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Beefalobrain

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

Overview​

Beefalobrain is the AI component responsible for controlling the behavior of beefalo entities in Don't Starve Together. It implements a Behavior Tree (BT) that orchestrates high-priority combat and panic responses, followed by social and foraging behaviors such as following owners (via follower and domesticatable), greeting players (especially those holding Beefalo bells), loitering in anticipation of food, and wandering based on time of day and herd location.

Key interactions include:

  • Using domesticatable to check domestication status for greeting triggers
  • Using follower and knownlocations to follow leaders and remember herd/saltlick positions
  • Using hitchable to handle hitching/unhitching from posts
  • Using rideable, combat, writeable, and inventory components to condition behavior (e.g., wait for heavy lifters)

Dependencies & Tags​

  • Components used:
    • combat: to check self.inst.components.combat.target
    • domesticatable: for IsDomesticated(), GetDomestication()
    • follower: for GetLeader()
    • hitchable: for Unhitch()
    • inventory: for IsHeavyLifting()
    • inventoryitem: for GetGrandOwner()
    • knownlocations: for GetLocation(), RememberLocation()
    • rideable: for canride
    • writeable: for IsBeingWritten()
  • Tags:
    • "hitched" (checked with HasTag("hitched"))
    • "notarget" (checked with HasTag("notarget"))
    • "playerghost" (checked with HasTag("playerghost"))
    • "bell" (checked with HasTag("bell"))
    • "pocketdimension_container" (checked with HasTag("pocketdimension_container"))

Properties​

No public properties are declared directly in the BeefaloBrain constructor. All logic is encapsulated within the Behavior Tree and helper functions using self.inst and local state.

Main Functions​

The following functions are used internally by the Behavior Tree to implement decision logic and actions. They are not called directly by external code.

GetFaceTargetFn(inst)​

  • Description: Returns a valid face target for the beefalo only if it is not domesticated, not seeking salt, and a player is within START_FACE_DIST. Excludes notarget and playerghost targets.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: The closest player target if conditions are met, otherwise nil.

KeepFaceTargetFn(inst, target)​

  • Description: Determines whether the beefalo should continue facing a given target. Ensures both instances are valid, not ghosts, within KEEP_FACE_DIST, and not seeking salt.
  • Parameters:
    • inst: The beefalo entity instance.
    • target: The entity the beefalo is facing.
  • Returns: true if conditions hold, otherwise false.

GetWanderDistFn(inst)​

  • Description: Returns the wandering radius based on time of day: WANDER_DIST_DAY during day, WANDER_DIST_NIGHT at night.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: number — The wandering radius.

GetLoiterTarget(inst)​

  • Description: Returns the closest player within LOITER_SEARCH_RADIUS (on land).
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: The closest player or nil.

GetGreetTarget(inst)​

  • Description: Prioritizes the beefalo's own bell (inst._beef_bell) if within GREET_SEARCH_RADIUS. Otherwise, returns the closest player on land within the same radius.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: The target entity (bell or player) or nil.

GetGreetTargetPosition(inst)​

  • Description: Returns the position of the greet target; defaults to the beefalo’s own position if no greet target exists.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: Vector — The 3D position of the greet target or inst:GetPosition().

GetLoiterAnchor(inst)​

  • Description: Manages and returns a loiter anchor point, updating it based on herd location or distance. Ensures anchor is remembered via knownlocations.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: Vector — The loiter anchor position.

TryBeginLoiterState(inst)​

  • Description: Prevents entering loiter if the beefalo is in a mood (GetIsInMood()). Otherwise, resets loiter timer if currently greeting.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: boolean — true if loiter should begin (or is resuming), false otherwise.

TryBeginGreetingState(inst)​

  • Description: Begins greeting state if the beefalo is domesticated (domestication > 0.0) and a greet target (player/bell) exists. Records inst._startgreettime.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: boolean — true if greeting should begin, otherwise false.

ShouldWaitForHeavyLifter(inst, target)​

  • Description: Checks if the target is a heavy lifter (via inventory:IsHeavyLifting()) and moving toward the beefalo (via dot product of facing and relative direction). Returns true if the beefalo should wait.
  • Parameters:
    • inst: The beefalo entity instance.
    • target: The potential heavy-lifting entity (resolves grand owner via inventoryitem:GetGrandOwner()).
  • Returns: boolean — true if waiting is required.

GetWaitForHeavyLifter(inst)​

  • Description: Returns the greet target if ShouldWaitForHeavyLifter() returns true for it.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: Entity or nil.

gotta hitchspot(inst)​

  • Description: Performs the action to hitch to inst.hitchingspot using BufferedAction. Unhitches first if currently hitched.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: Action — The hitching action.

InState(inst, state)​

  • Description: Determines which state the beefalo is currently in (GREETING, LOITERING, or WANDERING) based on time elapsed since inst._startgreettime.
  • Parameters:
    • inst: The beefalo entity instance.
    • state: One of "greeting", "loitering", "wandering".
  • Returns: boolean — true if the current time falls within the state’s window.

GetLeader(inst)​

  • Description: Returns the leader via follower:GetLeader() if available.
  • Parameters:
    • inst: The beefalo entity instance.
  • Returns: Entity or nil.

Events & Listeners​

The BeefaloBrain component itself does not register or push events directly. Event callbacks are handled at the inst level via the Behavior Tree and helper functions (e.g., onnewcombattarget is removed via inst:RemoveEventCallback("newcombattarget",onnewtarget) in hitchable:Unhitch()), but this is external to the brain script.

The Behavior Tree nodes (ChaseAndAttack, Follow, Wander, etc.) may internally manage event callbacks (e.g., on target loss or movement completion), but those are defined in behaviours/ and brains/braincommon.lua, not here.