Death to Mazes Like Moria!

I suppose that mazes are a staple of the MUD tradition. Starting with Adventure, you're underground and you're lost. Throw in some orcs and you're in Moria. Whatevs.

We follow the tradition with lotso mazes, but, we try to make them interesting. This post'll be about the technology rather than the content, but, we really do try to make the content interesting too.

TriadCity Maze types are implemented via the Strategy OO pattern. There's that word "Strategy" again. We do a lot of that. A Java Interface called Maze defines the contract; multiple concrete implementations can be swapped out at runtime. Among the implications: world authors not only have a ton of maze algorithms at their disposal, but we can actually swap out algorithms at runtime whenever that seems the thing to do.

TwoDMaze is a simple x/y grid of Rooms, always in a rectangular pattern. World authors can specify how many Rooms wide versus tall, and the Builder tools will prompt them if they provide the wrong number of Rooms. Thus a TwoDMaze defined as x=7 y=5 has gotta have 35 Rooms assigned, no more, no less. TwoDMaze puts the Rooms in consistent order across the grid, that is, Room 1 will always be the upper left corner, and the Rooms will be assigned in left-to-right order at every server boot. Exits between Rooms will be assigned dynamically according to what maze-drawing algorithm is chosen by the world author. You guessed it, these algorithms are again Strategy objects. We've got Kruksal, Prim, Depth-First, and a pile of others. Exits will be computed and distributed around the maze at server boot.

Add a z dimension and it's a ThreeDMaze. Have the Exits dynamically reassigned at random or semi-random during server uptime and it's a FourDMaze — think Harry and Cedric racing for the cup.

We can vary all of these by not assigning the Rooms in consistent order. Just shuffle the Room[] before laying out the grid. Now there'll always be a Room 1, but it won't always be in the upper left corner. It could be anywhere, meaning that special fountain or other object of interest will have to be searched for anew after every server boot. Or shuffle them every hour, or shuffle the grid and the Exits and really confuse people.

But wait, there's more. We don't have to always assign ordinary FreeExits — the Exits that allow movement between Rooms without impediment. They can be RandomDestinationTeleportationExits or any other Exit type we like, in whatever proportion we like. Yes, there's one extremely notorious maze full of nasty critters with pointy sharp teeth offering only a single teleporter to get out — no way you're going back the way you came. Bring a large party with supplies. Find that teleporter before you run out of grenades.

More still. Authors can assign Behaviors to the Rooms or the Exits, making things even more interesting. TelGar's writing a big slag heap you have to climb to reach something valuable. The slag heap kicks up tonso dust so there's no telling exactly where you are, and because the ground is loose, you're constantly being forced downward as the earth slides out from under you. It's a compelling adventure, enabled by combining a dynamically-changing Maze type with a SlideRoomBehavior which forces you to move in a certain direction, like a slide in a playground. You can eventually get to the top, but it's a struggle.

These Strategy Pattern objects allow the server code to remain tidy and easy to maintain, while putting a lot of power into the hands of world authors. Authors can assign whatever crazy algorithm best suits their thematic purpose. Just how lost do you want the punters to get? You've got lots of options. Somebody invents a new maze-generation algorithm? Great, we'll add it. Easy-peasy.

Death to mazes like Moria!