code: function() {
      var dir = game.player.dir;
      var sky = game.map.skybox;
      var ambient = game.map.light;
      var width = sky.width * (this.height / sky.height) * 2;
      var left = (dir / circle) * -width;
  
      ctx.save();
      ctx.drawImage(sky.image, left, 0, width, this.height);
      if (left < width - this.width) {
        ctx.drawImage(sky.image, left + width, 0, width, this.height);
      }
      if (ambient > 0) {
        ctx.fillStyle = '#fff';
        ctx.globalAlpha = ambient * 0.1;
        ctx.fillRect(0, this.height * 0.5, this.width, this.height * 0.5);
      }
      ctx.restore();
    }
docs: Draw the skybox based on the player's direction.