From 7c5e5588e2d95dbb9aaa4d32dff3f4cd5237fdb5 Mon Sep 17 00:00:00 2001
From: faiface <faiface@ksp.sk>
Date: Tue, 29 Aug 2017 20:23:32 +0200
Subject: [PATCH] fix Vec.Normal to rotate by pi/2, not -pi/2

---
 geometry.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/geometry.go b/geometry.go
index 52dfa73..d956bd0 100644
--- a/geometry.go
+++ b/geometry.go
@@ -112,7 +112,7 @@ func (u Vec) Rotated(angle float64) Vec {
 
 // Normal returns a vector normal to u. Equivalent to u.Rotated(math.Pi / 2), but faster.
 func (u Vec) Normal() Vec {
-	return Vec{u.Y, -u.X}
+	return Vec{-u.Y, u.X}
 }
 
 // Dot returns the dot product of vectors u and v.