Vector2.js

var App = App || {};

App.Vector2 = (function() {

    function Vector2(x, y) {
        this.x = x;
        this.y = y;
    }

    Vector2.prototype.length = function() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    };

    Vector2.prototype.scale = function(scale){
        this.x = this.x * scale;
        this.y = this.y * scale;
        return this;
    };

    Vector2.prototype.add = function(vec){
        return new Vector2(this.x + vec.x, this.y + vec.y);
    };

    Vector2.prototype.sub = function(vec){
        return new Vector2(this.x - vec.x, this.y - vec.y);
    };

    Vector2.add = function(vec1, vec2) {
        return new Vector2(vec1.x+vec2.x, vec1.y + vec2.y);
    };

    Vector2.sub = function(vec1, vec2) {
        return new Vector2(vec1.x-vec2.x, vec1.y-vec2.y);
    };

    return Vector2;
})();