From 25d6432dbd42ef2456709ea572567b14b6f38a1d Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Mon, 23 Feb 2009 22:26:46 +0000
Subject: [PATCH] trying to get a custom comparator to sort my IntersectionList
 after a merge()

git-svn-id: svn://anubis/fart/trunk@149 7f9b0f55-74a9-4bce-be96-3c2cd072584d
---
 shapes/Shape.cc | 39 +++++++++++++++++++++++++++++++++++++++
 shapes/Shape.h  |  4 ++--
 util/Vector.cc  |  5 +++++
 util/Vector.h   |  1 +
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/shapes/Shape.cc b/shapes/Shape.cc
index 2fef45b..e46e478 100755
--- a/shapes/Shape.cc
+++ b/shapes/Shape.cc
@@ -1,5 +1,8 @@
 
 #include "Shape.h"
+#include <algorithm>                /* sort() */
+#include <functional>               /* binary_function */
+using namespace std;
 
 Shape::Shape()
 {
@@ -15,4 +18,40 @@ Shape::IntersectionList
 Shape::IntersectionList::merge(const IntersectionList & other,
                                const Vector & startPoint)
 {
+    Shape::IntersectionList result;
+
+    for (size_t i = 0, sz = m_intersections.size();
+         i < sz;
+         i++)
+    {
+        result.add(m_intersections[i]);
+    }
+    for (size_t i = 0, sz = other.m_intersections.size();
+         i < sz;
+         i++)
+    {
+        result.add(other.m_intersections[i]);
+    }
+
+    class Comparator : public binary_function<Intersection,
+                                              Intersection,
+                                              bool>
+    {
+        public:
+            Comparator(const Vector & refPoint)
+            {
+                m_refPoint = refPoint;
+            }
+            bool operator()(Intersection const & i1, Intersection const & i2) const
+            {
+                return (m_refPoint.dist_to(i1.second)
+                            < m_refPoint.dist_to(i2.second));
+            }
+        protected:
+            Vector m_refPoint;
+    };
+
+    sort(result.m_intersections.begin(), result.m_intersections.end(), Comparator(startPoint));
+
+    return result;
 }
diff --git a/shapes/Shape.h b/shapes/Shape.h
index 9157b97..7116d7f 100644
--- a/shapes/Shape.h
+++ b/shapes/Shape.h
@@ -27,11 +27,11 @@ class Shape
                     return m_intersections[i];
                 }
                 size_t size() { return m_intersections.size(); }
-                std::vector<Intersection>::const_iterator begin()
+                std::vector<Intersection>::iterator begin()
                 {
                     return m_intersections.begin();
                 }
-                std::vector<Intersection>::const_iterator end()
+                std::vector<Intersection>::iterator end()
                 {
                     return m_intersections.end();
                 }
diff --git a/util/Vector.cc b/util/Vector.cc
index d970dc0..d2e0944 100644
--- a/util/Vector.cc
+++ b/util/Vector.cc
@@ -49,6 +49,11 @@ double Vector::mag2() const
          + m_array[2] * m_array[2];
 }
 
+double Vector::dist_to(const Vector & other) const
+{
+    return (other - *this).mag();
+}
+
 Vector Vector::proj(const Vector & target) const
 {
     Vector target_normalized = target;
diff --git a/util/Vector.h b/util/Vector.h
index cd14835..283f7f0 100644
--- a/util/Vector.h
+++ b/util/Vector.h
@@ -15,6 +15,7 @@ class Vector
         Vector & normalize();
         double mag() const;
         double mag2() const;
+        double dist_to(const Vector & other) const;
         Vector proj(const Vector & target) const;
         Vector reflect(const Vector & target) const;