yocto-8 is a high-performance PICO-8 implementation that aims to run unmodified games.
PICO-8 is a fantasy game console from Lexaloffle which allows you to create, edit, share and play small games in a virtual console. This project and its developers are unaffiliated with PICO-8.
That's the plan anyway -- see the current progress.
The main implementation goals are:
- To reach good PICO-8 compatibility.
- To be really fast, even if that entails modding Lua.
- To minimize the dynamic memory footprint as much as possible.
- Dynamic allocations are basically forbidden outside of Lua.
- Dual-heap support, prioritizing a faster heap.
- To be generally portable to platforms with a high quality C++20 toolchain (it's not great yet, but the plumbing is there for porting)
The current plan is not to be a PICO-8 devkit, that is, it will not provide any editor tools.
Support PICO-8 development, buy PICO-8 (and maybe Picotron or Voxatron)!
yocto = pico².
With some modifications, some demos and games run. Don't expect it to run much of anything, manual intervention is often needed to get a cartridge to work (but hopefully fewer as time goes on).
- PICO-8 Lua extensions are not fully tested and complete yet.
- Many APIs are left unimplemented.
- Many APIs are not fully tested and may be incorrect.
- Audio support is completely non-existent currently.
- Filesystem support is an early WIP and completely unimplemented on pico.
- There is no UI (yet).
It is possible to build and run yocto-8 on the desktop which is currently the preferred way for implementing new API features due to facilitated debugging and allowing a faster development cycle in general. The main target remains the embedded implementation.
This is currently in an early stage: there is no user-friendly way to get this working yet and most cartridges will not work.
On the hardware side, the idea is to prototype a RP2350-based handheld.
Obsolete PSRAM segment, relevant for RP2040 (discontinued)
A significant problem is the reliance on a hack that enables mapping of SPI RAM.
At the moment, this hack is very slow and may compromise the usage of the RP2040 for a real handheld project. Many games and demos rely on using way more memory than the RP2040 SRAM could provide no matter how many optimizations are done.
There is a lot of room for optimization for the RAM hack routine. It is currently not known what real world performance can be theoretically reached.
There are (uncertain) plans to design a real handheld. The main two contenders are the RP2040 and the ESP32-S3 (which supports QSPI RAM), but there are drawbacks to both of these.
- This does currently only aim to be a pico-8-compatible game runner, not an editor.
- There is currently no plan to support games that require the "devkit"'s mouse or extra keyboard keys.
- No emulation of "CPU cycles" as calculated by pico-8 is planned for now: Game performance will be limited by how fast the hardware can run it.
Not all platforms are regularly tested, there might be regressions, etc. etc.
yocto-8 running Celeste Classic on the PicoSystem.
Y8_ARCH=desktop: Desktop (y8SFML frontend,y8-headlessno graphics), primarily for testingY8_ARCH=pico: Raspberry Pi Pico based platformsY8_PLATFORM=asupico: RP2350 M33, my setup (Pimoroni Pico Plus 2 with onboard PSRAM+CO5300-based OLED display+push buttons although not yet). Note that documentation around this is not up to date, including pinouts!Y8_PLATFORM=picosystem: Pimoroni PicoSystem
Important
RP2040 ports for yocto-8 no longer support external PSRAM.
RP2350 with PSRAM is recommended.
Because PICO-8 emulates a Lua heap limit of 2MB; no amount of magic will allow
all games run on a MCU with a tenth of that.
Pros:
- Extremely fast bootup
- Fully hackable firmware
- The fuzzy warm feeling of a fully custom specific-purpose game console
- Possible to make it open hardware
- Probably lower cost
- Probably lower power
Cons:
- SBCs-based solutions are more general purpose (e.g. cheap emulation handhelds)
- SBCs are more versatile (WiFi & Bluetooth, etc)
- Will probably never be fully compatible with all PICO-8 games
- No editor tools, etc.
- More standard hardware