From 68842de56ed701b91e2865ee201a0dfdeb8aa5b1 Mon Sep 17 00:00:00 2001
From: Fraser Graham <frasergraham@me.com>
Date: Thu, 8 Aug 2013 23:14:18 -0700
Subject: [PATCH] Correct normalization of 0 vector

---
 govector_test.go | 8 ++++++++
 vectorpoint.go   | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/govector_test.go b/govector_test.go
index d38e232..42d066f 100644
--- a/govector_test.go
+++ b/govector_test.go
@@ -58,4 +58,12 @@ func TestNormalize(t *testing.T) {
 	if vn.Mag() != 1 {
 		t.Errorf("Normalize Error")
 	}
+
+	v0 := Vector2d{0, 0}
+	vn0 := v0.Normalize()
+
+	if vn0.Mag() != 0 {
+		t.Errorf("Normalize Error")
+	}
+
 }
diff --git a/vectorpoint.go b/vectorpoint.go
index 60b84fc..450323a 100644
--- a/vectorpoint.go
+++ b/vectorpoint.go
@@ -44,6 +44,10 @@ func (v Vector2d) Scale(s float64) Vector2d {
 }
 
 func (v Vector2d) Normalize() Vector2d {
+	if v.X == 0 && v.Y == 0 {
+		return v
+	}
+
 	m := v.Mag()
 	return Vector2d{v.X / m, v.Y / m}
 }