desc:GFX Mid/Side
//tags: mid side stereo width imaging mastering
//author: JGWizrad / Garden FX (GFX)
//
// Requires gfx-drift, gfx-input, gfx-output and gfx-ui (.jsfx-inc) in the same folder.
//
// Mid/side processor:
//   MID / SIDE gain, WIDTH (0-200 %, loudness kept steady), BASS MONO (sides removed below a frequency, 24 dB/oct),
//   AIR (high shelf on the sides), FOCUS (presence on the mid), L/R or M/S input and output formats.
//   Listen: STEREO, MID solo, SIDE solo (monitoring only).
// Drift: width breathes, air wanders, balance leans. The DRIFT dial scales the three drift amounts
// (50% = the drift settings, 100% = twice, 0 = none) and speeds the wander up with them.
// IN / OUT: TRIM (with the GUARD key), SAT and the OUT stage (OFF / CLIP / LIM) sit on the panel.

import gfx-drift.jsfx-inc
import gfx-input.jsfx-inc
import gfx-output.jsfx-inc
import gfx-ui.jsfx-inc
import gfx-panel.jsfx-inc
import gfx-dyn.jsfx-inc
import gfx-faceplate.jsfx-inc
import gfx-instrument.jsfx-inc

slider1:0<0,2,1{Stereo,Mid,Side}>-Listen
slider2:0<-12,12,0.1>-Mid gain (dB)
slider3:0<-12,12,0.1>-Side gain (dB)
slider4:100<0,200,1>-Width (%)
slider5:0<0,300,1>-Bass mono (Hz, 0 = off)
slider6:0<0,9,0.1>-Air (dB)
slider7:0<0,6,0.1>-Mid focus (dB)
slider8:0<0,1,1{L/R,M/S}>-Input format
slider9:0<0,1,1{L/R,M/S}>-Output format
slider10:10<0,50,1>-Width drift (%)
slider11:10<0,50,1>-Air drift (%)
slider12:5<0,50,1>-Balance drift (%)
slider13:0.25<0.02,2,0.01>-Drift speed (Hz)
slider14:0<-24,12,0.1>-Output (dB)
slider15:0<-100,100,1>-Balance (%)
slider16:0<0,100,1>-Band sat (%)
slider17:30<0,100,1>-Bias (%)
slider18:120<40,400,1>-Sat low band (Hz)
slider19:6000<2000,16000,10>-Sat high band (Hz)
slider20:-0.3<-24,0,0.1>-Ceiling / limit threshold (dB)
slider21:1<0,2,1{Off,Clip,Limit}>-Output stage
slider22:0<-24,12,0.1>-Input trim (dB)
slider23:1<0,1,1{Off,On}>-Input guard
slider24:50<0,100,1>-Drift (%)

in_pin:left input
in_pin:right input
out_pin:left output
out_pin:right output

@init
#ui_man = "gfx-midside";                                  // the ? pop-up links to this manual

// biquad (RBJ) with coefficients in the instance
function bq_hp(f) instance(b0, b1, b2, a1, a2) local(w0, cw, al, n) (
  w0 = 2 * $pi * min(f, srate * 0.45) / srate; cw = cos(w0); al = sin(w0) / (2 * 0.70710678); n = 1 + al;
  b0 = (1 + cw) * 0.5 / n; b1 = -(1 + cw) / n; b2 = b0; a1 = -2 * cw / n; a2 = (1 - al) / n;
);
function bq_shelf(f, gdb) instance(b0, b1, b2, a1, a2) local(amp, w0, cw, sw, al, sq, n) (
  amp = 10 ^ (gdb / 40); w0 = 2 * $pi * min(f, srate * 0.45) / srate; cw = cos(w0); sw = sin(w0);
  al = sw / 2 * sqrt(2); sq = 2 * sqrt(amp) * al;
  n = (amp + 1) - (amp - 1) * cw + sq;
  b0 = amp * ((amp + 1) + (amp - 1) * cw + sq) / n;
  b1 = -2 * amp * ((amp - 1) + (amp + 1) * cw) / n;
  b2 = amp * ((amp + 1) + (amp - 1) * cw - sq) / n;
  a1 = 2 * ((amp - 1) - (amp + 1) * cw) / n;
  a2 = ((amp + 1) - (amp - 1) * cw - sq) / n;
);
function bq_peak(f, gdb, q) instance(b0, b1, b2, a1, a2) local(amp, w0, cw, al, n) (
  amp = 10 ^ (gdb / 40); w0 = 2 * $pi * min(f, srate * 0.45) / srate; cw = cos(w0); al = sin(w0) / (2 * q);
  n = 1 + al / amp;
  b0 = (1 + al * amp) / n; b1 = -2 * cw / n; b2 = (1 - al * amp) / n; a1 = -2 * cw / n; a2 = (1 - al / amp) / n;
);
function bq_run(x) instance(b0, b1, b2, a1, a2, x1, x2, y1, y2) local(y) (
  y = b0 * x + b1 * x1 + b2 * x2 - a1 * y1 - a2 * y2;
  x2 = x1; x1 = x; y2 = y1; y1 = y;
  y;
);

function update() (
  listen = slider1;
  mid_t = 10 ^ (slider2 / 20);
  side_t = 10 ^ (slider3 / 20);
  wid_t = slider4 / 100;
  bmono = slider5;
  bmono >= 20 ? ( hpS.bq_hp(bmono); hpS2.bq_hp(bmono); );
  air_db = slider6;
  slider7 != lastfoc ? ( lastfoc = slider7; pkM.bq_peak(2500, slider7, 0.8); );
  infmt = slider8; outfmt = slider9;
  drift_macro(slider24);
  wd = slider10 / 100 * dm_a; ad = slider11 / 100 * dm_a; bd = slider12 / 100 * dm_a;
  dspd = slider13 * dm_s;
  out_t = 10 ^ (slider14 / 20);
  bal_t = slider15 / 100;
  in_setup(slider22, slider23);
  ost_setup(slider16 / 100, slider17 / 100, slider18, slider19, slider20, slider21);
);

// ---------- presets (leave Output, Drift speed and the I/O rows alone) ----------
function setp(ms, ss, w, bm, ai, fo, inf, outf, w_, a_, b_) (
  slider2 = ms; slider3 = ss; slider4 = w; slider5 = bm; slider6 = ai; slider7 = fo;
  slider8 = inf; slider9 = outf; slider10 = w_; slider11 = a_; slider12 = b_;
);
function load_preset(p) (
  p == 1 ? setp(0,  0,   120, 0,   1.5, 0, 0, 0, 10, 10, 5) :   // Subtle Widen
  p == 2 ? setp(0,  0.5, 140, 120, 2.5, 0, 0, 0,  8, 10, 3) :   // Wide Master
  p == 3 ? setp(0,  0,   100, 150, 0,   0, 0, 0,  0,  0, 0) :   // Mono Bass
  p == 4 ? setp(1,  0,    90, 100, 0,   3, 0, 0,  5,  5, 3) :   // Vocal Focus
  p == 5 ? setp(0,  1,   175, 200, 4,   0, 0, 0, 15, 15, 5) :   // Super Wide
  p == 6 ? setp(0, -2,    70, 150, 0,   0, 0, 0,  0,  0, 0) :   // Narrow & Tight
  p == 7 ? setp(0,  0,   100, 0,   0,   0, 1, 0,  0,  0, 0) :   // M/S Decode
  p == 8 ? setp(0,  0,   100, 0,   0,   0, 0, 1,  0,  0, 0);    // M/S Encode
  p >= 1 && p <= 8 ? slider_automate(4094);   // sliders 2-12
  p == 9 ? (                                   // Reset all to defaults
    slider1 = 0; slider2 = 0; slider3 = 0; slider4 = 100; slider5 = 0; slider6 = 0; slider7 = 0;
    slider8 = 0; slider9 = 0; slider10 = 10; slider11 = 10; slider12 = 5; slider13 = 0.25;
    slider14 = 0; slider15 = 0;
    slider16 = 0; slider17 = 30; slider18 = 120; slider19 = 6000; slider20 = -0.3; slider21 = 1;
    slider22 = 0; slider23 = 1; slider24 = 50;
    slider_automate(16777215);
  );
);

// ---------- memory ----------
scL = 0; scR = 512; scN = 512;   // vectorscope ring
memset(0, 0, 1024);
scw = 0; scd = 0;

// ---------- state ----------
sm  = 1 - exp(-1 / (0.03 * srate));
vuc = 1 - exp(-1 / (0.01 * srate));
crc = 1 - exp(-1 / (0.3 * srate));
drW.drift_init(0.8 + rand(0.5));
drA.drift_init(0.8 + rand(0.5));
drB.drift_init(0.8 + rand(0.5));
ost_init(20000); ostL.ost_ch_init(); ostR.ost_ch_init();
in_init();
pkL = 0; pkR = 0; vu_ms = 0; cLR = 0; cLL = 0; cRR = 0; eM = 0; eS = 0;
lastfoc = -1; lastair = -99;
!ui_dflt ? ui_thm = 5; !ui_dflt ? ui_hw = 0;   // defaults for new instances: Graphite, flat (saved projects keep their own)

update();
mid_s = mid_t; side_s = side_t; wid_s = wid_t; out_s = out_t; bal_s = bal_t;
ui_dflt = 1;   // theme defaults above apply once: @init re-runs (playback start, device reset) must not undo the saved theme

@slider
update();

@block
update();

@serialize
file_var(0, ui_thm);
file_var(0, ui_sz);
file_var(0, ui_hw);
file_avail(0) != 0 ? file_var(0, pr_cur);    // the preset in use (older projects end before it)

@sample
// input stage: DC block, trim, guard
in_process(spl0, spl1);
inL = in_l; inR = in_r;
vu_ms += (0.5 * (inL * inL + inR * inR) - vu_ms) * vuc;

// drift
dinc = dspd / srate;
vW = drW.drift_tick(dinc);
vA = drA.drift_tick(dinc);
vB = drB.drift_tick(dinc);

// smoothing
mid_s  += (mid_t  - mid_s)  * sm;
side_s += (side_t - side_s) * sm;
wid_s  += (wid_t  - wid_s)  * sm;
out_s  += (out_t  - out_s)  * sm;
bal_s  += (bal_t  - bal_s)  * sm;

// air shelf follows its drift (recomputed only when it moves noticeably)
airnow = air_db * (1 + ad * vA);
abs(airnow - lastair) > 0.05 ? ( lastair = airnow; shS.bq_shelf(8000, airnow); );

// encode
infmt ? ( m = inL; s = inR; ) : ( m = 0.5 * (inL + inR); s = 0.5 * (inL - inR); );

// process
bmono >= 20 ? s = hpS2.bq_run(hpS.bq_run(s));   // 24 dB/oct
air_db > 0.05 ? s = shS.bq_run(s);
slider7 > 0.05 ? m = pkM.bq_run(m);
w = max(wid_s * (1 + wd * 0.5 * vW), 0);
gM = min(sqrt(2 / (1 + w * w)), 1.4142);
m *= mid_s * gM;
s *= side_s * w * gM;

eM += (m * m - eM) * crc; eS += (s * s - eS) * crc;

// listen / decode
listen == 1 ? ( oL = m; oR = m; ) :
listen == 2 ? ( oL = s; oR = s; ) :
outfmt ? ( oL = m; oR = s; ) : ( oL = m + s; oR = m - s; );

// balance (with drift)
bal = min(max(bal_s + bd * 0.3 * vB, -1), 1);
oL *= min(1, 1 - bal); oR *= min(1, 1 + bal);

// output stage
oL = ostL.ost_band(oL) * out_s;
oR = ostR.ost_band(oR) * out_s;
ost_out(oL, oR);
spl0 = ost_l;
spl1 = ost_r;
pkL = max(pkL, abs(spl0)); pkR = max(pkR, abs(spl1));

// vectorscope + correlation
cLR += (spl0 * spl1 - cLR) * crc; cLL += (spl0 * spl0 - cLL) * crc; cRR += (spl1 * spl1 - cRR) * crc;
(scd += 1) >= 3 ? ( scd = 0; scL[scw] = spl0; scR[scw] = spl1; scw = (scw + 1) % scN; );

@gfx 640 392
ui_begin(640, 392);
ui_swb(); ui_swbg(14, 626, 45, 348, 392);   // drawn off-screen, then shown with the preset row moved up under the header
ui_header("MID/SIDE");

// ---------- header controls ----------
ui_theme_picker(148 * sc, 17 * sc);
ui_size_picker(184 * sc, 13 * sc);
ui_hw_toggle(248 * sc, 13 * sc);

// the preset row under the header: PRESETS, prev / next, LCD (click it for the list), at the right;
// designed below the panel and shown at the top
ui_swu(45 - 348);
pk_pextra = "Reset all to defaults";
k_ = pk_preset(244 * sc, 356 * sc, 380 * sc, 30 * sc, pr_cur, "Subtle Widen|Wide Master|Mono Bass|Vocal Focus|Super Wide|Narrow & Tight|M/S Decode|M/S Encode");
k_ > 0 ? ( load_preset(k_); pr_cur = k_ > 8 ? 0 : k_; );
ui_swu(0);

ui_button(410 * sc, 10 * sc, 70 * sc, 24 * sc, "STEREO", slider1 == 0, 1) ? ( slider1 = 0; slider_automate(slider1); );
ui_button(482 * sc, 10 * sc, 70 * sc, 24 * sc, "MID",    slider1 == 1, 1) ? ( slider1 = 1; slider_automate(slider1); );
ui_button(554 * sc, 10 * sc, 70 * sc, 24 * sc, "SIDE",   slider1 == 2, 1) ? ( slider1 = 2; slider_automate(slider1); );


ui_swu(44);   // the panel, shown below the preset row
// ---------- display window: vectorscope, correlation, mid / side energy ----------
ui_screen(16 * sc, 52 * sc, 454 * sc, 80 * sc);
vcx = 72 * sc; vcy = 92 * sc; vr = 34 * sc;
ui_col(C_SG);
gfx_line(vcx - vr, vcy, vcx + vr, vcy); gfx_line(vcx, vcy - vr, vcx, vcy + vr);
gfx_line(vcx - vr * 0.7, vcy - vr * 0.7, vcx + vr * 0.7, vcy + vr * 0.7);
gfx_line(vcx + vr * 0.7, vcy - vr * 0.7, vcx - vr * 0.7, vcy + vr * 0.7);
gfx_setfont(4); ui_col(C_ST);
gfx_x = vcx - vr * 0.7 - 6 * sc; gfx_y = vcy - vr * 0.7 - 10 * sc; gfx_drawstr("L");
gfx_x = vcx + vr * 0.7 + 1 * sc; gfx_y = vcy - vr * 0.7 - 10 * sc; gfx_drawstr("R");
vk = vr * 0.9 / max(sqrt(max(cLL, cRR)) * 2.5, 0.05);
ui_cola(C_VA, 0.7);
i = 0;
loop(scN,
  sl = scL[i]; sr_ = scR[i];
  qx = vcx + (sr_ - sl) * 0.7071 * vk; qy = vcy - (sl + sr_) * 0.7071 * vk;
  abs(qx - vcx) < vr && abs(qy - vcy) < vr ? gfx_rect(qx, qy, 1.5 * sc, 1.5 * sc);
  i += 1;
);
// correlation
corr = cLL > 0.0000001 && cRR > 0.0000001 ? cLR / sqrt(cLL * cRR) : 1;
bx0 = 140 * sc; bw0 = 300 * sc; by0 = 66 * sc;
ui_col(C_SG); gfx_rect(bx0, by0, bw0, 6 * sc);
gfx_line(bx0 + bw0 * 0.5, by0 - 3 * sc, bx0 + bw0 * 0.5, by0 + 9 * sc);
corr < 0 ? ui_col(C_CLIP) : ui_col(C_VB);
gfx_rect(bx0 + bw0 * 0.5 + min(corr, 0) * bw0 * 0.5, by0, abs(corr) * bw0 * 0.5, 6 * sc);
gfx_setfont(4); ui_col(C_ST);
gfx_x = bx0; gfx_y = by0 + 9 * sc; gfx_drawstr("-1");
gfx_x = bx0 + bw0 - 8 * sc; gfx_y = by0 + 9 * sc; gfx_drawstr("+1");
sprintf(#cr, "CORRELATION %+.2f", corr); ui_text(bx0 + bw0 * 0.5, by0 + 9 * sc, #cr);
// mid / side energy
mdb_ = 10 * log10(max(eM, 0.000000001)); sdb_ = 10 * log10(max(eS, 0.000000001));
ui_col(C_SG); gfx_rect(bx0, 96 * sc, bw0, 6 * sc); gfx_rect(bx0, 112 * sc, bw0, 6 * sc);
ui_col(C_VA); gfx_rect(bx0, 96 * sc, bw0 * min(max((mdb_ + 60) / 60, 0), 1), 6 * sc);
ui_col(C_VB); gfx_rect(bx0, 112 * sc, bw0 * min(max((sdb_ + 60) / 60, 0), 1), 6 * sc);
ui_col(C_ST);
gfx_x = 118 * sc; gfx_y = 94 * sc;  gfx_drawstr("MID");
gfx_x = 118 * sc; gfx_y = 110 * sc; gfx_drawstr("SIDE");

// ---------- input VU ----------
vdb = 10 * log10(max(vu_ms, 0.0000000001)) + 18;   // 0 VU = -18 dBFS RMS
vuIn.ui_vu(478 * sc, 52 * sc, 146 * sc, 80 * sc, vdb, "INPUT");

// ---------- M/S group ----------
ui_group(16 * sc, 140 * sc, 608 * sc, 96 * sc, 0, "M/S");
ui_noled = 1;
ui_button(42 * sc, 156 * sc, 78 * sc, 22 * sc, slider8 ? "IN  M/S" : "IN  L/R", slider8 == 1, 1) ?
  ( slider8 = 1 - slider8; slider_automate(slider8); );
ui_noled = 1;
ui_button(42 * sc, 186 * sc, 78 * sc, 22 * sc, slider9 ? "OUT  M/S" : "OUT  L/R", slider9 == 1, 1) ?
  ( slider9 = 1 - slider9; slider_automate(slider9); );
ui_knob(170 * sc, 186 * sc, 2, -12, 12, 0, 0, "MID",  "%+.1f dB");
ui_knob(244 * sc, 186 * sc, 3, -12, 12, 0, 0, "SIDE", "%+.1f dB");
ui_knob(318 * sc, 186 * sc, 4, 0, 200, 100, 0, "WIDTH", "%.0f%%");
ui_knob(392 * sc, 186 * sc, 5, 0, 300, 0, 0, "BASS MONO", slider5 < 20 ? "OFF" : "%.0f Hz");
ui_knob(466 * sc, 186 * sc, 6, 0, 9, 0, 0, "AIR",   "+%.1f dB");
ui_knob(540 * sc, 186 * sc, 7, 0, 6, 0, 0, "FOCUS", "+%.1f dB");

// ---------- DRIFT (row 4, left) ----------
ui_group(16 * sc, 244 * sc, 92 * sc, 96 * sc, 1, "DRIFT");
ui_knob(62 * sc, 290 * sc, 24, 0, 100, 50, 0, "DRIFT", "%.0f%%");

// ---------- IN / OUT (row 4, middle) ----------
ui_group(116 * sc, 244 * sc, 236 * sc, 96 * sc, 3, "IN / OUT");
ui_io(146, 262, 22, 23, 16, 21);

// ---------- MASTER group (row 4, right) ----------
ui_group(360 * sc, 244 * sc, 264 * sc, 96 * sc, 2, "MASTER");
ui_knob(414 * sc, 290 * sc, 15, -100, 100, 0, 0, "BALANCE", "%+.0f%%");
ui_knob(488 * sc, 290 * sc, 14, -24,  12,  0, 0, "OUTPUT",  "%.1f dB");
mL.ui_ledm(564 * sc, 256 * sc, 14 * sc, 70 * sc, pkL);
mR.ui_ledm(584 * sc, 256 * sc, 14 * sc, 70 * sc, pkR);
pkL *= 0.85; pkR *= 0.85;
gfx_setfont(4); ui_col(C_INK); ui_text(581 * sc, 328 * sc, "OUT");

ui_swrow(14, 626, 45, 348, 392, 0, 0, 0, 0, 0);
ui_end();