Unity3D Particle System + Audio Source = 音乐可视化

很简单的东西，上代码：

using UnityEngine;
using System.Collections;

public class particle_ocean : MonoBehaviour {

    public ParticleSystem particleSystem;
    private ParticleSystem.Particle[] particlesArray;

    public int resolution = 256;

    public float spacing = 0.5f;

    public float noiseScale = 0.2f;
    public float[] heightScale;

    private float perlinNoiseAnimX = 0.01f;
    private float perlinNoiseAnimY = 0.01f;

    public Gradient colorGradient;

    public float[] heightToGoto;
    private float heightGotoSpeed = 20f;
    private float heightRestoreSpeed = 2f;

    public float heightGoToTime = 1f;
    public float heightRestoreTime = 0.1f;

    public float heightClampMax = 40f;
    public float heightClampMin = 4f;

    public float particleSampleRate = 0.05f;

    private int frameCount = 0;

    //Audio
    public AudioSource audio;
    private float[] spectrum;
    public int spectrumScale = 60000;

    void Awake() {
        Application.targetFrameRate = 60;
    }

    void Start() {
        particlesArray = new ParticleSystem.Particle[resolution * resolution];
        particleSystem.maxParticles = resolution * resolution;
        particleSystem.Emit(resolution * resolution);
        particleSystem.GetParticles(particlesArray);

        heightScale = new float[resolution];
        heightToGoto = new float[resolution];
        spectrum = new float[resolution];

        InvokeRepeating ("updateHeight", 0, particleSampleRate);

    }

    void Update() {
        for (int i = 0; i < resolution; i++) {
            for (int j = 0; j < resolution; j++) {
                float zPos = Mathf.PerlinNoise (i * noiseScale + perlinNoiseAnimX, j * noiseScale + perlinNoiseAnimY) * heightScale[j];
                particlesArray [i * resolution + j].color = colorGradient.Evaluate (zPos * 0.025f);
                particlesArray [i * resolution + j].position = new Vector3 (i * spacing, zPos, j * spacing);
            }
        }

        perlinNoiseAnimX += 0.01f;
        perlinNoiseAnimY += 0.01f;

        particleSystem.SetParticles (particlesArray, particlesArray.Length);

        gotoHeight ();
        restoreTo2();
    }

    void updateHeight(){

        audio.GetSpectrumData (spectrum, 0, FFTWindow.BlackmanHarris);

        for (int k = 0; k < resolution; k++) {

            heightToGoto[k] = spectrum [k] * spectrumScale ;

            heightToGoto[k] = Mathf.Clamp (heightToGoto[k], heightClampMin, heightClampMax);
        }

    }

    void gotoHeight() {

        for (int k = 0; k < resolution; k++) {
            heightScale[k] = Mathf.SmoothDamp(heightScale[k], heightToGoto[k], ref heightGotoSpeed, heightGoToTime);
        }

    }

    void restoreTo2() {

        for (int k = 0; k < resolution; k++) {
            heightScale[k] = Mathf.SmoothDamp(heightScale[k], 2f, ref heightRestoreSpeed, heightRestoreTime);
        }
    }
}