AudioSource component collision on vessel gameObject

[HansAcker]

I was looking into an issue with the ShipEffects sound mod. On some launches, one of the sound effects would play the wrong clip (e.g. a decoupler sound) instead of the mod-provided sound. Additional logging showed that the first AudioSource component the mod attaches to a vessel's gameObject sometimes got its audio clip changed on launch.

"Using GameObject.GetComponent will return the first component that is found and the order is undefined." - So I *guess* KSP does GetComponent<AudioSource>() somewhere and re-uses the returned component for the vessel's launch sound effect. Does that sound like a plausible cause or am I missing something?

Here's a reduced variation of what ShipEffects does: It adds AudioSource(s) to the active vessel's gameObject and logs a line when its clip name changes.

Spoiler

using System;
using UnityEngine;
using KSP;

namespace AudioTest
{
	[KSPAddon(KSPAddon.Startup.Flight, false)]
	public class AudioTest : MonoBehaviour
	{
		AudioSource source1;
		String sourceName1 = null;

		void Start()
		{
			Vessel vessel = FlightGlobals.ActiveVessel;

			if (vessel != null)
			{
				source1 = vessel.gameObject.AddComponent<AudioSource>();
			}
		}

		void Update()
		{
			if (source1 != null && source1.clip?.name != sourceName1)
			{
				Debug.Log("AudioTest: source1 changed: " + source1.name + ":" + source1.clip?.name);
				sourceName1 = source1.clip?.name;
			}
		}
	}
}

 

 

 

Various engines cause the audio source to be changed on rollout from the VAB, e.g.:

[LOG] AudioTest: source1 changed: Thoroughbred:sound_rocket_hard

 

A tentative workaround is to create a sacrifical, unused AudioSource component but there's the "the order is undefined" of getComponent() to consider. It could as well pick a different component frorm the first one.

Should the mod create a new GameObject, attach it to the vessel and add the audio components to that child? Would that protect them from takeover and still play the sound? (I'll give it a try but didn't have time left to tests it right now)

Does it warrant a bug report?

 

 

 

Edited September 15, 2020 by HansAcker