function drawBackground()
{
    var image = [imgRoad,imgFloor,imgBegin,imgEnd,imgEnd,imgSpawn,imgBarbar]
    for(var i = 0; i < niveau.length; i++ )
    {
        for(var j = 0; j < niveau[i].length; j++)
        {
            ctx.drawImage(image[niveau[i][j]], 0, 0, 30, 30, j * 30, i * 30, 30, 30);
        }
    }
}