Bullkelp Plant

Based on game build 714014 | Last updated: 2026-03-04

Overview

The bullkelp_plant prefab represents a harvestable underwater vegetation structure in DST. It consists of two nested entities: a visible above-water root part and an underwater leaf part (bullkelp_plant_leaves). It uses the pickable component to manage harvesting, regrowth, and visual feedback. When moved ashore (e.g., via player collision or physics), it detects the beached condition and spawns a bullkelp_root item before removing itself. This prefab is part of the game's environmental decoration and resource-gathering loop, tied to underwater ecology mechanics.

Usage example

This prefab is not typically instantiated directly by modders. Instead, it is loaded via the world generation system in oceanic biomes. When spawning manually for testing or custom content, use:

local plant = SpawnPrefab("bullkelp_plant")
if plant ~= nil then
    plant.Transform:SetPosition(x, y, z)
    -- Optional: adjust properties via components
    plant.components.pickable.protected_cycles = 3
end

Dependencies & tags

Components used: pickable, inspectable
Tags: Adds kelp and DECOR (to underwater leaf entity); checks withered during regrowth.
Prefabs spawned internally: kelp, bullkelp_root, bullkelp_plant_leaves

Properties

Property	Type	Default Value	Description
AnimState	AnimState component	—	Manages above-ground visuals; bank "bullkelp", build "bullkelp", plays "idle" animation by default.
underwater	Entity	SpawnPrefab("bullkelp_plant_leaves")	The nested underwater leaf entity; parented to inst.entity.
pickable	Pickable component	—	Attached via inst:AddComponent("pickable"); regrowth time from TUNING.BULLKELP_REGROW_TIME.
_checkgroundtask	Task	nil	Delayed task used to debounce ground-checking after collisions.

Main functions

CheckBeached(inst)

• Description: Periodically checks if the bullkelp has been moved ashore (e.g., via collision or external forces). If so, it immediately harvests the plant as if picked by TheWorld, spawns a bullkelp_root item at the location, and removes the plant.
• Parameters: inst (Entity) — the bullkelp plant instance.
• Returns: Nothing.
• Error states: Uses inst:GetCurrentPlatform() and TheWorld.Map:IsVisualGroundAtPoint(...) to detect beached state; safely handles missing pickable component.

OnCollide(inst, other)

• Description: Collision callback invoked when the plant collides with another entity. Defers beached detection to a staggered task (CheckBeached) to avoid excessive checks during physics resolution.
• Parameters:
  inst (Entity) — the bullkelp plant.
  other (Entity) — the colliding entity (unused in implementation).
• Returns: Nothing.

Events & listeners

• Listens to: Collision (via inst.Physics:SetCollisionCallback(OnCollide))
• Pushes:
  • picked — fired when pickable:Pick() is called (includes picker and loot in event data)
  • Internally, onpickedfn and onregenfn callbacks also trigger animation events (e.g., "picking", "grow").

Note: The prefab itself does not register explicit inst:ListenForEvent() handlers; events are handled via callback hooks on the pickable component (onpickedfn, onregenfn, makeemptyfn).