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A random dungeon generator that fits on a business card (2019) (gist.github.com)
232 points by tosh 11 months ago | hide | past | favorite | 49 comments



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


> there's obviously no guarantees of solvability

In fact, as the size of the maze goes to infinity, the probability of solvability goes to zero. Source: https://cstheory.stackexchange.com/a/32381/20581


This is the modern equivalent of the classic Commodore BASIC

    10 PRINT CHR$(205.5+RND(1)); : GOTO 10


There's an entire book on this subject: https://10print.org

I can't recommend it without reservation, but if you're curious what a whole book about one line of code is like, you can find out.


That looks like a variant of Truchet Tiles: https://en.wikipedia.org/wiki/Truchet_tiles


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

Here is my orthogonal version:

`w=(├┤┴┬─\|);while :;do echo -n ${w:$RANDOM%6:1};done`

It is based on the 1-liner discussed at <https://www.youtube.com/watch?v=oPtjcSsS2MI>, and uses the PETSCII characters within Unicode.

Screenshot: <https://imgur.com/a/YrvpAqZ> (from `cool-retro-term`'s Apple II profile resized to 80x25, to sort of replicate a Commodore PET's look)


I don’t think there’s any spaces in that screenshot


Surprisingly good for what purpose?


probably fun


It's not much fun to solve because there's no guarantee that a path exists between any given openings on the edge, so it's mostly just "pick a point on the edge at random and see how far you can get". However, it does look very pretty.


It's fast enough that you can just check possible outcomes for whatever criterion you want.


Generating mazes


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...


> 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.

Yeah, it's surprising how well this approach works. Performance is actually decent.

There is a chance of "dud" levels that only have a couple of rooms, but it's rare. The nice thing about this approach is that it guarantees by construction that every room in the dungeon will be reachable from every other one.


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


Thanks! Those two threads were just a couple days apart so I've belatedly merged them, yielding:

A random dungeon generator that fits on a business card - https://news.ycombinator.com/item?id=19290215 - March 2019 (64 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();


Your business cards must be huge.


I don't like this business card :( -- me, a JS dev far too often

(but also, thank you for sharing this!)


Haha thanks for this laugh!


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.


Sorry about Ginny


Thanks. I still miss her sometimes.


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)


I love that it includes an explanation too. Thanks for sharing!


[flagged]


In what way is what ChatGPT outputs when asked about this code relevant? There are more than 20 LLMs, do we expect to see a comment from each LLM about code submissions?


The code isn't very readable in the submitted form, so I appreciated the interpretation, whether or not it's ChatGPT or something else.


The interpretation is not correct, according to this comment: https://news.ycombinator.com/item?id=39422210


I'm not proficient at reading minimized code. Maybe you're better at it than I am. The ChatGPT output helps kickstart a meaningful discussion about the content of the code.


It would probably help if you included that context in the beginning of the comment. Not just dumping ChatGPT output.

From an outside observer it just seems like you wanted ChatGPT to contribute on your behalf, not start a discussion of the code.


Fair enough. The Overton Window shifts quickly these days.


I sort of understand the knee-jerk reactions to this. Hacker News is for humans, not robots, and there was an annoying trend of commenters posting LLM-generated summaries of articles, which deserve to get flagged off the page until they stop.

But I find it noteworthy, and in fact impressive, that ChatGPT can de-obfuscate and discern the meaning of this code. Letting the rest of us know that is a worthy contribution to the discussion.

I would suggest leading with a clear statement of why you're posting chatbot output, though. Folks around here have an allergy to that sort of thing for a reason.


ChatGPT is not de-obfuscating this code. For one thing:

> basic cellular automaton algorithm

is completely wrong. A cellular automaton is a standard approach to level-generation in a roguelike, but this code implements a different approach, the rooms-and-corridors one.

Another issue here is that ChatGPT is using a few key context clues to make its (incorrect but plausible) guess. Robert Nystrom, aka munificient, is well-known in the roguelikedev community for his game programming tutorials. I confirmed that ChatGPT knows who he is by asking "Who is @munificentbob and what is he known for?" The name of the function, "cave", that carves rooms makes it clear that this is some kind of level-generation algorithm - in fact, that's probably where the incorrect guess about cellular automata came from, because those algorithms are often used for "caves" (versus "dungeons" made with rooms-and-corridors). The characters printed are also roguelike standards.

If I remove @munificient's name and rename "cave" to "X", ChatGPT's output is worse. It says: "This code is a compact implementation of a simple game where characters move around a grid.", which is...vaguely in the ballpark.


This is what I have to say about this comment === Why... Why would you do this, in what world does this contribute to the discussion? ===


See my reply to the sibling comment.


One of the comments has the unobfuscated and commented version: https://gist.github.com/Joker-vD/cc5372a349559b9d1a3b220d5ea...


Aha, I didn't see the comments to the Gist. Thanks for that.




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