Walrusbrain

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

Overview

The WalrusBrain is a brain component responsible for orchestrating the high-level AI behavior of the walrus entity in Don't Starve Together. It uses a behavior tree constructed from foundational behaviours and shared helpers (e.g., BrainCommon) to implement decision priorities such as fleeing from danger, returning home at night, following its leader or nearest player, eating food, and wandering. The component inherits from Brain and initializes a behavior tree in OnStart. It interacts with several components: combat (targeting and cooldowns), follower (leader tracking), homeseeker (home location), and leader (follower counting), all via standard ECS access patterns.

Usage example

local walrus = SpawnPrefab("walrus")
if walrus ~= nil then
    walrus:AddComponent("walrusbrain")
    -- The brain automatically initializes its behavior tree on first OnStart()
    -- No further calls are typically required by modders
end

Dependencies & tags

Components used:

• combat — accessed via inst.components.combat to check target presence and cooldown state
• follower — accessed via inst.components.follower to retrieve the current leader
• homeseeker — accessed via inst.components.homeseeker to obtain the home location
• leader — accessed via inst.components.leader to count followers and check taunt state

Tags:

• character — used in filtering food and flee targets
• monster — used as a positive filter in HUNTER_PARAMS for flee targets
• notarget — used to exclude invalid targets
• walrus — used as a negative filter in flee target evaluation
• hound — used as a negative filter in flee target evaluation
• edible_MEAT — used to identify valid food items
• INLIMBO, outofreach — used to exclude invalid food items
• taunt_attack — used in home-return logic under fear
• flare_summoned — used to conditionally enable leash origin as home

Properties

Property	Type	Default Value	Description
inst	Entity	nil (passed via constructor)	The entity instance this brain controls
bt	BehaviorTree	nil	Initialized in OnStart with the constructed behavior tree root node

Note: The constructor does not define additional public properties beyond inst (inherited from Brain), which is set by the ECS during component instantiation.

Main functions

WalrusBrain:OnStart()

• Description: Constructs and initializes the behavior tree root node. It arranges child behavior nodes in a PriorityNode, ordered by precedence: panic triggers first, then leash, runaway, home return on fear, leader-following, combat opportunities, home return at night, solo player-following, eating, face-targeting, and finally wandering.
• Parameters: None
• Returns: nil
• Error states: None documented; assumes all required components are attached.

GetFaceTargetFn(inst)

• Description: Returns the nearest character (or monster) within START_FACE_DIST that is not tagged notarget; used by FaceEntity to determine a target to face.
• Parameters:
  • inst (Entity) — the walrus instance querying for a face target
• Returns: Entity? — the closest valid face target or nil

KeepFaceTargetFn(inst, target)

• Description: Checks whether the walrus should continue facing the given target, based on presence of notarget and proximity within KEEP_FACE_DIST.
• Parameters:
  • inst (Entity) — the walrus instance
  • target (Entity) — the entity being faced
• Returns: boolean — true if the target remains valid and within range, otherwise false

GetLeader(inst)

• Description: Retrieves the current leader via inst.components.follower:GetLeader(), or nil if no follower component or leader is set.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Entity? — the leader entity or nil

GetNoLeaderFollowTarget(inst)

• Description: Finds the nearest character (or monster) within MAX_PLAYER_STALK_DISTANCE when the walrus has no leader, allowing solo wandering toward players.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Entity? — nearest eligible player/monster or nil

GetHome(inst)

• Description: Retrieves the home location (inst.components.homeseeker.home) if the component exists, otherwise nil.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Entity? — home entity (e.g., campfire, base) or nil

EatFoodAction(inst)

• Description: Returns a buffered ACTIONS.EAT action toward the nearest edible meat item within SEE_FOOD_DIST, provided it is on valid ground and no characters are nearby (within RUN_START_DIST). Excludes items owned by other entities.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Action? — a valid buffered action or nil
• Error states: Returns nil if no suitable food is found or the food is in invalid terrain/position.

ShouldGoHomeAtNight(inst)

• Description: Returns true if it is currently night, the walrus has no leader, a home exists, and it has no active combat target.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: boolean — true if conditions to return home are met

ShouldGoHomeScared(inst)

• Description: Returns true if the walrus has the taunt_attack tag, has zero followers, and lacks a valid leader (i.e., it is isolated and may retreat).
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: boolean — true if fear condition for home-return is met

GoHomeAction(inst)

• Description: Returns a buffered ACTIONS.GOHOME action toward the walrus’s home entity, if the home is valid and exists.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Action? — a valid buffered action or nil

GetHomeLocation(inst)

• Description: Returns the positional coordinates of the home entity (GetHome(inst):GetPosition()), or nil if no home exists.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Vector3? — 3D position of the home or nil

GetNoLeaderLeashPos(inst)

• Description: Returns the home location as the leash origin only if the walrus is not summoned via flare and has no leader.
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: Vector3? — leash origin position or nil

CanAttackNow(inst)

• Description: Returns true if the walrus has no combat target or if its current attack cooldown has elapsed (not combat:InCooldown()).
• Parameters:
  • inst (Entity) — the walrus instance
• Returns: boolean — true if the walrus is allowed to begin or continue attacking

Events & listeners

No event listeners or events are explicitly registered by this component. Behavior is driven entirely through the PriorityNode and WhileNode conditions in the behavior tree.

---