examples

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 impresicions 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:

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:

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 focusses 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

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

Launching BoxGame SyncTest (Checksum)

The checksum example showcases how to create a checksum for non-hashable components (like floats).

BoxGame SyncTest (Checksum) 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

cargo run --example box_game_synctest_checksum -- --num-players 2 --check-distance 7