Impulse.java

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

/**
   Generate impulses with time intervals.
   @author Kees van den Doel (kvdoel@cs.ubc.ca)
*/
public class Impulse extends Out {

    /** time interval */
    protected float t_pulse = 1.0f;

    // dt in samples
    private int dt_samples;
    
    // current time
    private long sampleTime=0;

    // last sample time impulse was generated
    private long lastImpulseTime = 0;

    public float srate;

    protected float volume=1;
    
    /** Construct
        @param srate sampling rate in Hertz.
        @param bufferSize bufferSize of this Out
    */
    public Impulse(float srate,int bufferSize) {
        super(bufferSize);
        this.srate = srate;
        reset();
    }

    public void reset() {
        sampleTime = 0;
        lastImpulseTime = 0;
    }

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

    /** Set impulse period
        @param dt period
    */
    public void setPeriod(float dt) {
        t_pulse = dt;
        dt_samples = (int)(t_pulse*srate); 
    }

    /** Compute the next buffer.
     */
    public void computeBuffer() {
        int bufsz = getBufferSize();
        for(int k=0;k<bufsz;k++) {
            sampleTime++;
            if(sampleTime - lastImpulseTime > dt_samples) {
                lastImpulseTime = sampleTime;
                buf[k] = volume;
            } else {
                buf[k] = 0;
            }
        }
    }

}