fledge_net

Multiplayer networking for Fledge games: host-authoritative sessions, an ECS replication layer (spawn/despawn, hierarchy, snapshots, interest management), owned inputs with authority checks, client prediction and reconciliation, tick-keyed interpolation, RPCs, and an encrypted UDP transport. Pure Dart.

Installation

dependencies:
  fledge_net: ^0.4.0

Quick Start

import 'package:fledge_ecs/fledge_ecs.dart';
import 'package:fledge_net/fledge_net.dart';

class Position {
  final double x, y;
  const Position(this.x, this.y);
}

class Move {
  final double dx, dy;
  const Move(this.dx, this.dy);
}

final replication = ReplicationRegistry()
  ..component<Position>(
    'position',
    NetCodec<Position>.of(
      encode: (p, out) => out..writeFloat32(p.x)..writeFloat32(p.y),
      decode: (r) => Position(r.readFloat32(), r.readFloat32()),
    ),
    interpolate: (a, b, t) =>
        Position(a.x + (b.x - a.x) * t, a.y + (b.y - a.y) * t),
  )
  ..input<Move>(
    NetCodec<Move>.of(
      encode: (m, out) => out..writeFloat32(m.dx)..writeFloat32(m.dy),
      decode: (r) => Move(r.readFloat32(), r.readFloat32()),
    ),
  )
  ..predict<Position, Move>(
    step: (s, m, dt) => Position(s.x + m.dx * 100 * dt, s.y + m.dy * 100 * dt),
    error: (a, b) => (a.x - b.x).abs() + (a.y - b.y).abs(),
  );

final config = NetworkConfig(tickRate: 60, syncRate: 20);
final app = App()
  ..insertResource(config.fixedTimestep())
  ..addPlugin(NetworkPlugin(config: config, replication: replication));

final session = app.world.getResource<NetworkSession>()!;
await session.host(port: 7777); // or: await session.join('192.168.1.20', 7777);

// Host: replicate an entity owned by peer 1.
app.world.spawn()
  ..insert(Replicated(owner: 1))
  ..insert(const Position(0, 0));

Clients submit input for entities they own through NetLocalInputs<Move> (in a Schedules.fixedPreUpdate system that joins NetSets.localInput); the owning client predicts immediately and the host applies the same step. Test whole sessions in one process with LoopbackNetwork and a ManualNetClock.

Documentation

See the Fledge documentation site for the co-op quickstart, how replication works, and the low-level API.

License

Apache 2.0 - See LICENSE for details.