From f579d2a0e22df758ae8278c03a07843a87c4562b Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Wed, 30 Jul 2014 13:11:45 -0700
Subject: [PATCH] add CollisionInfo::getShapePairKey()

---
 libraries/shared/src/CollisionInfo.cpp | 10 ++++++++++
 libraries/shared/src/CollisionInfo.h   |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/libraries/shared/src/CollisionInfo.cpp b/libraries/shared/src/CollisionInfo.cpp
index e862a22f4a..9dc321fa44 100644
--- a/libraries/shared/src/CollisionInfo.cpp
+++ b/libraries/shared/src/CollisionInfo.cpp
@@ -26,6 +26,16 @@ CollisionInfo::CollisionInfo() :
         _addedVelocity(0.f) {
 }
 
+quint64 CollisionInfo::getShapePairKey() const {
+    if (_shapeB == NULL || _shapeA == NULL) {
+        // zero is an invalid key
+        return 0;
+    }
+    quint32 idA = _shapeA->getID();
+    quint32 idB = _shapeB->getID();
+    return idA < idB ? ((quint64)idA << 32) + (quint64)idB : ((quint64)idB << 32) + (quint64)idA;
+}
+
 CollisionList::CollisionList(int maxSize) :
     _maxSize(maxSize),
     _size(0) {
diff --git a/libraries/shared/src/CollisionInfo.h b/libraries/shared/src/CollisionInfo.h
index 1ab06e2ef5..6e70654d15 100644
--- a/libraries/shared/src/CollisionInfo.h
+++ b/libraries/shared/src/CollisionInfo.h
@@ -15,6 +15,7 @@
 #include <glm/glm.hpp>
 #include <glm/gtc/quaternion.hpp>
 
+#include <QtGlobal>
 #include <QVector>
 
 class Shape;
@@ -47,6 +48,9 @@ public:
     Shape* getShapeA() const { return const_cast<Shape*>(_shapeA); }
     Shape* getShapeB() const { return const_cast<Shape*>(_shapeB); }
 
+    /// \return unique key for shape pair
+    quint64 getShapePairKey() const;
+
     const Shape* _shapeA;  // pointer to shapeA in this collision
     const Shape* _shapeB;  // pointer to shapeB in this collision