|Star Wars Galaxies|
|Publisher:||Sony Computer Entertainment|
|Released:||June 25, 2003|
A Star Wars themed massively multiplayer online role-playing game.
Use of Procedural Content Generation Methods
The worlds featured in the game were created using fractal generation. An article from the June 2002 issue of Computer Gaming World elaborates:
The fractal-based terrain engine is what drives the planets, allowing them to have massive mountains, lush trees, and weird crystal things all over the place.
Artists use a terrain editor developed by Andy Sommers to shape the base fractal terrain. A technical article and psuedo interview with John Roy 'Planet Design: The Shaping of Corellia' published by Sony back in 2001 goes into this in some detail:
Basically, these represent "rules" for a planet's terrain. Much like Photoshop and its use of layers, they begin with a base layer, a background. "I use these circles to change the level of terrain," says John. "I can decide to sink all of this down so far. Okay, now pull it up and make an island or two. Then, I want to just kind of put some brush marks here and there. It's just like painting in a way, only with trees and shrubs and hills. We're able to hit a huge area very quickly and create all that terrain right off the bat."
On the fly placement of fractal content can be problematic if the content cannot be placed in the locations players should be able to see it in, in a timely fashion. One case where this was evident in Star Wars Galaxies was the fractal placement of trees as detailed by Raph Koster:
The trees are placed using the fractal generation. We generate terrain at less and less detail the farther the distance from the camera. Less detail means that the trees would be placed inaccurately (if you know how fractals work, you'd see why) beyond the point at which the terrain is generated at full detail.
Sony's technical article also touches on artist customisation of scenery placement within the terrain editor it describes:
"These circles and the different boxes are little areas and boundaries I can mark off. For example, I can say, within this circle I want mountains with these kinds of pine trees on it." There are literally dozens of these circles and boxes, all different sizes, some overlapping each other, nesting within one another.
One tool which artists use to apply the natural look and feel which comes from the use of fractals is the ability to select areas of noise and apply it to regions of terrain as a brush:
He shows me a popup window filled with what looks like a piece of black cloth sporting a scatter of white tears. That's what he means by noise patterns. "I can go in here and create all sorts of interesting patterns, and in those patterns I can select areas and raise them smoothly and make hills with that kind of randomness."
The advantage which procedural generation gives is summarised by the interviewed artist:
This lake is special to John because of its uniqueness. "I had no idea it was here," he admits. "I just kind of walked around and saw it. And there's a lot of that. If this world were handcrafted, you'd pretty much just make corridors of interest, where our whole planet has interest because we're algorithmically generating it. We're covering so much more ground with broad sweeping rules."
PCG Wiki References
Star Wars Galaxies - Wikipedia entry for Star Wars Galaxies.