How to access distanceAttenuationParameters for an SKAudioNode

Question

I have an SKAudioNode in my scene but the audio from it is not falling off with range as much as I would like (my scene is very large, and when this node is a very long way away it is still clearly audible. Reducing its volume will just then make it too quite when it is at close range - I need to change the fall-off in volume with range).

I can see from the documentation that the parameters I need to adjust are the distanceAttenuationParameters in AVAudioEnvironmentNode.

When I look at SKScene I can see that it has an audioEngine AVAudioEngine property that in turn exposes a mainMixerMode AVAudioMixer property. But in none of these places can I find a handle to an AVAudioEnvironmentNode.

So how can I access the parameters needed to make my node's audio behave correctly in a large scene?

Answer 1

You can find the AVAudioEnvironmentNode in the audioEngine's attachedNodes array. Here is an extension of the SKScene that adds a computed property to directly access it from any SKScene.

import Foundation
import SpriteKit
import AVFoundation

extension SKScene {
    
    var audioEnvironmentNode : AVAudioEnvironmentNode? {
        audioEngine.attachedNodes.first(where: {audioNode in
            audioNode is AVAudioEnvironmentNode
        }) as? AVAudioEnvironmentNode
    }
    
}

Example:

if let environmetNode = scene.audioEnvironmentNode {
    environmetNode.distanceAttenuationParameters.distanceAttenuationModel = .linear
    environmetNode.distanceAttenuationParameters.referenceDistance = 400
    environmetNode.distanceAttenuationParameters.maximumDistance = 1500
}