code: function() {
      var x, angle, ray;
  
      ctx.save();
  
      for (var col=0; col<this.resolution; col++) {
        x = col / this.resolution - 0.5;
        angle = Math.atan2(x, this.focalLen);
        ray = game.map.cast(game.player, game.player.dir + angle, this.range);
  
        this.drawCol(col, ray, angle);
      }
  
      ctx.restore();
    }
docs: Based on the resolution, split the scene up and draw it column by column.