From 7ec63321413f10f68f389140c7488b2bb7d14fac Mon Sep 17 00:00:00 2001
From: Jesse Vincent <jesse@bestpractical.com>
Date: Sun, 7 Apr 2013 19:53:15 -0400
Subject: [PATCH] split apart the math in nearest_point_index and short-circuit
 if we know the candidate is no good

---
 lib/Slic3r/Geometry.pm | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/lib/Slic3r/Geometry.pm b/lib/Slic3r/Geometry.pm
index e1a591025f..9f0a631f41 100644
--- a/lib/Slic3r/Geometry.pm
+++ b/lib/Slic3r/Geometry.pm
@@ -248,13 +248,22 @@ sub nearest_point_index {
     my $point_y = $point->[Y];
 
     for my $i (0..$#$points) {
-        my $d = (($point_x - $points->[$i]->[X])**2) + (($point_y - $points->[$i]->[Y])**2);
-        if (!defined $distance || $d < $distance) {
-            $nearest_point_index = $i;
-            $distance = $d;
-            last if $distance < epsilon;
-        }
+        my $d = ($point_x - $points->[$i]->[X])**2;
+        # If the X distance of the candidate is > than the total distance of the
+        # best previous candidate, we know we don't want it
+        next if (defined $distance && $d > $distance);
+   
+        # If the total distance of the candidate is > than the total distance of the
+        # best previous candidate, we know we don't want it
+        $d += ($point_y - $points->[$i]->[Y])**2;
+        next if (defined $distance && $d > $distance);
+
+        $nearest_point_index = $i;
+        $distance = $d;
+        
+        last if $distance < epsilon;
     }
+
     return $nearest_point_index;
 }