Playing Music and Sound

Nu exposes a very simple audio API via the World module -

        /// Get the currently playing song, if any.
        static member getCurrentSongOpt world = ...
            
        /// Get the currently playing song's position or 0.0.
        static member getCurrentSongPosition world = ...

        /// Get the master volume.
        static member getMasterAudioVolume world = ...

        /// Get the master sound volume.
        static member getMasterSoundVolume world = ...

        /// Get the master song volume.
        static member getMasterSongVolume world = ...

        /// Set the master volume.
        static member setMasterAudioVolume volume world = ...

        /// Set the master sound volume.
        static member setMasterSoundVolume volume world = ...

        /// Set the master song volume.
        static member setMasterSongVolume volume world = ...

        /// Send a message to the audio system to play a song.
        static member playSong fadeInTime fadeOutTime startTime volume song world = ...

        /// Send a message to the audio system to play a sound.
        static member playSound volume sound world = ...

        /// Send a message to the audio system to fade out any current song.
        static member fadeOutSong fadeOutTime world = ...

        /// Send a message to the audio system to stop a song.
        static member stopSong world = ...

You don't have to call the song playing functions manually if each screen has its own associated song (here, Assets.Gameplay.DeadBlazeSong) like BlazeVector does -

        override this.Content (_, _) =
            [...
             Content.screen<GameplayDispatcher> Simulants.Gameplay.Name (Dissolve (Constants.Dissolve.Default, Some Assets.Gameplay.DeadBlazeSong)) [] []
             ...]

The Content.screen function allows you to associate a particular song asset with the given screen such that it plays when that screen becomes actively, managing cross-fading and cross-screen song persistence for you.

When you wish to control the music on a particular screen yourself, you can simply pass None, then in a command hooked to the screen's Screen.IncomingStartEvent event, call World.playSong yourself.

Additionally, you can control the master volume via Nu's editor, Gaia, via the Audio Player tab like so -