From 6654519d84c80e110ee18fe3361c15eda516cce5 Mon Sep 17 00:00:00 2001
From: karl <karl.bittner@hexaquo.at>
Date: Sun, 29 Nov 2020 01:38:07 +0100
Subject: [PATCH] Change distance_to to distance_squared_to

more efficiency! (and we only need it for comparisons anyways)
---
 Line.h      | 8 ++++----
 Quickhull.h | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Line.h b/Line.h
index 775fce6..95cf75d 100644
--- a/Line.h
+++ b/Line.h
@@ -1,7 +1,5 @@
 #pragma once
 
-#include <cmath>  // For abs, sqrt
-
 #include "Point.h"
 
 class Line
@@ -51,12 +49,14 @@ public:
         }
     }
 
-    float distance_to(Point other) const
+    float distance_squared_to(Point other) const
     {
         float a = from().y() - to().y();
         float b = to().x() - from().x();
         float c = from().x() * to().y() - to().x() * from().y();
+        
+        float d = abs(a * other.x() + b * other.y() + c);
 
-        return abs(a * other.x() + b * other.y() + c) / sqrt(a * a + b * b);
+        return (d * d) / (a * a + b * b);
     }
 };
\ No newline at end of file
diff --git a/Quickhull.h b/Quickhull.h
index ed1da94..96123c7 100644
--- a/Quickhull.h
+++ b/Quickhull.h
@@ -67,7 +67,7 @@ private:
 
         for (const Point &point : input)
         {
-            float this_distance = line.distance_to(point);
+            float this_distance = line.distance_squared_to(point);
             if (this_distance > furthest_distance)
             {
                 furthest_distance = this_distance;
@@ -85,17 +85,17 @@ private:
         //  Points inside the hull are added because of random lines.
         for (const Point &point : input)
         {
-            float this_distance = line.distance_to(point);
+            float this_distance = line.distance_squared_to(point);
             // TODO: Both are required, otherwise only one side of the rectangle is
             //  taken -- why?
-            if (this_distance == furthest_distance || line.distance_to(point) == 0)
+            if (this_distance == furthest_distance || line.distance_squared_to(point) == 0)
             {
                 output.emplace_back(point);
             }
         }
         input.remove_if([furthest_distance, line](Point point)
         {
-            return furthest_distance == line.distance_to(point);
+            return furthest_distance == line.distance_squared_to(point);
         });
         // Hotfix end