AudioSettings.dspTime

描述

返回音频系统的当前时间。

这是一个以秒为单位指定的值，它基于音频系统处理的实际样本数，因此比通过 Time.time 属性获得的时间精确得多。

using UnityEngine;
using System.Collections;

// The code example shows how to implement a metronome that procedurally generates the click sounds via the OnAudioFilterRead callback.
// While the game is paused or suspended, this time will not be updated and sounds playing will be paused. Therefore developers of music scheduling routines do not have to do any rescheduling after the app is unpaused

[RequireComponent(typeof(AudioSource))]
public class ExampleClass : MonoBehaviour
{
    public double bpm = 140.0F;
    public float gain = 0.5F;
    public int signatureHi = 4;
    public int signatureLo = 4;
    private double nextTick = 0.0F;
    private float amp = 0.0F;
    private float phase = 0.0F;
    private double sampleRate = 0.0F;
    private int accent;
    private bool running = false;
    void Start()
    {
        accent = signatureHi;
        double startTick = AudioSettings.dspTime;
        sampleRate = AudioSettings.outputSampleRate;
        nextTick = startTick * sampleRate;
        running = true;
    }

    void OnAudioFilterRead(float[] data, int channels)
    {
        if (!running)
            return;

        double samplesPerTick = sampleRate * 60.0F / bpm * 4.0F / signatureLo;
        double sample = AudioSettings.dspTime * sampleRate;
        int dataLen = data.Length / channels;
        int n = 0;
        while (n < dataLen)
        {
            float x = gain * amp * Mathf.Sin(phase);
            int i = 0;
            while (i < channels)
            {
                data[n * channels + i] += x;
                i++;
            }
            while (sample + n >= nextTick)
            {
                nextTick += samplesPerTick;
                amp = 1.0F;
                if (++accent > signatureHi)
                {
                    accent = 1;
                    amp *= 2.0F;
                }
                Debug.Log("Tick: " + accent + "/" + signatureHi);
            }
            phase += amp * 0.3F;
            amp *= 0.993F;
            n++;
        }
    }
}