Akso - Audio DSP Platform

ADSRcrv

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ADSR module with exp/inverse exp controls for attack, decay and release stages. Also outputs stage number and a gate high when it changes from stage (eg selecting different waveforms for my wavetable oscillators for each stage. you could use the autoCurve (patt-folder) to morph between settings at the different stages of the envelope.) the exponential/inverse exponential sides of the A, D and R are swapped for D and R. This is done for a more intuitive control: -dial it left->signal is mostly low (exp for attack, inv-exp for decay and release) -dial it right->signal is mostly high (inv-exp for attack, exp for decay and release)

Author: Remco van der Most

License: BSD

Github: sss/env/ADSRcrv.axo

Inlets

bool32 gate

frac32.bipolar A

frac32.bipolar crvA

frac32.bipolar D

frac32.bipolar crvD

frac32.bipolar S

frac32.bipolar R

frac32.bipolar crvR

Outlets

int32 stage

bool32 nxtStg

frac32 out

Parameters

frac32.s.map crvA

frac32.s.map crvD

frac32.s.map R

frac32.s.map crvR

frac32.u.map S

frac32.s.map.klineartime.exp A

frac32.s.map.klineartime.exp D

Declaration

int32_t env1;
int32_t env2;
int32_t env3;
int32_t Cenv1;
int32_t Cenv2;
int32_t Cenv3;
int32_t relLvl;
int trig;
int stage;
int trg;
int32_t curved;
int32_t ccomp;
int prev;
int32_t curving(int32_t in, int32_t Exp) {

  in = in >> 3;
  if (Exp < 0) {
    ccomp = (1 << 27) + Exp + ___SMMUL(-Exp << 3, in << 2);
    curved = ___SMMUL(in << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
  }
  if (Exp >= 0) {
    in = (1 << 27) - in;
    ccomp = (1 << 27) - Exp + ___SMMUL(Exp << 3, in << 2);
    curved = ___SMMUL(in << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ___SMMUL(curved << 3, ccomp << 2);
    curved = ((1 << 27) - curved);
  }
}

Control Rate

int32_t att;
int32_t dec;
int32_t sus;
int32_t CrvA = __SSAT(param_crvA + inlet_crvA, 28);
int32_t CrvD = __SSAT(param_crvD + inlet_crvD, 28);
int32_t CrvR = __SSAT((param_crvR << 1) + inlet_crvR, 28);
sus = __USAT((1 << 27) - 5 - param_S - inlet_S, 27);
int32_t rel;
MTOF(__SSAT(-param_A - inlet_A, 28), att)
MTOF(__SSAT(-param_D - inlet_D, 28), dec)
MTOF(__SSAT(-param_R - inlet_R, 28), rel)
int32_t choke;
MTOF(32 << 21, choke)
att = att >> 3;
dec = dec >> 3;
rel = rel >> 3;
if ((inlet_gate > 0) && !trig) {
  stage = 1;
  trig = 1;
} else if (!(inlet_gate > 0)) {
  trig = 0;
  stage = 0;
}

if (stage == 1) {
  env1 += att;
  env1 = __USAT(env1, 30);
  if (env1 >= ((1 << 30) - 1)) {
    stage = 2;
  }
}
if (stage == 2) {
  env2 += dec;
  env2 = __USAT(env2, 30);
  if (env2 >= ((1 << 30) - 1)) {
    stage = 3;
  }
}
curving(env1, CrvA);
Cenv1 = curved << 3;
curving(env2, -CrvD);
Cenv2 = curved << 3;
int32_t Env2 = ___SMMUL(Cenv2, sus << 3) << 2;

if (stage == 0) {
  env3 = env3 > 0 ? env3 - rel : 0;
  curving(env3, CrvR);
  Cenv3 = ___SMMUL(curved << 3, relLvl >> 1) << 3;
}
if (stage > 0) {
  env3 = env3 > 0 ? env3 - choke : 0;
  curving(env3, CrvR);
  Cenv3 = ___SMMUL(curved << 3, relLvl >> 1) << 3;
}

if ((stage == 0) & (!(trg))) {
  trg = 1;
  relLvl = Cenv1 - Env2;
  env3 = (1 << 30);
  env1 = 0;
  env2 = 0;
} else if (stage > 0) {
  trg = 0;
}

outlet_out = __USAT(Cenv1 - Env2 + Cenv3 >> 3, 27);
outlet_nxtStg = prev == stage ? 0 : 1;
outlet_stage = stage;

prev = stage;