campfire/Assets/Scripts/AmbientSoundGenerator.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class AmbientSoundGenerator : MonoBehaviour {
    public GameObject AmbientSfxPrefab;
    public AmbientEffect[] Effects;
    public float Cooldown;

    [Header("Runtime values")]
    public float AmbientNoiseCooldown = 0f;
    public float Roll = 0f;

    private Transform World;

    private float[] CumulativeChances;
    private float TotalCumulativeChance;
    private int[] RollsSince;

    private void Awake() {
        World = GameObject.FindGameObjectWithTag("World").transform;
        CumulativeChances = new float[Effects.Length];
        TotalCumulativeChance = 0;
        for (int I = 0; I < Effects.Length; I++) {
            CumulativeChances[I] = TotalCumulativeChance;
            TotalCumulativeChance += Effects[I].Chance;
        }
        RollsSince = new int[Effects.Length];
    }

    private void Update() {
        AmbientNoiseCooldown -= Time.deltaTime;
        if (AmbientNoiseCooldown <= 0) {
            AmbientNoiseCooldown += Cooldown;

            Roll = Random.Range(0, TotalCumulativeChance);
            AmbientEffect Effect = null;
            for (int I = CumulativeChances.Length - 1; I >= 0; I--) {
                if (Roll >= CumulativeChances[I]) {
                    if (Effects[I].RollsSinceLast <= RollsSince[I]) {
                        Effect = Effects[I];
                        RollsSince[I] = -1;
                    } else {
                        Effect = Effects[0];
                    }
                    break;
                }
            }

            for (int I = 0; I < RollsSince.Length; I++) {
                RollsSince[I]++;
            }

            float Distance = Random.Range(Effect.MinDistance, Effect.MaxDistance);
            float Rads = Random.Range(0, 2 * Mathf.PI);
            Vector3 Offset = new Vector3(Mathf.Cos(Rads) * Distance, Random.Range(Effect.MinY, Effect.MaxY), Mathf.Sin(Rads) * Distance);
            GameObject Obj = Instantiate(AmbientSfxPrefab, transform.position + Offset, new Quaternion(), World);
            AudioSource Sfx = Obj.GetComponent<AudioSource>();
            if (Sfx != null && Effect.Clips.Length > 0) {
                Sfx.clip = Effect.Clips[Random.Range(0, Effect.Clips.Length)];
                Sfx.volume = Mathf.Sqrt(Random.Range(0.3f, 1f));
                Sfx.Play();
            }
        }
    }
}