desc:GFX Aureus
// gfx-aureus - Golden Ratio & Decadic 4-Band EQ / Drive / Compressor
//tags: multiband eq saturation compressor mastering
//author: JGWizrad / Garden FX (GFX)
//
// DECADIC BANDS: LR4 crossovers at F1 / F1 x 10 / F1 x 100, with the top split kept between
//   5 and 10 kHz so the top band is always presence/air. F1 is picked from the Fibonacci
//   numbers 34, 55, 89, 144 Hz (each step ~ x PHI) or the classic 70 Hz (70 / 700 / 7k).
//   An LR4 low/high pair sums to ONE 2nd-order all-pass (Q 0.7071) at its corner, so every band
//   (and the dry path used by MIX) passes through exactly one all-pass per crossover it did not
//   go through. The four bands therefore sum back to a flat, phase-coherent signal.
//
// PER BAND: EQ (P / S / D) -> DRIVE (T / S / X) -> COMP (O / V / R) -> band GAIN, plus SOLO / MUTE.
//
// GOLDEN RATIO (PHI = 1.618034) sets everything the knobs don't:
//   EQ corners    Band 1 shelf F1/PHI, Band 4 shelf F3*PHI,
//                 Bands 2/3 bells at the geometric band centres
//   P (program)   broad Q = 1/PHI; boosting a shelf adds a classic program-EQ dip of gain/PHI^2
//                 exactly at the band edge (F1, F3)
//   S (console)   resonant shelves (Q = PHI); bells with proportional Q = PHI * (1 + |gain|/12)
//   D (dynamic)   S shape whose gain follows band energy above -30 dB over a 12*PHI dB range
//   Attack        30 ms / PHI^band  (30, 18.5, 11.5, 7.1 ms)
//   Release       attack * PHI^5    (x 11.09)
//   Ratios        PHI^k: Opto PHI^(2a), VCA PHI^(3a), Gentle PHI^(3a) over three stages
//   Knees         Opto 12*PHI dB, VCA 6/PHI dB, Gentle 6*PHI dB per stage
//   Drift         phi-breathing: each band's threshold wanders slowly (period 3 s * PHI^band)
//
// R (Gentle, after the GENTLE mode in GFX RND): three gentle compressors in series at
//   thresholds 6 dB apart, each carrying a third of the ratio, with program-dependent release.
//
// MASTER: INPUT, DRIFT, MIX (phase-aligned dry vs bands), OUTPUT, safety limiter (-0.3 dBFS).

slider1:0<0,7,1{Init,Golden Glue,Tape Polish,Opto Smooth,Air Lift,Iron Low End,VCA Punch,Dynamic Tame}>-Preset
slider2:25<0,100,1>-Drift (%)
slider3:0<-24,12,0.1>-Output (dB)
slider4:0<-24,24,0.1>-Input (dB)
slider5:100<0,100,1>-Mix (%)
slider6:2<0,4,1{34 Hz,55 Hz,70 Hz,89 Hz,144 Hz}>-Crossover F1

slider10:0<0,2,1{P Program,S Console,D Dynamic}>-B1 EQ Type
slider11:0<-12,12,0.1>-B1 EQ (dB)
slider12:1<0,2,1{T Transistor,S Tape,X Transformer}>-B1 Drive Type
slider13:0<0,100,1>-B1 Drive (%)
slider14:0<0,2,1{O Opto,V VCA,R Gentle}>-B1 Comp Type
slider15:0<0,100,1>-B1 Comp (%)
slider16:0<-12,12,0.1>-B1 Gain (dB)
slider17:0<0,1,1{Off,On}>-B1 Solo
slider18:0<0,1,1{Off,On}>-B1 Mute

slider20:0<0,2,1{P Program,S Console,D Dynamic}>-B2 EQ Type
slider21:0<-12,12,0.1>-B2 EQ (dB)
slider22:1<0,2,1{T Transistor,S Tape,X Transformer}>-B2 Drive Type
slider23:0<0,100,1>-B2 Drive (%)
slider24:0<0,2,1{O Opto,V VCA,R Gentle}>-B2 Comp Type
slider25:0<0,100,1>-B2 Comp (%)
slider26:0<-12,12,0.1>-B2 Gain (dB)
slider27:0<0,1,1{Off,On}>-B2 Solo
slider28:0<0,1,1{Off,On}>-B2 Mute

slider30:0<0,2,1{P Program,S Console,D Dynamic}>-B3 EQ Type
slider31:0<-12,12,0.1>-B3 EQ (dB)
slider32:1<0,2,1{T Transistor,S Tape,X Transformer}>-B3 Drive Type
slider33:0<0,100,1>-B3 Drive (%)
slider34:0<0,2,1{O Opto,V VCA,R Gentle}>-B3 Comp Type
slider35:0<0,100,1>-B3 Comp (%)
slider36:0<-12,12,0.1>-B3 Gain (dB)
slider37:0<0,1,1{Off,On}>-B3 Solo
slider38:0<0,1,1{Off,On}>-B3 Mute

slider40:0<0,2,1{P Program,S Console,D Dynamic}>-B4 EQ Type
slider41:0<-12,12,0.1>-B4 EQ (dB)
slider42:1<0,2,1{T Transistor,S Tape,X Transformer}>-B4 Drive Type
slider43:0<0,100,1>-B4 Drive (%)
slider44:0<0,2,1{O Opto,V VCA,R Gentle}>-B4 Comp Type
slider45:0<0,100,1>-B4 Comp (%)
slider46:0<-12,12,0.1>-B4 Gain (dB)
slider47:0<0,1,1{Off,On}>-B4 Solo
slider48:0<0,1,1{Off,On}>-B4 Mute

@init
// =====================================================================
// Constants & helpers
// =====================================================================
nextmem = 0;
function alloc(n) local(ptr) ( ptr = nextmem; nextmem += n; ptr; );

PHI = (1 + sqrt(5))/2;            // 1.6180339...
IPHI = 1/PHI;                     // 0.6180339...
TWO_PI = 2*$pi;
QBW = 0.70710678;                  // Butterworth Q (LR4 = two cascaded)

function tanh(v) ( v = max(-20, min(20, v)); 1 - 2/(exp(2*v) + 1); );
function db2g(d) ( 10^(d/20); );
function cms(t) ( 1 - exp(-1/(max(0.00001, t)*srate)); );     // one-pole coefficient from seconds
function softk(o, w) ( o <= -w*0.5 ? 0 : o >= w*0.5 ? o : (o + w*0.5)*(o + w*0.5)/(2*w); );

// ---- biquad: coefficients p[0..4], state p[5..8] (one block of 9 per channel) ----
function bq(x, p) local(y) (
  y = p[0]*x + p[1]*p[5] + p[2]*p[6] - p[3]*p[7] - p[4]*p[8];
  p[6] = p[5]; p[5] = x; p[8] = p[7]; p[7] = y;
  y;
);
// coefficient setters (state untouched, so parameter moves never click)
function sLP(p, f) local(w, c, al, a0) (
  w = TWO_PI*f/srate; c = cos(w); al = sin(w)/(2*QBW); a0 = 1 + al;
  p[0] = (1 - c)*0.5/a0; p[1] = (1 - c)/a0; p[2] = (1 - c)*0.5/a0; p[3] = -2*c/a0; p[4] = (1 - al)/a0;
);
function sHP(p, f) local(w, c, al, a0) (
  w = TWO_PI*f/srate; c = cos(w); al = sin(w)/(2*QBW); a0 = 1 + al;
  p[0] = (1 + c)*0.5/a0; p[1] = -(1 + c)/a0; p[2] = (1 + c)*0.5/a0; p[3] = -2*c/a0; p[4] = (1 - al)/a0;
);
function sAP(p, f) local(w, c, al, a0) (
  w = TWO_PI*f/srate; c = cos(w); al = sin(w)/(2*QBW); a0 = 1 + al;
  p[0] = (1 - al)/a0; p[1] = -2*c/a0; p[2] = 1; p[3] = -2*c/a0; p[4] = (1 - al)/a0;
);
function sBell(p, f, g, q) local(A, w, c, al, a0) (
  A = 10^(g/40); w = TWO_PI*min(f, srate*0.45)/srate; c = cos(w); al = sin(w)/(2*q); a0 = 1 + al/A;
  p[0] = (1 + al*A)/a0; p[1] = -2*c/a0; p[2] = (1 - al*A)/a0; p[3] = -2*c/a0; p[4] = (1 - al/A)/a0;
);
function sLS(p, f, g, q) local(A, w, c, al, sa, a0) (
  A = 10^(g/40); w = TWO_PI*min(f, srate*0.45)/srate; c = cos(w); al = sin(w)/(2*q); sa = 2*sqrt(A)*al;
  a0 = (A + 1) + (A - 1)*c + sa;
  p[0] = A*((A + 1) - (A - 1)*c + sa)/a0; p[1] = 2*A*((A - 1) - (A + 1)*c)/a0;
  p[2] = A*((A + 1) - (A - 1)*c - sa)/a0; p[3] = -2*((A - 1) + (A + 1)*c)/a0;
  p[4] = ((A + 1) + (A - 1)*c - sa)/a0;
);
function sHS(p, f, g, q) local(A, w, c, al, sa, a0) (
  A = 10^(g/40); w = TWO_PI*min(f, srate*0.45)/srate; c = cos(w); al = sin(w)/(2*q); sa = 2*sqrt(A)*al;
  a0 = (A + 1) - (A - 1)*c + sa;
  p[0] = A*((A + 1) + (A - 1)*c + sa)/a0; p[1] = -2*A*((A - 1) + (A + 1)*c)/a0;
  p[2] = A*((A + 1) + (A - 1)*c - sa)/a0; p[3] = 2*((A - 1) - (A + 1)*c)/a0;
  p[4] = ((A + 1) - (A - 1)*c - sa)/a0;
);
function sUnity(p) ( p[0] = 1; p[1] = 0; p[2] = 0; p[3] = 0; p[4] = 0; );
function cpy(p) ( p[9] = p[0]; p[10] = p[1]; p[11] = p[2]; p[12] = p[3]; p[13] = p[4]; );   // L coeffs -> R

// =====================================================================
// Crossover (decadic) - 18 slots per filter: L = 0..8, R = 9..17
// =====================================================================
function xf1(i) ( i == 0 ? 34 : i == 1 ? 55 : i == 2 ? 70 : i == 3 ? 89 : 144; );
function xf3(f1) ( max(5000, min(10000, f1*100)); );    // top split: decadic, held to 5 - 10 kHz
F1 = xf1(slider6); F2 = F1*10; F3 = xf3(F1);
xo = alloc(18*17); memset(xo, 0, 18*17);
lp1a = xo;        lp1b = xo + 18;   hp1a = xo + 36;   hp1b = xo + 54;
lp2a = xo + 72;   lp2b = xo + 90;   hp2a = xo + 108;  hp2b = xo + 126;
lp3a = xo + 144;  lp3b = xo + 162;  hp3a = xo + 180;  hp3b = xo + 198;
ap1_2 = xo + 216; ap1_3 = xo + 234; ap2_3 = xo + 252;     // band alignment all-passes
apd1 = xo + 270;  apd2 = xo + 288;                        // dry path (+ apd3 below)
apd3 = alloc(18); memset(apd3, 0, 18);
function xset(p, kind, f) ( kind == 0 ? sLP(p, f) : kind == 1 ? sHP(p, f) : sAP(p, f); cpy(p); );
// (Re)build the crossover for the current F1 / F2 / F3 (filter states are kept)
function xbuild() (
  xset(lp1a, 0, F1); xset(lp1b, 0, F1); xset(hp1a, 1, F1); xset(hp1b, 1, F1);
  xset(lp2a, 0, F2); xset(lp2b, 0, F2); xset(hp2a, 1, F2); xset(hp2b, 1, F2);
  xset(lp3a, 0, F3); xset(lp3b, 0, F3); xset(hp3a, 1, F3); xset(hp3b, 1, F3);
  xset(ap1_2, 2, F2); xset(ap1_3, 2, F3); xset(ap2_3, 2, F3);
  xset(apd1, 2, F1); xset(apd2, 2, F2); xset(apd3, 2, F3);
);
xbuild();

// Split x (channel offset co = 0 or 9) into globals xb1..xb4 and xdry
function split(x, co) local(lo, hi, m2, h2) (
  lo = bq(bq(x, lp1a + co), lp1b + co);
  hi = bq(bq(x, hp1a + co), hp1b + co);
  m2 = bq(bq(hi, lp2a + co), lp2b + co);
  h2 = bq(bq(hi, hp2a + co), hp2b + co);
  xb3 = bq(bq(h2, lp3a + co), lp3b + co);
  xb4 = bq(bq(h2, hp3a + co), hp3b + co);
  xb1 = bq(bq(lo, ap1_2 + co), ap1_3 + co);      // through the 700 Hz and 7 kHz all-passes
  xb2 = bq(m2, ap2_3 + co);                      // through the 7 kHz all-pass
  xdry = bq(bq(bq(x, apd1 + co), apd2 + co), apd3 + co);
);

// =====================================================================
// Per-band state
// =====================================================================
// bp: 40 slots per band
//  0 eqT  1 eqG  2 drT  3 drive d  4 cmT  5 cmp a  6 gain(lin)  7 active
//  9 tape LP coef  10 thr  11 slope (1-1/ratio)  12 knee  13 atk  14 rel  15 makeup
//  16 det coef  17 up slope  18 up cap  19 up thr  20 det ms  21 GR (dB, smoothed)
//  22/23 VCA feedback L/R  24 D-EQ env  25 D-EQ counter  26 last eqG  27 last eqT
//  28 thr base  29 drift wander  30 band out meter  31 drive base  32 eq centre freq
bp = alloc(160); memset(bp, 0, 160);
eqA = alloc(72); eqB = alloc(72); memset(eqA, 0, 72); memset(eqB, 0, 72);
ds = alloc(64); memset(ds, 0, 64);              // drive state: 8 per band per channel
rgs = alloc(12); memset(rgs, 0, 12);            // drift random generators (3 per band)

// Band EQ centres (decadic + phi) - recomputed when the crossover changes
function eqcentres() ( bp[32] = F1*IPHI; bp[72] = sqrt(F1*F2); bp[112] = sqrt(F2*F3); bp[152] = F3*PHI; );
eqcentres();
lastX = slider6;

// EQ coefficients for band b (type t, gain g) on both channels
function eqset(b, t, g) local(pa, pq, fc) (
  pa = eqA + b*18; pq = eqB + b*18; fc = bp[b*40 + 32];
  sUnity(pq);
  t == 0 ? (                                                   // P: program / passive-style
    b == 0 ? ( sLS(pa, fc, g, QBW); g > 0 ? sBell(pq, fc*PHI, -g/(PHI*PHI), IPHI); ) :
    b == 3 ? ( sHS(pa, fc, g, QBW); g > 0 ? sBell(pq, fc*IPHI, -g/(PHI*PHI), IPHI); ) :
             ( sBell(pa, fc, g, IPHI); );
  ) : (                                                        // S / D: console shape
    b == 0 ? sLS(pa, fc, g, PHI) :
    b == 3 ? sHS(pa, fc, g, PHI) :
             sBell(pa, fc, g, PHI*(1 + abs(g)/12));
  );
  cpy(pa); cpy(pq);
);
b = 0; loop(4, eqset(b, 0, 0); b += 1; );

// Smoothed random (drift): p[0] countdown, p[1] target, p[2] value
function rgen(p, period) (
  p[0] -= 1;
  p[0] <= 0 ? ( p[0] = period*srate; p[1] = rand(2) - 1; );
  p[2] += cms(period)*(p[1] - p[2]);
  p[2];
);

// ---- Drive: t 0 Transistor, 1 Tape, 2 Transformer; d = drive multiplier; st = 8-slot state ----
function drive(x, t, d, st, lpc) local(u, y, lo, ul, dir) (
  t == 0 ? (
    u = x*d;
    y = u/((1 + u*u*u*u)^0.25);                              // hard-ish, odd-order
  ) : t == 1 ? (
    dir = x >= st[0] ? 1 : -1; st[0] = x;                    // hysteresis: rising saturates earlier
    u = x*d*(1 + 0.05*dir*(d - 1)/9);
    y = tanh(u + 0.15*u*u);                                  // asymmetric soft saturation
    st[2] = y - st[1] + 0.9995*st[2]; st[1] = y; y = st[2];  // DC block
    st[3] += lpc*(y - st[3]); y = st[3];                     // HF roll-off with drive
  ) : (
    st[4] += xfLp*(x - st[4]); lo = st[4];                   // iron: lows saturate hardest
    ul = max(-1.5, min(1.5, lo*d*PHI));
    y = (ul - ul*ul*ul/6.75)*IPHI + tanh((x - lo)*d);
  );
  y/(1 + 0.6*(d - 1));
);

// =====================================================================
// Presets
// =====================================================================
function pb(b, eqt, eqg, drt, dra, cmt, cma, gn) local(i) (
  i = 10 + b*10;
  slider(i) = eqt; slider(i + 1) = eqg; slider(i + 2) = drt; slider(i + 3) = dra;
  slider(i + 4) = cmt; slider(i + 5) = cma; slider(i + 6) = gn; slider(i + 7) = 0; slider(i + 8) = 0;
);
// eq: 0 P 1 S 2 D | drive: 0 T 1 S 2 X | comp: 0 O 1 V 2 R
function apply_preset(n) (
  slider2 = 25; slider3 = 0; slider4 = 0; slider5 = 100;
  pb(0, 0, 0, 1, 0, 0, 0, 0); pb(1, 0, 0, 1, 0, 0, 0, 0); pb(2, 0, 0, 1, 0, 0, 0, 0); pb(3, 0, 0, 1, 0, 0, 0, 0);
  n == 1 ? (       // Golden Glue
    pb(0, 0, 0, 1, 15, 2, 30, 0); pb(1, 0, 0, 1, 15, 2, 30, 0); pb(2, 0, 0, 1, 15, 2, 30, 0); pb(3, 0, 0, 1, 10, 2, 30, 0);
  ) : n == 2 ? (    // Tape Polish
    pb(0, 0, 1.5, 1, 20, 0, 15, 0); pb(1, 0, 0, 1, 25, 0, 15, 0); pb(2, 0, 0, 1, 20, 0, 15, 0); pb(3, 0, 1.5, 1, 10, 0, 15, 0);
  ) : n == 3 ? (    // Opto Smooth
    pb(0, 0, 0, 1, 0, 0, 40, 0); pb(1, 0, 0, 1, 0, 0, 40, 0); pb(2, 0, 0, 1, 0, 0, 40, 0); pb(3, 0, 0, 1, 0, 0, 40, 0);
  ) : n == 4 ? (    // Air Lift
    pb(2, 1, 1.0, 1, 0, 0, 0, 0); pb(3, 0, 4.0, 1, 15, 2, 25, 0);
  ) : n == 5 ? (    // Iron Low End
    pb(0, 0, 2.5, 2, 45, 0, 30, 0); pb(1, 1, -1.5, 2, 20, 0, 0, 0);
  ) : n == 6 ? (    // VCA Punch
    pb(0, 0, 0, 1, 0, 1, 35, 0); pb(1, 0, 0, 0, 10, 1, 45, 0); pb(2, 0, 0, 1, 0, 1, 35, 0);
  ) : n == 7 ? (    // Dynamic Tame
    pb(1, 2, -2, 1, 0, 0, 15, 0); pb(2, 2, -5, 1, 0, 0, 15, 0); pb(3, 2, -4, 1, 0, 0, 15, 0);
  );
);

// Meters / GUI state
vuL = 0; vuR = 0; mOut = 0; mLim = 0; limEnv = 0;
limRel = exp(-1/(0.15*srate));
vuC = cms(0.3);
xfLp = 1 - exp(-TWO_PI*F1*PHI/srate);          // transformer low split: F1 * PHI
vnd = alloc(2); memset(vnd, 0, 2);            // VU needle positions (GUI)
drag_id = -1; pcap = 0; lastS = 0;
gfx_ext_retina = 1;

q_init == 0 ? (
  lastPreset = slider1;
  ui_sz = 2;
  ui_szinit = 1;
  q_init = 1;
);

@serialize
file_var(0, ui_sz);
file_var(0, ui_szinit);
file_var(0, lastPreset);
// added later: older projects end here, so they keep the defaults (yellow, flat)
file_avail(0) != 0 ? ( file_var(0, ui_hw); file_var(0, au_thm); );

@slider
slider1 != lastPreset ? ( apply_preset(slider1); lastPreset = slider1; );

@block
dr = slider2/100;
outG = db2g(slider3);
inG = db2g(slider4);

// Crossover picker: rebuild filters, EQ centres and transformer split when F1 changes
slider6 != lastX ? (
  lastX = slider6;
  F1 = xf1(slider6); F2 = F1*10; F3 = xf3(F1);
  xbuild(); eqcentres();
  xfLp = 1 - exp(-TWO_PI*F1*PHI/srate);
  b = 0; loop(4, bp[b*40 + 26] = -999; b += 1; );     // force EQ recalculation
);
mixW = slider5/100;
anySolo = slider17 || slider27 || slider37 || slider47;

b = 0;
loop(4,
  i = 10 + b*10;
  p = bp + b*40;
  p[0] = floor(slider(i) + 0.5);
  p[1] = slider(i + 1);
  p[2] = floor(slider(i + 2) + 0.5);
  p[3] = 1 + 0.09*slider(i + 3);                              // drive multiplier 1..10
  p[4] = floor(slider(i + 4) + 0.5);
  p[5] = slider(i + 5)/100;
  p[6] = db2g(slider(i + 6));
  p[7] = slider(i + 8) > 0.5 ? 0 : (anySolo && slider(i + 7) < 0.5) ? 0 : 1;   // mute / solo
  p[9] = 1 - exp(-TWO_PI*min(srate*0.45, 20000/(1 + 0.12*(p[3] - 1)))/srate);  // tape HF roll-off

  // EQ (D type is refreshed in @sample)
  (p[0] != 2 && (p[1] != p[26] || p[0] != p[27])) ? ( eqset(b, p[0], p[1]); p[26] = p[1]; p[27] = p[0]; );
  p[0] == 2 && p[27] != 2 ? ( p[27] = 2; p[26] = -999; );

  // Compressor: thresholds, ratios, knees and phi timings
  a = p[5];
  p[28] = -6 - 30*a;
  atk = 0.030/(PHI^b); rel = atk*(PHI^5);
  p[4] == 0 ? (            // Opto: smooth, RMS, slower
    p[11] = 1 - 1/(PHI^(2*a)); p[12] = 12*PHI; atk *= PHI; rel *= PHI; p[16] = cms(0.010*PHI);
  ) : p[4] == 1 ? (        // VCA: feedback, fast, firm knee
    p[11] = 1 - 1/(PHI^(3*a)); p[12] = 6*IPHI; atk *= IPHI*IPHI; rel *= IPHI; p[16] = cms(0.0005);
  ) : (                    // Gentle: three gentle stages, RMS, program-dependent release
    p[11] = 1 - 1/(PHI^(3*a)); p[12] = 6*PHI; p[16] = cms(0.005*PHI);
  );
  p[13] = cms(atk); p[14] = cms(rel);
  p[15] = 0.5*p[11]*max(0, -18 - p[28]);                     // half auto-makeup (all types)
  b += 1;
);

@sample
spl0 != spl0 ? spl0 = 0;
spl1 != spl1 ? spl1 = 0;
inL = spl0*inG; inR = spl1*inG;

outL = 0; outR = 0;
split(inL, 0); aL1 = xb1; aL2 = xb2; aL3 = xb3; aL4 = xb4; dryL = xdry;
split(inR, 9); aR1 = xb1; aR2 = xb2; aR3 = xb3; aR4 = xb4; dryR = xdry;

b = 0;
loop(4,
  p = bp + b*40;
  yl = b == 0 ? aL1 : b == 1 ? aL2 : b == 2 ? aL3 : aL4;
  yr = b == 0 ? aR1 : b == 1 ? aR2 : b == 2 ? aR3 : aR4;

  // ---- EQ ----
  p[0] == 2 ? (
    // D: gain follows band energy above -30 dB over a 12*PHI dB range (refreshed every 16 samples)
    p[24] += (max(abs(yl), abs(yr)) > sqrt(p[24]) ? p[13] : p[14])*(yl*yl + yr*yr - p[24]);
    (p[25] -= 1) <= 0 ? (
      p[25] = 16;
      ed = p[24] > 0.00000001 ? 10*log10(p[24]) : -160;
      eqset(b, 2, p[1]*max(0, min(1, (ed + 30)/(12*PHI))));
    );
  );
  yl = bq(bq(yl, eqA + b*18), eqB + b*18);
  yr = bq(bq(yr, eqA + b*18 + 9), eqB + b*18 + 9);

  // ---- DRIVE ----
  p[3] > 1.0001 ? (
    yl = drive(yl, p[2], p[3], ds + b*16, p[9]);
    yr = drive(yr, p[2], p[3], ds + b*16 + 8, p[9]);
  );

  // ---- COMP ----
  p[5] > 0 ? (
    det = p[4] == 1 ? max(abs(p[22]), abs(p[23])) : max(abs(yl), abs(yr));   // VCA = feedback
    p[20] += p[16]*(det*det - p[20]);
    ldb = p[20] > 0.00000000001 ? 10*log10(p[20]) : -140;
    thr = p[28] + 3*dr*p[29];                                  // phi-breathing threshold
    p[4] == 2 ? (
      // Gentle: three stages 6 dB apart, each a third of the slope
      gr = -(p[11]/3)*(softk(ldb - (thr + 6), p[12]) + softk(ldb - thr, p[12]) + softk(ldb - (thr - 6), p[12]));
    ) : (
      gr = -p[11]*softk(ldb - thr, p[12]);
    );
    // release: Opto slows as reduction deepens; Gentle adapts more gently; VCA fixed
    c = gr < p[21] ? p[13] : p[4] == 0 ? p[14]/(1 + PHI*abs(p[21])/6) : p[4] == 2 ? p[14]/(1 + abs(p[21])/(6*PHI)) : p[14];
    p[21] += c*(gr - p[21]);
    g = db2g(p[21] + p[15]);
    yl *= g; yr *= g;
    p[22] = yl; p[23] = yr;
  ) : ( p[21] = 0; );

  // ---- band gain, solo / mute ----
  yl *= p[6]*p[7]; yr *= p[6]*p[7];
  p[30] = max(p[30]*0.9995, max(abs(yl), abs(yr)));
  outL += yl; outR += yr;
  b += 1;
);

// phi-breathing: each band wanders on its own period, 3 s * PHI^band
bp[29]  = rgen(rgs,     3);
bp[69]  = rgen(rgs + 3, 3*PHI);
bp[109] = rgen(rgs + 6, 3*PHI*PHI);
bp[149] = rgen(rgs + 9, 3*PHI*PHI*PHI);

// ---- master ----
oL = (dryL*(1 - mixW) + outL*mixW)*outG;
oR = (dryR*(1 - mixW) + outR*mixW)*outG;
pk = max(abs(oL), abs(oR));
limEnv = pk > limEnv ? pk : limEnv*limRel;
lg = limEnv > 0.966 ? 0.966/limEnv : 1;
oL *= lg; oR *= lg;
spl0 = max(-1, min(1, oL));
spl1 = max(-1, min(1, oR));

vuL += vuC*(spl0*spl0 - vuL);
vuR += vuC*(spl1*spl1 - vuR);
mLim = lg < 0.98 ? 1 : mLim*0.9995;

@gfx 1680 504

// =====================================================================
// GUI - yellow rack faceplate, 1600 x 480 design space.
// Size picker: S 75% / M 90% / L 105% (shrinks further if the window is smaller).
// Knobs: drag vertically (Shift = fine), double-click or Ctrl-click = reset.
// The LCD shows the preset, or the parameter you are touching.
// =====================================================================

szf = ui_sz == 1 ? 0.75 : ui_sz == 2 ? 1.05 : 0.9;
S  = min(szf, min(gfx_w/1600, gfx_h/480));
ox = floor((gfx_w - 1600*S)*0.5);
oy = floor((gfx_h - 480*S)*0.5);
mx = (mouse_x - ox)/S;
my = (mouse_y - oy)/S;

// the ? pop-up is modal: while it is open the panel underneath takes no clicks
hlp ? ( (mouse_cap & 1) && !(pcap & 1) && !hlp_new ? hlp = 0; pcap = mouse_cap; );
hlp_new = 0;

S != lastS ? (
  gfx_setfont(1, "Arial Black", max(10, 44*S));           // AUREUS
  gfx_setfont(2, "Arial Bold", max(9, 18*S));             // band titles
  gfx_setfont(3, "Arial Bold", max(7, 13*S));             // labels
  gfx_setfont(4, "Arial Bold", max(7, 12*S));             // values
  gfx_setfont(5, "Arial Bold", max(7, 12*S));             // small print
  gfx_setfont(6, "Arial Bold", max(8, 15*S));             // selector letters / buttons
  gfx_setfont(7, "Courier New", max(9, 24*S), 'b');       // LCD line 2
  gfx_setfont(8, "Courier New", max(7, 13*S), 'b');       // LCD line 1
  gfx_setfont(9, "Arial Bold", max(6, 9*S));              // VU scale
  lastS = S;
);

// ---- palette: YELLOW (black print) or PETROL TEAL (cream print); HW adds the hardware finish ----
hw = ui_hw;
!au_thm ? (
  Y_R = 0.98; Y_G = 0.80; Y_B = 0.10;          // faceplate yellow
  K_R = 0.07; K_G = 0.07; K_B = 0.07;          // black ink
  A_R = 0.62; A_G = 0.42; A_B = 0.02;          // knob value arc
) : (
  Y_R = 0.184; Y_G = 0.369; Y_B = 0.353;       // faceplate petrol teal
  K_R = 0.910; K_G = 0.878; K_B = 0.796;       // lime white ink (#E8E0CB)
  A_R = 0.98; A_G = 0.72; A_B = 0.24;          // knob value arc (amber)
);

// ---- helpers (design-space coordinates) ----
function col(r, g, b) ( gfx_r = r; gfx_g = g; gfx_b = b; );
function cyel() ( col(Y_R, Y_G, Y_B); );
function cblk() ( col(K_R, K_G, K_B); );
function R(x, y, w, h) ( gfx_rect(ox + x*S, oy + y*S, max(1, w*S), max(1, h*S)); );
function RO(x, y, w, h) local(t, k) (
  t = max(1, floor(2*S + 0.5)); k = 0;
  loop(t, gfx_rect(ox + x*S + k, oy + y*S + k, max(1, w*S - 2*k), max(1, h*S - 2*k), 0); k += 1; );
);
function LN(x1, y1, x2, y2) ( gfx_line(ox + x1*S, oy + y1*S, ox + x2*S, oy + y2*S, 1); );
function TX(x, y, txt) ( gfx_x = ox + x*S; gfx_y = oy + y*S; gfx_drawstr(txt); );
function TC(cx, y, txt) local(w, h) ( gfx_measurestr(txt, w, h); gfx_x = ox + cx*S - w*0.5; gfx_y = oy + y*S; gfx_drawstr(txt); );
function TR(rx, y, txt) local(w, h) ( gfx_measurestr(txt, w, h); gfx_x = ox + rx*S - w; gfx_y = oy + y*S; gfx_drawstr(txt); );
function CIRC(x, y, rr, fill) ( gfx_circle(ox + x*S, oy + y*S, rr*S, fill, 1); );
function clicked(x, y, w, h) ( (mouse_cap & 1) && !(pcap & 1) && mx >= x && mx <= x+w && my >= y && my <= y+h; );
function cnear() ( col(0.07, 0.07, 0.07); );   // stays black in every theme (meters, wells)
function setk(idx, v) ( slider(idx) != v ? ( slider(idx) = v; slider_automate(2^(idx - 1)); ); );
// HW: a raised bevel (light top-left, dark bottom-right); inset = 1 for a recess
function bev(x, y, w, h, inset) (
  gfx_a = au_thm ? 0.18 : 0.30; inset ? col(0, 0, 0) : col(1, 1, 1); R(x, y, w, 1.5); R(x, y, 1.5, h);
  inset ? col(1, 1, 1) : col(0, 0, 0); R(x, y + h - 1.5, w, 1.5); R(x + w - 1.5, y, 1.5, h); gfx_a = 1;
);

function screw(x, y) (
  col(0.55, 0.55, 0.57); CIRC(x, y, 7, 1);
  col(0.25, 0.25, 0.27); CIRC(x, y, 7, 0);
  LN(x - 4, y + 4, x + 4, y - 4);
);

// Button: on = black with yellow text; off = yellow with black outline. red = 1 for MUTE (on = red)
function btn(x, y, w, h, lbl, on, fnt, red) local(sw, sh) (
  hw ? ( gfx_a = 0.35; col(0, 0, 0); R(x + 1, y + 2.5, w, h); gfx_a = 1; );
  on ? ( red ? col(0.86, 0.14, 0.10) : cblk(); ) : cyel();
  R(x, y, w, h);
  hw ? ( gfx_a = (on ? 0.10 : 0.22)*(au_thm ? 0.4 : 1); col(1, 1, 1); R(x + 2, y + 2, w - 4, h*0.42); gfx_a = 1; bev(x, y, w, h, on); );
  cblk(); RO(x, y, w, h);
  on ? ( red ? col(1, 1, 1) : cyel(); ) : cblk();
  gfx_setfont(fnt);
  gfx_measurestr(lbl, sw, sh);
  gfx_x = ox + (x + w*0.5)*S - sw*0.5;
  gfx_y = oy + (y + h*0.5)*S - sh*0.5;
  gfx_drawstr(lbl);
  clicked(x, y, w, h);
);

// Section frame with a black title tab
function frame(x, y, w, h, title) (
  cblk(); RO(x, y, w, h);
  title != 0 ? (
    gfx_setfont(5);
    gfx_measurestr(title, fw_, fh_);
    R(x + 10, y - 7, fw_/S + 14, 14);
    cyel(); TX(x + 17, y - 6, title);
  );
);

// Black knob with printed scale. bip = bipolar (centre tick), def = reset value.
function knob(id, cx, cy, rad, v, vmin, vmax, bip, def) local(dx, dy, fr, nf, ang, sx, sy, sr, k, t, ca, sa, ta) (
  fr = (v - vmin)/(vmax - vmin);
  dx = mx - cx; dy = my - cy;
  kn_hot = drag_id == id || (dx*dx + dy*dy) < (rad*rad*1.6);   // house style: values show on hover / drag only
  (mouse_cap & 1) && !(pcap & 1) && drag_id == -1 && (dx*dx + dy*dy) < (rad*rad*1.6) ? (
    ((mouse_cap & 4) || (kc_id == id && time_precise() - kc_t < 0.35)) ? (
      v = def; kc_t = 0; k_rst = id;
    ) : (
      drag_id = id; drag_sy = my; drag_sf = fr; kc_id = id; kc_t = time_precise();
    );
  );
  drag_id == id ? (
    (mouse_cap & 1) ? (
      nf = max(0, min(1, drag_sf + (drag_sy - my)/((mouse_cap & 8) ? 720 : 180)));
      v = vmin + nf*(vmax - vmin);
    ) : drag_id = -1;
  );
  fr = (v - vmin)/(vmax - vmin);
  ang = (-0.75 + 1.5*fr)*$pi;
  sx = ox + cx*S; sy = oy + cy*S; sr = rad*S;

  // printed scale: 11 ticks, longer at the ends (and centre for bipolar)
  cblk(); k = 0;
  loop(11,
    ta = (-0.75 + 1.5*k/10)*$pi;
    t = (k == 0 || k == 10 || (bip && k == 5)) ? 9 : 5;
    gfx_line(sx + sin(ta)*(sr + 4*S), sy - cos(ta)*(sr + 4*S), sx + sin(ta)*(sr + (4 + t)*S), sy - cos(ta)*(sr + (4 + t)*S), 1);
    k += 1;
  );
  // value marker: small yellow-on-black dot track of the travelled arc
  col(A_R, A_G, A_B);
  k = 0; loop(max(2, floor(3*S + 0.5)),
    gfx_arc(sx, sy, sr + 2*S + k, bip ? min(0, ang) : -0.75*$pi, bip ? max(0, ang) : ang, 1); k += 1; );

  // body: skirt, knurled edge, cap, highlight (HW: a drop shadow and a domed cap)
  hw ? ( gfx_a = 0.45; col(0, 0, 0); gfx_circle(sx + 2*S, sy + 4*S, sr, 1, 1); gfx_a = 1; );
  col(0.03, 0.03, 0.03); gfx_circle(sx, sy, sr, 1, 1);
  col(0.20, 0.20, 0.21); k = 0;
  loop(28,
    ta = k*2*$pi/28;
    gfx_line(sx + sin(ta)*sr*0.82, sy - cos(ta)*sr*0.82, sx + sin(ta)*(sr - 1), sy - cos(ta)*(sr - 1), 1);
    k += 1;
  );
  kc_r >= 0 ? (
    col(kc_r*0.7, kc_g*0.7, kc_b*0.7); gfx_circle(sx, sy, sr*0.76, 1, 1);
    col(kc_r, kc_g, kc_b); gfx_circle(sx, sy, sr*0.72, 1, 1);
    col(min(1, kc_r + 0.22), min(1, kc_g + 0.22), min(1, kc_b + 0.22)); gfx_circle(sx - sr*0.2, sy - sr*0.24, sr*0.2, 1, 1);
  ) : (
  col(0.11, 0.11, 0.12); gfx_circle(sx, sy, sr*0.74, 1, 1);
  col(0.22, 0.22, 0.24); gfx_circle(sx - sr*0.2, sy - sr*0.24, sr*0.2, 1, 1);
  );
  // white pointer
  col(0.97, 0.97, 0.95);
  sa = sin(ang); ca = cos(ang);
  t = max(2, floor(4*S + 0.5)); k = 0;
  loop(t,
    gfx_line(sx + sa*sr*0.2 + ca*(k - t*0.5), sy - ca*sr*0.2 + sa*(k - t*0.5),
             sx + sa*sr*0.95 + ca*(k - t*0.5), sy - ca*sr*0.95 + sa*(k - t*0.5), 1);
    k += 1;
  );
  v;
);

function touch(id, name, val) (
  (drag_id == id || k_rst == id) ? (
    strcpy(#lcdn, name); strcpy(#lcdv, val); lcd_t = time_precise();
    k_rst == id ? k_rst = -1;
  );
);

function fpct(v) ( sprintf(#vt, "%d%%", floor(v + 0.5)); #vt; );
function fdb(v) local(q) (
  q = floor(v*10 + 0.5)/10;
  q > 0 ? sprintf(#vt, "+%.1f dB", q) : q < 0 ? sprintf(#vt, "%.1f dB", q) : strcpy(#vt, "0.0 dB");
  #vt;
);
// Frequency as "34", "340", "3.4k", "14.4k" into the given string
function fq(f, dst) ( f >= 1000 ? sprintf(dst, "%.3gk", f/1000) : sprintf(dst, "%d", f); dst; );

function pname(n) (
  n == 0 ? "INIT" : n == 1 ? "GOLDEN GLUE" : n == 2 ? "TAPE POLISH" : n == 3 ? "OPTO SMOOTH" :
  n == 4 ? "AIR LIFT" : n == 5 ? "IRON LOW END" : n == 6 ? "VCA PUNCH" : "DYNAMIC TAME";
);
function step_preset(dir) (
  slider1 = (slider1 + dir + 8) % 8;
  apply_preset(slider1); lastPreset = slider1;
  lcd_t = 0;
  slider_automate(281474976710655);             // sliders 1-48
);

// VU meter: face at (x, y), 230 x 112; v = mean-square level; nd = needle state slot
function vu(x, y, v, lbl, np) local(db, pos, a, px_, py_, k, tv, tp, rr, cxv, cyv) (
  // bezel + face
  cnear(); R(x - 4, y - 4, 238, 120);
  col(0.99, 0.93, 0.62); R(x, y, 230, 112);
  col(1.0, 0.97, 0.78); R(x + 6, y + 6, 218, 40);
  cxv = x + 115; cyv = y + 150; rr = 122;
  // scale: VU values placed on a voltage scale
  k = 0;
  loop(10,
    tv = k == 0 ? -20 : k == 1 ? -10 : k == 2 ? -7 : k == 3 ? -5 : k == 4 ? -3 : k == 5 ? -1 : k == 6 ? 0 : k == 7 ? 1 : k == 8 ? 2 : 3;
    tp = (10^(tv/20) - 0.1)/(10^(3/20) - 0.1);
    a = (-48 + 96*tp)*$pi/180;
    tv >= 0 ? col(0.80, 0.10, 0.08) : cnear();
    gfx_line(ox + (cxv + sin(a)*rr)*S, oy + (cyv - cos(a)*rr)*S, ox + (cxv + sin(a)*(rr - 9))*S, oy + (cyv - cos(a)*(rr - 9))*S, 1);
    gfx_setfont(9);
    sprintf(#vut, tv > 0 ? "+%d" : "%d", tv);
    TC(cxv + sin(a)*(rr + 9), cyv - cos(a)*(rr + 9) - 6, #vut);
    k += 1;
  );
  // red zone arc
  col(0.80, 0.10, 0.08);
  k = 0; loop(max(2, floor(3*S + 0.5)),
    gfx_arc(ox + cxv*S, oy + cyv*S, (rr - 4)*S + k, (-48 + 96*(1 - 0.1)/(10^(3/20) - 0.1))*$pi/180, 48*$pi/180, 1); k += 1; );
  cnear(); gfx_setfont(3); TC(cxv, y + 76, "VU");
  gfx_setfont(5); TX(x + 8, y + 94, lbl);
  // needle (0 VU = -18 dBFS RMS), simple ballistics per frame
  db = v > 0.000000001 ? 10*log10(v) + 18 : -40;
  pos = max(-0.04, min(1.06, (10^(max(-30, db)/20) - 0.1)/(10^(3/20) - 0.1)));
  np[0] += 0.35*(pos - np[0]);
  a = (-48 + 96*np[0])*$pi/180;
  cnear();
  gfx_line(ox + cxv*S, oy + (y + 110)*S, ox + (cxv + sin(a)*(rr - 2))*S, oy + (cyv - cos(a)*(rr - 2))*S, 1);
  gfx_line(ox + cxv*S + 1, oy + (y + 110)*S, ox + (cxv + sin(a)*(rr - 2))*S + 1, oy + (cyv - cos(a)*(rr - 2))*S, 1);
  // pivot cover, then (HW) glass
  cnear(); R(x, y + 104, 230, 8);
  hw ? ( gfx_a = 0.10; col(1, 1, 1); gfx_triangle(ox + x*S, oy + y*S, ox + (x + 150)*S, oy + y*S, ox + x*S, oy + (y + 80)*S); gfx_a = 1; );
);

// =====================================================================
// Draw
// =====================================================================
col(0.10, 0.10, 0.10); gfx_rect(0, 0, gfx_w, gfx_h);       // chassis around the faceplate
kc_r = -1;
cyel(); R(0, 0, 1600, 480);
hw ? (
  // brushed enamel: fine streaks and a soft top light
  k = 0; loop(240, hv = sin(k*12.9898)*43758.5453; hv -= floor(hv);
    gfx_a = 0.025 + 0.035*hv; hv > 0.5 ? col(1, 1, 1) : col(0, 0, 0); R(44, k*2, 1512, 1); k += 1; );
  gfx_a = 1;
  gfx_gradrect(ox, oy, 1600*S, 200*S, 1, 1, 1, 0.10, 0, 0, 0, 0, 0, 0, 0, -0.10/(200*S));
  gfx_gradrect(ox, oy + 330*S, 1600*S, 150*S, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.16/(150*S));
  bev(0, 0, 1600, 480, 0);
);

// rack ears: yellow with black border, slots and a tube icon
ex = 0;
loop(2,
  exx = ex == 0 ? 0 : 1556;
  cblk(); RO(exx, 0, 44, 480);
  ey = 0;
  loop(2,
    eyy = ey == 0 ? 60 : 420;
    cblk(); CIRC(exx + 16, eyy, 7, 1); CIRC(exx + 28, eyy, 7, 1); R(exx + 16, eyy - 7, 12, 14);
    ey += 1;
  );
  // tube icon
  cblk(); RO(exx + 12, 200, 20, 80); RO(exx + 16, 212, 12, 46); LN(exx + 18, 264, exx + 18, 276); LN(exx + 26, 264, exx + 26, 276);
  ex += 1;
);
cblk(); R(44, 0, 1512, 3); R(44, 477, 1512, 3);

// ---- Left: brand, LCD, presets, size ----
cblk(); gfx_setfont(1); TX(60, 18, "AUREUS");
gfx_setfont(5); TX(64, 76, "MULTIBAND PROCESSOR");

cnear(); R(60, 104, 266, 92);
col(0.07, 0.05, 0.02); R(64, 108, 258, 84);
hw ? ( bev(58, 102, 270, 96, 1); gfx_a = 0.07; col(1, 1, 1); R(64, 108, 258, 30); gfx_a = 1; );
col(1.0, 0.68, 0.15);
time_precise() - lcd_t < 1.5 ? (
  gfx_setfont(8); TX(76, 118, #lcdn);
  gfx_setfont(7); TX(76, 146, #lcdv);
) : (
  gfx_setfont(8); sprintf(#lcd1, "PRESET %02d/08", slider1 + 1); TX(76, 118, #lcd1);
  gfx_setfont(7); TX(76, 146, pname(slider1));
);

// PRESETS key or a click on the LCD: drop-down menu of all presets (current one ticked)
pm_ = btn(60, 210, 130, 36, "PRESETS", 0, 6, 0);
clicked(60, 104, 266, 92) || pm_ ? (
  strcpy(#pmenu, ""); k = 0;
  loop(8,
    k == slider1 ? strcat(#pmenu, "!");
    strcat(#pmenu, pname(k));
    k < 7 ? strcat(#pmenu, "|");
    k += 1;
  );
  gfx_x = mouse_x; gfx_y = mouse_y;
  psel = gfx_showmenu(#pmenu);
  psel > 0 ? ( slider1 = psel - 1; apply_preset(slider1); lastPreset = slider1; lcd_t = 0; slider_automate(281474976710655); );
);

btn(198, 210, 60, 36, "◄", 0, 6, 0) ? step_preset(-1);
btn(266, 210, 60, 36, "►", 0, 6, 0) ? step_preset(1);

cblk(); gfx_setfont(5); TX(60, 270, "SIZE");
btn(60, 286, 48, 30, "S", ui_sz == 1, 6, 0) ? ui_sz = 1;
btn(114, 286, 48, 30, "M", ui_sz == 0, 6, 0) ? ui_sz = 0;
btn(168, 286, 48, 30, "L", ui_sz == 2, 6, 0) ? ui_sz = 2;
btn(222, 286, 30, 30, "?", hlp, 6, 0) ? ( hlp = 1; hlp_new = 1; );

// INPUT trim beside the size picker
setk(4, knob(94, 284, 300, 16, slider4, -24, 24, 1, 0));
cblk(); gfx_setfont(5); TC(284, 258, "INPUT");
gfx_setfont(4); kn_hot ? TC(284, 330, fdb(slider4)); touch(94, "INPUT", fdb(slider4));

// Crossover picker: F1 (x10, x100). Fibonacci 34 / 55 / 89 / 144 (steps ~ x phi) + classic 70
cblk(); gfx_setfont(5); TX(60, 352, "CROSSOVER  F1   x10   x100");
k = 0;
loop(5,
  btn(60 + k*54, 368, 48, 30, k == 0 ? "34" : k == 1 ? "55" : k == 2 ? "70" : k == 3 ? "89" : "144", slider6 == k, 4, 0) ? (
    setk(6, k);
    strcpy(#lcdn, "CROSSOVERS");
    xv = k == 0 ? 34 : k == 1 ? 55 : k == 2 ? 70 : k == 3 ? 89 : 144;
    sprintf(#lcdv, "%s/%s/%s", fq(xv, #fa), fq(xv*10, #fb), fq(xf3(xv), #fc));
    lcd_t = time_precise();
  );
  k += 1;
);
cblk(); gfx_setfont(3); TX(60, 404, "φ = 1.618034");
gfx_setfont(5); TX(60, 422, "FIBONACCI SPLITS  LR4");
screw(312, 452);
btn(60, 440, 48, 26, "HW", hw, 4, 0) ? ui_hw = !ui_hw;
btn(114, 440, 74, 26, au_thm ? "TEAL" : "GOLD", 0, 4, 0) ? au_thm = !au_thm;

// ---- Four bands ----
bb = 0;
loop(4,
  bx = 345 + bb*240;
  base = 10 + bb*10;
  bq_ = bp + bb*40;

  // frame + header tab
  hw ? ( gfx_a = 0.12; col(0, 0, 0); R(bx, 20, 230, 440); gfx_a = 1; bev(bx - 2, 18, 234, 444, 1); );
  cblk(); RO(bx, 20, 230, 440);
  R(bx, 20, 230, 34);
  cyel(); gfx_setfont(2);
  TX(bx + 12, 27, bb == 0 ? "SUB" : bb == 1 ? "LOW-MID" : bb == 2 ? "HIGH-MID" : F3 < 6500 ? "PRESENCE" : "AIR");
  gfx_setfont(5);
  bb == 0 ? sprintf(#rng, "< %s Hz", fq(F1, #fa)) :
  bb == 1 ? sprintf(#rng, "%s - %s Hz", fq(F1, #fa), fq(F2, #fb)) :
  bb == 2 ? sprintf(#rng, "%s - %s Hz", fq(F2, #fa), fq(F3, #fb)) :
            sprintf(#rng, "> %s Hz", fq(F3, #fa));
  TR(bx + 200, 32, #rng);
  // activity LED: off / green / red near clip
  lvl = bq_[30];
  lvl > 0.89 ? col(1.0, 0.18, 0.10) : lvl > 0.01 ? col(0.25, 0.95, 0.30) : col(0.12, 0.25, 0.12);
  CIRC(bx + 216, 37, 6, 1);

  // three rows: EQ / DRIVE / COMP  (HW: band-coloured caps - SUB brown, LOW-MID blue, HIGH-MID green, AIR red)
  hw ? (
    bb == 0 ? ( kc_r = 0.55; kc_g = 0.35; kc_b = 0.17; ) : bb == 1 ? ( kc_r = 0.24; kc_g = 0.44; kc_b = 0.80; ) :
    bb == 2 ? ( kc_r = 0.20; kc_g = 0.63; kc_b = 0.32; ) : ( kc_r = 0.82; kc_g = 0.18; kc_b = 0.16; );
  );
  rw = 0;
  loop(3,
    y0 = 60 + rw*92;
    rw > 0 ? ( cblk(); R(bx + 10, y0 - 2, 196, 2); );
    ti = base + rw*2;                      // type slider index
    vi = ti + 1;                           // amount slider index
    tsel = floor(slider(ti) + 0.5);
    cblk(); gfx_setfont(3); TX(bx + 12, y0 + 6, rw == 0 ? "EQ" : rw == 1 ? "DRIVE" : "COMP");
    // one key per row: click to step through the three types; it shows the one in use
    btn(bx + 12, y0 + 26, 112, 28, rw == 0 ? (tsel == 0 ? "PROGRAM" : tsel == 1 ? "CONSOLE" : "DYNAMIC") :
                                   rw == 1 ? (tsel == 0 ? "TRANSISTOR" : tsel == 1 ? "TAPE" : "TRANSFORMER") :
                                             (tsel == 0 ? "OPTO" : tsel == 1 ? "VCA" : "GENTLE"), 1, 3, 0) ? (
      k = (tsel + 1) % 3;
      setk(ti, k);
      strcpy(#lcdn, rw == 0 ? "EQ TYPE" : rw == 1 ? "DRIVE TYPE" : "COMP TYPE");
      strcpy(#lcdv, rw == 0 ? (k == 0 ? "PROGRAM" : k == 1 ? "CONSOLE" : "DYNAMIC") :
                    rw == 1 ? (k == 0 ? "TRANSISTOR" : k == 1 ? "TAPE" : "TRANSFORMER") :
                              (k == 0 ? "OPTO" : k == 1 ? "VCA" : "GENTLE"));
      lcd_t = time_precise();
    );
    // knob
    rw == 0 ? (
      setk(vi, knob(bb*10 + 1, bx + 162, y0 + 40, 25, slider(vi), -12, 12, 1, 0));
      cblk(); gfx_setfont(4); kn_hot ? TC(bx + 162, y0 + 70, fdb(slider(vi)));
      touch(bb*10 + 1, bb == 0 ? "SUB EQ" : bb == 1 ? "LOW-MID EQ" : bb == 2 ? "HIGH-MID EQ" : "AIR EQ", fdb(slider(vi)));
    ) : (
      setk(vi, knob(bb*10 + 1 + rw, bx + 162, y0 + 40, 25, slider(vi), 0, 100, 0, 0));
      cblk(); gfx_setfont(4); kn_hot ? TC(bx + 162, y0 + 70, fpct(slider(vi)));
      touch(bb*10 + 1 + rw, rw == 1 ? (bb == 0 ? "SUB DRIVE" : bb == 1 ? "LOW-MID DRIVE" : bb == 2 ? "HIGH-MID DRIVE" : "AIR DRIVE")
                                    : (bb == 0 ? "SUB COMP" : bb == 1 ? "LOW-MID COMP" : bb == 2 ? "HIGH-MID COMP" : "AIR COMP"), fpct(slider(vi)));
    );
    rw += 1;
  );

  kc_r = -1;
  // GR ladder (0 .. -20 dB, top to bottom)
  grv = bq_[21];
  cnear(); R(bx + 208, 62, 14, 266);
  k = 0;
  loop(14,
    ly = 66 + k*18.6;
    (-grv) >= (k + 0.5)*20/14 ? (k > 9 ? col(1.0, 0.18, 0.10) : col(1.0, 0.62, 0.08)) : col(0.25, 0.15, 0.04);
    R(bx + 211, ly, 8, 14);
    k += 1;
  );
  cblk(); gfx_setfont(5); TC(bx + 215, 332, "GR");

  // bottom row: band GAIN, SOLO, MUTE
  cblk(); R(bx + 10, 336, 196, 2);
  setk(base + 6, knob(bb*10 + 4, bx + 54, 386, 24, slider(base + 6), -12, 12, 1, 0));
  cblk(); gfx_setfont(3); TC(bx + 54, 420, "GAIN");
  gfx_setfont(4); kn_hot ? TC(bx + 54, 438, fdb(slider(base + 6)));
  touch(bb*10 + 4, bb == 0 ? "SUB GAIN" : bb == 1 ? "LOW-MID GAIN" : bb == 2 ? "HIGH-MID GAIN" : "AIR GAIN", fdb(slider(base + 6)));
  so = slider(base + 7) > 0.5; mu = slider(base + 8) > 0.5;
  btn(bx + 106, 366, 52, 34, "SOLO", so, 4, 0) ? setk(base + 7, !so);
  btn(bx + 164, 366, 52, 34, "MUTE", mu, 4, 1) ? setk(base + 8, !mu);

  bb += 1;
);

// ---- Right: twin VUs + master ----
frame(1305, 20, 245, 262, "OUTPUT");
vu(1312, 34, vuL, "LEFT", vnd);
vu(1312, 160, vuR, "RIGHT", vnd + 1);

frame(1305, 300, 245, 160, "MASTER");
setk(2, knob(91, 1352, 352, 24, slider2, 0, 100, 0, 25));
cblk(); gfx_setfont(3); TC(1352, 386, "DRIFT"); gfx_setfont(4); kn_hot ? TC(1352, 404, fpct(slider2)); touch(91, "DRIFT (PHI)", fpct(slider2));
setk(5, knob(92, 1428, 352, 24, slider5, 0, 100, 0, 100));
cblk(); gfx_setfont(3); TC(1428, 386, "MIX"); gfx_setfont(4); kn_hot ? TC(1428, 404, fpct(slider5)); touch(92, "MIX", fpct(slider5));
setk(3, knob(93, 1504, 352, 24, slider3, -24, 12, 1, 0));
cblk(); gfx_setfont(3); TC(1504, 386, "OUTPUT"); gfx_setfont(4); kn_hot ? TC(1504, 404, fdb(slider3)); touch(93, "OUTPUT", fdb(slider3));
mLim > 0.5 ? col(1.0, 0.18, 0.10) : col(0.35, 0.08, 0.05); CIRC(1328, 438, 6, 1);
cblk(); gfx_setfont(5); TX(1340, 432, "LIMIT");
screw(1530, 440);

// ? pop-up: design credit and the manual
hlp ? (
  gfx_a = 0.62; col(0, 0, 0); gfx_rect(0, 0, gfx_w, gfx_h); gfx_a = 1;
  col(0.11, 0.11, 0.13); R(560, 150, 480, 170);
  col(0.88, 0.38, 0.23); R(580, 194, 440, 1);
  gfx_setfont(2); col(0.95, 0.95, 0.93); TX(580, 166, "Design by JGWizrad.  © John Garden 2026");
  gfx_setfont(3); col(0.91, 0.70, 0.23); TX(580, 210, "https://www.gardenfx.uk/");
  col(0.85, 0.84, 0.82); TX(580, 236, "Manual - https://www.gardenfx.uk/manual/gfx-aureus.pdf");
  col(0.52, 0.51, 0.49); TX(580, 284, "Click anywhere to close.");
);
pcap = mouse_cap;