DrawTexture.cs

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

[RequireComponent (typeof(AudioSource))]
//[RequireComponent (typeof(GUITexture))]
public class DrawTexture : MonoBehaviour
{


	public int width = 500;
	// texture width
	public int height = 100;
	// texture height
	public Color backgroundColor = Color.black;
	public Color32 waveformColor = Color.white;
	public int size = 2048;
	// size of sound segment displayed in texture

	private Color[] blank;
	// blank image array
	private Texture2D texture;
	private float[] samples;
	// audio samples array
	public RawImage rawImage;

	IEnumerator Start ()
	{ 

		// create the samples array 
		samples = new float[size]; 

		// create the texture and assign to the guiTexture: 
		texture = new Texture2D (width, height);

		rawImage.GetComponent<RawImage> ().texture = texture; 

		// create a 'blank screen' image 
		blank = new Color[width * height]; 

		for (int i = 0; i < blank.Length; i++) { 
			blank [i] = backgroundColor; 
		} 

		// refresh the display each 100mS 
		while (true) {
			GetCurWave (); 
			yield return new WaitForSeconds (0.1f); 
		} 
	}

	void GetCurWave ()
	{ 
		// clear the texture 
		texture.SetPixels (blank, 0); 

		// get samples from channel 0 (left) 
		GetComponent<AudioSource> ().GetOutputData (samples, 0); 

		// draw the waveform 
		for (int i = 0; i < size; i++) { 
			texture.SetPixel ((int)(width * i / size),
				(int)(height * (samples [i] + .1f) / .2f),
				waveformColor);
		} // upload to the graphics card 

		texture.Apply (); 
	}
}