Skip to main content

Deerbrain

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

Overview​

The deerbrain component defines the behavior tree logic for deer entities. It dynamically selects between two modes: herd-based behavior (e.g., staying near the herd location, grazing, responding to herd-wide alerts) and solo behavior (e.g., wandering, facing players, fleeing from attackers). The brain prioritizes threat responses (panic, combat threats) over movement and idle behaviors, and integrates with the global deerherding system to synchronize herd-wide alert states and movement goals.

Dependencies & Tags​

  • Components used:
    • combat: Checks HasTarget() and accesses target.
    • deerherding: Queries IsActiveInHerd(), IsGrazing(), SetHerdAlertTarget(), GetClosestHerdAlertTarget(), HerdHasAlertTarget(), and reads herdlocation.
    • hauntable: Reads panic property.
    • knownlocations: Calls GetLocation("herdoffset") to compute herd-relative positions.
  • Tags: None explicitly added/removed by this component.

Properties​

No public properties are defined in the constructor. The component operates solely through behavior node logic and external component interactions.

Main Functions​

The deerbrain does not define any public methods beyond the constructor. Its behavior is entirely driven by behavior tree nodes initialized in OnStart(). Helper functions used internally include:

ResetData(inst)​

  • Description: Initializes or updates the deer's herd alert target by finding the closest player within START_ALERT_DIST and registers it via deerherding:SetHerdAlertTarget(). Called once per behavior tree loop at the root level.
  • Parameters:
    • inst: The deer entity instance.
  • Returns: nil

GetAlertTargetFn(inst)​

  • Description: Returns the closest herd alert target (e.g., a player or predator flagged as a threat) as determined by deerherding:GetClosestHerdAlertTarget().
  • Parameters:
    • inst: The deer entity instance.
  • Returns: Inst or nil

KeepAlertTargetFn(inst, target)​

  • Description: Returns true if the herd has any active alert targets, allowing the FaceEntity node to continue facing toward threats.
  • Parameters:
    • inst: The deer entity instance.
    • target: The current alert target (unused).
  • Returns: boolean

GetNonHerdingFaceTargetFn(inst)​

  • Description: Locates the closest player within SOLO_START_FACE_DIST for solo-mode face behavior.
  • Parameters:
    • inst: The deer entity instance.
  • Returns: Inst or nil

KeepNonHerdingFaceTargetFn(inst, target)​

  • Description: Continues facing a player unless the target has the "notarget" tag or is beyond SOLO_KEEP_FACE_DIST.
  • Parameters:
    • inst: The deer entity instance.
    • target: The entity currently being faced.
  • Returns: boolean

GetWanderDistFn(inst)​

  • Description: Returns the constant wandering distance WANDER_DIST_DAY (10).
  • Parameters:
    • inst: The deer entity instance (unused).
  • Returns: number

GetLocationInHerd(inst)​

  • Description: Computes the herd's target position by summing the global deerherding.herdlocation vector and the herdoffset location stored in knownlocations.
  • Parameters:
    • inst: The deer entity instance.
  • Returns: Vector3 or nil if either location is unavailable.

GetGrazingLocation(inst)​

  • Description: Computes a grazing position offset farther from the herd center (herdlocation + herdoffset * 2) used during grazing sequences.
  • Parameters:
    • inst: The deer entity instance.
  • Returns: Vector3 or nil if locations are missing.

GetGrazingAngle(inst)​

  • Description: Computes a random facing angle centered on the herd offset's direction, with a variance of 66 * DEGREES.
  • Parameters:
    • inst: The deer entity instance.
  • Returns: number (angle in radians)

IsHerdGrazing(self)​

  • Description: Returns true if the global deerherding component is currently in a grazing state (uses IsGrazing()).
  • Parameters:
    • self: The behavior tree context table (contains self.inst).
  • Returns: boolean

GetRunAwayTarget(inst)​

  • Description: Returns the current combat target only if it is a valid player entity.
  • Parameters:
    • inst: The deer entity instance.
  • Returns: Inst or nil

ShouldMoveAsHerd(self)​

  • Description: Checks whether the deer should move toward the herd center: returns true if its squared distance to GetLocationInHerd() exceeds half of TUNING.DEER_HERD_MOVE_DIST.
  • Parameters:
    • self: The behavior tree context table (contains self.inst).
  • Returns: boolean

Events & Listeners​

The component does not register any event listeners or push events directly. It relies entirely on the behavior tree infrastructure to react to state changes and component updates (e.g., via WhileNode and FailIfSuccessDecorator).