update.js

setVelocity: function () {
        var difX = ((ig.input.mouse.x - (this.size.x / 2)) - this.pos.x).round();
        var difY = ((ig.input.mouse.y - (this.size.y / 2)) - this.pos.y).round();


        var max = 100,
            maxX = (difX > 0)? max : -max,
            maxY = (difY > 0)? max : -max;


        this.vel.x += difX * 4;
        this.vel.y += difY * 4;

    },
    decayHandler: function () {
        if (this.vel.x > 0){
            this.vel.x -= 50;
        } else if (this.vel.x < 0){
            this.vel.x += 50;
        }

        if (this.vel.y > 0){
            this.vel.y -= 50;
        } else if (this.vel.y < 0){
            this.vel.y += 50;
        }

    },