GameMessenger

Lightweight, strongly typed pub/sub messenger for game loops. GameMessenger lets systems talk without tight coupling and supports both immediate and queued (pumpable) delivery.

Features

• Strongly typed subscribe/publish API with SubscriptionToken for safe unsubscription
• Immediate delivery or queued delivery you process later with PumpQueued
• Handlers can unsubscribe themselves while messages are flowing (dispatch uses snapshots)
• Tiny surface area: IGameMessenger, GameMessenger, Delivery, SubscriptionToken

Getting Started

1. Reference the library (package name OliveGameStudio.Messenger when published) or add the project directly:

   dotnet add package OliveGameStudio.Messenger
   # or
   dotnet add reference src/OliveGameStudio.Messenger.csproj

2. Create a messenger and subscribe:

   using OliveGameStudio;
   
   var messenger = new GameMessenger();
   
   var spawnedToken = messenger.Subscribe<PlayerSpawned>(msg =>
   {
       Console.WriteLine($"Spawned {msg.Id} at {msg.Position}");
   });
   
   messenger.Publish(new PlayerSpawned("alpha", (0, 0)));
   // For queued subscriptions, call PumpQueued() each frame to flush the queue.

Delivery Modes

• Delivery.Immediate: handlers fire as soon as Publish is called.
• Delivery.EndOfFrame: handlers are queued; call PumpQueued() (e.g., once per frame) to run them.

Example mixing both:

var messenger = new GameMessenger();

// Immediate handler
messenger.Subscribe<DamageTaken>(d => Console.WriteLine($"HP - {d.Amount}"), Delivery.Immediate);

// Queued handler (batch damage at end of frame)
messenger.Subscribe<DamageTaken>(d => pendingDamage += d.Amount, Delivery.EndOfFrame);

messenger.Publish(new DamageTaken(5));

// Later in the frame loop
messenger.PumpQueued();

Unsubscribing

Keep the SubscriptionToken to remove a handler later:

var token = messenger.Subscribe<InputEvent>(_ => HandleInput(), Delivery.Immediate);
// ... when no longer needed
messenger.Unsubscribe<InputEvent>(token);

Threading

GameMessenger is not thread-safe; interact with it from the same thread (typically your main game loop).

Building Locally

cd src
dotnet build OliveGameStudio.Messenger.csproj

License

Add your license information here.