From 9c93e52c8f313d4448006f06718a6dfdc5ec758a Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Sat, 8 Nov 2014 12:56:14 +0100
Subject: [PATCH] Workaround Clipper changing point coordinates while
 performing simplify_polygons(), thus causing a crash in Slic3r. #2306

---
 lib/Slic3r/GCode.pm                  | 11 +++++++++--
 xs/src/libslic3r/ExtrusionEntity.cpp |  6 +++---
 xs/src/libslic3r/ExtrusionEntity.hpp |  2 +-
 xs/xsp/ExtrusionLoop.xsp             |  2 +-
 4 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/lib/Slic3r/GCode.pm b/lib/Slic3r/GCode.pm
index 573d14bcb..03ef4ea94 100644
--- a/lib/Slic3r/GCode.pm
+++ b/lib/Slic3r/GCode.pm
@@ -148,12 +148,19 @@ sub extrude_loop {
         if ($self->config->seam_position eq 'nearest') {
             @candidates = @$polygon if !@candidates;
             $point = $last_pos->nearest_point(\@candidates);
-            $loop->split_at_vertex($point);
+            if (!$loop->split_at_vertex($point)) {
+                # On 32-bit Linux, Clipper will change some point coordinates by 1 unit
+                # while performing simplify_polygons(), thus split_at_vertex() won't 
+                # find them anymore.
+                $loop->split_at($point);
+            }
         } elsif (@candidates) {
             my @non_overhang = grep !$loop->has_overhang_point($_), @candidates;
             @candidates = @non_overhang if @non_overhang;
             $point = $last_pos->nearest_point(\@candidates);
-            $loop->split_at_vertex($point);
+            if (!$loop->split_at_vertex($point)) {
+                $loop->split_at($point);
+            }
         } else {
             $point = $last_pos->projection_onto_polygon($polygon);
             $loop->split_at($point);
diff --git a/xs/src/libslic3r/ExtrusionEntity.cpp b/xs/src/libslic3r/ExtrusionEntity.cpp
index 725693fae..34372c72b 100644
--- a/xs/src/libslic3r/ExtrusionEntity.cpp
+++ b/xs/src/libslic3r/ExtrusionEntity.cpp
@@ -224,7 +224,7 @@ ExtrusionLoop::length() const
     return len;
 }
 
-void
+bool
 ExtrusionLoop::split_at_vertex(const Point &point)
 {
     for (ExtrusionPaths::iterator path = this->paths.begin(); path != this->paths.end(); ++path) {
@@ -261,10 +261,10 @@ ExtrusionLoop::split_at_vertex(const Point &point)
                 // we can now override the old path list with the new one and stop looping
                 this->paths = new_paths;
             }
-            return;
+            return true;
         }
     }
-    CONFESS("Point not found");
+    return false;
 }
 
 void
diff --git a/xs/src/libslic3r/ExtrusionEntity.hpp b/xs/src/libslic3r/ExtrusionEntity.hpp
index cbcd80d52..aad36cb3d 100644
--- a/xs/src/libslic3r/ExtrusionEntity.hpp
+++ b/xs/src/libslic3r/ExtrusionEntity.hpp
@@ -92,7 +92,7 @@ class ExtrusionLoop : public ExtrusionEntity
     Point last_point() const;
     void polygon(Polygon* polygon) const;
     double length() const;
-    void split_at_vertex(const Point &point);
+    bool split_at_vertex(const Point &point);
     void split_at(const Point &point);
     void clip_end(double distance, ExtrusionPaths* paths) const;
     bool has_overhang_point(const Point &point) const;
diff --git a/xs/xsp/ExtrusionLoop.xsp b/xs/xsp/ExtrusionLoop.xsp
index e7f4f0319..944dd25ea 100644
--- a/xs/xsp/ExtrusionLoop.xsp
+++ b/xs/xsp/ExtrusionLoop.xsp
@@ -20,7 +20,7 @@
     void append(ExtrusionPath* path)
         %code{% THIS->paths.push_back(*path); %};
     double length();
-    void split_at_vertex(Point* point)
+    bool split_at_vertex(Point* point)
         %code{% THIS->split_at_vertex(*point); %};
     void split_at(Point* point)
         %code{% THIS->split_at(*point); %};