Heatrock

Based on game build 714014 | Last updated: 2026-03-05

Overview

The heatrock prefab represents the in-game Heat Rock item, which stores thermal energy and passively heats or cools its surroundings depending on its current temperature relative to the environment. It functions as a thermal buffer: absorbing ambient heat in warm conditions and releasing stored heat when cold (or vice versa for cooling). The behavior is implemented primarily via the temperature, heater, fueled, and inventoryitem components. Visual state, lighting, and scrapbook metadata are updated dynamically as temperature changes.

Usage example

local inst = Prefab("heatrock", fn)
inst:AddComponent("fueled")
inst:AddComponent("heater")
inst:AddComponent("temperature")
-- TemperatureChange will auto-trigger updates to visuals and heating behavior
inst:PushEvent("temperaturedelta", { hasrate = true })

Dependencies & tags

Components used: fueled, heater, temperature, inventoryitem, inspectable, tradable, light, soundemitter, animstate, transform, network
Tags added: heatrock, icebox_valid, bait, molebait, HASHEATER, FX (for light prefab)
Tags checked: pocketdimension_container, buried, INLIMBO (via temperature:IgnoreTags)

Properties

Property	Type	Default Value	Description
currentTempRange	number	0 (initialized to 3 on spawn)	Current temperature range index (1–5) corresponding to visual states
highTemp	number	nil	Stores the maximum recorded temperature if the rock reached HOT/HOTTEST states
lowTemp	number	nil	Stores the minimum recorded temperature if the rock reached FROZEN/COLD states
_light	Entity	SpawnPrefab("heatrocklight")	Reference to the attached light entity
_owners	table	{}	Map of owner entities (used for light parent tracking)
scrapbook_fueled_rate	number	TUNING.HEATROCK_NUMUSES	Scrapbook metadata: number of uses per fuel
scrapbook_fueled_uses	boolean	true	Scrapbook metadata: indicates fuel consumption on temperature shifts

Main functions

GetRangeForTemperature(temp, ambient)

• Description: Calculates which of five temperature bands the rock falls into, based on thresholds {-30, -10, 10, 30} relative to ambient.
• Parameters: temp (number) - current temperature of the rock; ambient (number) - current ambient temperature at location.
• Returns: number — an integer from 1 to 5, where 1 = FROZEN, 2 = COLD, 3 = NEUTRAL, 4 = WARM, 5 = HOT.
• Error states: None.

HeatFn(inst, observer)

• Description: Computes and sets the rock's thermal exchange behavior (endothermic/exothermic) and returns the effective temperature emitted to the environment.
• Parameters: inst (Entity) — the heat rock instance; observer (Entity, unused) — retained for API compatibility.
• Returns: number — one of { -10, 10, 25, 40, 60 } corresponding to the five temperature bands.
• Error states: None.

UpdateImages(inst, range)

• Description: Updates animations, image names, bloom effect, and light enable state based on the current temperature range.
• Parameters: inst (Entity) — the heat rock instance; range (number) — temperature band index (1–5).
• Returns: Nothing.
• Error states: If range == 5, enables bloom and light; otherwise, clears them.

TemperatureChange(inst, data)

• Description: Core update handler fired on temperaturedelta events. Adjusts light intensity, tracks min/max recorded temperatures, updates visuals, and consumes fuel if temperature shifts cross the NEUTRAL band.
• Parameters: inst (Entity) — the heat rock instance; data (table) — event data, optionally containing hasrate boolean.
• Returns: Nothing.
• Error states: Fuel is consumed only if hasrate == true and the temperature crosses into or out of the NEUTRAL band (range == 3) after recording extremes.

Events & listeners

• Listens to: temperaturedelta — triggers TemperatureChange to recompute heating behavior and visuals.
• Pushes: None directly, but interacts via component events:
  • onfueldsectionchanged, imagechange, onputininventory, ondropped, onremoveentity
• Subscribed events (via inst:ListenForEvent):
  • onputininventory, ondropped — handled by inst._onownerchange (alias for OnOwnerChange) to manage light parenting.