Network Authority

To prevent the client and server from fighting each other about the position / state of objects, Dreamlab has a way to explicitly declare the owner of an object.

When spawning an object, you can do the following to set the authority to the client which spawned it

const newPlayer = this.game.prefabs._.Player.cloneInto(this.game.world._.PlayersContainer, {
  name: "Player." + this.game.network.self,
  authority: this.game.network.self,
});

To change the authority, you can simply set authority to a network ID on a peer:

// set the authority to the first player in the list of connections
myEntity.authority = this.game.network.connections[0].id;

// relinquish authority of an entity
myEntity.authority = undefined;

Standard Player Spawning Model

To make interoperable development easier, Dreamlab has a standard procedure for spawning and managing the lifecycle of players in multiplayer games. A PlayerSpawner class (attached to an object in local) creates the player in the world under a PlayersContainer object in the world root with the authority set to the client which controls the player.

When using this, the player can always be accessed with PlayerSpawner.myLocalPlayer. This idiom is useful as it allows enemies and other objects in the world to make assumptions about where to find players.

Finally, this model includes a CleanupOnLeave behavior attached to an entity under the world root which is responsible for destroying entities when the player which owns them leaves:

import { Behavior, PlayerLeft, syncedValue } from "@dreamlab/engine";

export default class CleanUpOnLeave extends Behavior {
  onInitializeServer(): void {
    // This automatically removes any entity that a player has authority over when they disconnect.
    this.listen(this.game, PlayerLeft, ({ connection }) => {
      const entities = this.game.entities;
      for (const entity of entities) {
        if (entity.authority === connection.id) entity.destroy();
      }
    });
  }
}