SF_AnalogueChorus.java

/* For Copyright and License see LICENSE.txt and COPYING.txt in the root directory */
package com.nerdscentral.audio.time;

import java.util.ArrayList;
import java.util.List;

import com.nerdscentral.audio.core.SFConstants;
import com.nerdscentral.audio.core.SFData;
import com.nerdscentral.audio.core.SFSignal;
import com.nerdscentral.audio.pitch.algorithm.SFRBJFilter;
import com.nerdscentral.audio.pitch.algorithm.SFRBJFilter.FilterType;
import com.nerdscentral.sython.Caster;
import com.nerdscentral.sython.SFPL_Operator;
import com.nerdscentral.sython.SFPL_RuntimeException;

public class SF_AnalogueChorus implements SFPL_Operator
{

    private static final long serialVersionUID = 1L;

    @Override
    public String Word()
    {
        return Messages.getString("SF_AnalogueChorus.0"); //$NON-NLS-1$
    }

    private static double sat(double x)
    {
        double y = x >= 0 ? x / (x + 1) : x / (1 - x);
        return y;
    }

    @Override
    public Object Interpret(Object input) throws SFPL_RuntimeException
    {
        List<Object> lin = Caster.makeBunch(input);

        SFSignal inR = Caster.makeSFSignal(lin.get(0));
        SFSignal mod = Caster.makeSFSignal(lin.get(2));

        SFSignal in = SFData.realise(inR);
        double filt = 5000.0;
        if (lin.size() > 4)
        {
            filt = Caster.makeDouble(lin.get(5));
        }

        int delay = (int) ((Caster.makeDouble(lin.get(1))) * SFConstants.SAMPLE_RATE_MS);
        double feedBack = Caster.makeDouble(lin.get(3));
        double drive = Caster.makeDouble(lin.get(4));
        double r = in.getLength();
        double feedForward = 1.0 - feedBack;
        FilterType type = FilterType.LOWPASS;
        if (filt > 15000)
        {
            type = FilterType.ALLPASS;
            filt = 5000.0;
        }
        SFRBJFilter filter = new SFRBJFilter();
        filter.calc_filter_coeffs(type, filt, 1.0, 0);

        SFSignal buff = in.replicateEmpty();
        SFSignal outL = in.replicateEmpty();
        SFSignal outR = in.replicateEmpty();
        for (int n = 0; n < r; ++n)
        {
            buff.setSample(n, filter.filter(in.getSample(n)));
        }
        // reboot the filter
        filter = new SFRBJFilter();
        filter.calc_filter_coeffs(type, filt, 1.0, 0);
        for (int n = 0; n < r; ++n)
        {
            double mix = 0;
            int delayGet = n - delay - ((int) (mod.getSample(n) * SFConstants.SAMPLE_RATE_MS));
            if (delayGet < r && delayGet > -1)
            {
                mix = buff.getSample(delayGet);
            }
            double q = in.getSample(n);
            outL.setSample(n, (q + mix) / 2.0);
            outR.setSample(n, (q - mix) / 2.0);
            buff.setSample(n, drive * (buff.getSample(n) * feedForward + filter.filter(sat(mix)) * feedBack));
        }
        List<SFSignal> ret = new ArrayList<>(2);
        ret.add(outL);
        ret.add(outR);
        return ret;
    }
}