Re: [Haskell-cafe] How to model outer space for a MUD

I agree with Tikhon But a sparse matrix might be conceptually simpler to start with But are sparse matrices easy to implement in Haskell and then is it easy to change the data structure layer on? -- -- Sent from an expensive device which will be obsolete in a few months! :D Casey On Aug 14, 2015 1:50 PM, "Tikhon Jelvis" wrote:

It depends on exactly what you want to represent and how you want to do it.

The first thing that comes to mind for me would be using an octtree[1], which is the three-dimensional analog of a quadtree[2]. Conal Elliott has an interesting point about using quadtrees to represent images in Haskell[3], and you should be able to adapt the idea to indexing into a three dimensional world with an octtree.

[1]: https://en.wikipedia.org/wiki/Octree

[2]: https://en.wikipedia.org/wiki/Quadtree

[3]: http://conal.net/blog/posts/topless-data

On Fri, Aug 14, 2015 at 1:44 PM, David McBride wrote:

...

If you are thinking of it as a 3d grid, you might just have a (Map (Integer, Integer, Integer) Contents, where every room in this 3d grid that has something in it is in the map and every room that is empty space has no corresponding entry in the map.

Then when you enter a room you can quickly look up what is in that room, then reasonably quickly check the neighbors in every direction to see what the ship might be able to sense were it to travel in that direction.

In this case, space is infinite, but the datastructure is only as big as the amount of content you have.

On Fri, Aug 14, 2015 at 4:34 PM, Michael Litchard wrote:

...

Star Wars MUD has a 3-D coordinate system such that (0,0,0) is some planet. I'm curious as to how one might model this system that could simulate a ship's movement through a 3-D grid. Matrix, 3-D array, graph. None of these? Ideas?

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