An optimised Connect4 game implementation on Solidity
The ConnectFour.sol contract has been deployed on mainnet at address 0x7CD285b59f38afd61b2Ab0505b5F9c318158ea42. GameMinter.sol will be deployed soon, along with a frontend for a better experience.
Still to do:
- Review & deploy GameMinter.sol (do I need to make it
Ownablefor OpenSea details access?). - Set up a subgraph for easier frontend data access.
- Build a simple frontend that lists current games, and shows the board.
The ConnectFour.sol uses two bitboards (one for each player) to store the board state (uint64[2] Game.board). It also stores the height of each row (the position of the last empty block per row) for easier computation (uint64[7] Game.height). When making a move, we shift a single byte to the position stored in height for that row, and use the XOR operator to store it into our bitboard.
This module allows you to mint any games you have won as ERC-721 tokens. The metadata for these tokens is completely on-chain down to the image, which is a vector image generated by the contract and displaying the Connect4 board.
The design of this contract is inspired from Fhourstones, a program written by John Tromp in 1996 to calculate the best moves in the game of Connect4.