Berniebigbrain

Based on game build 714014 | Last updated: 2026-03-03

Overview

BernieBigBrain is an AI behavior tree implementation that controls Bernie (a bee companion) in DST. It dynamically selects a leader from eligible players (bernieowner tag) based on sanity thresholds, hot-headedness, or being "crazy" (e.g., under lunacy effects). It prioritizes combat when a valid target exists, otherwise follows the leader using walk/run logic depending on proximity, and deactivates when inactive for a period or after shrinking.

The component interacts with the combat component to track targets and combat timing, and uses sanity:GetPercent() to assess player sanity for leader selection.

Usage example

local inst = CreateEntity()
inst:AddComponent("brain")
inst.components.brain = require("brains/berniebigbrain")(inst)
inst:AddTag("bernieowner") -- for leader registration, though Bernie is the dependent entity
inst:ListenForEvent("onLeaderChanged", function(inst, data) print("New leader:", data.leader and data.leader:GetDebugName()) end)

Dependencies & tags

Components used: combat, sanity
Tags: Checks bernieowner on players; sets running state tag based on follow mode.

Properties

Property	Type	Default Value	Description
_leader	Entity?	nil	The current leader entity (a player with bernieowner tag).
_isincombat	boolean	false	Whether Bernie is currently in combat mode.

Main functions

OnStart()

• Description: Initializes and attaches the behavior tree. Registers an event listener for onremove to clear leader references. Constructs a priority-based behavior tree with states for deactivation, combat, walking/running follow, face leader, and wandering.
• Parameters: None.
• Returns: Nothing.

OnStop()

• Description: Cleans up event listeners and clears the leader reference when the AI is stopped (e.g., on entity removal or brain replacement).
• Parameters: None.
• Returns: Nothing.

Events & listeners

• Listens to:
  • onremove – triggers SetLeader(self, nil) to unregister from the leader's bigbernies collection.
• Pushes:
  • onLeaderChanged – fired internally via self.inst:onLeaderChanged(leader) when the leader is set (non-nil only).