Graveguard Ghostbrain

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

Overview

The GraveGuardBrain component defines the behavior tree for the Graveguard ghost entity in Don't Starve Together. It orchestrates high-level behaviors such as following a target character, playing with other ghosts (e.g., Abigail), wandering near the ghost's home location, and eventually despawning after a full game cycle. It extends the base Brain class and constructs a BT (Behavior Tree) instance in OnStart, delegating movement and decision logic to external behavior nodes (Follow, Wander, Leash, StandStill, etc.). The brain interacts with key components: health (to verify targets are alive), knownlocations (to locate the "home" point), and timer (to enforce play cooldowns).

Dependencies & Tags

• Components used:
  • health — checks if targets are alive via IsDead()
  • knownlocations — retrieves the "home" location via GetLocation("home")
  • timer — checks for a "played_recently" timer via TimerExists("played_recently")
• Tags used in filtering:
  • PLAYMATE_NO_TAGS: {"abigail", "busy"}
  • PLAYMATE_ONEOF_TAGS: {"ghost"}
  • TARGET_CANT_TAGS: {"INLIMBO", "noauradamage"}
  • TARGET_ONEOF_TAGS: {"character", "hostile", "monster", "smallcreature"}

Properties

Property	Type	Default Value	Description
playfultarget	Entity	nil	Reference to the ghost currently being played with; set/cleared by FindPlaymate and PlayWithPlaymate.
followtarget	Entity	nil	The living target the ghost is currently following; updated by GetFollowTarget.
bt	BehaviorTree	nil	Behavior tree instance created in OnStart; stores the active root node.

Main Functions

GraveGuardBrain:OnStart()

• Description: Initializes the behavior tree for the ghost. Constructs a priority-weighted root node that evaluates in order: (1) follow a valid target, (2) despawn if requested, (3) play with another ghost if conditions allow, and (4) wander near home until timing out and despawning.
• Parameters: None.
• Returns: None.

FindPlaymate(self)

• Description: Determines whether the ghost can or should play with another ghost. Checks proximity to home, cooldown state (played_recently timer), and searches for a valid ghost within range using FindEntity. If a playmate is found and valid, it is stored in self.playfultarget.
• Parameters:
  • self (GraveGuardBrain): The brain instance.
• Returns: true if a valid playmate is found and selected; false otherwise.

PlayWithPlaymate(self)

• Description: Triggers a start_playwithghost event with the current playfultarget and clears the playmate reference. Used after the ghost has completed its playful interaction sequence.
• Parameters:
  • self (GraveGuardBrain): The brain instance.
• Returns: None.

IsAlive(target)

• Description: Helper function to verify if a target entity is alive and visible, used during target selection. Checks visibility, presence of a health component, and that the entity is not dead.
• Parameters:
  • target (Entity): The entity to evaluate.
• Returns: true if the target is visible, has a health component, and health:IsDead() is false; otherwise false.

GetFollowTarget(ghost)

• Description: Updates and returns the ghost's current follow target. Clears the stored target if it becomes invalid (e.g., dead, hidden, too far). If no valid target exists, it searches for the nearest living character within 10 units that satisfies _target_test (e.g., not an ally under PvP rules). Updates ghost.brain.followtarget as a side effect.
• Parameters:
  • ghost (Entity): The ghost entity whose brain is performing the search.
• Returns: Entity or nil — the selected follow target, or nil if none found.

Events & Listeners

• Pushes:
  • "start_playwithghost" — Fired by PlayWithPlaymate with payload {target=self.playfultarget} to signal a play interaction has started.