This is a library mostly for compressing graphics and maps, but can also be adapted to compress sfx. It is designed for data-heavy carts and requires around 450 tokens for decompression, although this can be reduced if needed by removing remap(), hard-coding parameters, and/or removing predicted spans at the cost of compression performance. If someone wants a smaller/weaker version, let me know!
To use it, compress a 2D rectangle to an address in memory, and supply a function for fetching the source values (normally SGET or MGET). For map data, you probably want to set p.cbits to something like 4 first.
COMP(0, 0, 128, 64, 0x2000, SGET)
0x2000 is the address of the top half of the map, so this will compress the top half of the sprite sheet (128 sprites) and write the compresed data over the map data.
DECOMP() takes the memory address of the compressed data, the top left corner of where to decompress to, and functions for getting and setting decompressed values. So to decompress this data at 0x2000 back to the screen, starting 32 pixels down:
DECOMP(0x2000, 0, 32, PGET, PSET)
Only the decompression section of the code is needed once you have compressed data stored on a cart. A typical workflow would be to make a utility cartridge that grabs data from multiple source cartridges (using RELOAD() with a 4th parameter to indicate where to read from), and then CSTORE them to a single cartridge (again, using CSTORE()'s 4th external cart parameter).
Here's an example that stores 2-byte lengths at the start of each compressed block, to allow seeking out the start of any given gfx. I've commented the cstore and reload lines so that it will work if you paste it at the end of the main PX8 cart example:
-- px8 workflow example:
-- storing multiple compressed images and fetching them
-- 1. make a utility cart that
-- compresses all the needed
-- data to a single cart
local base_offset = 0x2000
local offset = base_offset
-- compress some gfx and
-- add the length of the compressed
-- data at the start (2 bytes)
local len = comp(x,y,w,h,offset+2,sget)
offset += len+2
I started working on PX8 while working on PICO-8's specs, as an important question was how large a game could theoretically be for hard-core users who want to go to the trouble of compressing stuff. It became something of a brainworm, and releasing PX8 is a way to get this out of my system. I hope it is also useful to someone, or at least interesting.
PX8 is (AFAIK) a novel algorithm that appears to work well for typical PICO-8 data, and out-performs pngcrush -brute for the few 16-colour images I tested. Alternating spans of predicted and non-predicted values are stored:
1. Predicted values (colours) are calculated by maintaing a table of the last encountered matching neighbours: if a match top & left is found, that is taken to be the prediction. Otherwise, a match for only top, and then only left are considered. Failing those, the value is taken to be non-predicted.
2. Non-predicted values are stored as indexes into CLIST; a list of literal values that are stored in the order they were last encountered. This means that recently encountered values have smaller indexes, and the encoding exploits this, along with the fact that each index can not possibly be for the failed prediction (in which case it would be part of a predicted span).
Each span is strictly made of either all predicted or all non-predicted values. This means that for predicted spans, no additional information needs to be stored except the length of the span itself. And conversely for unpredicted values, the index into CLIST is known to not point at the predicted value. This means that no colour index data needs to be stored for 2 colour images at all, and the compressed data is composed entirely of span lengths.
Hey All -- PICO-8 0.1.8 builds are now live on Lexaloffle and Humble! Note that there was no 0.1.7 release for Desktop; there were in-development versions of 0.1.7 released early for web and Pocket C.H.I.P. to resolve pressing issues, so I'm calling this 0.1.8 to keep version numbers in sync across platforms. New stuff:
60 FPS support
This breaks the 'every cart runs the same on all PICO-8s' rule of PICO-8's design philosophy a little bit, but I think it's worth it! On all of the desktop host platforms, it is now possible to make cartridges that display and update at 60 frames per second instead of 30. You don't get any more CPU though, so that means half the usual CPU allowance per frame. From the manual:
:: Running PICO-8 at 60fps
If _update60() is defined instead of _update(), PICO-8 will run in 60fps mode:
- both _update60() and _draw() are called at 60fps
- half the PICO-8 CPU is available per frame before dropping down to 30fps
** please note that not all PICO-8s support 60fps. On machines that do not support it, _update60() will instead be called twice per frame and _draw() at 30fps. You can check the behaviour of your program running at 30fps by adding the following snippet to the bottom of your code:
u60=_update60 _update60=nil function _update() u60() u60() end
The two action buttons on the PICO-8 controller are called O (BTN(4)) and X (BTN(5)). To make it easier to print instruction in-game explaining the controls, you can now insert glyph characters directly into strings in your code with Shift - U D L R O X.
Adjust the maximum GIF length in config.txt or by running PICO-8 with -gif_len n switch, where n is the number of seconds to record for (maximum: 120). The GIF output is not optimized, so you might want to run it through an optimizer to get smaller file sizes.
Custom Menu Items
It is now also possible to add your own items to the pause menu to trigger things like 'RESTART PUZZLE' or 'EXIT TO OVERWORLD'. Here's an example program:
col = (col+1)
menuitem(1, "change colour", changecol)
The first parameter is the position (1-5) in the menu to insert the item, the second is the item's label, and the 3rd is a function to be called when the item is selected. I opted to keep this simple and quite rigid, so there's no way to have extra stuff going on in the background while the cart is paused, or to re-appropriate the pause button as an in-game button.
To record a .wav of a PICO-8 tune, first navigate to the pattern you'd like to start from in the music editing mode, then press escape to enter the console and type:
If the song is looping, it will export around 4:30 that you can then manually trim in a sound editing program.
There are now 5 BBS games that ship included with PICO-8, so that it's easy to get up and playing something more than the demo carts, even when internet access is not immediately available. To install them, use INSTALL_GAMES -- they will be accessible from your favourites list in SPLORE. The games are Celeste, Frog Home, Tower of Archeos, Hug Arena, and Dusk Child.
I've included both statically and dynamically linked versions of the executables for i386, amd64 and Raspberry Pi. The RasPi build still depends on bcm, so it is tricky (impossible?) to get it up and running on Chromebooks.
I plan to look at better Chromebook support at some point, but it will probably have to be during beta. Pocket C.H.I.P. owners, and later on regular C.H.I.P. owners can expect updates too, of course --- but we are still sorting out details and it will take a while. o(_ _)o
Next up, 0.1.9 will be mostly ongoing bugfixes, and improvements to the web player (optimization, fold-out touch controls for mobile, and controller instructions).
Added: 60fps support
Added: Music exporter
Added: Custom GIF length (maximum 120 seconds)
Added: -,+ to navigate sprite tabs, sfx, music patterns
Added: sfx editor: navigate with home, end, pageup/down, mousewheel
Added: <, > to modify sfx speed, or click and drag
Added: Middle mouse button to pan around spritesheet / map
Added: Shortcut command for splore: S
Added: Pre-installed selection of BBS cart (use INSTALL_GAMES)
Added: Warning when saving .p8.png with no label
Added: (OSX) logging to ~/Library/Logs (viewable with Console.app)
Changed: Can not CTRL-S save over a loaded bbs cart
Changed: Only .p8 files listed by dir() and by splore
Changed: Command history increased to 256
Changed: exit() / shutdown() have no effect while running cart
Fixed: Memory useage (stat(0)) inconsistent across host platforms
Fixed: Spinny disks shows when reloading current cart with load()
Fixed: GIF saver does not respect 64x64 / mirrored modes
Fixed: Miscellaneous multi-line comments / strings issues
Fixed: Empty map cels cost cpu in mapdraw()
Fixed: mapdraw() slowdown when drawing bottom half of map
Fixed: preprocess changes semantics when += and : operators on same line
Fixed: Identifiers starting with underscore counted as extra token
Fixed: Saving .png exceeding compressed code limit fails silently
Fixed: Right-clicking a sprite does not set the currently edited sprite
Fixed: (Windows) extra space added to pasted lines
Fixed: spr() expensive when drawn with low negative coordinates
Fixed: pipe character identical to colon character
Fixed: (Raspberry Pi) shift key appends a character when entering text
Fixed: Editor mode buttons are still clickable during cart runtime
Fixed: When loading a .p8.png file, label is reset and needs to be re-captured
Fixed: export() does not report failure
Fixed: mset()'d changes in shared memory not readable via peek() / sget()
Fixed: cstore() saving edited code
Fixed: audio pop between patterns during music playback
Added: button glyphs in code (shift-L, R, U, D, X, O)
Added: Customisable data directory (e.g. pico8 -home mydata)
Added: Web gpio pins: read and write pico8_gpio in javscript
Fixed: SPLORE search doesn't reset
Fixed: Splore skipping 33rd cart listing after loading more items
Fixed: Crash when selecting a local binary file in splore
Fixed: Semicolon can't be used as a list or statement separator
Fixed: Exported html can not cstore self
The theme for the second PICO-8 Jam was Chain Reaction, and there were 35 entries. Thanks to everyone who contributed and made this jam a another splendid event. I hope you'll join me in congratulating the winning entry, which received a whopping 7.3 PICO-8 star average.. *theatrically opens invisible envelope*
If you'd like to take part in P8JAM2, please select one or more themes by clicking on the PICO-8 star next to it (you need to be logged in). You can change it anytime before the 24h voting phase ends -- at 00:00 PST on Saturday the 21st. Check out the jam thread for more details.
Edit: times's up! The winning theme is Chain Reaction. You have 9 days! Good luck!
I'm in the process of simplifying the website a little. In particular, I wanted to improve the experience of playing cartridges in threads by removing clutter. They now look more like a page dedicated to the cart:
- The player starts open
- There's a big obvious play button and large thumbnail
- There's no banner at the top of each page
I removed the PLAY buttons from the thread previews, and autoplay, as I think they're no longer needed -- the whole playable region of a cart is now visible without scrolling after opening the cart's thread, and it's more obvious to new visitors what to do next.
There are still a few small things to finish, but let me know what you think of the new layout, and if there's anything that bugs you.
If you'd like to continue working on your cartridges, feel free -- but please leave the compo version at the top of the p8jam2-tagged threads until voting finishes in one week (June 5, 24:00 PST). Good luck!
Same deal as last time, except with some limited theme voting:
Duration: The Jam will take place from 00:00 PST on Saturday the 21st of May 2016 and will finish at 24:00 PST on Sunday the 29th. So, it spans 2 weekends and 5 weekdays. You can spend as much or little time on your carts as you like. Tiny silly cartridges are more than welcome.
Theme: As is customary with other jams, a theme will be posted at the start and the goal is simply to make a cart (or some carts) during the jam that reflect your interpretation of the theme. Any type of cartridge is ok: games, toys, demos, music carts or pixels.
This time, the theme will be selected by a small twitter poll that begins 24 hours before the jam starts.
Submitting: To submit or update a jam cart before the deadline, just tag it with p8jam2. You can update your cartridge as often as you like before the deadline.
Voting: Jam participants will be able to use a voting widget on all p8jam2-tagged carts, and exactly 1 week after the jam finished, ratings will be tallied.
There will be a small mystery prize for the highest rated cart, but you should enter for glory and honor (or just for kicks).
Rules: Teams / collaborations are allowed, in which case you should nominate one user to be the submitter (and voter). Re-using existing PICO-8 cart material is allowed as long as it is ok by the author, and that the carts are publicly available before the jam starts. Submissions should be mostly new material created during the jam, but it's ultimately up to other participants making ratings to decide what's cool and what's not.
If you're looking for a complete portable PICO-8 solution, good news! PICO-8 is going to ship pre-installed on Next Thing Co.'s upcoming PocketC.H.I.P. -- a complete portable mini-computer with built-in storage, wifi, keyboard, battery, touchscreen and everything else PICO-8 needs! The last few months, I've been working closely with the team at Next Thing Co. to create "PICO-8 C" -- a fully functioning and compatible edition designed to integrate nicely with NTC's hardware and software. It will be available to Kickstarter backers, or you can also pre-order one for just $49 bucks.
You can read more about the PocketC.H.I.P. over at getchip.com
Here's 0.1.6! You can download it from your updates page while you're logged in, or from your Humble Store Library. Just a reminder, that if you're a Voxatron alpha customer, you also own PICO-8! (it should show up automatically in both places).
By far the biggest change is the addition of SPLORE, a complete bbs and local cartridge explorer. You can run it by typing SPLORE, or start PICO-8 with "pico-8 -splore". If you plug a joystick in and auto-boot into splore, it's possible to navigate everything using only the 6 buttons + menu button.
This version also has a lot of new data storage functionality. Cartridges can cstore() to themselves in order to save extra data, and this is now officially supported on the web, so don't feel like it's a weird hack that's going to break! (actually it might break, but it's supported, so I'll fix it :p).  Here's a demo:
Notes on cartridge storage, and the full change log:
Each cartidge is able to store 64 numbers (256 bytes) of persistent data
on the user's PICO-8 (rather than on the cart itself). This can be used as
a lightweight way to store things like high scores or to save player progress.
If you need more than 256 bytes, it is also possible to write directly to the
cartridge using cstore(). The disadvantage is that the data is tied to that
particular version of the cartridge. e.g. if a game is updated, players will
lose their savegames.
Another alternative is to write directly to a second cartridge by specifying
a fourth parameter to cstore(). This requires a cart swap though (so is
slightly slower), and leaves data-cart litter when run from a local folder.
Added: SPLORE local & bbs cartridge explorer
Added: setmetatable(), cocreate(), coresume(), costatus(), yield()
Added: Spinning cart icon to show when a cart is swapped / written to
Added: Permanent storage when carts played in a browser
Added: Adjustable aspect ratio (-aspect 420 for 1:1)
Changed: Lua memory limit: 1024k (was 512k)
Changed: Music channel now resumes after being clobbered by an sfx
Changed: Arpeggios double speed when SFX speed <= 8
Changed: Exceeding compressed code limit does not block saving in .p8 format
Changed: spr() half as expensive, to be consistent with map()
Changed: Fractional hex number notation: 0x0.3 == 0x0.3000, (was 0x0.0003)
Changed: : operator doesn't count as an extra token (same as .)
Changed: cstore() writes directly to disk
Changed: cstore(), reload() return number of bytes read / written
Changed: save() while running does nothing. (use cstore() instead)
Changed: load() while running loads and runs the specified cartridge
Fixed: Small pops in audio mixer caused by sound wave discontinuities
Fixed: HTML5-exported sound clicks badly under Chrome
Fixed: Display palette is not oberserved when exporting GIFs
Fixed: Rapid keypresses causes duplicate readings in tracker & text editor
Fixed: += inside comments breaks preprocessor
Fixed: sspr() cpu cost the same when clipped
Fixed: cartdata() with bad parameters crashes
Fixed: EXPORT from commandline can not be used without brackets and quotes
A build of PICO-8 0.1.5 is now available for Raspberry Pi! Check your updates page or look in your Humble library under the Linux downloads section.
It works in fullscreen under either X Windows or directly from the terminal (using directfb). For speed, the default resolution is 280,280; you can set this with the -width and -height switches:
pico8 -width 720 -height 480
- After quitting, keypresses during the session are sometimes dumped to terminal (annoying if you quit by typing shutdown instead of CTRL-Q!)
- Freeze on exit (observed on a zero)
- Some math-heavy cartridges (e.g. /demos/cast.p8) don't run at full speed on first generation models.
There are two builds included in the archive. pico8 is compiled statically (so no need to install SDL2), and pico8_dyn dynamically loads libraries, in case you'd like to supply your own SDL2.
Have fun, and please post pictures if you get pico-8 running on any cute displays!