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Hermitcrabbrain

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

Overview​

The Hermitcrabbrain component implements the behavior tree (BT) for the Hermit Crab NPC. It governs all autonomous actions and reactions, including trading with players, harvesting resources (meat, berries), fishing, soaking in hot springs, sitting on chairs, managing weather gear (umbrella/coat), feeding critters via petleash, speaking at appropriate times, fleeing from aggressive targets, and returning home during night or dangerous conditions (e.g., burning homes). The behavior prioritizes high-level environmental state detection (day/night, rain/snow) and interacts with multiple components including inventory, npc_talker, petleash, locomotor, friendlevels, homeseeker, trader, timer, bathingpool, burnable, and health.

Dependencies & Tags​

  • Components used:

    • bathingpool (calls LeavePool)
    • burnable (calls IsBurning)
    • combat (calls TargetIs)
    • dryable, dryer, dryingrack, edible, equippable, friendlevels, health, hunger, inventory, locomotor, npc_talker, petleash, sanity, timer, trader
    • homeseeker (calls GetHomePos, uses home property)

  • Tags added/checked:

    • umbrella, lightsource, pickable, bush, hermitcrab_marker_fishing, oceanfish, oceanfishable, INLIMBO, cansit, uncomfortable_chair, fire, hermithotspring, bathbombable, critter, notarget, playerghost, busy, alert, mandatory, sitting, fishing_idle, talking, teleporting, soakin

Properties​

PropertyTypeDefault ValueDescription
tea_shopstable{}Map of currently active tea shops this hermit crab plans to visit.
selected_tea_shopEntity?nilReference to the currently selected tea shop to travel toward.

Main Functions​

HermitBrain:AddActiveTeaShop(teashop)​

  • Description: Registers a tea shop as active for this hermit crab. It is added to self.tea_shops and used later when selecting a destination.
  • Parameters:
    • teashop (Entity): The tea shop entity to add.
  • Returns: None.

HermitBrain:RemoveActiveTeaShop(teashop)​

  • Description: Removes a tea shop from the active set. If it was the selected shop, the locomotion is stopped and selected_tea_shop is cleared.
  • Parameters:
    • teashop (Entity): The tea shop entity to remove.
  • Returns: None.

HermitBrain:AnyActiveTeaShop()​

  • Description: Returns whether any tea shop is currently active.
  • Parameters: None.
  • Returns: boolean — true if at least one tea shop exists in tea_shops.

HermitBrain:GetFirstTeaShop()​

  • Description: Returns the first tea shop in tea_shops (or nil if none).
  • Parameters: None.
  • Returns: Entity? — First active tea shop or nil.

HermitBrain:ValidateTeaShops()​

  • Description: Filters out invalid tea shops (burnt, burning, or non-existent) from tea_shops and clears selected_tea_shop if it was invalid.
  • Parameters: None.
  • Returns: None.

HermitBrain:SelectTeaShop()​

  • Description: Validates tea shops, selects the first valid one, announces via NPC talker, and sets selected_tea_shop. Returns true on success.
  • Parameters: None.
  • Returns: boolean? — true if a valid tea shop was selected; nil otherwise.

HermitBrain:CheckSelectedTeaShop()​

  • Description: Verifies that the currently selected tea shop is still valid.
  • Parameters: None.
  • Returns: boolean — true if selected_tea_shop is valid.

HermitBrain:GetSelectedTeaShopPos()​

  • Description: Returns the world position of the selected tea shop, or nil if none is valid.
  • Parameters: None.
  • Returns: Vector3? — Position of tea shop or nil.

HermitBrain:GetSelectedTeaShop()​

  • Description: Returns the selected tea shop entity if valid, or nil.
  • Parameters: None.
  • Returns: Entity? — Selected tea shop or nil.

HermitBrain:OnStart()​

  • Description: Initializes the behavior tree root. Contains high-priority nodes for weather gear toggling, talk queue handling, tea shop navigation, critter feeding, trading, fleeing, soaking, and daily vs. nightly behavior sub-trees. Uses a PriorityNode to evaluate conditions in order of priority.
  • Parameters: None.
  • Returns: None. (Assigns self.bt.)

Helper Functions (Internal)​

IsTeaShopValid(teashop)​

  • Returns true if the tea shop is valid (exists, not burnt, not burning).

getfriendlevelspeech(inst, target)​

  • Constructs appropriate greeting text based on friendlevels.level. Applies custom logic for level 10 (player condition-based remarks). Uses npc_talker:Say or Chatter based on whether it’s chatter or full speech.

GetTraderFn(inst)​

  • Finds a nearby player attempting to trade within TRADE_DIST. Triggers a chatter line and updates timers (speak_time, complain_time). Returns the player entity.

KeepTraderFn(inst, target)​

  • Returns true if the target is still the same trader and not talking.

HasValidHome(inst)​

  • Verifies that homeseeker.home exists, is valid, not burning, and not burnt.

GetHomePos(inst)​

  • Returns home position using homeseeker:GetHomePos() if valid.

GetFaceTargetFn(inst)​

  • Finds the closest player within START_FACE_DIST. Triggers a greeting based on friendship level using getfriendlevelspeech. Returns the player if appropriate.

KeepFaceTargetFn(inst, target)​

  • Ensures face target remains valid and within range (KEEP_FACE_DIST).

DoCommentAction(inst)​

  • Handles action to move or speak at a pre-defined comment location (inst.comment_data).

DoFeedPetCritterAction(inst)​

  • Checks if any critter pet is hungry. If so, finds honey in inventory (spawns one if missing), then creates a BufferedAction to feed the hungry critter. Announces feeding using npc_talker.

CanWanderAtPoint(pos)​

  • Determines if wandering is permitted at a position: always true in day; in night, only if within range of a lightsource (to avoid being in the dark).

GetFirstHungryPetCritter(inst)​

  • Returns the first pet critter that is hungry, not on the ocean, and not in a blocked area.

GetFoodForCritter(inst)​

  • Tries to find honey in inventory; spawns one if not found.

DoChairSit(inst)​

  • Finds a valid sittable chair and creates BufferedAction to sit.

DoSoakin(inst)​

  • Checks for a valid hermithotspring that isn’t bath-bombed or depleted, and returns BufferedAction to SOAKIN.

ExitHotSpring(inst)​

  • Calls LeavePool on the bathing pool if currently soaking.

DoReel(inst)​

  • Returns buffered action to reel if currently hooked and idle.

DoHarvestMeat(inst)​

  • Harvests dried meat from drying racks or done dryers if CHEVO_marker is set.

DoHarvestBerries(inst)​

  • Picks a nearby pickable or bush if CHEVO_marker is set.

DoFishingAction(inst)​

  • Checks for fishing markers, finds the one with the most fish nearby, spawns and equips a rod if needed, and initiates ocean fishing.

DoBottleToss(inst)​

  • Tosses a messagebottle_throwable into the ocean near fishing markers, if no umbrella is equipped and not in a bad living area.

DoTalkQueue(inst)​

  • Advances NPC talk queue if not busy or talking.

DoThrow(inst)​

  • Pushes "tossitem" event if inst.itemstotoss is set.

runawaytest(inst)​

  • Determines whether to flee from players when friendlevels.level is low or unfriendly.

Events & Listeners​

Listens to​

None explicitly registered via inst:ListenForEvent. The brain responds to game events indirectly via stategraph state tags (e.g., busy, talking, soakin) and condition checks.

Pushes​

  • "setoverflow" (via inventory:Unequip)
  • "unequip" (via inventory:Unequip)
  • "setoverflow" (in EquipUmbrella, UnEquipUmbrella, EquipCoat, UnEquipBody)
  • "oceanfishing_stoppedfishing" (when fishing is interrupted to face player)
  • "hermitcrab_entered" (on tea shop entry)
  • "tossitem" (in DoThrow)
  • "locomote" (via locomotor:Stop)
  • "ms_leavebathingpool" (via bathingpool:LeavePool)