Beargerbrain

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

Overview

The BeargerBrain component implements the core AI logic for the Bearger character in Don't Starve Together. It constructs and maintains a behavior tree (self.bt) that orchestrates complex, context-sensitive behaviors such as chasing and attacking enemies, seeking and consuming food, stealing food from structures, harvesting resources (e.g., beehives, farms), and seasonal wander patterns. It integrates with multiple components to make decisions based on game state (e.g., season, base proximity) and entity properties (e.g., tags, health, position). This brain is responsible for autonomous decision-making during both active (summer) and migratory (autumn) phases, and it respects seasonal tuning parameters like travel distance and attack range.

Dependencies & Tags

• Components used:
  • combat: for targeting,CanTarget checks, and target property.
  • eater: for food compatibility (CanEat, GetEdibleTags), used in food search.
  • inventory: for checking if inventory is full, and finding edible items.
  • container: for checking container emptiness and finding items via FindItem.
  • stewer, dryer, crop, harvestable, pickable: to determine readiness for harvesting and interaction.
  • timer: for checking timer existence (e.g., "GroundPound").
  • knownlocations: to store/retrieve spawn point location for seasonal home logic.
  • workable: used implicitly via item.components.workable checks (though no direct method is called on workable in this script).
• Tags added/checked:
  • structure, beehive, honeyed, lunar_aligned, busy, wantstoeat, running, jumping, staggered.
  • Tags excluded from search (NO_TAGS): FX, NOCLICK, DECOR, INLIMBO, burnt, outofreach.
  • BASE_TAGS: { "structure" }, used to detect proximity to player structures.
  • PICKABLE_FOODS: internal lookup table (berries, cave_banana, carrot, red_cap, blue_cap, green_cap).

Properties

Property	Type	Default Value	Description
inst.seenbase	boolean	false	Tracks whether the Bearger has entered the vicinity of a player structure; becomes true once 2 or more structure tagged entities are within SEE_STRUCTURE_DIST.
inst.wanderdirection	number	nil	Stores the current wander angle (in radians) set by SetWanderDirection and used by GetWanderDirection.
inst.canrunningbutt	boolean	inferred (not set here)	Controls whether the ChaseAndRam behavior should terminate early if GroundPound timer is active.

Main Functions

EatFoodAction(inst)

• Description: Constructs a priority-based food-gathering action. First checks inventory for edible items to eat. If none found and Bearger is not busy, scans nearby entities (within SEE_FOOD_DIST) for edible, unharvested food. Prioritizes picking up honeyed items first (via PICKUP), then other edible items (via PICKUP).
• Parameters:
  • inst: The Bearger entity instance.
• Returns: BufferedAction if a valid target and action (EAT, PICKUP) is identified; otherwise nil.

StealFoodAction(inst)

• Description: Implements a priority-based foraging and stealing behavior. Scans nearby structures (within SEE_STRUCTURE_DIST) and categorizes them into priority tiers: cooking pots/stewers and drying racks/crops/honeyed structures (fridge/chest/backpack) take precedence over unprocessed food sources (beeboxes, mushroom farms, raw plants). Prioritizes honeyed items when possible, and returns appropriate actions (e.g., HARVEST, HAMMER, STEAL, PICK).
• Parameters:
  • inst: The Bearger entity instance.
• Returns: BufferedAction for the highest-priority food source found, or nil.

AttackHiveAction(inst)

• Description: Finds and targets a beehive within SEE_STRUCTURE_DIST that is targetable (combat:CanTarget) and on valid ground, returning an ATTACK buffered action.
• Parameters:
  • inst: The Bearger entity instance.
• Returns: BufferedAction(inst, hive, ACTIONS.ATTACK) if a valid hive is found; otherwise nil.

ShouldEatFoodFn(inst)

• Description: Predicate function that returns true if the Bearger is at or near a player base (i.e., has encountered 2 or more structure entities within SEE_STRUCTURE_DIST). Used by the behavior tree to enable eating/stealing prioritization when near bases.
• Parameters:
  • inst: The Bearger entity instance.
• Returns: true if inst.seenbase is true or base proximity condition is met during call; otherwise false.

GetHome(inst)

• Description: Returns the spawn point location during summer (via knownlocations:GetLocation("spawnpoint")); returns nil in other seasons. Used by Wander as the home point for movement.
• Parameters:
  • inst: The Bearger entity instance.
• Returns: Vector position of spawn point in summer, nil otherwise.

GetTargetDistance(inst)

• Description: Returns season-dependent movement distance via TUNING.BEARGER_SHORT_TRAVEL (summer) or TUNING.BEARGER_LONG_TRAVEL (autumn); returns 0 otherwise.
• Parameters:
  • inst: The Bearger entity instance.
• Returns: Numeric distance threshold for Wander behavior based on season.

GetWanderDirection(inst)

• Description: Returns the stored wander direction (angle in radians) from inst.wanderdirection.
• Parameters:
  • inst: The Bearger entity instance.
• Returns: Number (radian angle) or nil.

SetWanderDirection(inst, angle)

• Description: Stores the given angle (radians) in inst.wanderdirection.
• Parameters:
  • inst: The Bearger entity instance.
  • angle: Number (radian angle) to store.
• Returns: Nothing.

OceanDistanceTest(inst, target)

• Description: Determines the maximum range at which Bearger can attack a target, respecting boat/water obstacles and special conditions. Returns TUNING.BEARGER_ATTACK_RANGE - 0.25 if Bearger can reach the target from shore (using CanProbablyReachTargetFromShore) and target is not a beehive or while GroundPound timer is inactive; otherwise returns a large offset (OUTSIDE_CATAPULT_RANGE).
• Parameters:
  • inst: The Bearger entity instance.
  • target: Entity to test distance against.
• Returns: Numeric distance threshold (e.g., TUNING.BEARGER_ATTACK_RANGE - 0.25) or OUTSIDE_CATAPULT_RANGE.

InRamDistance(inst, target)

• Description: Predicate used to determine if the Bearger should initiate a charge/ram based on target proximity. Returns false if target is within 10 units (i.e., already in melee range); otherwise returns true for land targets, or for off-land targets (boats/water) if CanProbablyReachTargetFromShore allows approaching within attack range.
• Parameters:
  • inst: The Bearger entity instance.
  • target: Entity to test distance against.
• Returns: true if ram/charge is appropriate; false otherwise.

BeargerBrain:OnStart()

• Description: Initializes the behavior tree (self.bt) with a hierarchical priority node structure that governs Bearger’s behavior. The root handles non-busy states, with sub-priorities for panic (if not lunar-aligned), charging/ramming, combat, base-near behavior (eating/stealing), wander, and idle. Integrates custom DoAction nodes (EatFoodAction, StealFoodAction, AttackHiveAction) and behavioral utilities (ChaseAndAttack, ChaseAndRam, Wander, StandStill). Uses tuning parameters for chase duration, distance thresholds, and ocean reachability.
• Parameters: None (uses self.inst).
• Returns: Nothing.

BeargerBrain:OnInitializationComplete()

• Description: Registers the Bearger’s current position as "spawnpoint" in knownlocations, preserving it for seasonal use (e.g., return to spawn in summer).
• Parameters: None (uses self.inst).
• Returns: Nothing.

Events & Listeners

• Listens to: None.
• Pushes: None.

Note: This brain does not directly register event listeners or push events; it relies on stategraph transitions and the behavior tree for reaction to game state changes.