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Beefalobrain

Based on game build 7140014 | Last updated: 2026-03-03

Overview​

BeefaloBrain is a behavior tree (BT) implementation that defines the decision-making logic for beefalo entities in DST. It orchestrates high-priority responses (e.g., panic, combat), interaction states (greeting feeders with a bell, loitering), and movement behaviors (wandering, following). It interacts heavily with components like domesticatable, follower, hitchable, knownlocations, rideable, and writeable, using helper functions to determine target positions, states, and priority actions.

Usage example​

-- Typically added automatically to beefalo prefabs
local inst = CreateEntity()
inst:AddComponent("brain")
inst.components.brain:SetBrain("beefalobrain")
-- No direct manual interaction needed; the game engine handles activation

Dependencies & tags​

Components used: combat, domesticatable, follower, hitchable, inventory, inventoryitem, knownlocations, rideable, writeable
Tags: Checks hitched, notarget, playerghost, bell, pocketdimension_container; uses ACTIONS.HITCH

Properties​

No public properties. All state and data are managed internally via local constants, component properties, and closure-scoped variables.

Main functions​

OnStart()​

  • Description: Initializes the behavior tree root node with a priority-based hierarchical task network for beefalo AI. It constructs a complex PriorityNode with sub-trees for panic responses, combat, naming, hitching, following, greeting, loitering, wandering, and saltlick anchoring.
  • Parameters: None.
  • Returns: Nothing.
  • Error states: None — assumes all required components exist or are properly guarded by IfNode/WhileNode conditions.

GetFaceTargetFn(inst)​

  • Description: Determines a target for the beefalo to face (e.g., a nearby player). Returns nil if the beefalo is domesticated or seeking salt, or if no valid player is within range and not tagged notarget.
  • Parameters: inst (entity instance) — the beefalo entity.
  • Returns: entity? — closest player within START_FACE_DIST, or nil.
  • Error states: Returns nil if the player is ghosted or has notarget.

KeepFaceTargetFn(inst, target)​

  • Description: Continues facing a target only if both entities are valid, within KEEP_FACE_DIST, not domesticated/seeking salt, and the target is neither a ghost nor tagged notarget.
  • Parameters:
    • inst (entity) — the beefalo.
    • target (entity) — current facing target.
  • Returns: boolean — true if continue facing, else false.
  • Error states: Returns false if either entity is invalid or out of range.

GetGreetTarget(inst)​

  • Description: Finds the target the beefalo should greet — either its Beef Bell owner (if bell is nearby) or the closest player on land within GREET_SEARCH_RADIUS.
  • Parameters: inst (entity).
  • Returns: entity? — bell owner or closest player, or nil.
  • Error states: Returns nil if no bell or player is within search radius.

GetLoiterAnchor(inst)​

  • Description: Maintains and updates the loiter anchor position using knownlocations. Resets it if too far from the current anchor (LOITER_ANCHOR_RESET_DIST), or if herd location is nearby, updates anchor to herd position.
  • Parameters: inst (entity).
  • Returns: vec3? — stored anchor position from knownlocations.
  • Error states: None — ensures anchor is always present.

ShouldWaitForHeavyLifter(inst, target)​

  • Description: Determines if the beefalo should pause to wait for a heavy-lifting entity approaching it (e.g., a player carrying a large item).
  • Parameters:
    • inst (entity) — the beefalo.
    • target (entity) — potential target (e.g., player holding item).
  • Returns: boolean — true if target is heavy lifting and moving toward the beefalo.
  • Error states: Returns false if target is invalid, not heavy lifting, or not moving in the right direction.

InState(inst, state)​

  • Description: Helper to determine if the beefalo is currently in a given state (GREETING, LOITERING, or WANDERING) by comparing elapsed time since _startgreettime.
  • Parameters:
    • inst (entity).
    • state (string) — one of "greeting", "loitering", "wandering".
  • Returns: boolean — whether current state matches expected state.
  • Error states: If _startgreettime is nil, initializes it to a large negative value to force WANDERING initially.

TryBeginGreetingState(inst)​

  • Description: Begins greeting state if domestication level > 0 and a greet target exists; sets _startgreettime.
  • Parameters: inst (entity).
  • Returns: boolean — true if greeting started, else false.
  • Error states: Returns false if in mood or no valid greet target.

TryBeginLoiterState(inst)​

  • Description: Transitions from greeting to loitering state if greeting duration has elapsed or is still active; resets timer if loitering prematurely.
  • Parameters: inst (entity).
  • Returns: boolean — true if loitering should start or timer reset, false if still in mood.
  • Error states: Returns false if in mood; resets timer to avoid loiter state exit.

Events & listeners​

  • Listens to: newcombattarget — stops listening via RemoveEventCallback when unhitching (handled in Hitchable:Unhitch, not directly in this file).
  • Pushes: None — this brain does not emit events itself. Actions (Follow, Wander, etc.) may fire their own callbacks internally.