Carla/source/backend/native/zynaddsubfx/Effects/Echo.cpp

/*
  ZynAddSubFX - a software synthesizer

  Echo.cpp - Echo effect
  Copyright (C) 2002-2005 Nasca Octavian Paul
  Copyright (C) 2009-2010 Mark McCurry
  Author: Nasca Octavian Paul
          Mark McCurry

  This program is free software; you can redistribute it and/or modify
  it under the terms of version 2 of the GNU General Public License
  as published by the Free Software Foundation.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License (version 2 or later) for more details.

  You should have received a copy of the GNU General Public License (version 2)
  along with this program; if not, write to the Free Software Foundation,
  Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA

*/

#include <cmath>
#include "Echo.h"

#define MAX_DELAY 2

Echo::Echo(bool insertion_, float *efxoutl_, float *efxoutr_)
    :Effect(insertion_, efxoutl_, efxoutr_, NULL, 0),
      Pvolume(50),
      Pdelay(60),
      Plrdelay(100),
      Pfb(40),
      Phidamp(60),
      delayTime(1),
      lrdelay(0),
      avgDelay(0),
      delay(new float[(int)(MAX_DELAY * synth->samplerate)],
            new float[(int)(MAX_DELAY * synth->samplerate)]),
      old(0.0f),
      pos(0),
      delta(1),
      ndelta(1)
{
    initdelays();
    setpreset(Ppreset);
}

Echo::~Echo()
{
    delete[] delay.l;
    delete[] delay.r;
}

//Cleanup the effect
void Echo::cleanup(void)
{
    memset(delay.l, 0, MAX_DELAY * synth->samplerate * sizeof(float));
    memset(delay.r, 0, MAX_DELAY * synth->samplerate * sizeof(float));
    old = Stereo<float>(0.0f);
}

inline int max(int a, int b)
{
    return a > b ? a : b;
}

//Initialize the delays
void Echo::initdelays(void)
{
    cleanup();
    //number of seconds to delay left chan
    float dl = avgDelay - lrdelay;

    //number of seconds to delay right chan
    float dr = avgDelay + lrdelay;

    ndelta.l = max(1, (int) (dl * synth->samplerate));
    ndelta.r = max(1, (int) (dr * synth->samplerate));
}

//Effect output
void Echo::out(const Stereo<float *> &input)
{
    for(int i = 0; i < synth->buffersize; ++i) {
        float ldl = delay.l[pos.l];
        float rdl = delay.r[pos.r];
        ldl = ldl * (1.0f - lrcross) + rdl * lrcross;
        rdl = rdl * (1.0f - lrcross) + ldl * lrcross;

        efxoutl[i] = ldl * 2.0f;
        efxoutr[i] = rdl * 2.0f;

        ldl = input.l[i] * pangainL - ldl * fb;
        rdl = input.r[i] * pangainR - rdl * fb;

        //LowPass Filter
        old.l = delay.l[(pos.l + delta.l) % (MAX_DELAY * synth->samplerate)] =
                    ldl * hidamp + old.l * (1.0f - hidamp);
        old.r = delay.r[(pos.r + delta.r) % (MAX_DELAY * synth->samplerate)] =
                    rdl * hidamp + old.r * (1.0f - hidamp);

        //increment
        ++pos.l; // += delta.l;
        ++pos.r; // += delta.r;

        //ensure that pos is still in bounds
        pos.l %= MAX_DELAY * synth->samplerate;
        pos.r %= MAX_DELAY * synth->samplerate;

        //adjust delay if needed
        delta.l = (15 * delta.l + ndelta.l) / 16;
        delta.r = (15 * delta.r + ndelta.r) / 16;
    }
}


//Parameter control
void Echo::setvolume(unsigned char _Pvolume)
{
    Pvolume = _Pvolume;

    if(insertion == 0) {
        outvolume = powf(0.01f, (1.0f - Pvolume / 127.0f)) * 4.0f;
        volume    = 1.0f;
    }
    else
        volume = outvolume = Pvolume / 127.0f;
    if(Pvolume == 0)
        cleanup();
}

void Echo::setdelay(unsigned char _Pdelay)
{
    Pdelay   = _Pdelay;
    avgDelay = (Pdelay / 127.0f * 1.5f); //0 .. 1.5 sec
    initdelays();
}

void Echo::setlrdelay(unsigned char _Plrdelay)
{
    float tmp;
    Plrdelay = _Plrdelay;
    tmp      =
        (powf(2.0f, fabsf(Plrdelay - 64.0f) / 64.0f * 9.0f) - 1.0f) / 1000.0f;
    if(Plrdelay < 64.0f)
        tmp = -tmp;
    lrdelay = tmp;
    initdelays();
}

void Echo::setfb(unsigned char _Pfb)
{
    Pfb = _Pfb;
    fb  = Pfb / 128.0f;
}

void Echo::sethidamp(unsigned char _Phidamp)
{
    Phidamp = _Phidamp;
    hidamp  = 1.0f - Phidamp / 127.0f;
}

void Echo::setpreset(unsigned char npreset)
{
    const int     PRESET_SIZE = 7;
    const int     NUM_PRESETS = 9;
    unsigned char presets[NUM_PRESETS][PRESET_SIZE] = {
        {67, 64, 35,  64,  30,  59, 0 }, //Echo 1
        {67, 64, 21,  64,  30,  59, 0 }, //Echo 2
        {67, 75, 60,  64,  30,  59, 10}, //Echo 3
        {67, 60, 44,  64,  30,  0,  0 }, //Simple Echo
        {67, 60, 102, 50,  30,  82, 48}, //Canyon
        {67, 64, 44,  17,  0,   82, 24}, //Panning Echo 1
        {81, 60, 46,  118, 100, 68, 18}, //Panning Echo 2
        {81, 60, 26,  100, 127, 67, 36}, //Panning Echo 3
        {62, 64, 28,  64,  100, 90, 55}  //Feedback Echo
    };

    if(npreset >= NUM_PRESETS)
        npreset = NUM_PRESETS - 1;
    for(int n = 0; n < PRESET_SIZE; ++n)
        changepar(n, presets[npreset][n]);
    if(insertion)
        setvolume(presets[npreset][0] / 2);  //lower the volume if this is insertion effect
    Ppreset = npreset;
}


void Echo::changepar(int npar, unsigned char value)
{
    switch(npar) {
        case 0:
            setvolume(value);
            break;
        case 1:
            setpanning(value);
            break;
        case 2:
            setdelay(value);
            break;
        case 3:
            setlrdelay(value);
            break;
        case 4:
            setlrcross(value);
            break;
        case 5:
            setfb(value);
            break;
        case 6:
            sethidamp(value);
            break;
    }
}

unsigned char Echo::getpar(int npar) const
{
    switch(npar) {
        case 0:  return Pvolume;
        case 1:  return Ppanning;
        case 2:  return Pdelay;
        case 3:  return Plrdelay;
        case 4:  return Plrcross;
        case 5:  return Pfb;
        case 6:  return Phidamp;
        default: return 0; // in case of bogus parameter number
    }
}