LEARN HOLONET/Tutorials
TutorialHoloNET 4.x · Holochain 0.7.0 / 0.7.1

Real-time multiplayer with HyperNET

You'll build: a game loop where players in a zone see each other move and exchange messages directly, peer to peer, with no game server. Only nearby players get your traffic. Time: 25 minutes. You need: a running conductor, and the OASIS hApp (it has HyperNET's zome functions). Finished code: examples/04-HyperNET, which runs three players in one process.

1. Add HyperNET

bash
dotnet add package NextGenSoftware.Holochain.HoloNET.HyperNET

2. Join a zone

Each player is one Holochain agent: one app client. Connect it as in the first tutorial, then:

csharp
using NextGenSoftware.Holochain.HoloNET.HyperNET;

var session = new HyperNETSession(client, zone: "forest-1", playerName: "Alice", new HyperNETOptions
{
    AreaOfInterestRadius = 100,   // only players this close get your game traffic
    MaxFullRatePeers = 64         // and at most the nearest 64 get every update
});

session.OnPeerJoined += (s, e) => Spawn(e.Peer);
session.OnPeerMoved  += (s, e) => Move(e.Peer, e.Peer.Position.Value);
session.OnMessage    += (s, e) => Handle(e.From, e.Channel, e.Payload);
await session.JoinAsync();

3. The game loop

csharp
// Every tick: only sent if you moved, and only to the players who need it.
await session.UpdatePositionAsync(new HyperNETVector3(x, y, z));

// Game events go to your area of interest by default.
await session.SendAsync("shot", new byte[] { 1 });

// Things that must arrive are sent reliably: acknowledged, retried, delivered once.
await session.SendAsync("trade", new Trade { Item = "sword", Quantity = 1 }, HyperNETTarget.Specific,
    reliable: true, agentPubKeys: new[] { bobAgentPubKey });

To read a typed message, use HyperNETSession.Deserialize<Trade>(e.Payload). To measure latency, use await session.PingAsync(bobAgentPubKey).

4. Moving between zones

csharp
await session.ChangeZoneAsync("forest-2");   // the players you leave are told; the new zone's players see you join

What just happened

  • Presence. Joining wrote one link to the DHT (your presence in the zone). Everything after that went straight from player to player.
  • Area of interest. It keeps each player's traffic down to how crowded their surroundings are, not how many players are online. That's what lets a world grow without a central limit.
  • The honest limits. Latency is still real network distance. Signals aren't guaranteed, which is why reliable messages exist. And with no server there's no server-side authority, so anti-cheat belongs in your hApp's validation rules.

Next

  • The HyperNET guide covers every option, the service, and the zome functions to copy into your own hApp.
  • Generate a hApp for your game's own data.