Promoted pawn should be shown as such, as opposed to met, in Makruk

gbtami / pychess-variants

Chess variant server

https://www.pychess.org

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Promoted pawn should be shown as such, as opposed to met, in Makruk #87

Closed Fulmene closed 4 years ago

Fulmene commented 4 years ago

In a real Makruk game, promoted pawns are represented by flipping the pawn piece over. Although they are functionally the same as the met, the discrepancy from the OTB game is quite jarring. Furthermore, they are also notated differently in game notation.

I'm willing to solve this issue myself, but I think I'll need some guidance on how each part of the code works.

gbtami commented 4 years ago

Screenshot from PlayOK

gbtami commented 4 years ago

Our problem as @ianfab explained in Discord chat: "promoted pawns and met can not be distinguished in makruk FENs". The site is based on Fairy-Stockfish (server side) and chessgroundx (client side), and they are communicating via FEN.

ianfab commented 4 years ago

Proposed solution as discussed:

[x] Implement option in Fairy-Stockfish for Position::fen to indicate promoted pieces with ~ even if not required (in contrast e.g. to crazyhouse).
[x] Allow to use the aforementioned option in get_fen of pyffish.
[ ] Use it in pychess-variants to generate the FEN passed to chessgroundx for makruk.
[ ] Add SVGs for promoted makruk pawns.

ianfab commented 4 years ago

I pushed a first version of the code that allows to generate makruk FENs with promoted pawns in Fairy-Stockfish. However, although the changes are small, they touch core parts of the board representation and could potentially completely break multiple variants, therefore it needs extensive testing before it can be merged.