Sunday, January 14, 2007


For the last couple weeks, I've been working on artwork for Tale, the MUD, you know. That is, two weekends ago, I got back from visiting the family down south and had an itch to make something, so I've spent all of my off-time since scratching my brain and mouse-pad with fervor. The first thing I drew was a multi-layer sea and sky vessel graphic, the Mallard. The Mallard is one of the seminal concepts for Tale, a Norse style galley with steam and blimp upgrades. It's the focal point for blending a mediaeval theme with a fantasy theme with a Victorian sci-fi (steam-punk) theme. I finished it, cranked out some permutations, called it amazing, and moved on. Since then, I've populated a wiki with bunches of monsters, items, and game design memes.

Today's project was to finish writing the automation for generating permuations (sail plans) of the Mallard. To that end I did a bunch of technial stuff. Skip to the next paragraph if you don't care about technical stuff. The mallard graphic proper is a single SVG file with something like 120 layers. These layers include such wonders as "mizzen-top-gallant-yard", "bow-jib-outer-sail", and "sweeps". Constructing a mallard graphic is a two step process replete with danger. The first step is to filter the graphic for the desired layers. I've constructed several layers files which include all of the necessary layers for a particular sail plan. The second process is sorting those layers to preserve the three dimensional illusion. To this end, I have several sets of "rules" for sorting the layers, rules like "the yard arm is behind the mast", employed exhaustively and brutally. There's one set of common rules, one set of rules for ships that appear to be sailing away from the observer, and one for vessels that appear to be sailing toward the observer. Using these rules, I construct a "digraph", merely a set of layer names associated with layers that are known to be behind them, and then perform a "topological sort" on those layers. I do this all with the command line, so constructing boat-100.png looks like: cat mallard.svg | svg-filter boat.layers | svg-sort rules boat.rules | rsvg -w 100 - boat-100.png. That process applied iteratively renders our 29 (so far) selected sail plans. I can't wait to play a game where these vessels are set in bitter competition and players scramble to arrange their sails to catch the wind and their prey or their daring escape.

So, here, in all their glory, selected permutations of a mallard.

Mallard Ship

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