QuenchableModalObjectWithOneContact.java

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

/** Vibration model of object, capable of playing sound.
    Extended to keep track of current excitation and capable of modes being turned
    on/off.
    @author Kees van den Doel (kvdoel@cs.ubc.ca)
*/
public class QuenchableModalObjectWithOneContact extends ModalObjectWithOneContact {
    /** True for the modes that are on */
    protected boolean[] onBit;
    
    /** Create and initialize, but don't set any modal parameters.
        @param srate sampling rate in Hertz.
        @param nf number of modes.
        @param np number of locations.
        @param bufferSize Buffer size used for real-time rendering.
    */
    public QuenchableModalObjectWithOneContact(float srate,int nf,int np,int bufferSize) {
        super(srate,nf,np,bufferSize);
        allocateonBit(nf);
    }

    /** Create and initialize with provided modal data.
        @param m modal model to load.
        @param srate sampling rate in Hertz.
        @param bufferSize Buffer size used for real-time rendering.
    */
    public QuenchableModalObjectWithOneContact(ModalModel m,float srate,int bufferSize) {
        super(m,srate,bufferSize);
        allocateonBit(m.nf);
    }

    /**
       Allocate and turn on modes
     */
    private void allocateonBit(int nf) {
        onBit = new boolean[nf];
        for(int i=0;i<nf;i++) {
            onBit[i] = true;
        }
    }

    /**
       Turn mode on/off.
       @param mode mode number
       @param on true if turn on, fals if turn off
     */
    public void setOnBit(int mode,boolean on) {
        if(on) {
            onBit[mode] = true;
        } else {
            if(onBit[mode]) {
                onBit[mode] = false;
                yt_1[mode] = yt_2[mode] = 0;
            } // else was off already
        }
    }
           
    /** Return current excitation of mode. Approximated as (y(t)^2 + (dy/dt)^2/(2pif)^2)/2).
        A pulse excitation of strength x  should produce excitation of (ax)^2/2, with "a"
        gain of mode.
        @param k mode number
        @return excitation
     */
    public float getModeExcitation(int k) {
        double y2term = yt_1[k]*yt_1[k];
        double dy2term = (yt_1[k] - yt_2[k])*srate/(6.2831853*modalModel.fscale*modalModel.f[k]);
        dy2term *= dy2term;
        return (float)((y2term + dy2term)/2);
    }

        
    /** Apply external force[] and compute response through bank of modal filters.
        As in super class but skip off modes.
        @param output user provided output buffer.
        @param force input force.
        @param nsamples number of samples to compute.
    */
    protected void computeModalFilterBank(float[] output, float[] force, int nsamples) {
        boolean isnul = true;
        for(int k=0;k<nsamples;k++) {
            output[k] = 0;
            if(Math.abs(force[k])>=eps) {
                isnul = false;
            }
        }
        int nf = modalModel.nfUsed;
        if(isnul) {
            for(int i=0;i<nf;i++) {
                if(Math.abs(yt_1[i]) >= eps || Math.abs(yt_2[i]) >= eps) {
                    isnul = false;
                    break;
                }
            }
        }
        if(isnul) {
            return;
        }

        for(int i=0;i<nf;i++) {
            if(onBit[i]) {
                float tmp_twoRCosTheta = twoRCosTheta[i];
                float tmp_R2 = R2[i];
                float tmp_a = ampR[i];
                float tmp_yt_1 = yt_1[i];
                float tmp_yt_2 = yt_2[i];
                for(int k=0;k<nsamples;k++) {
                    float ynew = tmp_twoRCosTheta * tmp_yt_1 -
                        tmp_R2 * tmp_yt_2 + tmp_a * force[k];
                    // commenting out the force[k] changes performance 650->718
                    tmp_yt_2 = tmp_yt_1;
                    tmp_yt_1 = ynew;
                    output[k] += ynew;
                }
                yt_1[i] = tmp_yt_1;
                yt_2[i] = tmp_yt_2;
            }
        }
    }


}