I'm looking for advice on how to implement online chess move validation using a winboard chess engine. I am creating a mobile battle chess game in Unity 2020.3. Right now I have the possible moves for each player, castle rights, check status, etc being generated by an open source C# chess engine. I chose this engine because it's written in C# and the code could be directly included in my Unity Project. I successfully wrote my own code that connects this chess engine to a 3D battle chess game.
How the game works (video preview):
- A piece is selected by the player clicking it with their mouse or tapping the screen.
- The possible moves for the current board are calculated by the chess engine.
- I use the possible move indexes to show possible move highlights.
- When a player makes one of these possible moves, the move is applied on the chess engine.
- It becomes the other player's turn.
I have some custom code to run player animations, based on the kind of move (ex. an attack animation runs when a piece is captured). I also show have screens that show when it's time for a promotion, a player is in check, or the game is over.
I'd like to somehow make the process of calculating possible moves and applying moves to be done on a server. My goal is to protect from players sending illegal moves to the board and breaking the game.
How would you recommend I approach this problem? This is the last thing I need to turn this game into an enjoyable online experience. I just lack the crucial skill of understanding how to make this game online.