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Centipedebrain

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

Overview​

This brain component defines the AI behavior for the centipede entity. It uses a priority-based behavioral tree (BT) to coordinate high-priority actions such as panic, rolling attacks, combat engagement with a maximum chase duration, evasion (dodging) during cooldowns, homing to a designated home location, and following a leader when assigned. It integrates with components like combat, follower, and knownlocations to make contextual decisions, and relies heavily on predefined behaviors (ChaseAndAttack, RunAway, Follow, FaceEntity, StandStill) imported via the behaviours directory and BrainCommon.

The brain prioritizes reactive responses (e.g., panic, dodging) over exploratory behaviors (e.g., homing, following), ensuring combat stability and survival.

Dependencies & Tags​

  • Components used:
    • combat: accessed via inst.components.combat.target, inst.components.combat:InCooldown()
    • follower: accessed via inst.components.follower:GetLeader()
    • knownlocations: accessed via inst.components.knownlocations:GetLocation("home")
  • Tags:
    • "notarget": checked via target:HasTag("notarget") to invalidate potential targets.
  • External behavior modules used: standstill, runaway, doaction, follow, braincommon.

Properties​

No public properties are declared in the constructor. The component relies on inst (the entity) and behavioral tree (self.bt) stored on self, as per DST brain conventions.

Main Functions​

CentipedeBrain:OnStart()​

  • Description: Initializes and assigns the behavioral tree root node to self.bt. This function is called when the brain becomes active (typically on state graph start or entity spawn). It constructs a hierarchical priority tree that dictates the centipede's behavior in response to internal conditions and external stimuli (e.g., presence of a target, cooldown status, distance to home).
  • Parameters: None.
  • Returns: nil.

GoHomeAction(inst)​

  • Description: A factory function returning a BufferedAction that walks the centipede to its stored home location. Returns nil if the centipede currently has a combat target or if no home location is defined.
  • Parameters:
    • inst: The centipede entity instance.
  • Returns: A BufferedAction or nil.

GetFaceTargetFn(inst)​

  • Description: Finds the closest player within START_FACE_DIST (6 units) who does not have the "notarget" tag. Used by FaceEntity to determine a target to maintain orientation toward.
  • Parameters:
    • inst: The centipede entity instance.
  • Returns: A valid player entity or nil.

KeepFaceTargetFn(inst, target)​

  • Description: Determines whether the centipede should continue facing a given target. It evaluates whether the target still exists and is within KEEP_FACE_DIST (8 units), and lacks the "notarget" tag.
  • Parameters:
    • inst: The centipede entity instance.
    • target: The entity currently being faced.
  • Returns: true if the target should still be faced, false otherwise.

ShouldGoHome(inst)​

  • Description: Checks if the centipede should initiate movement toward its home location. Returns false if the centipede has a valid leader (via follower component); otherwise, checks if the centipede is farther than GO_HOME_DIST (1 unit) from its home location.
  • Parameters:
    • inst: The centipede entity instance.
  • Returns: true if the centipede should go home, false otherwise.

ShouldRoll(inst)​

  • Description: Conditionally triggers a "rollattack" event if the centipede has a target and is farther than CHARGE_RANGE (10 units) away from it. Intended to initiate a charge/roll maneuver for closing distance.
  • Parameters:
    • inst: The centipede entity instance.
  • Returns: nil (side-effect only: pushes "rollattack" event).

GetRunAwayTarget(inst)​

  • Description: Returns the current combat target as the source of danger that should be evaded.
  • Parameters:
    • inst: The centipede entity instance.
  • Returns: The combat target entity (or nil), passed to the RunAway behavior.

Events & Listeners​

  • Pushes:

    • "rollattack": Triggered by ShouldRoll when the centipede begins a charge attack phase. Used by the state graph to transition into the "charge" state.

  • Listens to:

    • None explicitly registered in this file (event-driven reactions are handled by the behaviors referenced in the behavioral tree, e.g., ChaseAndAttack, RunAway internally manage state changes).
Note: `inst.sg:HasStateTag("charge")` is used internally to conditionally disable the main priority tree while the centipede is in the charge state. This indicates tight coupling with the state graph (SGcentipede) but no explicit event registration occurs in this brain file.