fungus/Assets/Fungus/Scripts/Interfaces/IMusicController.cs

// This code is part of the Fungus library (http://fungusgames.com) maintained by Chris Gregan (http://twitter.com/gofungus).
// It is released for free under the MIT open source license (https://github.com/snozbot/fungus/blob/master/LICENSE)

using UnityEngine;

namespace Fungus
{
    /// <summary>
    /// Music manager which provides basic music and sound effect functionality.
    /// Music playback persists across scene loads.
    /// </summary>
    public interface IMusicController
    {
        /// <summary>
        /// Plays game music using an audio clip.
        /// One music clip may be played at a time.
        /// </summary>
        void PlayMusic(AudioClip musicClip, bool loop, float fadeDuration, float atTime);

        /// <summary>
        /// Plays a sound effect once, at the specified volume.
        /// </summary>
        /// <param name="soundClip">The sound effect clip to play.</param>
        /// <param name="volume">The volume level of the sound effect.</param>
        void PlaySound(AudioClip soundClip, float volume);

        /// <summary>
        /// Shifts the game music pitch to required value over a period of time.
        /// </summary>
        /// <param name="pitch">The new music pitch value.</param>
        /// <param name="duration">The length of time in seconds needed to complete the pitch change.</param>
        /// <param name="onComplete">A delegate method to call when the pitch shift has completed.</param>
        void SetAudioPitch(float pitch, float duration, System.Action onComplete);

        /// <summary>
        /// Fades the game music volume to required level over a period of time.
        /// </summary>
        /// <param name="volume">The new music volume value [0..1]</param>
        /// <param name="duration">The length of time in seconds needed to complete the volume change.</param>
        /// <param name="onComplete">Delegate function to call when fade completes.</param>
        void SetAudioVolume(float volume, float duration, System.Action onComplete);

        /// <summary>
        /// Stops playing game music.
        /// </summary>
        void StopMusic();
    }
}