How Do I Replay Oscillator With Envelope in AudioKit? - swift

Question

I have the player below that makes a short beep. However, "Player.shared.play()" only plays once for the first time.
I can't trigger it again on demand.
Any help would be appreciated.
import Foundation
import AudioKit
class Player {
static let shared = Player()
let osc = AKOscillator()
let env:AKAmplitudeEnvelope
var panner = AKPanner()
init() {
osc.amplitude = 0.3
env = AKAmplitudeEnvelope(osc)
env.attackDuration = 0.01
env.decayDuration = 0.01
env.sustainLevel = 0.0
env.releaseDuration = 0.01
panner = AKPanner(env)
AudioKit.output = panner
try! AudioKit.start()
osc.start()
env.start()
panner.start()
}
func play() {
osc.stop()
osc.start()
env.stop()
env.start()
}
}

Answer 1

#jl303,
For some reason, you have to add a delay between the starting and stopping of the oscillator and the envelope. I added it with a DispatchQueue delay like this:
func playOsc() {
osc.start()
env.start()
DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) { [unowned self] in
self.osc.stop()
self.env.stop()
}
}
Here's the revised Player class in context:
import Foundation
import AudioKit
class Player {
static let sharedInstance = Player()
let osc = AKOscillator()
let env: AKAmplitudeEnvelope
var panner = AKPanner()
init() {
AKSettings.bufferLength = .medium
AKSettings.playbackWhileMuted = true
do {
try AKSettings.setSession(category: .playAndRecord, with: [.defaultToSpeaker, .allowBluetooth, .mixWithOthers])
} catch {
AKLog("Could not set session category.")
}
osc.amplitude = 0.3
env = AKAmplitudeEnvelope(osc)
env.attackDuration = 0.01
env.decayDuration = 0.01
env.sustainLevel = 0.0
env.releaseDuration = 0.01
panner = AKPanner(env)
AudioKit.output = panner
try! AudioKit.start()
}
func playOsc() {
osc.start()
env.start()
DispatchQueue.main.asyncAfter(deadline: .now() + 0.05) { [unowned self] in
self.osc.stop()
self.env.stop()
}
}
}
Here's the ViewController to trigger the Oscillator sound on command:
import UIKit
class ViewController: UIViewController {
var player = Player.sharedInstance
#IBOutlet weak var oscPlayStopButton: UIButton!
override func viewDidLoad() {
super.viewDidLoad()
setUpButtonStyle()
}
fileprivate func setUpButtonStyle() {
oscPlayStopButton.layer.cornerRadius = 12.0
oscPlayStopButton.layer.borderColor = UIColor.systemBlue.cgColor
oscPlayStopButton.layer.borderWidth = 1.0
}
#IBAction func playOscAction(_ sender: UIButton) {
player.playOsc()
}
}
You can download the Xcode project here:
https://github.com/markjeschke/osc-player