onRelease

Registers a function to be executed when the script is stopped. This is primarily used to clean up resources, stop sounds, or revert state changes before the script terminates.

Execution Reliability

While this function is called during normal script reloads and session exits, it will not be called if Assetto Corsa crashes or is closed abruptly via the task manager. You should not use this function for critical data saving.

Usage Patterns

Standard Callback

A simple function call when the script unloads.

ac.onRelease(function()
    ac.log("Script is shutting down")
end)

With Weak Reference

Pass an object to the callback. If the object is garbage collected before the script unloads, the callback will not run.

local myData = { id = 123 }

ac.onRelease(function(item)
    ac.log("Cleaning up for item ID: " .. item.id)
end, myData)

Description

The ac.onRelease function allows you to hook into the script lifecycle. When you save a file in your editor, CSP triggers a hot-reload which unloads the current script instance before starting the new one. This function is the designated place to reset any modifications made to the simulation, such as emissive materials or active UI elements.

If you provide an item as the second argument, CSP stores it with a weak reference. This ensures that the documentation doesn’t accidentally prevent the object from being garbage collected. If the object naturally leaves memory during script execution, the associated cleanup callback is automatically discarded.

Parameters

Parameter	Type	Required	Description
callback	function	Yes	The function to run on release. It receives the item as its first argument.
item	any	No	An optional object to pass to the callback, stored using a weak reference.

Examples

Material Cleanup

Ensuring a car mesh stops glowing when the script reloads or the session ends.

local meshes = ac.findMeshes("EXT_LIGHT_GLOW")
meshes:setMaterialProperty("ksEmissive", 1.0)

ac.onRelease(function()
    -- reset the emissive property so it doesn't stay stuck 'on'
    meshes:setMaterialProperty("ksEmissive", 0.0)
end)

Audio Disposal

Stopping an active audio event to prevent it from looping after the script unloads.

local sound = ac.AudioEvent("event:/cars/my_car/horn")
sound:start()

ac.onRelease(function()
    -- stop and dispose of the audio resource
    sound:dispose()
end)