From 3bc7dceca5dbd5d3e97262b006e3f655b8a0189b Mon Sep 17 00:00:00 2001
From: sippeangelo <holmberg.simon@gmail.com>
Date: Mon, 18 Jan 2016 14:55:49 +0100
Subject: [PATCH] Made EntityWrapper hashable

---
 include/Engine/Core/EntityWrapper.h | 17 ++++++++++++++++-
 src/Engine/Core/EntityWrapper.cpp   |  2 +-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/include/Engine/Core/EntityWrapper.h b/include/Engine/Core/EntityWrapper.h
index e4be8d78..79f90f33 100644
--- a/include/Engine/Core/EntityWrapper.h
+++ b/include/Engine/Core/EntityWrapper.h
@@ -2,6 +2,7 @@
 #define EntityWrapper_h__
 
 #include <boost/optional.hpp>
+#include <boost/functional/hash.hpp>
 #include "ComponentWrapper.h"
 
 class World;
@@ -26,9 +27,23 @@ struct EntityWrapper
     bool Valid();
 
     ComponentWrapper operator[](const char* componentName);
-    bool operator==(const EntityWrapper& e);
+    bool operator==(const EntityWrapper& e) const;
     explicit operator EntityID() const;
     operator bool();
 };
 
+namespace std
+{
+	template<> struct hash<EntityWrapper>
+	{
+		std::size_t operator()(const EntityWrapper& e) const
+		{
+            std::size_t seed = 0;
+            boost::hash_combine(seed, e.World);
+            boost::hash_combine(seed, e.ID);
+            return seed;
+		}
+	};
+}
+
 #endif
diff --git a/src/Engine/Core/EntityWrapper.cpp b/src/Engine/Core/EntityWrapper.cpp
index c3c5cf27..8c1ab10d 100644
--- a/src/Engine/Core/EntityWrapper.cpp
+++ b/src/Engine/Core/EntityWrapper.cpp
@@ -3,7 +3,7 @@
 
 const EntityWrapper EntityWrapper::Invalid = EntityWrapper(nullptr, EntityID_Invalid);
 
-bool EntityWrapper::operator==(const EntityWrapper& e)
+bool EntityWrapper::operator==(const EntityWrapper& e) const
 {
     return (this->World == e.World) && (this->ID == e.ID);
 }