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Deergemmedbrain

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

Overview​

The DeerGemmedBrain component implements the behavior tree logic for deer entities under the influence of a keeper (e.g., Gemmed Deer). It manages movement relative to a keeper position, combat engagement rules (including release conditions), and panic/avoidance states. This brain is used when the deer is not fully enslaved (i.e., not a permanent slave) and must be guided or recalled when too far from the keeper. It interacts with the combat, entitytracker, health, and knownlocations components to determine target status, keeper presence, and position offsets.

The behavior tree prioritizes panic/avoidance over formation following, then alternates between forming near the keeper, chasing a target if combat conditions are met, and eventually unshackling if the keeper is lost long enough.

Dependencies & Tags​

  • Components used:
    • entitytracker: to retrieve the "keeper" entity (GetKeeper)
    • health: to check if the keeper is dead (IsDead)
    • knownlocations: to retrieve the "keeperoffset" position (GetKeeperOffset)
    • combat: to manage target (SetTarget, TargetIs)
  • Tags: None explicitly added, removed, or checked in this file.

Properties​

PropertyTypeDefault ValueDescription
_farfromkeeperbooleanfalseTracks whether the entity is currently beyond the "far" distance threshold from its keeper position.
_lostkeepertimenumber?nilTimestamp (game time) after which the entity should unshackle if the keeper remains missing. nil means not tracking loss yet.

Main Functions​

DeerGemmedBrain:OnStart()​

  • Description: Initializes and assigns the behavior tree (self.bt) for the entity. Constructs a priority-based behavior tree with multiple WhileNode conditions that define state transitions — such as panic, formation, chasing, far-from-keeper召回, combat reset, and unshackling. The root node has a priority threshold of 0.5.
  • Parameters: None.
  • Returns: nil. Assigns self.bt.

Helper Functions (Internal)​

GetKeeper(inst)​

  • Description: Retrieves the entity tagged as the "keeper" using entitytracker:GetEntity.
  • Parameters: inst — The entity instance.
  • Returns: Entity? — The keeper entity or nil.

GetKeeperPos(inst)​

  • Description: Returns the current world position of the keeper.
  • Parameters: inst — The entity instance.
  • Returns: Vector3? — The keeper's position or nil if the keeper is absent.

GetKeeperOffset(inst)​

  • Description: Retrieves the stored offset position for the keeper (used for formation alignment).
  • Parameters: inst — The entity instance.
  • Returns: Vector3? — The offset vector or nil.

GetSlavePos(inst)​

  • Description: Computes the target position for the entity (formation position) by adding the keeper offset to the keeper's position, if available.
  • Parameters: inst — The entity instance.
  • Returns: Vector3? — The target position or nil.

IsFarFromKeeper(self)​

  • Description: Computes whether the entity is beyond FAR_DIST_SQ (7 * 7 = 49) units squared from the slave position. Updates self._farfromkeeper and returns the result.
  • Parameters: self — The brain instance.
  • Returns: boolean — true if far, false otherwise.

GetFaceTargetFn(inst)​

  • Description: Returns the current combat target as the face target (used by FaceEntity behavior).
  • Parameters: inst — The entity instance.
  • Returns: Entity? — The combat target.

KeepFaceTargetFn(inst, target)​

  • Description: Checks whether the given target is still the current combat target.
  • Parameters:
    • inst — The entity instance.
    • target — The candidate target entity.
  • Returns: boolean — true if the target matches the combat target.

ShouldPanic(self)​

  • Description: Determines if the entity should panic due to magic avoidance or general panic triggers (via BrainCommon.ShouldTriggerPanic).
  • Parameters: self — The brain instance.
  • Returns: boolean — true if panic condition is met.

ShouldChase(self)​

  • Description: Determines whether the entity should break formation and chase. Logic:
    • If no keeper exists (not enslaved), always returns false (handled separately by ChaseAndAttack with MAX_CHASE_TIME).
    • If the keeper is unchained and dead, returns true.
    • If a combat target exists and is within attack range (TUNING.DEER_ATTACK_RANGE + target:GetPhysicsRadius(0)), returns true.
    • Otherwise, clears the combat target and returns false.
  • Parameters: self — The brain instance.
  • Returns: boolean — Whether the entity should chase.

ShouldResetCombat(self)​

  • Description: Resets the combat state when a keeper is present or starts tracking keeper loss timing. Returns true when the entity can safely disengage (e.g., after a delay if keeper lost).
  • Parameters: self — The brain instance.
  • Returns: boolean — true if combat should be reset.

ShouldUnshackle(self)​

  • Description: Returns true if the keeper loss timer has expired (_lostkeepertime < GetTime()), indicating the entity is ready to unshackle.
  • Parameters: self — The brain instance.
  • Returns: boolean — Whether the entity should unshackle.

Events & Listeners​

  • Pushes:

    • "unshackle" — Pushed when the unshackle behavior triggers; signals the entity should detach from keeper control.

  • Listens to: None explicitly registered in this file (inherited event handling from Brain base class or behaviors may exist but are not declared here).