class Sine
{
  private float freq, newFreq;
  private float amp;
  private float stepSize;
  private float step;
  
  Sine(float f, float a, float s)
  {
    freq = f;
    newFreq = freq;
    amp = a;
    stepSize = 1/s;
    step = 0;
  }
  
  void setFreq(float f)
  {
    newFreq = f;
  }
  
  boolean generate(AudioOutput ao)
  {
    float[] buff = new float[ao.buffer.length];
    boolean alert = generate(buff);
    arraycopy(buff, 0, ao.buffer2, ao.buffer.length, buff.length);
    arraycopy(buff, 0, ao.buffer, 0, buff.length);
    return alert;
  }
  
  boolean generate(float[] buff)
  {
    boolean alert = freq != newFreq;
    for ( int i = 0; i < buff.length; i++ )
    {
      buff[i] = amp*sin(freq*TWO_PI*step);
      if ( abs(freq-newFreq) < 0.1f ) freq = newFreq;
      else if ( freq < newFreq ) freq += 0.1f;
      else if ( freq > newFreq ) freq -= 0.1f;
      step += stepSize;
      if ( step > 1/freq ) step %= 1/freq;
    }
    return alert;
  }
}