers.begin(), this->layers.end())),  // cast LayerPtrs to std::queue<Layer*>
+        boost::bind(&Slic3r::Layer::process_external_surfaces, _1),
+        this->_print->config.threads.value
+    );
 }
 
 /* This method applies bridge flow to the first internal solid layer above