# Chaos Game

The [Chaos Game](https://en.wikipedia.org/wiki/Chaos_game) (wikipedia) is a fractal generator. This program works by iteratively walking half way between the current location (initially the center of the sprite but could be random) and a randomly selected vertex. Each time a step is made, a pixel is filled in at the destination. The color is based on the vertex's color.

Right now, this program uses a hard-coded triangle and so generates a [Sierpinsky triangle](https://en.wikipedia.org/wiki/Sierpi%C5%84ski_triangle). Other shapes can be used -- see the Chaos Game Wikipedia link for examples. I have not provided a UI for altering these shapes at run time.

## Building

### For desktop

Run `cargo run --release`, just like any other binary crate.

Use `cargo run --features=dynamic_linking` for faster cycle times when modifying the code. This feature is a pass-through to Bevy's dynamic linking feature.

### For WASM

Run `cargo run --release --target=wasm32-unknown-unknown`. This will start a dummy webserver, *wasm-server-runner*, which in turn hosts a dummy webpage that loads the WASM file. Run the program by visiting the dummy site in your browser: [http://localhost:1334]

To make a "real" deployment, I use the output of `wasm-bindgen --web` and the tiny index.html here in the repo. These are thrown at whatever webserver is available at hand.

```sh
# Build the program
user@host:~/chaos-game-rs$ cargo build --release --target wasm32-unknown-unknown
user@host:~/chaos-game-rs$ wasm-bindgen --no-typescript --target web --out-dir out/ --out-name "chaos-game-rs" target/wasm32-unknown-unknown/release/chaos-game-rs.wasm

# Place the HTML, JS, and WASM all together in a web root.
# Here, I'll reuse the ./out/ folder
user@host:~/chaos-game-rs$ cp index.html ./out/index.html

# Host the files with an HTTP server. Any will do, but some are easier to
# configure than others.

# BusyBox's httpd (note that "httpd" might mean Apache2 or Nginx on your
# machine. Check the manual for the right flags).
user@host:~/chaos-game-rs$ httpd -f -p 8080 -h ./out

# Python's http.server module
user@host:~/chaos-game-rs$ python3 -m http.server -p 8080 -d ./out

# Or, again, the wasm-sever-runner, from the start of this section
user@host:~/chaos-game-rs$ cargo run --target=wasm32... # etc, etc
```

The `wasm-bindgen` tool offers [other module formats](https://rustwasm.github.io/docs/wasm-bindgen/reference/deployment.html), which may be of interest for anyone trying to use this as one of many pages on a site. I may come back to explore that later, but for now it's just a couple of files to manually move around.