Safi Engine

    Events & Communication

    Headers: Core/include/Core/EventBus.h, Core/include/Core/Events.h

    EventBus

    The engine provides a publish/subscribe event system for communication between behaviors and systems:

    auto &bus = engine.GetEventBus();

    Subscribing to Events

    void OnStart(flecs::entity e, Engine &engine) override {
  auto &bus = engine.GetEventBus();

  m_SubId = bus.Subscribe<KeyEvent>([this](const KeyEvent &evt) {
    if (evt.key == GLFW_KEY_P && evt.action == GLFW_PRESS) {
      m_Paused = !m_Paused;
    }
  });
}
    Warning

    Store the SubscriptionID and unsubscribe when the behavior is destroyed to avoid dangling callbacks.

    Publishing Events

    // Immediate delivery
engine.GetEventBus().Publish(MyCustomEvent{42, "hello"});

// Queued (processed on next Flush)
engine.GetEventBus().Queue(MyCustomEvent{42, "hello"});

    Built-in Events

    EventFieldsWhen Fired
    WindowResizeEventint width, heightWindow resized
    KeyEventint key, action, modsKey press/release
    MouseMoveEventdouble x, y, deltaX, deltaYMouse moved
    MouseButtonEventint button, action, modsMouse button click
    MouseScrollEventdouble xOffset, yOffsetScroll wheel

    Custom Events

    Define your own event structs for behavior-to-behavior communication:

    // Define in a shared header
struct DamageEvent {
  uint64_t targetId;
  float amount;
};

// Publisher (e.g., weapon behavior)
engine.GetEventBus().Publish(DamageEvent{enemy.id(), 25.0f});

// Subscriber (e.g., health behavior)
bus.Subscribe<DamageEvent>([this, e](const DamageEvent &evt) {
  if (evt.targetId == e.id()) {
    m_Health -= evt.amount;
  }
});

    EventBus API

    MethodDescription
    Subscribe<T>(callback)Register a handler, returns ID
    Unsubscribe(id)Remove a subscription
    Publish<T>(event)Deliver immediately to all subscribers
    Queue<T>(event)Queue for delivery on next Flush()
    Flush()Process all queued events