Added geo and gl packages from gogeline and improved documentation.

geo/vec2.go

@@ -0,0 +1,62 @@
+package geo
+
+import (
+	"math"
+)
+
+// A 2D vector.
+type Vec2 struct {
+	X, Y float64
+}
+
+// Creates a copy of actual vector.
+func (v *Vec2) Copy() Vec2 {
+	return Vec2{v.X, v.Y}
+}
+
+// Adds and saves the given vector to actual vector.
+func (v *Vec2) Add(vec Vec2) {
+	v.X += vec.X
+	v.Y += vec.Y
+}
+
+// Subtracts and saves the given vector to actual vector.
+func (v *Vec2) Sub(vec Vec2) {
+	v.X -= vec.X
+	v.Y -= vec.Y
+}
+
+// Multiplies and saves the given vector to actual vector.
+func (v *Vec2) Mult(vec Vec2) {
+	v.X *= vec.X
+	v.Y *= vec.Y
+}
+
+// Divides and saves the given vector to actual vector.
+func (v *Vec2) Div(vec Vec2) {
+	v.X /= vec.X
+	v.Y /= vec.Y
+}
+
+// Calculates and returns the dot product of actual vector.
+func (v *Vec2) Dot() float64 {
+	return v.X*v.X + v.Y*v.Y
+}
+
+// Calculates and returns the dot product of combination of given vector and actual vector.
+func (v *Vec2) DotVec(vec Vec2) float64 {
+	return v.X*vec.X + v.Y*vec.Y
+}
+
+// Returns the length of actual vector.
+func (v *Vec2) Length() float64 {
+	return float64(math.Sqrt(float64(v.Dot())))
+}
+
+// Normalizes actual vector to length 1.
+func (v *Vec2) Normalize() {
+	l := v.Length()
+
+	v.X /= l
+	v.Y /= l
+}