I’ve created pretty simple chess for Pokitto, using SAF and my chess library/engine smallchesslib found here. Graphically it’s nothing impressive, just very simple interface, I was focused on just making Pokitto play chess – if you want, you can use my library to create something more shiny. Of course everything is CC0, public domain.
firmware.bin (63.7 KB)
The library/engine is another one of my KISS/suckless C libraries, it supports all you need for playing chess and manipulating some standard chess formats plus it includes a moderately strong AI – the strength depends on settings and hardware, I’ve let it play as a bot on lichess.org under the nickname smolchessbot and it achieved an ELO of about 1600 (well not really ELO but “Glicko” rating). On Pokitto I’ve limited AI to maximum level of 3 (full search to depth of 2 plys with possibility to extend to another 2 plys for interesting moves) which is a little weaker than this, it’s because of the CPU speed, something stronger would take too long to compute a move. In the future I’ll probably try to optimize and improve the AI, e.g. with transposition tables, so maybe it will get stronger and faster over time.
If anyone’s more interested in chess programming, there’s a hugely useful and interesting chess programming wiki.
Some features and limitation of this program:
- Graphics is extremely simple.
- All rules of chess are implemented, even the lesser known such as en passant etc. 50 move rule also applies. Draw via repetition is also implemented, but for simplicity only consecutive positions are considered.
- Board is automatically rotated if the game thinks it should be rotated.
- Each player can be either human or AI of strength 1 to 3. This can be changed any time during play.
- Sometimes the stronger AI needs more time to compute the move and there is no indication of it working so it seems frozen, just wait
- On Pokitto if two AIs play against each other, you have to press A after each move. This is basically for technical reasons and due to simplicity of SAF (basically if I let AIs just move as they wish there’s no “multithreading” and when AI is computing for a long time it delays a frame for very long and it messes up rendering so that you wouldn’t see the game unwind until it would end).
- You can undo moves with C.
- After the game ends the whole game is being repeatedly replayed in the background so that you can write it down.
- There are also simple chess variant: chess 960 (Fisher random, but without castling), horde and knights vs knights.