powerup_device: Grant Buffs and Track Their Timers

What you'll learn

• How to spawn and despawn a powerup_device from Verse instead of relying on editor triggers.
• How to grant a buff directly to a player with Pickup(Agent) and check it with HasEffect.
• How to read the live remaining time of a buff with GetRemainingTime.
• How to react the moment any agent picks up the powerup off the ground via ItemPickedUpEvent.

How it works

powerup_device is the shared abstract base behind Fortnite's collectible buffs — Health Powerup, Damage Amplifier, and friends. Because it's abstract you place a concrete powerup in your level and reference it, but every method below works on all subclasses.

The key surface, resolved from the live digest:

Watch the effect specifiers: IsSpawned and HasEffect end in <decides>, so you call them with [] inside a failure context. GetRemainingTime and GetDuration return a real float, so you call them with () and read the value — calling them with [] would not compile.

Let's build it

We build a reward-orb objective: stepping on a finish plate spawns the powerup (if needed), stretches its duration, and grants it straight to that player. When anyone picks a powerup up off the ground, we announce who got it and how many seconds of buff remain.

using { /Fortnite.com/Devices }
using { /Verse.org/Simulation }
using { /UnrealEngine.com/Temporary/Diagnostics }

# Drives a concrete powerup (Health / Damage Amplifier) from Verse as a reward orb.
reward_orb := class(creative_device):

    # A concrete powerup placed in the level (e.g. Health Powerup or Damage Amplifier).
    @editable
    RewardPowerup : health_powerup_device = health_powerup_device{}

    # A trigger standing in for "challenge complete".
    @editable
    FinishPlate : trigger_device = trigger_device{}

    OnBegin<override>()<suspends>: void =
        # React whenever a player steps on the finish plate.
        FinishPlate.TriggeredEvent.Subscribe(OnFinished)
        # React whenever ANY agent scoops the powerup off the ground.
        RewardPowerup.ItemPickedUpEvent.Subscribe(OnPickedUp)

    # Triggered param is ?agent, so bind it before use.
    OnFinished(MaybeAgent : ?agent): void =
        if (Agent := MaybeAgent?):
            # Make sure the orb is in the world; Spawn is fallible-free but IsSpawned decides.
            if (RewardPowerup.IsSpawned[]):
                Print("Reward orb already spawned.")
            else:
                RewardPowerup.Spawn()
            # Stretch the buff to 30s (clamped to the device's Min/Max), then read it back.
            RewardPowerup.SetDuration(30.0)
            Duration := RewardPowerup.GetDuration()  # returns float -> use ()
            Print("Reward duration set to {Duration}s.")
            # Grant the buff straight to the player who finished.
            RewardPowerup.Pickup(Agent)
            # Confirm the effect actually landed (HasEffect decides -> use []).
            if (RewardPowerup.HasEffect[Agent]):
                Print("Buff applied directly to finisher.")

    # ItemPickedUpEvent sends the agent that picked it up.
    OnPickedUp(Agent : agent): void =
        # GetRemainingTime returns a float: -1.0 infinite, 0.0 none.
        Remaining := RewardPowerup.GetRemainingTime(Agent)
        if (Remaining < 0.0):
            Print("Player grabbed the orb: infinite duration buff!")
        else:
            Print("Player grabbed the orb: {Remaining}s of buff remaining.")```

## Try it yourself

- Swap the referenced powerup between a Health Powerup and a Damage Amplifier — the same code drives both because they share the `powerup_device` base.
- Add a second `@editable trigger_device` that calls `RewardPowerup.Despawn()` to pull the orb out of the world when a timer expires.
- In `OnPickedUp`, iterate `GetPlayspace().GetPlayers()` and only announce for players who *don't* already have the effect using `if (not RewardPowerup.HasEffect[OtherAgent]):`.
- Use `SetDuration` with a very large value and confirm the device clamps it to its editor-defined Max via the value returned by `GetDuration()`.

## Recap

You drove a `powerup_device` entirely from Verse: `Spawn`/`IsSpawned` to place it, `SetDuration`/`GetDuration` to control its timer, `Pickup(Agent)` to grant it directly, `HasEffect`/`GetRemainingTime` to inspect a player's buff, and `ItemPickedUpEvent` to react to grabs. The one rule to remember: `<decides>` methods (`IsSpawned`, `HasEffect`) use `[]` inside a failure context, while methods that return a `float` (`GetDuration`, `GetRemainingTime`) use `()` and are read as values.