MicroDexed/dx7note.cpp

/*
   Copyright 2016-2017 Pascal Gauthier.
   Copyright 2012 Google Inc.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
*/

#include <math.h>
#include <stdlib.h>
#include "synth.h"
#include "freqlut.h"
#include "porta.h"
#include "exp2.h"
#include "controllers.h"
#include "dx7note.h"
#include "dexed.h"

const int FEEDBACK_BITDEPTH = 8;

int32_t midinote_to_logfreq(int midinote) {
  //const int32_t base = 50857777;  // (1 << 24) * (log(440) / log(2) - 69/12)
  const int32_t base = 50857777;  // (1 << 24) * (LOG_FUNC(440) / LOG_FUNC(2) - 69/12)
  const int32_t step = (1 << 24) / 12;
  return base + step * midinote;
}

int32_t logfreq_round2semi(int freq) {
  const int base = 50857777;  // (1 << 24) * (log(440) / log(2) - 69/12)
  const int step = (1 << 24) / 12;
  const int rem = (freq - base) % step;
  return freq - rem;
}

const int32_t coarsemul[] = {
  -16777216, 0, 16777216, 26591258, 33554432, 38955489, 43368474, 47099600,
  50331648, 53182516, 55732705, 58039632, 60145690, 62083076, 63876816,
  65546747, 67108864, 68576247, 69959732, 71268397, 72509921, 73690858,
  74816848, 75892776, 76922906, 77910978, 78860292, 79773775, 80654032,
  81503396, 82323963, 83117622
};

int32_t osc_freq(int midinote, int mode, int coarse, int fine, int detune) {
  // TODO: pitch randomization
  int32_t logfreq;
  if (mode == 0) {
    logfreq = midinote_to_logfreq(midinote);
    // could use more precision, closer enough for now. those numbers comes from my DX7
    //FRAC_NUM detuneRatio = 0.0209 * exp(-0.396 * (((float)logfreq) / (1 << 24))) / 7;
    FRAC_NUM detuneRatio = 0.0209 * EXP_FUNC(-0.396 * (((float)logfreq) / (1 << 24))) / 7;
    logfreq += detuneRatio * logfreq * (detune - 7);

    logfreq += coarsemul[coarse & 31];
    if (fine) {
      // (1 << 24) / log(2)
      //logfreq += (int32_t)floor(24204406.323123 * log(1 + 0.01 * fine) + 0.5);
      logfreq += (int32_t)floor(24204406.323123 * LOG_FUNC(1 + 0.01 * fine) + 0.5);
    }

    // // This was measured at 7.213Hz per count at 9600Hz, but the exact
    // // value is somewhat dependent on midinote. Close enough for now.
    // //logfreq += 12606 * (detune -7);
  } else {
    // ((1 << 24) * log(10) / log(2) * .01) << 3
    logfreq = (4458616 * ((coarse & 3) * 100 + fine)) >> 3;
    logfreq += detune > 7 ? 13457 * (detune - 7) : 0;
  }
  return logfreq;
}

const uint8_t velocity_data[64] = {
  0, 70, 86, 97, 106, 114, 121, 126, 132, 138, 142, 148, 152, 156, 160, 163,
  166, 170, 173, 174, 178, 181, 184, 186, 189, 190, 194, 196, 198, 200, 202,
  205, 206, 209, 211, 214, 216, 218, 220, 222, 224, 225, 227, 229, 230, 232,
  233, 235, 237, 238, 240, 241, 242, 243, 244, 246, 246, 248, 249, 250, 251,
  252, 253, 254
};

// See "velocity" section of notes. Returns velocity delta in microsteps.
int ScaleVelocity(int velocity, int sensitivity) {
  int clamped_vel = max(0, min(127, velocity));
  int vel_value = velocity_data[clamped_vel >> 1] - 239;
  int scaled_vel = ((sensitivity * vel_value + 7) >> 3) << 4;
  return scaled_vel;
}

int ScaleRate(int midinote, int sensitivity) {
  int x = min(31, max(0, midinote / 3 - 7));
  int qratedelta = (sensitivity * x) >> 3;
#ifdef SUPER_PRECISE
  int rem = x & 7;
  if (sensitivity == 3 && rem == 3) {
    qratedelta -= 1;
  } else if (sensitivity == 7 && rem > 0 && rem < 4) {
    qratedelta += 1;
  }
#endif
  return qratedelta;
}

const uint8_t exp_scale_data[] = {
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 14, 16, 19, 23, 27, 33, 39, 47, 56, 66,
  80, 94, 110, 126, 142, 158, 174, 190, 206, 222, 238, 250
};

int ScaleCurve(int group, int depth, int curve) {
  int scale;
  if (curve == 0 || curve == 3) {
    // linear
    scale = (group * depth * 329) >> 12;
  } else {
    // exponential
    int n_scale_data = sizeof(exp_scale_data);
    int raw_exp = exp_scale_data[min(group, n_scale_data - 1)];
    scale = (raw_exp * depth * 329) >> 15;
  }
  if (curve < 2) {
    scale = -scale;
  }
  return scale;
}

int ScaleLevel(int midinote, int break_pt, int left_depth, int right_depth,
               int left_curve, int right_curve) {
  int offset = midinote - break_pt - 17;
  if (offset >= 0) {
    return ScaleCurve((offset + 1) / 3, right_depth, right_curve);
  } else {
    return ScaleCurve(-(offset - 1) / 3, left_depth, left_curve);
  }
}

static const uint8_t pitchmodsenstab[] = {
  0, 10, 20, 33, 55, 92, 153, 255
};

// 0, 66, 109, 255
static const uint32_t ampmodsenstab[] = {
  0, 4342338, 7171437, 16777216
};

Dx7Note::Dx7Note() {
  for (int op = 0; op < 6; op++) {
    params_[op].phase = 0;
    params_[op].gain_out = 0;
  }
}

//void Dx7Note::init(const uint8_t patch[156], int midinote, int velocity) {
void Dx7Note::init(const uint8_t patch[173], int midinote, int velocity, int srcnote, int porta) {
  int rates[4];
  int levels[4];
  for (int op = 0; op < 6; op++) {
    int off = op * 21;
    for (int i = 0; i < 4; i++) {
      rates[i] = patch[off + i];
      levels[i] = patch[off + 4 + i];
    }
    int outlevel = patch[off + 16];
    outlevel = Env::scaleoutlevel(outlevel);
    int level_scaling = ScaleLevel(midinote, patch[off + 8], patch[off + 9],
                                   patch[off + 10], patch[off + 11], patch[off + 12]);
    outlevel += level_scaling;
    outlevel = min(127, outlevel);
    outlevel = outlevel << 5;
    outlevel += ScaleVelocity(velocity, patch[off + 15]);
    outlevel = max(0, outlevel);
    int rate_scaling = ScaleRate(midinote, patch[off + 13]);
    env_[op].init(rates, levels, outlevel, rate_scaling);

    int mode = patch[off + 17];
    int coarse = patch[off + 18];
    int fine = patch[off + 19];
    int detune = patch[off + 20];
    int32_t freq = osc_freq(midinote, mode, coarse, fine, detune);
    opMode[op] = mode;
    basepitch_[op] = freq;
    porta_curpitch_[op] = freq;
    ampmodsens_[op] = ampmodsenstab[patch[off + 14] & 3];

    if (porta >= 0)
      porta_curpitch_[op] = osc_freq(srcnote, mode, coarse, fine, detune);
  }
  for (int i = 0; i < 4; i++) {
    rates[i] = patch[126 + i];
    levels[i] = patch[130 + i];
  }
  pitchenv_.set(rates, levels);
  algorithm_ = patch[134];
  int feedback = patch[135];
  fb_shift_ = feedback != 0 ? FEEDBACK_BITDEPTH - feedback : 16;
  pitchmoddepth_ = (patch[139] * 165) >> 6;
  pitchmodsens_ = pitchmodsenstab[patch[143] & 7];
  ampmoddepth_ = (patch[140] * 165) >> 6;
  porta_rateindex_ = (porta < 128) ? porta : 127;
  porta_gliss_ = patch[68];
}

void Dx7Note::compute(int32_t *buf, int32_t lfo_val, int32_t lfo_delay, const Controllers *ctrls) {
  // ==== PITCH ====
  uint32_t pmd = pitchmoddepth_ * lfo_delay;  // Q32
  int32_t senslfo = pitchmodsens_ * (lfo_val - (1 << 23));
  int32_t pmod_1 = (((int64_t) pmd) * (int64_t) senslfo) >> 39;
  pmod_1 = abs(pmod_1);
  int32_t pmod_2 = (int32_t)(((int64_t)ctrls->pitch_mod * (int64_t)senslfo) >> 14);
  pmod_2 = abs(pmod_2);
  int32_t pitch_mod = max(pmod_1, pmod_2);
  pitch_mod = pitchenv_.getsample() + (pitch_mod * (senslfo < 0 ? -1 : 1));

  // ---- PITCH BEND ----
  int pitchbend = ctrls->values_[kControllerPitch];
  int32_t pb = (pitchbend - 0x2000);
  if (pb != 0) {
    if (ctrls->values_[kControllerPitchStep] == 0) {
      pb = ((float) (pb << 11)) * ((float) ctrls->values_[kControllerPitchRange]) / 12.0;
    } else {
      int stp = 12 / ctrls->values_[kControllerPitchStep];
      pb = pb * stp / 8191;
      pb = (pb * (8191 / stp)) << 11;
    }
  }
  int32_t pitch_base = pb + ctrls->masterTune;
  pitch_mod += pitch_base;

  // ==== AMP MOD ====
  lfo_val = (1 << 24) - lfo_val;
  uint32_t amod_1 = (uint32_t)(((int64_t) ampmoddepth_ * (int64_t) lfo_delay) >> 8); // Q24 :D
  amod_1 = (uint32_t)(((int64_t) amod_1 * (int64_t) lfo_val) >> 24);
  uint32_t amod_2 = (uint32_t)(((int64_t) ctrls->amp_mod * (int64_t) lfo_val) >> 7); // Q?? :|
  uint32_t amd_mod = max(amod_1, amod_2);

  // ==== EG AMP MOD ====
  uint32_t amod_3 = (ctrls->eg_mod + 1) << 17;
  amd_mod = max((1 << 24) - amod_3, amd_mod);

  // ==== OP RENDER ====
  for (int op = 0; op < 6; op++) {
    // if ( ctrls->opSwitch[op] == '0' )  {
    if (!(ctrls->opSwitch & (1 << op)))  {
      env_[op].getsample(); // advance the envelop even if it is not playing
      params_[op].level_in = 0;
    } else {
      //int32_t gain = pow(2, 10 + level * (1.0 / (1 << 24)));

      int32_t basepitch = basepitch_[op];

      if ( opMode[op] )
        params_[op].freq = Freqlut::lookup(basepitch + pitch_base);
      else {
        if ( porta_rateindex_ >= 0 ) {
          basepitch = porta_curpitch_[op];
          if ( porta_gliss_ )
            basepitch = logfreq_round2semi(basepitch);
        }
        params_[op].freq = Freqlut::lookup(basepitch + pitch_mod);
      }

      int32_t level = env_[op].getsample();
      if (ampmodsens_[op] != 0) {
        uint32_t sensamp = (uint32_t)(((uint64_t) amd_mod) * ((uint64_t) ampmodsens_[op]) >> 24);

        // TODO: mehhh.. this needs some real tuning.
        //uint32_t pt = exp(((float)sensamp) / 262144 * 0.07 + 12.2);
        uint32_t pt = EXP_FUNC(((float)sensamp) / 262144 * 0.07 + 12.2);
        uint32_t ldiff = (uint32_t)(((uint64_t)level) * (((uint64_t)pt << 4)) >> 28);
        level -= ldiff;
      }
      params_[op].level_in = level;
    }
  }

  // ==== PORTAMENTO ====
  int porta = porta_rateindex_;
  if ( porta >= 0 ) {
    int32_t rate = Porta::rates[porta];
    for (int op = 0; op < 6; op++) {
      int32_t cur = porta_curpitch_[op];
      int32_t dst = basepitch_[op];

      bool going_up = cur < dst;
      int32_t newpitch = cur + (going_up ? +rate : -rate);

      if ( going_up ? (cur > dst) : (cur < dst) )
        newpitch = dst;

      porta_curpitch_[op] = newpitch;
    }
  }

  ctrls->core->render(buf, params_, algorithm_, fb_buf_, fb_shift_);
}

void Dx7Note::keyup() {
  for (int op = 0; op < 6; op++) {
    env_[op].keydown(false);
  }
  pitchenv_.keydown(false);
}

void Dx7Note::update(const uint8_t patch[156], int midinote, int velocity, int porta) {
  int rates[4];
  int levels[4];
  for (int op = 0; op < 6; op++) {
    int off = op * 21;
    int mode = patch[off + 17];
    int coarse = patch[off + 18];
    int fine = patch[off + 19];
    int detune = patch[off + 20];
    int32_t freq = osc_freq(midinote, mode, coarse, fine, detune);
    basepitch_[op] = freq;
    porta_curpitch_[op] = freq;
    ampmodsens_[op] = ampmodsenstab[patch[off + 14] & 3];
    opMode[op] = mode;

    for (int i = 0; i < 4; i++) {
      rates[i] = patch[off + i];
      levels[i] = patch[off + 4 + i];
    }
    int outlevel = patch[off + 16];
    outlevel = Env::scaleoutlevel(outlevel);
    int level_scaling = ScaleLevel(midinote, patch[off + 8], patch[off + 9],
                                   patch[off + 10], patch[off + 11], patch[off + 12]);
    outlevel += level_scaling;
    outlevel = min(127, outlevel);
    outlevel = outlevel << 5;
    outlevel += ScaleVelocity(velocity, patch[off + 15]);
    outlevel = max(0, outlevel);
    int rate_scaling = ScaleRate(midinote, patch[off + 13]);
    env_[op].update(rates, levels, outlevel, rate_scaling);
  }
  algorithm_ = patch[134];
  int feedback = patch[135];
  fb_shift_ = feedback != 0 ? FEEDBACK_BITDEPTH - feedback : 16;
  pitchmoddepth_ = (patch[139] * 165) >> 6;
  pitchmodsens_ = pitchmodsenstab[patch[143] & 7];
  ampmoddepth_ = (patch[140] * 165) >> 6;
  porta_rateindex_ = (porta < 128) ? porta : 127;
  porta_gliss_ = patch[68];
}

void Dx7Note::peekVoiceStatus(VoiceStatus &status) {
  for (int i = 0; i < 6; i++) {
    status.amp[i] = Exp2::lookup(params_[i].level_in - (14 * (1 << 24)));
    env_[i].getPosition(&status.ampStep[i]);
  }
  pitchenv_.getPosition(&status.pitchStep);
}

/**
   Used in monophonic mode to transfer voice state from different notes
*/
void Dx7Note::transferState(Dx7Note &src) {
  for (int i = 0; i < 6; i++) {
    env_[i].transfer(src.env_[i]);
    params_[i].gain_out = src.params_[i].gain_out;
    params_[i].phase = src.params_[i].phase;
  }
}

void Dx7Note::transferSignal(Dx7Note &src) {
  for (int i = 0; i < 6; i++) {
    params_[i].gain_out = src.params_[i].gain_out;
    params_[i].phase = src.params_[i].phase;
  }
}

void Dx7Note::transferPortamento(Dx7Note &src) {
  for (int i = 0; i < 6; i++) {
    porta_curpitch_[i] = src.porta_curpitch_[i];
  }
}

void Dx7Note::oscSync() {
  for (int i = 0; i < 6; i++) {
    params_[i].gain_out = 0;
    params_[i].phase = 0;
  }
}