Sine.java

package jass.generators;
import jass.engine.*;

/**
   Output sine wave. (Highly inefficient implementation.)
   @author Kees van den Doel (kvdoel@cs.ubc.ca)
*/

public class Sine extends Out {
    /** Sampling rate in Hertz of Out. */
    public float srate;

    /** Amplitude or volume of sine */
    protected float volume = 1;

    /** Current phase */
    protected float phase = 0;

    /** Freq. in Hertz */
    protected float freq = 440;
    private float oldFreq = freq;
    
    public static final float TWOPI = (float)(2*Math.PI);
    
    public Sine(float srate,int bufferSize) {
        super(bufferSize);
        this.srate = srate;
    }

    /** Set amplitude
        @param val Volume.
    */
    public void setVolume(float val) {
        volume = val;
    }

    /** Set frequency
        @param f frequency.
    */
    public void setFrequency(float f) {
        freq = f;
    }
    
    protected void computeBuffer() {
        int bufsz = getBufferSize();
        float fact = (freq-oldFreq)/(bufsz-1);
        float f;
        for(int i=0;i<bufsz;i++) {
            f = oldFreq + fact*i;
            phase += (float)(TWOPI*f/srate);
            buf[i] = (float) (volume * Math.sin((double)phase));
        }
        while(phase > TWOPI) {
            phase -= TWOPI;
        }

        oldFreq = freq;
    }
    
}