Pigbrain

Based on game build 722832 | Last updated: 2026-04-22

Overview

Pigbrain defines the complete AI behavior tree for pig NPCs in Don't Starve Together. It manages daily routines including following leaders, trading with players, finding food, combat responses, and special event participation (Year of the Beast contests, minigames). The brain prioritizes survival behaviors (panic, fleeing fire) over normal activities and adapts behavior based on day/night cycles and leader presence.

Usage example

local inst = SpawnPrefab("pigman")
local brain = require "brains/pigbrain"
RunBrain(inst, brain:new(inst))

-- Brain automatically handles:
-- Following assigned leaders
-- Trading when players approach with trade actions
-- Finding and eating food during day/night
-- Panicking from fire, monsters, or haunted entities
-- Participating in contest events when tagged

Dependencies & tags

External dependencies:

• behaviours/wander -- wandering behavior node
• behaviours/follow -- following leader behavior node
• behaviours/faceentity -- facing target entity node
• behaviours/chaseandattack -- combat chase and attack node
• behaviours/runaway -- fleeing behavior node
• behaviours/doaction -- action execution node
• behaviours/findlight -- light source seeking node
• behaviours/panic -- panic state behavior node
• behaviours/chattynode -- chatter dialog during behaviors
• behaviours/leash -- home leash constraint node
• brains/braincommon -- shared brain utility functions

Components used:

• trader -- checks IsTryingToTradeWithMe() for trade interactions
• inventory -- uses FindItem(), Has(), GetItemByName() for item management
• eater -- uses CanEat(), TimeSinceLastEating(), GetEdibleTags() for food logic
• edible -- checks foodtype property for diet restrictions
• follower -- uses GetLeader(), GetLoyaltyPercent() for leader following
• homeseeker -- uses GetHomePos(), home property for home location
• burnable -- checks IsBurning() for fire detection on home
• health -- checks takingfiredamage property for self-fire status
• combat -- uses HasTarget(), InCooldown(), TargetIs(), target for combat
• hauntable -- checks panic property for ghost haunting
• pinnable -- checks IsStuck() for rescuing stuck leaders
• minigame_spectator -- uses GetMinigame() for minigame participation
• minigame -- accesses gametype, watchdist_min, watchdist_target, watchdist_max
• timer -- uses TimerExists() for contest panic timer
• shelf -- checks itemonshelf, cantakeitem for shelf food access

Tags:

• outofreach -- excluded from food finding
• takeshelfitem -- identifies shelf items for food finding
• lightsource -- identifies light sources for night behavior
• player -- checked for trade and runaway behavior
• playerlight -- checked for safe light distance calculation
• pig -- checked for pig-vs-pig combat avoidance
• _combat -- checked for pig-vs-pig combat avoidance
• NPC_contestant -- enables contest behavior tree branch
• INLIMBO -- excluded from prize collection
• spider -- triggers runaway behavior at night
• minigame_participator -- triggers runaway during minigames
• burnt -- checked for valid home status

Properties

Property	Type	Default Value	Description
None			No properties are defined.

Main functions

OnStart()

• Description: Initializes the pig behavior tree with prioritized nodes for survival, daily routines, and special events. Builds a PriorityNode root with branches for panic states, combat, trading, leader rescue, contest participation, minigame watching, and day/night cycles.
• Parameters: None
• Returns: None
• Error states: Errors if self.inst is nil when accessing components (no nil guard on self.inst.components.X calls throughout the function).

Events & listeners

Not applicable — this brain file uses behavior tree nodes rather than direct event listeners. Events are handled through the behavior system (e.g., ChattyNode, Panic, RunAway nodes respond to entity state changes).