From 32839006f33f988daf86cadc4de715233a9dc858 Mon Sep 17 00:00:00 2001
From: jgoppert <james.goppert@gmail.com>
Date: Thu, 5 Nov 2015 20:22:17 -0500
Subject: [PATCH] Implemented vector 3 cross product.

---
 matrix/Vector3.hpp | 12 +++++-------
 test/vector3.cpp   |  2 ++
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/matrix/Vector3.hpp b/matrix/Vector3.hpp
index ad852a88d9..0629099088 100644
--- a/matrix/Vector3.hpp
+++ b/matrix/Vector3.hpp
@@ -50,14 +50,12 @@ public:
         v(2) = z;
     }
 
-    Vector3 cross(const Vector3 & b) {
-        // TODO
-        Vector3 &a(*this);
-        (void)a;
+    Vector3 cross(const Vector3 & b)  const {
+        const Vector3 &a(*this);
         Vector3 c;
-        c(0) = 0;
-        c(1) = 0;
-        c(2) = 0;
+        c(0) = a(1)*b(2) - a(2)*b(1);
+        c(1) = -a(0)*b(2) + a(2)*b(0);
+        c(2) = a(0)*b(1) - a(1)*b(0);
         return c;
     }
 };
diff --git a/test/vector3.cpp b/test/vector3.cpp
index a7a033bf38..e60a3f201f 100644
--- a/test/vector3.cpp
+++ b/test/vector3.cpp
@@ -12,6 +12,8 @@ int main()
     Vector3f a(1, 0, 0);
     Vector3f b(0, 1, 0);
     Vector3f c = a.cross(b);
+    c.print();
+    assert (c == Vector3f(0,0,1));
     return 0;
 }