SF_Granulate.java

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

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

import com.nerdscentral.audio.core.SFConstants;
import com.nerdscentral.audio.core.SFSignal;
import com.nerdscentral.audio.core.SFSingleTranslator;
import com.nerdscentral.sython.Caster;
import com.nerdscentral.sython.SFMaths;
import com.nerdscentral.sython.SFPL_Operator;
import com.nerdscentral.sython.SFPL_RuntimeException;

public class SF_Granulate implements SFPL_Operator
{
    class BaseTranslator extends SFSingleTranslator
    {

        @Override
        protected double getInputSample(int index)
        {
            if (index >= super.getLength()) return 0;
            return super.getInputSample(index);
        }

        final int start;
        final int rolloff;

        @Override
        public int getLength()
        {
            return rolloff * 2;
        }

        protected BaseTranslator(SFSignal input, int startIn, int rolloffIn)
        {
            super(input);
            start = startIn;
            rolloff = rolloffIn;
        }

        @Override
        public double getSample(int index)
        {
            if (index < rolloff)
            {
                return getInputSample(index);
            }
            double offset = rolloff * 2 - index;
            double attenue = offset / rolloff;
            return getInputSample(index) * attenue;
        }

    }

    class MiddleTranslator extends BaseTranslator
    {

        protected MiddleTranslator(SFSignal input, int startIn, int rolloffIn)
        {
            super(input, startIn, rolloffIn);
        }

        @Override
        public double getSample(int index)
        {
            int relIndex = index + start;
            if (index < rolloff)
            {
                double offset = index;
                double attenue = offset / rolloff;
                return getInputSample(relIndex) * attenue;
            }
            double offset = rolloff * 2 - index;
            double attenue = offset / rolloff;
            return getInputSample(relIndex) * attenue;
        }
    }

    class EndTranslator extends BaseTranslator
    {

        protected EndTranslator(SFSignal input, int startIn, int rolloffIn)
        {
            super(input, startIn, rolloffIn);
        }

        @Override
        public double getSample(int index)
        {
            int relIndex = index + start;
            if (index < rolloff)
            {
                double offset = index;
                double attenue = offset / rolloff;
                return getInputSample(relIndex) * attenue;
            }
            return getInputSample(relIndex);
        }
    }

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Override
    public Object Interpret(final Object input) throws SFPL_RuntimeException
    {
        List<Object> lin = Caster.makeBunch(input);
        SFSignal data = Caster.makeSFSignal(lin.get(0));

        int rollOffSamples = (int) (Caster.makeDouble(lin.get(1)) * SFConstants.SAMPLE_RATE_MS);
        int randSamples = lin.size() > 2 ? (int) (Caster.makeDouble(lin.get(2)) * SFConstants.SAMPLE_RATE_MS) : 0;
        rollOffSamples /= 2;
        List<Object> retOuter = new ArrayList<>();
        int len = data.getLength();
        int start = 0;
        while (true)
        {
            int rollOffSamplesOld = rollOffSamples;
            rollOffSamples += SFMaths.random() * randSamples;
            int k = rollOffSamples * 2;
            int end = start + k;
            BaseTranslator trans = null;
            if (start == 0)
            {
                BaseTranslator x = new BaseTranslator(data, start, rollOffSamples);
                trans = x;
            }
            else if (end >= len)
            {
                BaseTranslator x = new EndTranslator(data, start, rollOffSamples);
                trans = x;
            }
            else
            {
                BaseTranslator x = new MiddleTranslator(data, start, rollOffSamples);
                trans = x;
            }
            // add to retout,
            List<Object> thisRet = new ArrayList<>(2);
            thisRet.add(trans);
            thisRet.add(start / SFConstants.SAMPLE_RATE_MS);
            retOuter.add(thisRet);
            // All done
            if (end >= len) break;
            // move on by rolloutsamples
            start += rollOffSamples;
            rollOffSamples = rollOffSamplesOld;
        }
        return retOuter;
    }

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

}