L2 Helicopter

<canvas id="canvas" width="600" height="500"/>

var cnv = document.getElementById('canvas');

var ctx = cnv.getContext("2d");

var img = new Image();

img.src = "http://lnxprog.studenthosting.sk/heli/heli.png";

var img2 = new Image();

img2.src = "http://lnxprog.studenthosting.sk/heli/heli_crash.png";

var key_up = false;

var key_down = false;

var key_left = false;

var key_right = false;

var key_a = false;

var key_d = false;

var key_space = false;

/* 38 - up, 40 - down, 37 - left, 39 - right, 65 - a, 68 - d */

window.addEventListener("keydown", function(e) {

    if (e.keyCode == 38) key_up = true;

    if (e.keyCode == 40) key_down = true;

    if (e.keyCode == 37) key_left = true;

    if (e.keyCode == 39) key_right = true;

    if (e.keyCode == 65) key_a = true;

    if (e.keyCode == 68) key_d = true;

    if (e.keyCode == 32) key_space = true;

});

window.addEventListener("keyup", function(e) {

    if (e.keyCode == 38) key_up = false;

    if (e.keyCode == 40) key_down = false;

    if (e.keyCode == 37) key_left = false;

    if (e.keyCode == 39) key_right = false;

    if (e.keyCode == 65) key_a = false;

    if (e.keyCode == 68) key_d = false;

    if (e.keyCode == 32) key_space = false;

});

function draw(im, x, y, uhol, cx, cy) {

    ctx.save();

    ctx.translate(x, y);

    ctx.rotate(uhol * Math.PI/180);

    ctx.translate(-cx, -cy);

    ctx.drawImage(im, 0, 0);

    ctx.restore();

}

var x = 100;

var y = 100;

var dx = 0;

var dy = 0;

function heli_move() {

    if (key_left) dx -= 1;   

    if (key_right) dx += 1;   

    if (y <= 448) {

      dy += 1;

    } else {

      y = 450;

      dy = 0;

      if (dx > 0) dx -= 1;

      if (dx < 0) dx += 1;

    }

    if (key_up) dy -= 2;   

    x += dx;

    y += dy;

}

function update() {

    ctx.fillStyle = "lightblue";

    ctx.fillRect(0, 0, 600, 500);

    ctx.fillStyle = "green";

    ctx.fillRect(0, 450, 600, 50);

    draw(img, x, y, 0, 88, 41);

    heli_move();   

}

setInterval(update, 50);