Unity——炫酷的音频可视化

public void GetSpectrumData(float[] samples, int channel, FFTWindow window);

这是AudioSoucre类型的方法，获取频谱数据；

• samples:采样率，就是说采集多长一段的频谱，必须为2^n，但是最小64，最大8192。

• channel:信道，默认0

• window:采样方式(Enum)，有下列几种

  Rectangular W[n] = 1.0.
  Triangle W[n] = TRI(2n/N).
  Hamming W[n] = 0.54 - (0.46 * COS(n/N) ).
  Hanning W[n] = 0.5 * (1.0 - COS(n/N) ).
  Blackman W[n] = 0.42 - (0.5 * COS(n/N) ) + (0.08 * COS(2.0 * n/N) ).
  BlackmanHarris W[n] = 0.35875 - (0.48829 * COS(1.0 * n/N)) + (0.14128 * COS(2.0 * n/N)) - (0.01168 * COS(3.0 * n/N)).

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22050HZ的频率分在几个范围：（从小到大声音越来越尖锐）

20~60:
60~250:
250~500:
500~2000:
2000~4000:
4000~6000:
6000~20000:

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22050采样512个数据，一个sample 43hz；

分成8段：

0： 2      86hz
1： 4      172hz
2： 8      344hz
3： 16    688hz
4： 32    1376hz
5： 64    2752hz
6： 128  5504hz
7： 256  11008hz

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Unity中新建一个类，AudioVisable

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

[RequireComponent(typeof(AudioSource))]
public class AudioVisable : MonoBehaviour {
    AudioSource audioSource;
    public  float[] samples = new float[512];
      float[] freqBand = new float[8];
      float[] bandBuffer = new float[8];
    float[] bufferDecrease = new float[8];

    float[] _freqBandHighest = new float[8];
    public static float[] _audioBand = new float[8];
    public static float[] _audioBandBuffer = new float[8];

    public static float _Amplitude, _AmplitudeBuffer;
    float _AmplitudeHighest;
	void Start () {
        audioSource = GetComponent<AudioSource>();
	}
	
    void CreateAudioBands()
    {
        for (int i = 0; i < 8; i++)
        {
            if (freqBand[i] > _freqBandHighest[i])
            {
                _freqBandHighest[i] = freqBand[i];
            }
            _audioBand[i] = (freqBand[i]/_freqBandHighest[i]);
            _audioBandBuffer[i] = (bandBuffer[i]/_freqBandHighest[i]);
        }
    }

	void Update () {
        GetSpectrumAduioSource();
        MakeFrequencyBands();
        BandBuffer();
        CreateAudioBands();
        GetAmplitude();
    }
    void GetAmplitude()
    {
        float _CurrentAmplitude = 0;
        float _CurrentAmplitudeBuffer = 0;
        for (int i = 0; i < 8; i++)
        {
            _CurrentAmplitude += _audioBand[i];
            _CurrentAmplitudeBuffer += _audioBandBuffer[i];
        }
        if (_CurrentAmplitude > _AmplitudeHighest)
            _AmplitudeHighest = _CurrentAmplitude;
        _Amplitude = _CurrentAmplitude / _AmplitudeHighest;
        _AmplitudeBuffer = _CurrentAmplitudeBuffer / _AmplitudeHighest;
    }
    void GetSpectrumAduioSource()
    {
        audioSource.GetSpectrumData(samples, 0, FFTWindow.Blackman);
    }
    void MakeFrequencyBands()
    {
        int count = 0;
        for (int i = 0; i < 8; i++)
        {
            float average = 0;
            int sampleCount = (int)Mathf.Pow(2,i+1);
            if (i == 7)
            {
                sampleCount += 2;
            }
            for (int j = 0; j < sampleCount; j++)
            {
                average += samples[count]*(count+1);
                count++;
            }
            average /= count;
            freqBand[i] = average * 10;
        }
    }

    void BandBuffer()
    {
        for (int i = 0; i < 8; i++)
        {
            if (freqBand[i] > bandBuffer[i])
            {
                bandBuffer[i] = freqBand[i];
                bufferDecrease[i] = 0.005f;
            }
            if (freqBand[i] < bandBuffer[i])
            {
                bandBuffer[i] -= bufferDecrease[i];
                bufferDecrease[i] *= 1.2f;
            }
        }
    }
}

这个脚本挂在Camera上，可以看到采样的数据的变化；

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Unity中，新建一个cube预制体开启，使用standard材质，打开hdr的外发光emission；

再新建一个脚本ParamCube，挂在cube预制体上；

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

public class ParamCube : MonoBehaviour {

    public int band;
    public float startScale, scaleMultiplier;

    Material material;
	void Start () {
        material = GetComponent<MeshRenderer>().materials[0];
	}
	
	// Update is called once per frame
	void Update () {
    
            transform.localScale = new Vector3(transform.localScale.x, (AudioVisable._audioBandBuffer[band]) * scaleMultiplier + startScale, transform.localScale.z);
            Color color = new Color(AudioVisable._audioBandBuffer[band], AudioVisable._audioBandBuffer[band], AudioVisable._audioBandBuffer[band]);
            material.SetColor("_EmissionColor",color);      
    }
}

然后在Scene中放8个cube预制体，把脚本中StartScale和scaleMultiplier调为1和10，band为0~7；

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最后，在Camera的AudioSource组件上添加音频，运行~

参考：
国外Youtube上的大神，链接如下：
https://www.youtube.com/playlist?list=PL3POsQzaCw53p2tA6AWf7_AWgplskR0Vo