Split out maths functions into maths, vector and bearing

pkg/vector/vector.go

@@ -0,0 +1,47 @@
+package vector
+
+import "math"
+
+// Vector desribes a 3D vector
+type Vector struct {
+	X int `json:"x"`
+	Y int `json:"y"`
+}
+
+// Add adds one vector to another
+func (v *Vector) Add(v2 Vector) {
+	v.X += v2.X
+	v.Y += v2.Y
+}
+
+// Added calculates a new vector
+func (v Vector) Added(v2 Vector) Vector {
+	v.Add(v2)
+	return v
+}
+
+// Negated returns a negated vector
+func (v Vector) Negated() Vector {
+	return Vector{-v.X, -v.Y}
+}
+
+// Length returns the length of the vector
+func (v Vector) Length() float64 {
+	return math.Sqrt(float64(v.X*v.X + v.Y*v.Y))
+}
+
+// Distance returns the distance between two vectors
+func (v Vector) Distance(v2 Vector) float64 {
+	// Negate the two vectors and calciate the length
+	return v.Added(v2.Negated()).Length()
+}
+
+// Multiplied returns the vector multiplied by an int
+func (v Vector) Multiplied(val int) Vector {
+	return Vector{v.X * val, v.Y * val}
+}
+
+// Divided returns the vector divided by an int
+func (v Vector) Divided(val int) Vector {
+	return Vector{v.X / val, v.Y / val}
+}