Synchronizing Weapon Effects with Notify States

In this lesson, you will learn how to use AnimNotify States to keep weapon effects, like sword trails or active hitboxes, perfectly synced with your character's movement.

From Single Events to Continuous States

While standard AnimNotify events (the ones we covered in lesson 23) are great for "fire and forget" actions like spawning a footstep sound, they aren't ideal for effects that need to exist over a specific duration. If you want a glowing trail to follow a sword blade during a swing, you need a way to tell the engine: "Start the effect here, keep it active during this arc, and stop it exactly when the animation ends."

This is where AnimNotify States come in. Unlike standard notifies, a state has a clear Begin, Tick, and End point.

Implementing a Weapon Trail State

To implement this, you create a custom class derived from AnimNotifyState. Within this class, you override the three core functions:

1. Received_NotifyBegin: Triggered when the animation reaches the start of the state bar. This is where you spawn your particle system or activate a component.
2. Received_NotifyTick: Triggered every frame while the state bar is active. This is perfect for updating the position of a hitbox or refreshing the orientation of a trail effect.
3. Received_NotifyEnd: Triggered when the bar finishes. Use this to deactivate the trail or destroy the collision component.

// Inside your custom AnimNotifyState class
void UMyWeaponTrailNotify::NotifyBegin(USkeletalMeshComponent* MeshComp, ...) {
    // Spawn the trail emitter attached to the weapon socket
    MyTrailComponent = UGameplayStatics::SpawnEmitterAttached(TrailTemplate, MeshComp, SocketName);
}

void UMyWeaponTrailNotify::NotifyEnd(USkeletalMeshComponent* MeshComp, ...) {
    // Clean up the effect once the swing animation is over
    if (MyTrailComponent) {
        MyTrailComponent->DeactivateSystem();
    }
}

By dragging a Notify State onto your Animation Montage, you gain a visual bar. You can stretch or shrink this bar directly in the timeline to change exactly how long the weapon effect stays "live," ensuring your visual feedback never hangs or cuts off prematurely.

Key Takeaway: Use AnimNotify States to define the temporal boundaries of your effects, allowing for precise control over when gameplay elements like hitboxes and weapon trails start, update, and end.