 document.querySelector('canvas'),
                context = canvas.getContext('2d'),
                cw = canvas.width=document.body.offsetWidth,
                ch = canvas.height=document.body.offsetHeight,
                ship = new Ship();
            var vr = 0,
                vx = 0,
                vy = 0,
                thrust = 0;
            ship.x = cw / 2;
            ship.y = ch / 2;
            ship.draw(context);
            window.addEventListener("keydown", function (event) {
           