Director Article

Tile-Based Scrolling in Director

Challenges of Tile-Based Scrolling

All is not so easy. There are some challenges to using this technique.

Difficulty of Application

Unfortunately, this technique does not apply very easily to any kind of image. For instance, if you use it with photographs, there is very little chance you'll achieve any size reduction because a photo rarely ever features exactly repetitive areas. Nevertheless, you can still use the scrolling, as Pat McClellan shows in his article, Scrolling Images Using Imaging Lingo. Tile-based scrolling specs are best used on images created completely from scratch for the sole purpose of being used with this technique. This leads me to the second challenge.

Difficulty of Creation

To create a level map, you'd better do it backwards—that is, start with the tiles and then create an image with them. You still have to create the map, which can be rather tedious to do by hand. You'll probably want to create or use an existing level editor for this purpose (see Figure 2).

Figure 2. Level editor

Once you create such a tool, it becomes much easier to generate such images at will.

Repetitive Aspect of Tiling

A bitmap created for scrolling purposes often has a repetitive quality. Because it's very easy to see the tiles, the image has an artificial appearance. While this may not be annoying in an image showing something like a space hangar, it can be annoying in a country landscape. The more the tiles are similar, the more this problem becomes apparent. Still, this technique allows an image file to be very small.

There are different ways to remedy this problem. You can create transition tiles or create them in such a way that they connect with other tiles to create many varied areas without the need for additional tiles. Solutions to this problem require additional work and some brainstorming, but the advantages of using this technique—and the results—are well worth the effort.

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