A random dungeon generator that fits on a business card | Hacker News Reader

A random dungeon generator that fits on a business card

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142 pointsmunificent64 comments

This is really cool, nice work (and sorry about your dog).

It reminds me that once upon a time the roguelike dev newsgroup had a "1k (source code) roguelike challenge".

The thread is here [1] and submissions are here in a slightly annoying format [2] but sadly I can't find the entry I remember, which I thought was in C and actually quite playable, if slightly at the mercy of the random number generator to make each new level solvable. Perhaps it was for a later iteration of the same challenge.

[1] https://rec.games.roguelike.development.narkive.com/3tm7xGpn... [2] https://sites.google.com/site/1024brl/

If like me you're interested in looking at how the code actually works I put a deobfuscated fork here

https://gist.github.com/femto113/28f69626acddc70a002ecead0b3...

Just expands the macros/typedefs and applies standard indenting, code is otherwise same as the original.

There are a few tweaks I made along the way while tightening it up, but here's the readable original I started from:

https://gist.github.com/munificent/ce8f7a9e6b09938ca8d2d43fa...

This is not mine, but from the “clojure grams” twitter account:

  (defn maze [n]
    (->> (repeatedly (* n n) #(rand-nth "╱╲"))
      (partition n)
      (transduce
        (comp
          (map #(apply str %))
          (interpose "\n"))
        str)))

Simpler output but related and also quite interesting!

Looks like a port of this Basic one-liner: http://www.slate.com/articles/technology/books/2012/11/compu...

He's the same guy that wrote the book Game Programming Patterns. http://gameprogrammingpatterns.com/

And is currently writing the online book Crafting Interpreters http://www.craftinginterpreters.com/

I like the old-school notion that I can just copy and paste it into vi and then compile with gcc. It just works. No complicated installation of a runtime or dependencies.

For me this is the appeal of C and I feel it as well. Any unix will have a C compiler supporting at least C89

Except a recent gcc will refuse to compile that code because of a technicality.

Here's some modified code that runs on my machine if pasted directly into bash:

gcc -x c - <<EOF

  #include <time.h> //  Robert Nystrom
  #include <stdio.h> // @munificentbob
  #include <stdlib.h> //     for Ginny
  #define  r return    //    2008-2019
  #define  l(a, b, c, d) for (i y=a;y\
  <b; y++) for (int x = c; x < d; x++)
  typedef int i;const i H=40;const i W
  =80;i m[40][80];i g(i x) {r rand()%x;}
  void cave(i s){i w=g(10)+5;i h=g(6)+
  3;i t=g(W-w-2)+1;i u=g(H-h-2)+1;l(u-
  1,u+h+2,t-1,            t+w+2)if(m[y
  ][x]=='.')                  r;i d=0;
  i e,f;        if(!s){l(u      -1,u+h
  +2,t-1    ,t+w+2){i s=x<t||     x>t+
  w; i    t=y<u||           y>    u+h;
  if(s    ^t&&              m[      y]
  [x    ]=='#'    ){d++;    if(g    (d
  )     ==0)    e=x,f=y;    }}if    (d
  ==    0)r;    }l(u-1,u    +h+2    ,t
  -1    ,t+w    +2){i s=    x< t    ||
  x>    t+w;    i t= y<u    ||y>    u+
  h;    m[y]      [x]= s    &&t?   '!'
  :s^t    ?'#'                    :'.'
  ;}if    (d>0)m                  [f][
  e]=g(2    )?'\'':'+';for(i j=0;j<(s?
  1:g(6)        +1);j++)m[g(h)+u][g(w)
  +t]=s?'@'                 :g(4) ==0?
  '$':65+g(62)              ;}i main(i
  argc, const char* argv[]) {srand((i)
  time(NULL));l(0, H, 0,W)m[y][x]=' ';
  for(i j=0;j<1000;j++)cave(j==0);l(0,
  H,0,W) {i c=m[y][x]; putchar(c=='!'?
  '#':c);if(x==W-1)printf("\n");}r 0;}

EOF

./a.out

                                                               ###############  
                                                               #.......^...$.#  
  ###################                ##############            #.....Z.......#  
  #..$...#..........#                #............#            #.....e.......#  
  #..a...#........$.#                #...$....$...# ############.............#  
  #......#.}........#      ###########....y.......# #.........#######+########  
  #......#..........#      #........##............# #.........##....~.#         
  #......#..........#      #........########'###### #....d....##......#         
  #......+..........#      #H....^$.#.....$...#     #.........##......#         
  ###########'#######      #........+c......O.#     #.........##......#         
   #...........#           ##########.........#     #...$.....##.z$...#         
   #.....x.$...#                    #.........#     #.........##......########  
   #...........#                    #.....Q...#     #.........##Q.....+......#  
   #...........#       ###########  #.........#     #.........##......#......#  
   ######'#########    #.........#  #.........#  ###########'###+######......#  
       #........`.#    #.....H...#  #.........#  #...............#    #.C....#  
       #..R.......#    #.........####+############~........P.....#    #..d...#  
       #..........#    #..{......#...............#...............#    #......#  
       #..$.......#    #.........#...............#....t..........#    #......#  
       #..........#    #.........#...............#...............#    #...`V.#  
     #######+######    #.........+...............#...............#    #......#  
     #....$...#        #.........#...............+....v..........#    ########  
     #fT......#        ###########....@..........#...............#              
     #........#                  #...............#########'#####'############   
     #...H....#                  #...............#    #......#..............#   
     #........#           ########+#######'#######    #..d.b.#..............#   
     #........#           #...X...s.#   #....$.#      #.J....#..............#   
   #######'#'##############..|....E.#   #...]a.#      #......#..............#   
   #.......#..............+$........#   #......#      ########..............#   
   #.......#..............#.........#   #......#             #..............#   
   #.......#......~.......#########'#   #......#             #$.............#   
   #.......#..v...........# #...\...#   #......#             #..............#   
   #n......#........}.....# #.......#   #......#             #..............#   
   #....$..#......`.......# #....u$.#   #......#             ################   
   #...r...#..............# #.......#   #......#                                
   #.......#..............# #########   ########                                
   #########..............#                                                     
           ################

My favorite part is that you get a totally different dungeon each time you run it. It really is a working procedural generator, and not something more like a demo that only produces a single carefully selected result.

I fixed the technicality in the latest version of the Gist. Interestingly, Clang doesn't seem to have any problems with the original code.

Added a javascript version, for those who want to try it out without compiling anything: https://gist.github.com/munificent/b1bcd969063da3e6c298be070....

Online version: https://jsfiddle.net/dfu7ws69/

Very cool.

To try and understand it I reformated it to make it somewhat readable:

https://gitlab.com/snippets/1832264

Thanks... But someone was there first, with expanded macros.

https://gist.github.com/femto113/28f69626acddc70a002ecead0b3...

https://gist.github.com/munificent/ce8f7a9e6b09938ca8d2d43fa... (from the author)

https://gist.github.com/femto113/28f69626acddc70a002ecead0b3... (from https://news.ycombinator.com/item?id=19290841 )

Hopefully without sounding like I am trying to boast or anything... I find the difference in readability and clarity dramatic between those two on one hand and my own deobfuscated, refactored and commented version of the OP. https://gist.github.com/ctsrc/fef3006e1d728bb7271cff0656eb02...

regarding your comment:

>// Probably plus means a locked door, and single quote means unlocked, or the other way around.

http://angband.oook.cz/stuff/manual.txt gives

' An open /broken door

+ A closed door

$ Gold or gems

A Angelic being

~ Light sources, Tools, Chests, Junk, Sticks, Skeletons, etc

Nice, thanks. I've updated the comments with the information you provided here :)

Been spending the past hour deobfuscating it a bit.

https://gist.github.com/ctsrc/fef3006e1d728bb7271cff0656eb02...

Meanwhile others have posted fully deobfuscated versions that the original author and someone else has published in the past. Oh well :P

Either way, deobfuscating this is fun so I'll keep going.

The link above goes to the first revision.

Here is a link to the most recent revision at all times:

https://gist.github.com/ctsrc/fef3006e1d728bb7271cff0656eb02...

Pretty much done deobfuscating, refactoring and commenting the code now.

I think at this point most of it is pretty understandable.

https://gist.github.com/ctsrc/fef3006e1d728bb7271cff0656eb02...

I worked a little bit more on it, and thanks to my refactoring I have identified a bug in the original code (which I have intentionally retained in my own code because the point is to produce the same output as the original version, all the way down to and including bug-for-bug compatibility).

Description of bug, which I also posted as a comment on the OP gist:

> Player and other entities will never be placed on the rightmost column of the room floor, nor on the bottom-most row of the room floor. See https://gist.github.com/ctsrc/fef3006e1d728bb7271cff0656eb02... [...]. In my refactored version of your code the bug is explained at the line I linked to in this comment.

https://gist.github.com/munificent/b1bcd969063da3e6c298be070...

Backported this to run on MS Visual Studio 2008 in case anyone is equally constrained and still wants to give it a go. Did it based on @Joker-vD's deobfuscated gist

https://gist.github.com/airstrike/66e0152e75c3a81fd1496bfbf5...

Author here. I love all of the deobfuscations. Usually, when I put code online, I try to make it as clear as possible. It's really interesting to see that going the other direction actually makes it a more interactive experience for the reader.

This one is great: https://gist.github.com/airstrike/66e0152e75c3a81fd1496bfbf5...

A couple of remarks:

    // The door should not be created in the cave's corner or over
    // another door, or in another cave's corner. It's impossible
    // to make a cave without a door, because randInt(1) always
    // returns 0.
    if (atWallButNotAtCorner && FIELD[y][x] == TILE_WALL) {
        doorCounter++;
        if (randInt(doorCounter) == 0) {
            doorX = x;
            doorY = y;
        }
    }

The randInt() part here is pretty confusing. Here's the intent of the code. It picks a random boundary for the new room. Then it walks over the edges and finds every tile where the room's wall overlaps the wall of an existing room. Those are candidates where a door can be placed to connect this room to the existing one.

If no candidates are found, the room is discarded. This ensures the dungeon is always connected.

If there are multiple candidates, we only need to pick one. We want to pick one randomly because otherwise you'd get obviously biased choices where the door always appeared at the left-most edge between two rooms or something. The obvious way to do that is to build a list of the candidate coordinates and then choose a random element from the list.

But that's a lot of code. Instead, I use Algorithm R [0]. It's a streaming algorithm for selecting a random item as you walk the set of items being sampled. The idea is that you keep a running winner. Each new element, you have a random chance of replacing the winner. As the number of elements visited increases, the chances of replacing the winner decreases. So the first element has a 1/1 chance of being the winner. The second has a 1/2 chance of replacing the winner, the third 1/3, etc.

    // If the cave's walls were made completely out of corners
    // and doors, don't make such a cave
    if (doorCounter == 0) { return; }

This case actually means the new room didn't share a wall with any existing room.

    // We need to somehow record corners of all caves to check
    // for intersections later, so we use a special tile for it
    FIELD[y][x] = atCorner
        ? TILE_CORNER
        : (atWallButNotAtCorner ? TILE_WALL : TILE_FLOOR);

For a room to connect to an existing one, they need to share a tile on their actual sides, like:

    #####
    #...#
    #...#####
    #...X...#
    #####...#
        #...#
        #####

That's leaves at least one tile where we can place a door. If only the corners overlap, there may not be enough room to connect them:

    #####
    #...#
    #...#
    #...#####
    #####...# ???
        #...#
        #...#
        #####

    #####
    #...#
    #...#
    #...#
    ######### ???
        #...#
        #...#
        #...#
        #####

So, during room placement, the corners are not treated as part of the room:

     ###
    #...#
    #...####
    #...X...#
     ####...#
        #...#
         ### 

     ###
    #...#
    #...#
    #...####
     ####...# ???
        #...#
        #...#
         ### 

     ###
    #...#
    #...#
    #...#
     ### ###  ???
        #...#
        #...#
        #...#
         ###

But, when rendering the rooms, I want them to look rectangular. So the special "!" means "render like a wall, but don't act like a wall".

    // 1d6 of entities total, 25% chance of gold, 75% of a mob.
    // Mob letters range from 'A' to '~', inclusive

Technically, the "mob" case includes all of the non-"$" treasure too. Punctuation characters are in that character range as well and represent items.

Otherwise, the comments are all spot on. It's really gratifying seeing people figure this all out.

[0]: https://en.wikipedia.org/wiki/Reservoir_sampling#Algorithm_R

Fucking black magic obfuscation. Is it possible to learn this power?

I want to see someone try to rewrite C++'s entire syntax in the form of another language (I just have to assume it has already been done.)

I'm no expert, but in this case there are a few strategic definitions that help a lot to both conserve space and obfuscate:

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

My goal was less to obfuscate than it was to compress the code. I kept it as clear as I could within the limits of trying to get the code really small. There weren't any deliberate obfuscations like using misleading variable names.

The "l" macro cut the code down significantly and is one of the tricks I'm most proud of.

"r" and "i" aren't that impactful in terms of length. Their main benefit is that they make it easier to split the code where I need to in order to render the big ASCII art "@" sign. That's a lot harder when you have multiple-letter identifiers that can't be split in the middle.

you may enjoy this article, where the author of a really clever bit of obfuscated C breaks down everything the code is doing.

https://www.a1k0n.net/2011/07/20/donut-math.html

The maze generator at http://tromp.github.io/pearls.html#maze is similarly accompanied by a link to a book chapter documenting the obfuscation.

There are a lot of examples to read through here: http://ioccc.org

C is used rather than C++, because C++ is a car crash before you even start trying to obfuscate.

I have written an obfuscated cryptographically secure random password generator:

https://github.com/samboy/rg32hash/blob/master/C/tinyrg32.c

The file has test cases, documentation:

https://github.com/samboy/rg32hash/blob/master/C/tinyrg32.md

and I even have a 12-page de-obfuscation of an earlier version of this program:

https://github.com/samboy/rg32hash/blob/master/C/nanorg32.md

(I have since then come up more size optimizations)

Here's my quick port to Swift. It can run in a playground.

https://gist.github.com/donarb/1502a12cb16fa74f4fd2e295867da...

Does anyone know of a dungeon generated tool that takes a few, or many inputs? Type of creatures, terrain, season, presence of water, etc etc?

I really hope Ginny was a dog or a cat or some other pet. Terrifying thought, it might have been a child.

dog https://twitter.com/munificentbob/status/1101903466111283200

Not sure how I'd feel about someone writing a piece of code in response to the death of their young child. Equally terrifying.

People cope with grief and loss in a lot of different ways. Some dwell, others distract. Similarly, while some folks need to be surrounded by family and friends, others just want to be alone for a while. What's sure is you're never the same afterwards.

She was my dog: https://imgur.com/a/p1QQosK

Sorry for your loss :(

here is one in python(a very very basic version, big enough to fill an A4 size sheet :D ) https://github.com/anekix/dungeon-generator

Port to Lobster: https://gist.github.com/munificent/b1bcd969063da3e6c298be070...

Why not go for a full roguelike game in 1KB: https://wasyl.eu/games/another-visit-in-hell.html

...still waiting for the google maps to for instance counterstrike map generator that must not fit on a business card...

So this creates random maps? What does one do with the output of this thing?

Well i'm not sure it is meant to be 'used' as input to anything else.

It's nice as it is: just someone having fun coding with self-imposed constraints (in this case: doing something interesting with a really small card/code size).

Same as the business card raytracer :)

I think this could be useful for old-school table gaming D&D style.

My favourite "world" generator one-liner (two liner in python):

  import random as r
  print(''.join([r.choice(["/", "\\"]) for _ in range(9999)]))

Output:

  //\\/\//\\/\\\\/\\\/\//\\\\/\\/\\/\///\\\\///\\/\//\\\\/\\/\ 
  /\\\\/////\\\\\/\\\\////\/\//////\////\\\//////\\\\\/\//\\\/
  //\\\\\\/\/\\//\/\\\\///\\/\\//\\///\\/\/\\//\/\\/\///\\\\//
  \\/\//\\\//////\/\/\/\\/\\//\/\///\\///\/\////\//\/\\\/\/\//
  \\\\\\\\\/\//\\\//\\\/\\/\\\\\/\\\\\///\/\\/\\\\//\\/\\/\///
  //\\/\//////////\\//\\\////\\/////\/\/\\\\\\\\///\/\\/\///\/
  \///\//\\//\\\/\/\\\\\//\\\\\\//\/\\//\\\/\/\/////\/\//\/\//
  /\\\\//\\\\/\\///\\\\/\\\/////\\\\\\//\///\//\\////\//\/\\\/
  /\\/\\\//\/\/\//\//\//\\\//\\\\\\\/\\\/\\\\/\\///\/\/\//\///
  \\/\\/////\/\\\///\\\/\\/\//\/\/\/\\\//\\\\\\\\/////\\/\\/\/
  //\\\\\\\\/\\/////\\/\\\\\///\/\\/\\\/\\//\\\\\\/\\/\\\/////
  \\//\\\\/\\/\\///\///\/\\\/\/\/////\//\\//\/\/\/\/\/\/\\/\//
  \//\\\\\\///\/\\/\\\\/\\\/\/\/\/\//\////\/////\\\/\/\\/\\\\/
  //\\\/\\//\\/\\/\/\\////\/\\//\/\/\///\//////\\///////\/\\//
  \/\////\/\//\\\\//\\/\\/\\\\/\/////\///\/\\/\///\\\\/\\\//\/
  \///\\/\\/\\\\\\/\\\\\\\/\\\///\\\/\\///\\\\//\/\/\/\\//\/\\
  /\\\////\/\//\/////\\///\\//\/\\\/\/\\\/\/\\\\\////\\/\\////

This is inspired by this classic BASIC program, which is the inspiration for a whole book:

https://10print.org/

(Note that this version of the original is half the size of this Python adaptation!)

Also, I guess you didn't sign up for a code golf session, but this version is 11 bytes shorter:

   import random
   print(''.join(random.choice("/\\") for _ in "x"*9999))

I was surprised to discover that "import random\nrandom.choice", "import random as r\nrandom.choice", and "__import__("random").choice" are all exactly 27 bytes, so no byte count is saved by preferring any of these forms over another!

granted that it's probably safe, but seeing a screenshot in the comments of someone running this code with no clue as to what it actually does under an "admin" user is kind of funny.

Is there an executable available somewhere?

This is kind of a pet peeve of mine, but if you post simple, standalone code you really ought to post the compiled executable(s) as well. I don't currently have a C compiler installed on my home Windows box.

I hear Visual Studio Code is all right at doing compile stuff with C++

But more seriously, this is a toy implementation and the value is in reading it to see how it works, not in seeing its output

You can go to online GDB and run it : https://www.onlinegdb.com/

But you have to use the modified code in the comments above or you will get a : main.c:8:7: error: variably modified ‘m’ at file scope =80;i m[H][W];i g(i x) {r rand()%x;}

Why use an executable when you can run it on someone else's computer™: https://repl.it/repls/NiceEvilBoard

I swear the URL wasn't chosen by me.

Thanks for an actually constructive answer! That's pretty neat. I hadn't heard of Repl.it before.

But then you need to trust that the executable is the same as the source!

Here, you can just disassemble the binary and it will be more readable than the code.

If you don't have a compiler, you probably don't have a disassembler...

If he'd posted an executable, unless it was for exactly your platform, wouldn't you just have complained you didn't currently have a machine running the correct operating system on the correct hardware?

Not at all. Tiny textmode programs do not generally require specific hardware or OS versions. Windows/Mac/Linux should cover the large majority of users. Or you could just do Windows, since Unix machines (including Macs) most likely have gcc installed already. Or you could skip all that and include a Repl.it link, like Yorwba thoughtfully provided in the sibling comment.

If it did require specific hardware or software, that would be different, which is why I specifically said "simple, standalone code."

Or you could "just" install a C compiler.

Hang on, I'll get you an executable. Be sure to run it, okay?

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