Singingshelltrigger

Overview

This component monitors the entity's surroundings for nearby entities tagged with "singingshell" (and not "INLIMBO") within a fixed range, and invokes a custom _activatefn callback on each newly detected shell. It automatically starts/stops its update loop in response to death and resurrection events, ensuring activation logic only runs while the entity is alive.

Dependencies & Tags

• Component Requirements: None (uses only built-in engine APIs like TheSim:FindEntities and component update infrastructure).
• Tags Added: "singingshelltrigger"
• Tags Removed on Remove: "singingshelltrigger"
• Listened Events: "death", "respawnfromghost"
• External Dependency Check: Verifies existence of TheWorld.components.singingshellmanager before starting updates.

Properties

Property	Type	Default Value	Description
trigger_range	number	4	Radius (in units) within which to scan for singing shells.
findentitiesfn	function	findentities (local closure)	Function used to locate entities matching shell criteria.
updating	boolean	false	Tracks whether the component’s OnUpdate is currently scheduled.
overlapping	table	{}	Tracks which entities are currently overlapping; keys are entity instances, values are true (first frame) or false (subsequent frames).

Main Functions

StartUpdating()

• Description: Begins invoking OnUpdate each game tick by registering the component with the entity’s update manager. Ensures idempotency by only starting if not already updating.
• Parameters: None.

StopUpdating()

• Description: Halts the OnUpdate loop by unregistering the component from the entity’s update manager. Prevents unnecessary processing when inactive (e.g., on death).
• Parameters: None.

OnUpdate()

• Description: Executes each tick while updating is true. Clears stale overlap tracking, then scans for nearby singing shells and invokes _activatefn(v, self.inst) on newly detected shells. Maintains overlap state to differentiate first-frame detection from continued presence.
• Parameters: None.

OnRemoveFromEntity()

• Description: Cleans up upon component removal: removes the "singingshelltrigger" tag, and unregisters death/resurrection event callbacks.
• Parameters: None.

Events & Listeners

• Listens to "death" → invokes ondeath(inst), which calls StopUpdating().
• Listens to "respawnfromghost" → invokes onresurrect(inst), which calls StartUpdating().