camp39 [Lexaloffle Blog Feed]

question about realtime play

Sat, 18 Oct 2025 02:41:09 UTC

Is it going to be possible to have 2-player, online play with picotron?
I've seen some stuff with chat (that I never got to work). Is a 2-player picotron game in real-time feasible for the future? Can it be done now?

Diana Chess

Wed, 24 Sep 2025 05:26:49 UTC

Diana Chess

by camp39

[Click to Play]

6x6 chess with no queens (Diana Chess).
I have larger ambitions and made this as practice but thought its good enough
to share.
engine only looks for material and mate, but is still fun to play.
Although, no 3-fold repetition or insufficient material draws.
Play as white against the engine

sorting tables

Sat, 20 Sep 2025 16:56:38 UTC

I have a table:
a={0,0,1,2,0,6,9,2,0,5,3,0,7,0,0}
I want to sort it so the 0's are moved to the front
This works:

 a={0,0,1,2,0,3,4,0,0,5,6,7,8,0,9,10}
 b={}
 c={}
 for v in all(a) do
  if v==0 then
   add(b,v)
  else
   add(c,v)
  end
 end
 for v in all(c) do
 add(b,v)
 end
 a=b

but is clunky and since this will be in a recursive function, efficiency is essential.
what is a more elegant/quicker way to do this?

Gravity Chess Puzzles

Sun, 07 Sep 2025 04:53:38 UTC

Gravity Chess Puzzles

by camp39

[Click to Play]

Gravity Chess Puzzles

knock the red king from his perch

Credits

based off of itch.io game, Chessformer by Robert Alvarez

Alice Chess (Mate in 2 Vol. 5)

Fri, 18 Jul 2025 21:01:28 UTC

Alice Chess (Mate in 2 Vol. 5)

by camp39

[Click to Play]

Alice Chess

50 Alice Chess Mate-in-2 puzzles

About Alice Chess Mate-in-2

Alice chess is a chess variant played on 2 boards. What is cool is that there is no fairy-stockfish engine for it. Therefore, these puzzles are custom built using an experimental engine made by ubdip over at pychess.org. These are very fun once you understand how to play.

How to play Alice Chess

from chessvariants.com :

*The standard game of Alice Chess is played using two boards, A and B. All pieces move as in standard chess. The normal array is on board A; board B starts empty.

The rules are very simple. In turn, each player makes a single move on either board following these three rules:

A move must be legal on the board where it is played.

A piece can only move or capture if the corresponding destination square on the other board is vacant.

After moving, the piece is transfered to the corresponding square on the other board.*

In this cart, both boards are combined into one. Pieces on the second board are shown as 'grayed-out' in the same convention used at pychess.org

Features

puzzlemap
autosaves progress

Credits

thanks to
ubdip and gbtami for the puzzles file and the direction.

trouble moving sprite, atan2()

Thu, 03 Apr 2025 03:59:17 UTC

Moving game pieces using atan2().
I check to see if the position (px,py)
has reached the target (tx,ty) by
absolute values of positions minus targets.
If they havent reached the destination I increment
by the dx I got from the atan2() calculation.

This works as it is. But I cannot actually control the speed.
If I want it to go faster, say speed 8, there are certain
situations where condition if abs(px-tx)<3 and abs(py-ty)<3 will never
be met and piece will just go forever. And I cant fine tune the <3 either
because sometimes the math just wont allow it.

How do I write code or think about this to move my sprite so I can actually control
the speed and/or accuracy?
Must be able to move any direction at any angle.
Thank you.

speed=5	
px,py=getxy(location)
tx,ty=getxy(destination)
local angle=atan2(ty-py,tx-px)
dx=sin(angle)*speed
dy=cos(angle)*speed  --PROBLEM HERE

function _update_move()
 if abs(px-tx)<3 and abs(py-ty)<3 then --AND PROBLEM HERE
  --ARRIVED AT LOCATION
 else
  px+=dx
  py+=dy
 end
end

config files?

Sat, 22 Mar 2025 02:10:04 UTC

Are there config files for the editors?
So if I wanted to say, change the tab size or key-bindings in the code-editor.

if not, does anyone know where I could start poking around?

update: i did find /system/apps/code.p64 which looks promising. any other info is welcome

YinYang

Fri, 21 Mar 2025 07:48:00 UTC

YinYang

by camp39

[Click to Play]

YinYang

30 yinyang puzzles

Rules

all spaces be filled
some spaces are pinned with balls that cannot be changed
all dark balls connected orthogonally in single group
all light balls connected orthogonally in single group
no 2x2 group of the same color allowed

Solitaire Chess -- Vol. 2

Sun, 16 Mar 2025 07:30:04 UTC

Solitaire Chess -- Vol. 2

by camp39

[Click to Play]

If you find a puzzle you think is impossible, let me know in the comments. enjoy!

Solitaire Chess -- Vol. 2

-400 solitaire chess puzzles
-50 puzzles each from 4 to 11 pieces
-navigation map and autosave

Piconissimo v1.5

Mon, 03 Mar 2025 04:11:00 UTC

Piconissimo v1.5

by camp39

[Click to Play]

Piconissimo v1.5

Sound editor

Version 1.5 Additions

copy/paste
(Z=copy,X=paste)
horizontal pattern scroll
(click right/left icons on either side of note display.)

Getting started

click garbage icon at top right for fresh start. This will permanently erase everything...Including theme music :(
all numbers can be right/left clicked
rightclick a piano key to test, leftclick to insert note into selected sfx
red 'stop sign' stops anything playing
unmute dark blue sfx in patterns by clicking on dot
click blue floppy icon to save. save often.
see manual for detailed info

Manual

--[[
Piconissimo v1.0 2025 by camp39
Uses mouse and keyboard.

   --Piconissimo has a full PICO-8 keyboard GUI.--

SET KEYBOARD VALUES:   right/left click on pink/blue/gray to right of keyboard

PLAY NOTE:             rightclick on keyboard

SET SPEED:             right/left click on top red number 
                       --only selected track/sfx speed displayed

SET JUMP:              right/left click on green number
                       --when a note is set, if there is room, 
                         the cursor will "jump" this many slots forward in the sfx

TOGGLE BARS:           press X btn while on gray dots above tracks												 
                       --will turn on/off bar displays												 
                       --useful as a visual aid for timing

SELECT NOTE:           Arrow keys to move square cursor to track/sfx/position

COPY/PASTE:            Z to copy. X to paste.

NOTE DISPLAY:          Selected note displays beneath tracks

SET NOTE:              leftclick on keyboard (track/sfx must be selected)
	               --overwrites any selected note

SET TRACK:             right/left click on lefthand track numbers to desired sfx

PLAY SINGLE SFX:       select track, click right hand play icon (red triangle)

ERASE SINGLE SFX:      select track, click righthand "x" icon

PLAY SELECTED NOTE:    Click pink triangle right of note display

ERASE SELECTED NOTE:   Click gray "X" icon left of note display.
                       Or copy (Z BTN) and paste (X BTN) a blank space.

ADJUST SELECTED NOTE:  Right/left click note display values

SAVE WORK:             leftclick blue floppy disk icon in top right corner
                        --cntrl-s does NOT save your music!
			--save often
			--Rebooting, pressing ESC or CNTRL-R will lose any unsaved work

ERASE ALL:             leftclick garbage can icon
			--all channels set to sfx(0)
			--all channels set to mute, no loop or stop flags.
		        --all sfx notes set to C0 000 (note,ins,vol,eff)
		        --all saved work will be lost
			--do this first thing to erase theme music

PLAY CURRENT TRACKS:    left click 4-shafted, red triangle icon on right of screen.																		 
                        --this plays current track sfxs regardless of whether they 																				 
                          are in a pattern channel or not.

STOP ALL:	         Click red "stop sign" icon. Stops anything currently playing.

		--Piconissimo displays up to 5 patterns at once--

SELECT PATTERNS:          Right/left click on pink pattern numbers.

SET CHANNELS:             Right/left click on 4 sfx numbers beneath pattern number.
			  --displays red if sfx is currently selected in tracks

PATTERN TO TRACKS:        click "up arrow" icon to right of pattern number																	 
                          --this changes each track to the sfx in each channel of pattern

MUTE SFX:                 leftclick dot to left of sfx to toggle. Displays dark blue if muted.

LOOPS AND STOPS:          same as built-in editor

PLAY PATTERN:             Click triangle icon under pattern.
			  --Current playing pattern displayed in bright yellow next to JUMP value.
]]

Credits

This thread started by @eruonna 10 years ago was ...instrumental... in making this cart. And @PennDraken's more recent contributions as well. Its a good thread, you should check it out.

100 Headaches (Mate in 2 -- vol. 4)

Sat, 22 Feb 2025 02:56:47 UTC

100 Headaches (mate-in-2 vol.4)

by camp39

[Click to Play]

100 Headaches

100 extremely difficult mate in 2 chess puzzles.
Based on the book 100 Headachingly Hard Mate In Two Chess Puzzles by Sam Loyd by Martin B. Justesen.

Gameplay

It is white to move on every puzzle. But the player ALSO makes black's move rather than a computer-automated response. That way, you can try out different moves for black to prove to yourself that it is, indeed, mate in 2.

Scoring

Plus 5 for every correct move. Minus 1 for every wrong move. Only on unsolved puzzles. Once a puzzle is completed, you can replay it as many times as you like and not lose/gain points.

Navigation

All progress is automatically saved. There is a handy 'map' of all 100 puzzles and you are free to jump to any number you like.

I do not expect anyone to finish this. Let alone with a positive score. But if there is a true masochist out there, please share a screenshot!

Thanks to @phil for helpful feedback on my last cart. It made this cart better.

mate in 1-2-3

Fri, 24 Jan 2025 06:10:49 UTC

mate in 1-2-3 vol. 1

by camp39

[Click to Play]

Mate in 1-2-3 vol.1

each level is a mate in 1, a mate in 2, and a mate in 3.
50 levels for a total of 150 puzzles.

progress saves with each puzzle.

about the puzzles and the code

NICE 1.0 Freestyle Chess

Sat, 28 Dec 2024 06:52:41 UTC

NICE 1.0 Freestyle Chess

by camp39

[Click to Play]

Freestyle Chess == Chess960 == Fischer Random

NICE: Nice Is Camp39's Engine

The Good

pass n play and board flip option
clean interface & themes
play against computer
opening book for standard chess
endless openings with Freestyle Chess (press up while on chess960 to view positions)
all rules, including 50 move and 3-fold repetition

The Bad

my first engine ever... its a little slow
my first engine ever... its a little dumb
maybe 2.0 will be better!

About NICE

This was a real accomplishment for me and is my first engine. The move generation follows the tutorial of Bluefever Software video series on Youtube: Programming a Chess Engine in Pure Javascript.

When it came to the search functions I learned a ton by following the book: Chess Algorithms by Noah Caplinger.

The limitations of Pico-8 though make for a challenging adaptation of these types of tutorials. (translating from zero-based arrays can give some crazy nasty bugs). The speed limitations make some variation strategies useless e.g. "killer moves" only make sense with a depth of at least 4. It was a really cool experience and gave me more insight into the game.

I liked the board layout from cart #quickchessyness-4 by @Adam_Howell so much that I copied it :)

This cart will need some updates however. I was unable to get quiesence to work without a move taking FOREVER. Maybe due to my move ordering, maybe due to the evaluation function, maybe due to lots of things. Its all very complicated and hurts my brain since it is recursive at iterative depths. Hard to pinpoint problems like that. If any kind soul wants to offer tips, I'm all ears!

@Krystman of course released the fabulous Pico Checkmate, cart #54038 6 years ago. I definitely looked through his code for clues but couldn't manage to find a way to cut off a search if time got too long. But I did follow his lead and purge illegal moves right off the bat instead of making and taking them. Without a full quiesence search though, I don't think NICE will stand a chance against Pico Checkmate.

This cart, while not having the best engine still has some nice features. Chess960 is chess but with almost random starting positions. Its just like standard chess with the exception that castling can be a little weird. Just remember that king and rook end up in the same ending positions as in regular chess, regardless of where they started. Otherwise, same rules apply. This eliminates the same opening every time you play against the computer. Also, to prevent that from happening in standard chess, I coded in a small opening book with response options being chosen randomly so that you can get different responses even if you play the same.

I hope this cart is popular with hand-held users (I don't personally own one). The pass n play is not something I've seen on other chess carts and I imagine a game of chess on a long flight or bus ride would be cool, but playing upside down is a bit awkward.

Crazy idea: what if there was a cart with the move generation and graphics already on it (and optimized to the max) and then two different users could put in a tiny engine each and let them battle. Maybe more realistic on picotron?

numbers equivalence

Wed, 25 Dec 2024 04:04:35 UTC

how do i test for big numbers that print different than their true value?

function _init()
 srand(39)
 a=rnd(-1) --prints -20954.2428
 b=-20954.2428
end

function draw()
 if b==a then
  ?"true"
 else
  ?"false"
 end  --prints false
end

I have some big numbers that would be nice to know their true value.
thanks and merry Christmas!

coroutines?

Sat, 30 Nov 2024 09:05:13 UTC

When the AI plays itself in my game, it is too much for the _update() so PICO-8 drops _draw() frames. The moves are correct, but its awkward because both pieces move at once.

How do I remedy this? Is it a coroutine I need? I've been playing with them and have gotten some crazy results, not really knowing what I am trying to accomplish. But is that even the right approach?

Or can I make some kind of delay between moves to give the cpu time to catch up? I tested by making it only run the engine after a button press and it works fine.

I also tried calling flip() explicitly after the resource-heavy function but no dice.

any pointers are appreciated.

lichess api

Fri, 29 Nov 2024 06:54:04 UTC

@toadofsky
I moved the conversation to chat so as not to clog up the cartridge section.

in response to your last post;
how are you going to hook up PICO-8 to the internet though? Can you do that?

PICO in Nano

Sun, 27 Oct 2024 00:03:26 UTC

made external editor feel more like pico...does anyone else do this too?

string to assoc array

Wed, 23 Oct 2024 04:36:07 UTC

I'd like to make some associative tables e.g. table={x=7,y=90,z=40}
but I want to save tokens by using a string because I'm going to have a lot of them, and make a function that returns a table based on whatever is in the string.

So something like:

string1="x=7,y=90,z=40"
string2="empty=100, dinner=casserole, transport=horse, weight=150"

table1=assoc_table(string1)
table2=assoc_table(string2)

?table1.z          -- 40
?table2.transport  -- horse

how do I go about this? split wont work. what does my function assoc_table(str) look like?

hide_mouse_cursor bug

Thu, 17 Oct 2024 01:09:08 UTC

v0.2.6b
The hide_mouse_cursor feature is very buggy. That is the option that makes the mouse cursor disappear while typing in the PICO-8 editor. Length in seconds can be configured in config.txt but the problem is there even with the default of 5 sec.

On startup it works but after a while of coding it stops working at all. I posted this before but deleted my post because the steps I gave to reproduce didn't always make it happen. So it's hard for me to say exactly when it stops working. But I think that everyone here will notice if they pay attention, that after a some time working on a game, the mouse cursor will remain in the way while typing.

If you ctrl-r ctrl-r it will start working again. But if you type something at the command prompt and say, get a syntax error, or even just ls to show whats in the directory, or cls(), most of the time (but not always!) when you esc back to the editor it will be broken and the mouse will show even while you are typing. This will persist for the rest of the session. ctrl-r TWICE seems to reset it, but once is not enough.

I know this is a small thing, but once you notice it, its sort of annoying because of how nice it is when it is working. I've been coding directly in the editor lately. I used to think it was impossible but now I realize just how cool it is.

gamepad support please...(Linux)

Wed, 04 Sep 2024 02:59:17 UTC

I bought a couple of bluetooth gamepads off Amazon:
KIWITATA 2.4G Wireless NES USB Controller
Which are imitation NES classic, 2-button, D-pad, select start controllers.

It gets recognized right away by my latest Linux Mint OS and works in Pico-8
EXCEPT that both buttons do the same thing (I think they are both X).

I ran this code:

function _draw()
 cls()
 ?btn()
end

--both B and A output 32

and sure enough I get different values for all the buttons except both B1 and B2 print 32.

I've found this thread https://www.lexaloffle.com/bbs/?tid=3623 where one poster talks about the same problem. But its from 2016 and was for pocketCHIP and they solved it by getting a different controller.

I've also installed the SDL2 gamepad-tool for Linux but had issues. It sort of works EXCEPT that it wont recognize left/right on the dpad. I tried a million times and also tried skipping and mapping it to the little joysticks instead but it didn't work.

my understanding is that I am to copy/paste the resulting mapping line into
.lexaloffle/pico-8/sdl_controllers.txt
but haven't yet because it doesn't do me any good without right and left on the dpad.

I've got to think this is a pretty easy fix in 2024. Any suggestions?

Or at least, which NES classic style wireless controllers DO work?