SineInst.java

package vafusion.inst;
import jm.audio.io.*;
import jm.audio.synth.*;
import jm.music.data.Note;
import jm.audio.AudioObject;

/**
 * A basic additive synthesis jMusic instrument implementation
 * which implements envelope and volume control
 * @author Andrew Sorensen
 */

public final class SineInst extends jm.audio.Instrument{
	//----------------------------------------------
	// Attributes
	//----------------------------------------------
	
	/** The number of channels */
	private int channels;
	/** the sample rate passed to the instrument */
	private int sampleRate;
	/** The pitch in hertz of a fixed frequency oscillator */
	private float frequency = -1.0f;
	/** The bereak point values fo the amplitude envelope */
	private double[] envPoints;
    private SampleOut sout;

	//----------------------------------------------
	// Constructor
	//----------------------------------------------
	/**
	 * Basic default constructor that creates 
	 * a stereo signal at 44100 hz.
	 */
	public SineInst(){
	    this(44100, 2);
	}
    
    /**
	 * Basic default constructor to set an initial 
	 * sampling rate.
	 * @param sampleRate 
	 */
	public SineInst(int sampleRate){
	    this(sampleRate, 2);
	}
    
	/**
	 * A constructor to set an initial 
	 * sampling rate and number of channels.
	 * @param sampleRate
     * @param channels the number of channels in the sound 1 = mono, 2 = stereo, etc
	 */
	public SineInst(int sampleRate, int channels){
		this(sampleRate, channels, new double[] {
                                            0.0, 0.0, 
                                            0.15, 1.0, 
                                            0.3, 0.5, 
                                            1.0, 0.0});
	}
    
	/**
	* A constructor to set sampleRate, channels, and 
	* the pitch of the sine wave in hertz.
	* @param sampleRate
	* @param channels the number of channels in the sound 1 = mono, 2 = stereo, etc
	* @param points The bereak point values fo the amplitude envelope
	*/
	public SineInst(int sampleRate, int channels, double[] points){
		this(sampleRate, channels, points, -1.0f);
	}

	/**
	* A constructor to set sampleRate, channels, and 
	* the pitch of the sine wave in hertz.
	* @param sampleRate
	* @param channels the number of channels in the sound 1 = mono, 2 = stereo, etc
	* @param points The bereak point values fo the amplitude envelope
	* @param frequency a positive float value specifying a fixed pitch
	*/
	public SineInst(int sampleRate, int channels, double[] points, float frequency){
		this.sampleRate = sampleRate;
		this.channels = channels;
		this.frequency = frequency;               
		this.envPoints = points;
	}
                
	//----------------------------------------------
	// Methods 
	//----------------------------------------------
	/**
	* Specify a fixed frequency oscillator.
	* @param The frequency in hertz
	*/
	public void setFrequency(float freq) {
		this.frequency = freq;
	}
        
        /**
        * Specify a particular envelope.
        * @param newValues The array of time percent, amplitude pairs of double values.
        */
        public void setEnvPoints(double[] newValues) {
            this.envPoints = newValues;
        }
	
	/**
	 * Initialisation method used to build the objects that
	 * this instrument will use.
	 */
	@Override
	public void createChain(){
		Oscillator osc = new Oscillator(this, Oscillator.SINE_WAVE, this.sampleRate, this.channels);
		// set a fixed, rather the note determined, frequency
		if (frequency != -1.0f) { 
			osc.setChoice(0);
			osc.setFrq(frequency);
		}
		Envelope env = new Envelope(osc, envPoints);
		Volume vol = new Volume(env);
		StereoPan span = new StereoPan(vol);
		if(output == RENDER) sout = new SampleOut(span);
	}	
}