desc:GFX Grunt
//tags: amp preamp drive saturation console grunt
//author: JGWizrad / Garden FX (GFX)
//
// Requires gfx-input, gfx-output, gfx-ui, gfx-panel and gfx-dyn (.jsfx-inc) in the same folder.
//
// "Waka" faceplate: a fixed warm sunrise-orange/red skin (not tied to the usual theme swatches),
// with a row of matching ribbed black amp knobs (cream pointers) on a recessed control strip.
//
// Signal path: input (trim + guard) -> 140Hz low-shelf bypass splits off the sub-140Hz band ->
// boost / gain drive -> soft pre-clip -> grunt waveshaping (cubic warmth) -> low band rejoins ->
// band saturation / tone -> dynamic 330Hz dip -> stereo-linked clipper / limiter -> master.
//   GAIN   - drive into the stage. The higher it goes, the more of the
//            sub-140Hz content is routed around the gain/grunt stage untouched (tighter low end).
//   BOOST  - smaller amp knob (gold pointer): extra drive on top of GAIN, plus an asymmetric warmth bias
//   GRUNT  - amount of cubic waveshaping character. Together with SAG, dynamically pulls gain
//            out at 330Hz (up to ~6 dB) so heavier settings don't turn boxy/congested.
//   SAG    - output-stage saturation bias
//   SQUASH - output-stage band saturation amount
//   MASTER - output level
//   Out stage: Off, Clip (soft, zero latency) or Limit (lookahead, PDC reported)

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

slider1:0<-24,12,0.1>-Gain (dB)
slider2:0<0,100,1>-Boost (%)
slider3:0.5<0,1,0.01>-Grunt
slider4:0.2<0,1,0.01>-Sag
slider5:0.5<0,1,0.01>-Squash
slider6:0<-24,12,0.1>-Master (dB)
slider7:1<0,2,1{Off,Clip,Limit}>-Out stage

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

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

in_init();
ost_init(16384); ostL.ost_ch_init(); ostR.ost_ch_init();
pkL = 0; pkR = 0;   // stereo output meter peaks
ui_thm = 15; ui_hw = 1;   // "Waka" skin is fixed (Ember: burnt orange / warm brown) - no theme picker on this panel

// one-pole lowpass, used to split out the sub-140Hz band so it can bypass the gain/grunt stage
function lp140_set(freq) instance(a) (
  a = 1 - exp(-2 * $pi * freq / srate);
);
function lp140_run(x) instance(a, z) (
  z += a * (x - z);
  z;
);

// TPT state-variable filter (Zavalishin) - bandpass tap used to carve a dynamic dip at 330Hz
function svf_set(freq, q) instance(g, k, a1, a2, a3) (
  g = tan($pi * freq / srate);
  k = 1 / q;
  a1 = 1 / (1 + g * (g + k));
  a2 = g * a1;
  a3 = g * a2;
);
function svf_bp(x) instance(ic1eq, ic2eq, g, k, a1, a2, a3) local(v1, v2, v3) (
  v3 = x - ic2eq;
  v1 = a1 * ic1eq + a2 * v3;
  v2 = ic2eq + a2 * ic1eq + a3 * v3;
  ic1eq = 2 * v1 - ic1eq;
  ic2eq = 2 * v2 - ic2eq;
  v1;
);

function update() (
  in_setup(slider1, 1);
  ost_setup(slider5, slider4, 90, 7500, 0, slider7);
  lpL140.lp140_set(140); lpR140.lp140_set(140);
  nL.svf_set(330, 0.9); nR.svf_set(330, 0.9);
);

update();

// amp knob + a big label underneath that shows the value while touched (house style)
function gx_knob(cx, r, idx, lo, hi, def, ptr, label, fmt) (
  dy_knob(cx, gx_y, r, idx, lo, hi, def, 0, ptr, "", "");
  gfx_setfont(2); ui_col(dy_act ? 0xFFFDD0 : dy_ink);
  dy_act ? sprintf(#gx_lbl, fmt, slider(idx)) : strcpy(#gx_lbl, label);
  ui_text(cx * sc, (gx_y + 39) * sc, #gx_lbl);
);

// printed section outline with its title set into the top edge (readable font 5)
function gx_box(x, title) local(tw, th) (
  gfx_setfont(5); gfx_measurestr(title, tw, th); ui_cola(0xE6CDB4, 0.75);
  gfx_line(x * sc, 84 * sc, (x + 73) * sc - tw * 0.5 - 5 * sc, 84 * sc);
  gfx_line((x + 73) * sc + tw * 0.5 + 5 * sc, 84 * sc, (x + 146) * sc, 84 * sc);
  gfx_line(x * sc, 84 * sc, x * sc, 204 * sc); gfx_line((x + 146) * sc, 84 * sc, (x + 146) * sc, 204 * sc);
  gfx_line(x * sc, 204 * sc, (x + 146) * sc, 204 * sc);
  ui_col(0xE6CDB4); ui_text((x + 73) * sc, 84 * sc - th * 0.5, title);
);

@slider
update();

@block
update();

@serialize
file_var(0, ui_sz);
file_avail(0) != 0 ? file_var(0, pr_cur);    // the preset in use (older projects end before it)
// ui_thm and ui_hw are fixed for this skin and not saved/restored (no theme picker on this panel)

@sample
in_process(spl0, spl1);

// --- Core Grunt Amp Sim DSP Engine (true stereo) ---
// Low-shelf pass-through at 140Hz: as GAIN is pushed up, an increasing fraction of the sub-140Hz
// band skips the gain/grunt stage entirely (bypassed dry) instead of being driven and waveshaped,
// so the low end stays tight and un-fuzzed under heavy drive instead of turning to mush.
low_l = lpL140.lp140_run(in_l); low_r = lpR140.lp140_run(in_r);
high_l = in_l - low_l; high_r = in_r - low_r;
gain_n = (slider1 + 24) / 36;                    // 0 at -24dB .. 1 at +12dB
lowshelf_bypass = gain_n * gain_n * 0.85;        // up to 85% of the low band skips the gain module at max GAIN
dry_low_l = low_l * lowshelf_bypass; dry_low_r = low_r * lowshelf_bypass;

sig_l = high_l + low_l * (1 - lowshelf_bypass);
sig_r = high_r + low_r * (1 - lowshelf_bypass);

// Boost & Gain stage - BOOST (0-100%) adds extra drive on top of GAIN
boost_amt = slider2 / 100;
drive = 1 + (slider1 + 24) / 36 * 3 + boost_amt * 4;
sig_l *= drive;
sig_r *= drive;

// Soft pre-clip: with GAIN and BOOST both driven hard, "drive" above can reach 8x (+18 dB).
// Taming it here with a tanh soft-knee keeps the cubic/even-harmonic terms below from
// exploding into huge, DC-shifted peaks that blow straight past the output stage (even in
// Clip/Limit mode) and can trigger a DAW's protective mute on the master bus.
sig_l = ost_tanh(sig_l);
sig_r = ost_tanh(sig_r);

// Grunt character waveshaping, with BOOST also adding an asymmetric (even-harmonic) warmth bias
grunt_amt = slider3;
grunt_bias = boost_amt * 0.15;
sig_l = sig_l + grunt_amt * 0.4 * (sig_l * sig_l * sig_l) + grunt_bias * (sig_l * sig_l);
sig_r = sig_r + grunt_amt * 0.4 * (sig_r * sig_r * sig_r) + grunt_bias * (sig_r * sig_r);

// Re-introduce the untouched low end that skipped the gain/grunt stage above; it still goes
// through the output stage (squash/sag + clipper/limiter) and master gain like everything else.
sig_l += dry_low_l;
sig_r += dry_low_r;

// Independent stereo band saturation via the output stage
sig_l = ostL.ost_band(sig_l);
sig_r = ostR.ost_band(sig_r);

// Dynamic 330Hz dip: Grunt and Sag both pile up midrange harmonic energy, so the more they're
// driven the more gain is pulled out at 330Hz to stop the amp sounding boxy/congested.
notch_amt = min((slider3 + slider4) * 0.5, 1);     // 0-1, from Grunt + Sag
notch_coeff = notch_amt * 0.5;                     // ~ -6 dB max cut at 330Hz when both are maxed
sig_l -= notch_coeff * nL.svf_bp(sig_l);
sig_r -= notch_coeff * nR.svf_bp(sig_r);

// Stereo-linked output limiter / clipper stage
ost_out(sig_l, sig_r);

master_g = 10 ^ (slider6 / 20);
spl0 = ost_l * master_g;
spl1 = ost_r * master_g;

pkL = max(pkL, abs(spl0)); pkR = max(pkR, abs(spl1));   // post-master stereo output peaks

@gfx 620 252
ui_begin(620, 252);

// warm sunrise wash (burnt orange -> red ember), under everything else - the "Waka" mood
gfx_gradrect(0, 0, gfx_w, gfx_h, 0.62, 0.22, 0.08, 0.16, 0, 0, 0, 0, 0.14 / gfx_h, 0.02 / gfx_h, -0.03 / gfx_h, 0);

// --- Header: logo + name, preset bar [PRESETS][<][>][LCD], S/M/L/? ---
ui_header("GRUNT");
k_ = pk_preset(134 * sc, 7 * sc, 396 * sc, 30 * sc, pr_cur, "Default|Warm Console|American Crunch|British Punch");
k_ > 0 ? (
    preset = k_; pr_cur = k_;
    preset == 1 ? ( slider1 = 0; slider2 = 0;   slider3 = 0.5; slider4 = 0.2; slider5 = 0.5; slider6 = 0;  slider7 = 1; );
    preset == 2 ? ( slider1 = 6; slider2 = 100; slider3 = 0.3; slider4 = 0.4; slider5 = 0.7; slider6 = -2; slider7 = 2; );
    preset == 3 ? ( slider1 = 9; slider2 = 100; slider3 = 0.8; slider4 = 0.1; slider5 = 0.3; slider6 = -4; slider7 = 1; );
    preset == 4 ? ( slider1 = 4; slider2 = 0;   slider3 = 0.6; slider4 = 0.5; slider5 = 0.8; slider6 = -1; slider7 = 2; );
    preset > 0 ? slider_automate(127);   // sliders 1-7
);
// Size picker & help (no theme picker - this panel's "Waka" skin is fixed)
// ui_begin() already clamps sc to the picked Size preset (never scales past it, only down
// to fit a smaller window), so the panel content stops growing once the host window is
// dragged bigger - it just leaves the warm gradient background around it instead of stretching.
ui_size_picker(546 * sc, 15 * sc);

// --- Recessed amp control strip: six matching amp knobs + the output meter ---
pk_inset(26 * sc, 64 * sc, 568 * sc, 162 * sc, 0x2F1A0F);
gfx_gradrect(26 * sc, 140 * sc, 568 * sc, 86 * sc, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0.12 / (86 * sc));   // shade towards the bottom
dy_ink = 0xF6E6D4; dy_numc = 0xE6CDB4; dy_kst = 33; dy_num = 1;
gx_y = 146;
// printed section brackets over the knob pairs
gfx_setfont(5);
gx_box( 37, "PREAMP"); gx_box(197, "CHARACTER"); gx_box(357, "OUTPUT");
gx_knob(70, 24, 1, -24, 12, 0,   0xFFFDD0, "GAIN",   "%+.1f dB");
gx_knob(150, 17, 2, 0, 100, 0,    0xD8B040, "BOOST",  "%.0f%%");
gx_knob(230, 24, 3, 0, 1, 0.5,    0xFFFDD0, "GRUNT",  "%.2f");
gx_knob(310, 24, 4, 0, 1, 0.2,    0xFFFDD0, "SAG",    "%.2f");
gx_knob(390, 24, 5, 0, 1, 0.5,    0xFFFDD0, "SQUASH", "%.2f");
gx_knob(470, 24, 6, -24, 12, 0,   0xFFFDD0, "MASTER", "%+.1f dB");

// stereo output meter tucked into the right end of the strip (L | R, bottom to top)
ui_screen(518 * sc, 76 * sc, 64 * sc, 128 * sc);
mL.ui_ledm(531 * sc, 86 * sc, 14 * sc, 108 * sc, pkL);
mR.ui_ledm(555 * sc, 86 * sc, 14 * sc, 108 * sc, pkR);
pkL *= 0.85; pkR *= 0.85;   // per-redraw decay of the held peaks
gfx_setfont(5); ui_col(dy_ink);
ui_text(538 * sc, 208 * sc, "L"); ui_text(562 * sc, 208 * sc, "R");

ui_end();