Create Sine Wave Envelope in OnAudioFilterRead

Hi all, I'm trying to make a sine wave in OnAudioFilterRead() method to generate it using an equation a = sin((2 * phi * frequency * sample length) / sampling rate). But I have two problem with this,

1. How to limit the sine wave length and assign it to sample length?
2. How to implement an envelope so I can create a waveform with attack, decay, sustain, and release?

Below is simple code that I've implemented.

private void OnAudioFilterRead (float[] data, int channels) {

Code (CSharp):

1. private void OnAudioFilterRead (float[] data, int channels) {
2.         increment = (frequency * 2.0 * Mathf.PI ) / samplingFq;
3.        
4.         for (int i = 0; i < data.Length; i += channels) {
5.             phase         += increment;
6.             data[i]     = phase;
7.  
8.             if (channels == 2)                data[i + 1] = data[i];
9.             if (phase > (Mathf.PI * 2))        phase         = 0.0;
10.         }
11.        
12.     }

Thank you.

 

Anyone can help?

 

Have same questions. Did you ever figure this out?