Networking and metadata

Multiplayer is experimental

These APIs work in single player and in multiplayer, but OMX multiplayer is at an early stage. AI traffic is not synchronised between players yet, and multiplayer behaviour may change between beta releases.

In single player your server half runs inside the game, against the same rules, so a resource behaves the same way in both modes.

Custom events

A client resource sends with EmitToServer (server handlers only), EmitToAll (every other client and the server) or EmitTo(entity) (the client owning a player or vehicle, plus the server). A server resource broadcasts with EmitToAll or targets one entity’s owner with EmitTo. Receive events with On(name, handler).

Events travel inside OMX’s own multiplayer protocol and its rate limits; a resource never defines a packet type. The server checks event namespaces, who sent each event, and its target. Sending needs network.events.

Typed payloads

The typed helpers send one value, serialised into the closed NetworkValue format:

// Client
Network.EmitToServer("register", new RegisterDriver("76"));
Network.On<DutyAssignment>("assignment", assignment => Show(assignment));

// Server: the extra argument resolves the sending player.
Network.On<RegisterDriver>("register", (player, request) => Register(player, request), Players.Get);

A raw event carries at most 16 arguments. Strings and byte arrays are limited to 4096 characters or bytes each.

Metadata

Every player and vehicle has key/value metadata (entity.Meta) in three scopes:

Scope	Who owns it	Who receives it
Local	This side	Nobody. Changes apply immediately.
Synced	The authority	Every client, reliably, including players who join later.
StreamSynced	The authority	The entity’s owner and clients whose vehicle is within the server’s metadataStreamingRange.

var route = new MetadataKey<RouteDefinition>("route");
vehicle.Meta.Set(route, assignment, MetadataScope.StreamSynced);

A server resource writes replicated metadata on any entity. A client resource can only ask for changes on its own player or vehicle; the change appears, and Meta.Changed fires, once the authority accepts it. A stream-synced key appears and disappears for a client as it crosses the streaming range. Replicated writes need network.metadata.

Namespaces

Keys and event names have the form resource-id:name. Your own names can be written short (route); OMX adds your resource id. Any resource can read every key, but only writes within its own namespace. On a server, AllowedResources lists which namespaces clients may use.