90 lines
2.4 KiB
Markdown
90 lines
2.4 KiB
Markdown
# SNEK is Not an Acronym
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## About
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`snek` is a simple data structure for working with vertices and edges. More
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importantly it is a programming pattern for applying changes to the structure.
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It is specifically written to be useful for a broad range of ways in which i
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usually write generative algorithms for creating art.
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The pattern depends on the concept of `alterations`. In short: an `alteration`
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is a change that will be applied to the structure at the end of a given
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context. `alterations` are further described in
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http://inconvergent.net/snek-is-not-an-acronym/.
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Here is and example of manipulating a `snek` instance called `snk` using
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`alterations`:
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; context start
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(with-snek (snk)
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; iterate
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(with-all-verts (snk v)
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; move alteration
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(move-vert v (rnd-in-circ))
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; w will be an arbitrary
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; vertex in snk
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(with-rnd-vert (snk w)
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; join v and w if they are closer than d
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(if (< (vert-dst snk (v w)) d)
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; join vertices alteration
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(join-verts v w))))
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; context end
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; alterations have been applied
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There are two more examples. They can be executed like this:
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./run-slope.lisp res/slop.png
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./run-lines.lisp res/lines.png
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Notice that the resulting image will end up in `res`.
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`snek` is used in
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- http://moment.inconvergent.net/
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- https://twitter.com/sandpaintbot
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- https://twitter.com/scratchpaintbot
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## Dependencies
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This code requires `Quicklisp` and `zpng`. Note that the The path to quicklisp
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must be set in `src/load`. `zpng` is automatically installed via `quicklisp`.
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- http://www.xach.com/lisp/zpng/
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- https://www.quicklisp.org/beta/
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## Run tests
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There are some tests included. Run them like this:
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./run-test.lisp
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## Stability changes and Versioning
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This code is highly experimental on my part. It is likely to change with no
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warning or explanation. I will keep a note of the version number in `VERSION`.
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## On Use and Contributions
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This code is a tool that I have written for my own use. I release it publicly
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in case people find it useful. It is not however intended as a
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collaboration/Open Source project. As such I am unlikely to accept PRs, reply
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to issues, or take requests.
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## Todo
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- Randomized order of alteration apply
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- Maintain list of singly-connected vertices?
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- zonemaps? kd-tree?
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## Done
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- Reject/attract force move alterations, or force calc funcs? (sort of)
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