The Secret Origin

As I mentioned in Can You See It?, ever since high school I've wanted to be able to visualize four-dimensional objects. At some point—I'm not sure when, possibly a few years before I wrote the game—I had the idea of taking a four-dimensional maze and projecting it onto a three-dimensional retina. That was a good idea, and led to some nice mental images, but I couldn't figure out how to do anything with it. I could imagine writing a program to draw translucent volumes, but to actually write such a thing was beyond me.

Then, one night (September 25, 2002), inspiration struck, and I came up with two more ideas. I could draw boundary lines instead of translucent volumes, and I could avoid the difficult problem of clipping by drawing squares only to depth 1 (the current square and any adjacent squares). At that point it became possible for me to write a program.

I spent most of the next two weeks in a state of continuous inspiration. After two days I'd written what I'd set out to write: a maze game with a fixed maze, motion in discrete steps, and a simple display that represented cubes in the following way. (What do you call this representation? It's not an orthogonal projection.)

Basically, it was a four-dimensional version of the maze part of Wizardry.

The rest of the two weeks was spent adding features and exploring possibilities. Among other things …

• I realized that it wouldn't be too hard to write ad hoc clipping code for depth 2; that was followed by ad hoc code for depth 3, and eventually by a general algorithm for square mazes.
• I replaced the original display representation with a true perspective view, and then, because that had required thinking about the location of the eye, had the bright idea to make stereo pairs.
• I added wall textures.
• I animated the motion between squares, so that intermediate points were visible; later I allowed the motion to be continuous and unaligned.

After that, I spent two more weeks rewriting the whole thing (and adding boring but necessary features like the options screen), and then a month organizing and writing the documentation.

So, that's how it happened. Besides being a nice story, it's also an example of how much I can do in a extremely good month, and so is relevant to the essay How Much Time?.