MiasmaWatcher

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

Overview

MiasmaWatcher monitors whether an entity is inside a miasma cloud and manages the associated movement speed penalty. It integrates with the playervision, rider, and locomotor components to dynamically adjust speed based on vision state (goggle/ghost vision), mount status, and presence of miasma sources. It also applies/removes the miasmadebuff debuff on the entity.

This component is primarily used by player entities and relies on world-level events (miasmacloudexists) to detect miasma presence. When enabled, it adds/removes speed modifiers and event listeners as needed.

Usage example

local inst = ThePlayer
inst:AddComponent("miasmawatcher")
inst.components.miasmawatcher:SetMiasmaSpeedMultiplier(0.7)
inst.components.miasmawatcher:AddMiasmaSource("player_walking")
-- Later, remove the source when exiting miasma
inst.components.miasmawatcher:RemoveMiasmaSource("player_walking")

Dependencies & tags

Components used: locomotor, playervision, rider, player_classified (optional, for network sync), miasmamanager (via TheWorld events)
Tags: Adds debuff "miasmadebuff" when in miasma. No static tags are added/removed.

Properties

Property	Type	Default Value	Description
enabled	boolean	false	Whether miasma detection is active (true after ToggleMiasma(true)).
miasmaspeedmult	number	TUNING.MIASMA_SPEED_MOD	Speed multiplier applied when in miasma and not masked by vision/mount. Clamped to [0, 1].
hasmiasmasource	SourceModifierList	—	Tracks which sources currently indicate miasma presence (e.g., player movement, item effects).

Main functions

AddMiasmaSource(src)

• Description: Registers a source indicating the entity is in miasma. If this is the first source, applies miasmadebuff and updates speed.
• Parameters: src (string or hashable) — Unique identifier for the source of miasma presence (e.g., "player_walking", "item_effect").
• Returns: Nothing.

RemoveMiasmaSource(src)

• Description: Removes a miasma source. If this was the last source, removes miasmadebuff and resets speed.
• Parameters: src (string or hashable) — The source identifier previously passed to AddMiasmaSource.
• Returns: Nothing.

IsInMiasma()

• Description: Returns whether the entity is currently considered to be inside miasma (i.e., has at least one active miasma source).
• Parameters: None.
• Returns: boolean — true if any miasma source is active, false otherwise.

ToggleMiasma(active)

• Description: Enables or disables miasma detection globally for this entity. Activates/deactivates event listeners and speed modifier setup based on miasmaspeedmult.
• Parameters: active (boolean, default false) — Whether miasma tracking should be active.
• Returns: Nothing.

SetMiasmaSpeedMultiplier(mult)

• Description: Sets the speed penalty multiplier for miasma. Clamps value to [0, 1]. Updates listeners and speed only if enabled is true.
• Parameters: mult (number) — Speed multiplier (e.g., 0.7 for 70% speed). Values outside [0, 1] are clamped.
• Returns: Nothing.

UpdateMiasmaWalkSpeed()

• Description: Recalculates and applies/removes the external speed multiplier based on current miasma presence and state (e.g., goggle/ghost vision, riding status). Only affects speed if miasmaspeedmult < 1.
• Parameters: None.
• Returns: Nothing.

Events & listeners

• Listens to (world): miasmacloudexists — triggered by TheWorld to indicate miasma presence; calls ToggleMiasma(exists).
• Listens to (entity): gogglevision, ghostvision, mounted, dismounted — triggers UpdateMiasmaWalkSpeed when vision or mount status changes.
• Pushes: None directly. Indirectly affects debuff state via inst:AddDebuff("miasmadebuff") / inst:RemoveDebuff("miasmadebuff").