test/Assets/PerfectWorld/Scripts/Sound/AudioManager.cs

using System.Collections;
using BrewMonster;
using UnityEngine;
using UnityEngine.Audio;

public class AudioManager : MonoBehaviour
{
    public static AudioManager Instance;

    public AudioSource bgmSource;

    [SerializeField] private AudioMixerGroup _bgmMixerGroup;
    [SerializeField] private AudioMixerGroup _ambienceMixerGroup;
    [SerializeField] private AudioMixerGroup _sfxMixerGroup;
    public AudioMixerGroup GetSfxMixerGroup => _sfxMixerGroup;
    private AudioSource _ambienceSource;

    void Awake()
    {
        if (Instance == null)
        {
            Instance = this;
            DontDestroyOnLoad(gameObject);
        }
        else
        {
            Destroy(gameObject);
            return;
        }

        DiscoverAudioSources();
    }

    private void DiscoverAudioSources()
    {
        var sources = GetComponents<AudioSource>();

        if (sources.Length > 0)
        {
            bgmSource = sources[0];
            if (_bgmMixerGroup != null)
                bgmSource.outputAudioMixerGroup = _bgmMixerGroup;
        }

        if (sources.Length > 1)
        {
            _ambienceSource = sources[1];
            if (_ambienceMixerGroup != null)
                _ambienceSource.outputAudioMixerGroup = _ambienceMixerGroup;
        }
    }

    // ── BGM ──────────────────────────────────────────────────────────────────

    public void PlayBGM(AudioClip clip, float fadeTime = 1f)
    {
        StartCoroutine(FadeInBGM(clip, fadeTime));
    }

    public void StopBGM(float fadeTime = 1f)
    {
        StartCoroutine(FadeOutBGM(fadeTime));
    }

    IEnumerator FadeInBGM(AudioClip clip, float fadeTime)
    {
        // BMLogger.LogError($"HoangDev: FadeInBGM fadeTime {fadeTime} clip: {clip.name}" );
        if (bgmSource.isPlaying)
            yield return StartCoroutine(FadeOutBGM(fadeTime));

        bgmSource.clip = clip;
        bgmSource.Play();

        float t = 0f;
        while (t < fadeTime)
        {
            t += Time.deltaTime;
            bgmSource.volume = Mathf.Lerp(0f, 1f, t / fadeTime);
            yield return null;
        }
        bgmSource.volume = 1f;
    }

    IEnumerator FadeOutBGM(float fadeTime)
    {
        float startVol = bgmSource.volume;
        float t = 0f;
        while (t < fadeTime)
        {
            t += Time.deltaTime;
            bgmSource.volume = Mathf.Lerp(startVol, 0f, t / fadeTime);
            yield return null;
        }
        bgmSource.volume = 0f;
        bgmSource.Stop();
    }

    // ── World music (BGM + ambience together) ────────────────────────────────

    public void PlayWorldMusic(AudioClip bgm, AudioClip ambience, float fadeTime = 1f)
    {
        if (bgm != null)
            StartCoroutine(FadeInBGM(bgm, fadeTime));

        if (ambience != null && _ambienceSource != null)
            StartCoroutine(FadeInAmbience(ambience, fadeTime));
    }

    public void StopWorldMusic(float fadeTime = 1f)
    {
        StopBGM(fadeTime);

        if (_ambienceSource != null && _ambienceSource.isPlaying)
            StartCoroutine(FadeOutAmbience(fadeTime));
    }

    // ── Ambience ─────────────────────────────────────────────────────────────

    IEnumerator FadeInAmbience(AudioClip clip, float fadeTime)
    {
        if (_ambienceSource.isPlaying)
            yield return StartCoroutine(FadeOutAmbience(fadeTime));

        _ambienceSource.clip = clip;
        _ambienceSource.loop = true;
        _ambienceSource.Play();

        float t = 0f;
        while (t < fadeTime)
        {
            t += Time.deltaTime;
            _ambienceSource.volume = Mathf.Lerp(0f, 1f, t / fadeTime);
            yield return null;
        }
        _ambienceSource.volume = 1f;
    }

    IEnumerator FadeOutAmbience(float fadeTime)
    {
        float startVol = _ambienceSource.volume;
        float t = 0f;
        while (t < fadeTime)
        {
            t += Time.deltaTime;
            _ambienceSource.volume = Mathf.Lerp(startVol, 0f, t / fadeTime);
            yield return null;
        }
        _ambienceSource.volume = 0f;
        _ambienceSource.Stop();
    }
}