Play a sound effect in a C# game

dotnet tool install -g RecursiveAI.OneGame.Cli --version 1.15.2
onegame new chime && cd chime
rm -r art scenarios/*
curl -s --create-dirs -o data/chime.wav \
  https://recursiveai.org/onegame/sounds/chime.wav

using System;
using Chime;
using OneGame.Audio;
using OneGame.Host;
 
internal static class Program
{
    internal static int Main(string[] args)
    {
        // Open the speakers once, at startup. A headless run (onegame test, a replay)
        // records instead, so tests make no noise and can still check what played.
        bool headless = Array.IndexOf(args, "--headless") >= 0;
        AudioServiceOptions? options = headless ? new AudioServiceOptions { Capture = true } : null;
        using AudioService audio = AudioService.Create(options);
        return GameApp.Run(new ChimeGame(audio), args);
    }
}

using OneGame.Audio;
using OneGame.Core;
using OneGame.Host;
using OneGame.Platform;
using OneGame.UI;
 
namespace Chime;
 
/// <summary>A bell. The simulation counts rings and never plays sound.</summary>
[Entity]
public partial class Bell : Entity
{
    [Synced] public partial int Rings { get; private set; }
 
    [Command]
    public void Ring() => Rings++;
}
 
public sealed class ChimeGame(AudioService audio) : GameDefinition
{
    private Asset<Sound>? _chime;
    private Bell? _bell;
    private int _heard;
 
    public override string Name => "chime";
 
    public override void RegisterEntities(EntityRegistry registry) =>
        OneGame.Generated.Chime.EntityTypes.Register(registry);
 
    public override void Setup(World world) => world.Add(new Bell());
 
    public override void DefineActions(ActionMap actions) =>
        actions.Context("play", c =>
            c.Button("ring", Bind.Key(Key.Space), Bind.Pad(GamepadButton.South)));
 
    public override void OnEachFrame(GameInstance game)
    {
        // Decoded once and cached. In a Debug run, saving data/chime.wav swaps it in.
        _chime ??= game.Assets.LoadSound("data/chime.wav");
 
        var bell = (Bell)game.World.Entities[0];
        if (!ReferenceEquals(bell, _bell))
        {
            // A new world (a loaded save, a replay, the next test): old rings aren't news.
            (_bell, _heard) = (bell, bell.Rings);
        }
 
        if (game.Actions.Pressed("ring"))
        {
            bell.Send.Ring();
        }
 
        // Sound is output, like drawing: play it when the state changes,
        // so replays and every client hear the same.
        if (bell.Rings != _heard)
        {
            _heard = bell.Rings;
            audio.Play(_chime.Value, new PlayOptions
            {
                Bus = AudioBus.Sfx,
                Volume = 0.8f,
                Pitch = 1f + 0.06f * (_heard % 3),   // so repeats don't sound identical
            });
        }
    }
 
    public override void DefineScreens(ScreenSet screens) =>
        screens.Add("main", game => Ui
            .Label(() => $"Space rings the bell: {((Bell)game.World.Entities[0]).Rings}")
            .Padding(Length.Px(8))
            .TextColor(Color.White));
}

name: ring
description: Each press of ring plays the chime once.
steps:
  - step: 2
  - action: ring
  - step: 2
  - expect: { sound: { name: chime, count: 1 } }
  - action: ring
  - step: 2
  - action: ring
  - step: 2
expect:
  - sound: { name: chime, count: 3 }
  - state: { entity: Bell, property: Rings, equals: 3 }

onegame test

PASS ring (44 ms, tick 8, hash bdf10b7fc3c12c4d)
1 passed, 0 failed

audio.SetBusVolume(AudioBus.Sfx, 0.5f);      // effects at half volume
audio.SetBusMuted(AudioBus.Music, true);     // mute keeps the volume for later
audio.MasterVolume = 0.8f;
audio.Paused = true;                         // a pause menu: sounds hold where they are