# Example Instructions

Gathered here are some additional instructions on how to build and run the examples.

## BoxGame

BoxGame is a very basic 2-4 player game example with each player controlling a coloured box.
There is no real game, just movement with ice physics. Optionally,
you can specify spectators.

- W, A, S, D to move around

### Important Disclaimer - Determinism

Since BoxGame is based on floats and uses floating-point sin, cos and sqrt,
I fully expect this example to desync when compiled on two different architectures/platforms.
This is intentional to see when and how that happens. If you plan to implement your own
deterministic game, make sure to take floating-point imprecisions and non-deterministic results into consideration.

### Launching BoxGame P2P and Spectator

The P2P example is launched by command-line arguments:

- `--local-port / -l`: local port the client is listening to
- `--players / -p`: a list of player addresses, with the local player being identified by `localhost`
- `--spectators / -s`: a list of spectator addresses. This client will act as a host for these spectators

For the spectator, the following command-line arguments exist:

- `--local-port / -l`: local port the client is listening to
- `--num-players / -n`: number of players that will participate in the game
- `--host / -h`: address of the host

For example, to run a two-player game, run these commands in separate terminals:

```shell
cargo run --example box_game_p2p -- --local-port 7000 --players localhost 127.0.0.1:7001
cargo run --example box_game_p2p -- --local-port 7001 --players 127.0.0.1:7000 localhost
```

In order to run a two-player game with a spectator,
run these commands in separate terminals:

```shell
cargo run --example box_game_p2p -- --local-port 7000 --players localhost 127.0.0.1:7001 --spectators 127.0.0.1:7002
cargo run --example box_game_p2p -- --local-port 7001 --players 127.0.0.1:7000 localhost
cargo run --example box_game_spectator -- --local-port 7002 --num-players 2 --host 127.0.0.1:7000 
```

## BoxGame SyncTest

The same game, but without network functionality.
Instead, the SyncTestSession focuses on simulating rollbacks and comparing checksums.

### Launching BoxGame SyncTest

BoxGame SyncTest is launched by a single command-line argument:

- `--num-players / -n`: number of players that will participate in the game
- `--check-distance / -c`: number of frames that will be rolled back and resimulated each frame

```shell
cargo run --example box_game_synctest -- --num-players 2 --check-distance 7
```