fix Vec.Normal to rotate by pi/2, not -pi/2
@@ -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.
