Examples

This folder contains various examples that showcase various lightyear features.

The top level Cargo.toml workspace defines the deps that examples can use and pick features from.

Easy

• simple_setup: minimal example that just shows how to create the lightyear client and server plugins
• simple_box: example that showcases how to send inputs from client to server, and how to add client-prediction and interpolation

Medium

• replication_groups: example that shows how to replicate entities that refer to other entities (e.g. they have a component containing an Entity id). You need to use ReplicationGroup to ensure that the those entities are replicated in the same message
• interest_management: example that shows how to use interest management to only replicate a subset of entities to each player, via the VisibilityManager and the RoomManager
• client_replication: example that shows how to replicate entities from the client to the server. (i.e. the client has authority)
• priority: example that shows how to manage bandwidth by enabling priority accumulation. Messages will be sent in order of their priority.

Advanced

• avian_physics: example that shows how to replicate a physics simulation using xpbd. We also use the leafwing feature for a better way to manage inputs.
• avian_3d_character: example that shows clients controlling server-authoritative 3D objects simulated using avian.
• spaceships: more advanced version of avian_physics with player movement based on forces, fully server authoritative, predicted bullet spawning.
• bullet_prespawn: example that shows how to spawn player-objects on the Predicted timeline. This is useful to avoid having to wait a full round-trip before the object is spawned.
• auth: an example that shows how a client can get a ConnectToken to connect to a server
• lobby: an example that shows how the network topology can be changed at runtime. Every client can potentially act as a host for the game (instead of the dedicated server).

Running an example

• Run the server: cargo run --features=server
• Run client with id 1: cargo run --features=client -- -c 1
• Run client with id 2: cargo run --features=client -- -c 2 (etc.)
• Run the client and server in two separate bevy Apps: cargo run --features=server,client
• Run the server with a gui: cargo run --features=server,gui
• Run the client and server in "HostServer" mode, where the server is also a client (there is only one App): cargo run --features=server,client -- -m=host-server

You can modify the file assets/settings.ron to modify some networking settings.

Testing in wasm with webtransport

NOTE: I am using trunk to build and serve the wasm example.

To test the example in wasm, you can run the following commands: trunk serve --features=client

You will need a valid SSL certificate to test the example in wasm using webtransport. You will need to run the following commands:

• cd "$(git rev-parse --show-toplevel)" && sh examples/certificates/generate.sh (to generate the temporary SSL certificates, they are only valid for 2 weeks)
• cargo run -- server to start the server. The server will print out the certificate digest (something like 1fd28860bd2010067cee636a64bcbb492142295b297fd8c480e604b70ce4d644)
• You then have to replace the certificate digest in the assets/settings.ron file with the one that the server printed out.
• then start the client wasm test with trunk serve --features=client

NOTES

The common crate provides the initial UI setup along with a connect/disconnect button, and manages the bevygap stuff if needed.

Building for Edgegap

# building the game server container
docker build -t examples -f examples/Dockerfile.server --progress=plain --build-arg examples="simple_box spaceships" .

# and to run, specify the example name as an env:
docker run --rm -it -e EXAMPLE_NAME=simple_box examples
# or with a key and an extra SANs for self-signed cert:
 docker run --rm -it -e EXAMPLE_NAME=simple_box -e LIGHTYEAR_PRIVATE_KEY="1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1" -e SELF_SIGNED_SANS="example.com,10.1.2.3" examples