From 4e8d9e793b350faa85bb619037ae82d35c31bf8e Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Tue, 6 Aug 2013 14:31:46 +1000
Subject: [PATCH] Add subtraction operators for point - vector

---
 point.cpp | 22 ++++++++++++++++++++++
 point.hpp |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/point.cpp b/point.cpp
index beb6f416..873b731c 100644
--- a/point.cpp
+++ b/point.cpp
@@ -87,6 +87,27 @@ util::point<S>::operator* (double f) const {
 }
 
 
+//-----------------------------------------------------------------------------
+template <size_t S>
+util::point<S>
+util::point<S>::operator- (const util::vector<S> &rhs) const {
+    util::point<S> out;
+
+    for (size_t i = 0; i < S; ++i)
+        out.data[i] = this->data[i] - rhs.data[i];
+    return out;
+}
+
+
+template <size_t S>
+util::point<S>&
+util::point<S>::operator-= (const util::vector<S> &rhs) {
+    for (size_t i = 0; i < S; ++i)
+        this->data[i] -= rhs.data[i];
+    return *this;
+}
+
+//-----------------------------------------------------------------------------
 template <size_t S>
 util::point<S>
 util::point<S>::operator+ (const util::vector<S> &rhs) const {
@@ -107,6 +128,7 @@ util::point<S>::operator+= (const util::vector<S> &rhs) {
 }
 
 
+//-----------------------------------------------------------------------------
 template <size_t S>
 util::point<S>
 util::point<S>::operator- (const util::point<S> &rhs) const {
diff --git a/point.hpp b/point.hpp
index 48b02e35..e16399f6 100644
--- a/point.hpp
+++ b/point.hpp
@@ -46,6 +46,8 @@ namespace util {
         point<S>  operator*  (double) const;
         point<S>  operator-  (const point<S>&) const;
 
+        point<S>  operator-  (const util::vector<S>&) const;
+        point<S>& operator-= (const util::vector<S>&);
         point<S>  operator+  (const util::vector<S>&) const;
         point<S>& operator+= (const util::vector<S>&);