Skip to main content

Rocky

Based on game build 714014 | Last updated: 2026-03-07

Overview​

rocky.lua defines the Rocky prefab, a controllable NPC character in DST. It integrates multiple components to handle movement, health, combat, trading, sleep cycles, and dynamic scaling. Growth is influenced by time awake, acid rain, and haunt reactions. Key interactions include gaining loyalty from players by accepting Elemental food items and sharing combat aggro with nearby Rockies or shadowthrall-parasite-hosted characters.

Usage example​

local inst = TheWorld:SpawnPrefab("rocky")
if inst and TheWorld.ismastersim then
    inst.components.combat:SetDefaultDamage(150)
    inst.components.scaler:SetScale(1.2)
    inst.components.health:SetMaxHealth(200)
    inst.components.sleeper:WakeUp()
end

Dependencies & tags​

Components used: spawnfader, acidinfusible, combat, eater, follower, health, herdmember, inventory, inspectable, knownlocations, locomotor, lootdropper, scaler, sleeper, trader, hauntable
Tags added: rocky, character, animal, electricdamageimmune, trader, herdmember

Properties​

PropertyTypeDefault ValueDescription
colour_idxnumbermath.random(#colours)Index (1–2) of Rocky’s color variant; applied via AnimState:SetMultColour.
sizeupdatetaskTasknilPeriodic task tracking growth/shrinkage due to time awake or acid rain.
_target_sharing_testfunctionnilPredicate function used by combat:ShareTarget for non-parasite Rockies.

Main functions​

ShouldSleep(inst)​

  • Description: Determines if Rocky should fall asleep based on total time awake exceeding 2 * TOTAL_DAY_TIME.
  • Parameters: inst (Entity) — the Rocky entity.
  • Returns: true if Rocky is overdue for sleep, otherwise false.

ShouldWake(inst)​

  • Description: Determines if Rocky should wake up after sleeping for at least half a day.
  • Parameters: inst (Entity) — the Rocky entity.
  • Returns: true if sleep duration exceeds 0.5 * TOTAL_DAY_TIME, otherwise false.

OnAttacked(inst, data)​

  • Description: Handles incoming attacks by setting the attacker as Rocky’s target and sharing the target with nearby allies.
  • Parameters:
    inst (Entity) — Rocky entity.
    data (table) — event payload containing attacker.
  • Returns: Nothing.
  • Error states: Sharing depends on tags (shadowthrall_parasite_hosted) and follows different share rules: 10_hosts for parasite cases, 2_Rockies otherwise.

grow(inst, dt)​

  • Description: Increases Rocky’s scale toward TUNING.ROCKY_MAX_SCALE over time.
  • Parameters:
    inst (Entity) — Rocky entity.
    dt (number) — time delta (usually seconds).
  • Returns: true if scale increased; false if already at max scale.

on_size_update(inst, dt)​

  • Description: Main growth/shrinkage loop: shrinks during acid rain; otherwise grows gradually.
  • Parameters:
    inst (Entity) — Rocky entity.
    dt (number) — time delta.
  • Returns: Nothing.
  • Error states: Cancels sizeupdatetask if no further growth or shrinkage is needed.

applyscale(inst, scale)​

  • Description: Recalculates and applies stats (damage, speed, health) based on current scale.
  • Parameters:
    inst (Entity) — Rocky entity.
    scale (number) — current scale factor.
  • Returns: Nothing.

OnGrowthStateDirty(inst)​

  • Description: Re-queues sizeupdatetask to adjust growth/shrink rate in response to acid rain changes.
  • Parameters: inst (Entity) — Rocky entity.
  • Returns: Nothing.

ShouldAcceptItem(inst, item)​

  • Description: Predicate used by trader to decide if an item is tradeable.
  • Parameters:
    inst (Entity) — Rocky entity.
    item (Entity) — candidate item.
  • Returns: true if item is edible and of FOODTYPE.ELEMENTAL.

OnGetItemFromPlayer(inst, giver, item)​

  • Description: Handles successful item trades: grants loyalty, updates leader/follower relationship, may change target, and wakes Rocky.
  • Parameters:
    inst (Entity) — Rocky entity.
    giver (Entity) — player giving the item.
    item (Entity) — traded item.
  • Returns: Nothing.
  • Error states: Ignores trade if item isn’t Elemental or grand-owner is neither Rocky nor part of a matching stack.

OnRefuseItem(inst, item)​

  • Description: Handles rejected trade attempts by waking Rocky and pushing refuseitem.
  • Parameters:
    inst (Entity) — Rocky entity.
    item (Entity) — refused item.
  • Returns: Nothing.

CustomOnHaunt(inst, haunter)​

  • Description: Handles haunt reactions: with 25% chance, triggers growth and resets acid handling.
  • Parameters:
    inst (Entity) — Rocky entity.
    haunter (Entity) — haunter entity.
  • Returns: true if haunt succeeded; false otherwise.

Events & listeners​

  • Listens to: attacked — triggers OnAttacked to set/agro target and share.
  • Listens to: gainrainimmunity, loserainimmunity — triggers OnGrowthStateDirty to re-schedule growth/shrink updates.
  • Pushes: refuseitem — fired in OnRefuseItem when trade is denied.
  • Pushes: gainloyalty, startfollowing — dispatched by follower component internally during loyalty gain/follower join.