A random dungeon generator that fits on a business card (2019)

I've always been a fan of generating mazes by randomly printing /, \, or a space. It ends up slanted, and there's obviously no guarantees of solvability, but it's surprisingly good for how simple it is.

Here's a bash version in 50 characters (https://codegolf.stackexchange.com/a/26011/7934):

    w=(╱ ╲);while :;do echo -n ${w[RANDOM%2]};done

and how it looks like:

https://i.stack.imgur.com/fRX05.png

I saw this post about 2 hours ago, and I was fascinated by it and curious how it worked. So I decided to de-obfuscate it and add comments.

The code was too large for a comment, so here's the gist:

https://gist.github.com/paskozdilar/48d7532733ccd11144bb43fe...

The approach is quite interesting - it (ab)uses the preprocessor to shorten the syntax of for loops:

    #define l(a, b, c, d) for (int y = a; y < b; y++) for (int x = c; x < d; x++)

And then it does the heavy lifting by iterating over the whole map thousand times, randomly selecting a rectangle on the map and checking if the selected area is adjacent to an already-generated cave. It's a probabilistic algorithm, so there's a tiny chance that it will just print a single cave in the middle and nothing else.

EDIT: Then I found that many other people also de-obfuscated it in the gist comments. :') This guy did a much better job than me:

https://gist.github.com/Joker-vD/cc5372a349559b9d1a3b220d5ea...

That functionality could probably fit in 1 line of APL... which means a business card could be enough space for a 3D renderer of the random dungeon.

Related: https://news.ycombinator.com/item?id=6425714

Of course there's the demoscene productions where binary size is the measure (no cheating by using lots of libraries); and in a 1K binary, comparable in size to this source, they've gone much further with what can be generated.

https://news.ycombinator.com/item?id=19309378 - A random dungeon generator in C, small enough to fit on a business card (2019) - 42 comments

https://news.ycombinator.com/item?id=19290215 - original post referenced above - 23 comments

I heard you like javascript so here you go:

const H = 40; const W = 80; let m = new Array(H).fill().map(() => new Array(W).fill(" "));

function g(x) { return Math.floor(Math.random() * x); }

function cave(s) { const w = g(10) + 5; const h = g(6) + 3; let t = g(W - w - 2) + 1; let u = g(H - h - 2) + 1;

  for (let y = u - 1; y < u + h + 2; y++) {
    for (let x = t - 1; x < t + w + 2; x++) {
      if (m[y][x] === ".") return;
    }
  }

  let d = 0;
  let e, f;

  if (!s) {
    for (let y = u - 1; y < u + h + 2; y++) {
      for (let x = t - 1; x < t + w + 2; x++) {
        const s = x < t || x > t + w;
        const v = y < u || y > u + h;

        if (s ^ v && m[y][x] === "#") {
          d++;
          if (g(d) === 0) {
            e = x;
            f = y;
          }
        }
      }
    }
    if (d === 0) return;
  }

  for (let y = u - 1; y < u + h + 2; y++) {
    for (let x = t - 1; x < t + w + 2; x++) {
      const s = x < t || x > t + w;
      const v = y < u || y > u + h;

      m[y][x] = s && v ? "!" : s ^ v ? "#" : ".";
    }
  }

  if (d > 0) m[f][e] = g(2) ? "'" : "+";

  for (let j = 0; j < (s ? 1 : g(6) + 1); j++) {
    m[g(h) + u][g(w) + t] = s
      ? "@"
      : g(4) === 0
      ? "$"
      : String.fromCharCode(65 + g(62));
  }

}

function main() { for (let y = 0; y < H; y++) { for (let x = 0; x < W; x++) { m[y][x] = " "; } }

  for (let j = 0; j < 1000; j++) {
    cave(j === 0);
  }

  for (let y = 0; y < H; y++) {
    let row = "";
    for (let x = 0; x < W; x++) {
      const c = m[y][x];
      row += c === "!" ? "#" : c;
    }
    console.log(row);
  }

}

main();

I'd love a random dungeon generator that includes multiple plateaus inside one room. For example, a dungeon with a waterfall or a tree.

Whenever I'd run an adventure, my players would often try me out, and open a door of some sorts. But the 2D maps feel very artificial. Guillaume Tavernier on Patreon makes maps with plateaus and multiple stories: https://www.patreon.com/dearchitecturart

A generator like that, would be awesome.

I love that people rediscover this every year or so. It was a really fun little distraction for me, and I'm delighted at how it came out.

Someone deobfuscated it here

https://gist.github.com/Joker-vD/cc5372a349559b9d1a3b220d5ea...

Pretty interesting reading this code. Also nice to see things written in C around here.

I converted this to formulas in calculang, a language for calculations I'm developing, and visualize the dungeon and its evolution.

I really liked this output from a very logical process (although I'll admit, I needed to use one of the commented versions linked in the discussion!)

Here it is: https://declann.observablehq.cloud/calculang-dx-pattern-exam...

If you were wondering about the tribute to Ginny, here's the context: https://journal.stuffwithstuff.com/2022/02/13/stupid-dog/.

Love the "on a business card" format, thank you for creating this and sharing!

Now also make it a text QR code

The comments on that introduced me to cxx, which is also a really neat thing to learn about!

Suave.

The output reminds me of nethack.

Love/hate that in 2023 someone is still writing CoffeeScript

would it fit in a QR code

Here's a random dungeon generator GAME (get potion, avoid snake, explore dungeon) that fits in 10 lines of BASIC [1] and would probably easily fit on a business card, too:

https://bunsen.itch.io/the-snake-temple-by-rax

([1] - The 10-line BASIC competition is happening again this year, details here: https://gkanold.wixsite.com/homeputerium/copy-of-rules)