Seabattle game

Here is demo of Seabattle game, implemented on Noir.

Circuits are available here.

Game rules

Variation of the Battleship game is used:

The ocean is a 5x5 grid, on which each ship takes up one square. Each player has 3 ships. Ships cannot be positioned on the neighbor squares.

On every turn each ships can move or fire. Each ship can sustain 3 hits before sinking. Infromation about successfull hit or sinking must be announced to one's opponent.

Game ends when all ships are sunk for some player.

Build

Noir

Use this description how to install noir from source.

Seabattle circuit & verifier

git clone https://github.com/snjax/zkships.git
cd zkships/circuit
nargo build
nargo compile p
nargo contract

To test the circuit with some data, try

# 
node test/generate_sample_inputs.js > Prover.toml
nargo prove p

Frontend

Game UI:

Wallet connection:

Game creation:

Explored Noir issues

Examples are availble here.

Segmentation fault

'nargo prove' fails with Segmentation fault error:

Segmentation fault (core dumped)

Code:

fn main(x : Field, y : pub Field) {
    let flag = (x == 1) & (y == 2);
    constrain flag == true;
}

Stack overflow

'nargo build' fails with stack overflow error:

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
Aborted (core dumped)

Code:

fn main(x : Field, y : pub Field) {
    let flag = (x == 1) & (y == 2);
    constrain flag | false == flag;
}

Pedersen hash error:

'nargo compile' can fail when Pedersen hash is used:

thread 'main' panicked at 'Cannot find witness assignment for GadgetInput { witness: Witness(5), num_bits: 254 }', crates/acvm/src/pwg/mod.rs:18:17
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Code:

use dep::std;

fn main(solnHash: pub Field, raw_data: [Field; 2], salt: Field) {
    let mut state = 0;
    for i in 0..2 {
        state = state * 8 + raw_data[i];
    };
    state = state + salt;

    let hash = std::haAsh::pedersen([state])[0];
    constrain solnHash == hash;
}

WASM

Next patches were required for WASM worker: https://github.com/snjax/zkships/tree/master/worker/patches

Apple silicon mac issue

Nargo build does not work on Mac computers with Apple silicon. System libraries path is incorrect in rust wrapper for barretenberg.