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Chest Mimicbrain

Based on game build 714014 | Last updated: 2026-02-27

Overview​

This component implements the behavior tree for the Chest Mimic entity, a hostile mob that simulates a chest until approached by a player, then reveals itself to attack. It coordinates interaction cooldowns, inventory-based hiding (via transformation), ground item collection, player chasing, and wandering behavior. It extends Brain and integrates with components including inventory, eater, timer, and knownlocations to determine appropriate actions.

Dependencies & Tags​

  • Components used:
    • inventory: Checks capacity (IsFull) and item hold status (inventoryitem:IsHeld).
    • eater: Determines whether a found item is edible (CanEat).
    • timer: Manages interaction cooldown (INTERACT_COOLDOWN_NAME) and the "angry" timer.
    • knownlocations: Remembers and retrieves the spawn point (RememberLocation, GetLocation).
    • braincommon: Supplies shared behavior nodes like PanicTrigger.
    • Custom helpers: FindWalkableOffset, FindEntity, FindGroundItemAction, TryToHide, BufferedAction.
  • Tags: Uses busy (via HasStateTag) to prevent re-entry during critical actions. No tags are added or removed by this brain itself.

Properties​

No public instance properties are initialized in the constructor. The brain stores behavior-related state via internal variables (INTERACT_COOLDOWN_NAME, SEE_DIST) and assigns self.bt after constructing the behavior tree in OnStart.

Main Functions​

Chest_MimicBrain:OnStart()​

  • Description: Initializes and assigns the behavior tree root. Constructs a priority-based behavior tree with the highest-priority node being PanicTrigger, followed by conditional and reactive logic including transformation attempts when inventory is full, item-finding and eating/picking up while not jumping, player chasing, and wandering.
  • Parameters: None.
  • Returns: nil.

Chest_MimicBrain:OnInitializationComplete()​

  • Description: Records the Chest Mimic’s current position as the "spawnpoint" location in knownlocations after initialization finishes. This location is used later as a fallback target for wandering behavior.
  • Parameters: None.
  • Returns: nil.

Supporting Functions​

The following functions are defined locally in the file and used by the behavior tree:

TryToHide(inst)​

  • Description: Attempts to transform the Chest Mimic back into a chest by moving to a nearby walkable position and performing the ACTIONS.MOLEPEEK action. Fails silently if the stategraph has the "busy" tag or no valid offset is found.
  • Parameters: inst (Entity) — the Chest Mimic instance.
  • Returns: nil on failure, or a BufferedAction configured to perform ACTIONS.MOLEPEEK.

FindGroundItemAction(inst)​

  • Description: Searches for a suitable item on the ground (minimum age ≥ 1 second, has inventoryitem component, meets must/cannot tag constraints) within SEE_DIST. If found, creates a BufferedAction to either ACTIONS.EAT or ACTIONS.PICKUP depending on edibility. Sets up a success callback to start a cooldown timer and defines a validfn ensuring the target is still reachable and unheld.
  • Parameters: inst (Entity) — the Chest Mimic instance.
  • Returns: nil if the stategraph is busy, an interact cooldown exists, or inventory is full; otherwise returns a BufferedAction.

GetWanderPoint(inst)​

  • Description: Determines a wander target: the nearest player’s position if one exists, otherwise the stored "spawnpoint".
  • Parameters: inst (Entity).
  • Returns: Vector3 position or nil if no target location is available.

Events & Listeners​

The brain does not register or emit any events directly. It relies on the behavior tree to trigger actions and stategraph transitions, and on stategraph busy tags for concurrency control.