(function () {
  "use strict";

  var W = 1920, H = 1080, TARGET = 325000, SEED = 8262707;
  var photoLayer, sourceLayer, paintLayer, painted = false, skyMask;
  var REFERENCE_DATA = "__REFERENCE_DATA__";
  // Calibrated from the user-selected atmospheric proof, then widened with
  // a few pearly notes from the Rouen reference palette.
  var MONET_LIGHT = ["#cbc2a4", "#c5b396", "#c2a37d", "#b3aa95", "#d3c9b2", "#d6d2c7"];
  var MONET_COOL = ["#788688", "#697b82", "#66757a", "#8d9490", "#817e7a", "#8fadcB"];
  var MONET_STONE = ["#c2a37d", "#c5b396", "#b3aa95", "#968a7c", "#817e7a", "#ccae70"];
  var MONET_DARK = ["#526975", "#66757a", "#6e7178", "#817e7a", "#756c6d"];
  var MONET_ROSE = ["#b9827f", "#c69587", "#a87978", "#c2a37d", "#9f8582"];

  function embeddedReferenceCanvas() {
    var binary = atob(REFERENCE_DATA), bytes = new Uint8ClampedArray(binary.length);
    for (var i = 0; i < binary.length; i += 1) bytes[i] = binary.charCodeAt(i);
    // Chroma-key only the photographed blue sky, retaining every dome,
    // statue, cornice, and balustrade pixel. A continuous warm-to-cool field
    // removes the photographic rectangle without drawing a hard replacement
    // shape around the architecture.
    skyMask = new Uint8Array(960 * 540);
    for (var y = 0; y < 310; y += 1) {
      for (var x = 0; x < 960; x += 1) {
        var p = (y * 960 + x) * 4, r = bytes[p], g = bytes[p + 1], b = bytes[p + 2];
        if (b > 118 && b > r * 1.28 && b > g * 1.05) {
          skyMask[y * 960 + x] = 1;
          var t = x / 959, warm = Math.exp(-Math.pow((t - .22) / .34, 2));
          var cloud = Math.sin(x * .019 + y * .037) * 5 + Math.sin(x * .007 - y * .021) * 4;
          bytes[p] = Math.max(0, Math.min(255, 159 + warm * 55 + cloud));
          bytes[p + 1] = Math.max(0, Math.min(255, 181 + warm * 36 + cloud));
          bytes[p + 2] = Math.max(0, Math.min(255, 201 + warm * 10 + cloud * .5));
        }
      }
    }
    var canvas = document.createElement("canvas");
    canvas.width = 960; canvas.height = 540;
    canvas.getContext("2d").putImageData(new ImageData(bytes, 960, 540), 0, 0);
    return canvas;
  }

  function glow(ctx, x, y, radius, inner, outer) {
    var g = ctx.createRadialGradient(x, y, 0, x, y, radius);
    g.addColorStop(0, inner); g.addColorStop(1, outer);
    ctx.fillStyle = g; ctx.fillRect(x - radius, y - radius, radius * 2, radius * 2);
  }

  function buildReference() {
    photoLayer.clear();
    photoLayer.drawingContext.drawImage(embeddedReferenceCanvas(), 0, 0, W, H);
    sourceLayer.clear();
    sourceLayer.image(photoLayer, 0, 0, W, H);
    var c = sourceLayer.drawingContext;

    // Pull the midday photograph toward a pearly after-rain key without
    // flattening its architecture. All passages are soft gradients; there are
    // no rectangular cloud masks for the sampler to reinforce.
    c.save();
    c.globalCompositeOperation = "screen";
    var veil = c.createLinearGradient(0, 0, W, H);
    veil.addColorStop(0, "rgba(239,230,205,.28)");
    veil.addColorStop(.45, "rgba(205,217,221,.16)");
    veil.addColorStop(1, "rgba(189,201,212,.08)");
    c.fillStyle = veil; c.fillRect(0, 0, W, H);
    glow(c, 360, 175, 520, "rgba(255,223,165,.48)", "rgba(255,232,182,0)");
    c.restore();

    c.save();
    c.globalCompositeOperation = "soft-light";
    glow(c, 1580, 120, 650, "rgba(82,111,145,.62)", "rgba(82,111,145,0)");
    glow(c, 1210, 500, 470, "rgba(229,190,145,.38)", "rgba(229,190,145,0)");
    c.restore();

    // A compressed, softened echo of the facade becomes the wet piazza.
    sourceLayer.push();
    sourceLayer.translate(0, 1800);
    sourceLayer.scale(1, -1);
    sourceLayer.tint(196, 118);
    sourceLayer.image(photoLayer, 0, 720, W, 360, 0, 420, W, 420);
    sourceLayer.noTint();
    sourceLayer.pop();
    c.save();
    var wet = c.createLinearGradient(0, 690, 0, H);
    wet.addColorStop(0, "rgba(151,175,184,.30)");
    wet.addColorStop(.55, "rgba(102,132,151,.42)");
    wet.addColorStop(1, "rgba(78,105,128,.58)");
    c.fillStyle = wet; c.fillRect(0, 690, W, H - 690);
    c.globalCompositeOperation = "screen";
    glow(c, 1110, 760, 520, "rgba(238,211,167,.28)", "rgba(238,211,167,0)");
    c.restore();

    window.__referenceAttribution = {
      title: "Saint Peter's Square", creator: "Fatima ezzahra el bouabi",
      source: "https://commons.wikimedia.org/wiki/File:Saint_Peter%E2%80%99s_square.jpg",
      license: "CC0 1.0",
      use: "architectural geometry only; reframed, recolored, reflected, and repainted"
    };
  }

  function frac(x) { return x - Math.floor(x); }
  function colorFor(sample, palette, amount, jitter) {
    return impressionist.sampledColor(sample, { palette: palette, amount: amount, jitter: jitter });
  }
  function opticalField(spec) {
    impressionist.setLayer(spec.layer);
    var phi = 0.6180339887498949, psi = 0.7548776662466927;
    var painted = 0, attempt = 0;
    while (painted < spec.calls) {
      var i = attempt;
      attempt += 1;
      if (attempt > spec.calls * 30) throw new Error("optical field could not fill " + spec.layer);
      var u = frac((i + 1) * phi + spec.phase), v = frac((i + 1) * psi + spec.phase * .71);
      var x = spec.x + u * spec.w, y = spec.y + v * spec.h;
      var px = impressionistSampler.sample(x, y);
      if (spec.accept && !spec.accept(px, x, y)) continue;
      var grad = impressionistSampler.orientation(x, y, spec.gradientRadius || 3);
      var angle = typeof spec.angle === "function" ? spec.angle(x, y, grad, i) : grad.angle;
      angle += (impressionist.random() - .5) * 2 * spec.angleJitter;
      var depth = Math.max(0, Math.min(1, y / H));
      var lengthRange = typeof spec.length === "function" ? spec.length(x, y, i) : spec.length;
      var widthRange = typeof spec.width === "function" ? spec.width(x, y, i) : spec.width;
      var opacityRange = typeof spec.opacity === "function" ? spec.opacity(x, y, i) : spec.opacity;
      var length = lengthRange[0] + (lengthRange[1] - lengthRange[0]) * impressionist.random();
      var width = widthRange[0] + (widthRange[1] - widthRange[0]) * impressionist.random();
      var opacity = opacityRange[0] + (opacityRange[1] - opacityRange[0]) * impressionist.random();
      var scale = spec.distanceScale ? impressionist.distanceScale(depth, { near: spec.distanceScale[0], far: spec.distanceScale[1], maxDistance: 1 }) : 1;
      impressionist.curvedBristle(x, y, {
        color: colorFor(px, spec.palette, spec.paletteAmount, spec.paletteJitter),
        opacity: opacity, length: length * scale, width: width * scale,
        angle: angle, bend: (impressionist.random() - .5) * 2 * spec.bend,
        segments: 5, bristles: spec.bristles, spread: spec.spread,
        type: spec.type
      });
      painted += 1;
    }
  }

  function blueAir(px, x, y) {
    var sx = Math.max(0, Math.min(959, Math.floor(x / W * 960)));
    var sy = Math.max(0, Math.min(539, Math.floor(y / H * 540)));
    return Boolean(skyMask[sy * 960 + sx]);
  }
  function observedStone(px, x, y) {
    return y > 135 && y < 850 && !blueAir(px, x, y);
  }

  function paint() {
    var ctx = paintLayer.drawingContext;
    impressionist.reset({ seed: SEED, ctx: ctx });
    impressionistSampler.reset({ seed: SEED, source: sourceLayer.drawingContext, width: W, height: H });
    ctx.fillStyle = "#8799a3"; ctx.fillRect(0, 0, W, H);

    opticalField({ layer: "pearly-ground", type: "broad-underpainting", calls: 18000, bristles: 1, x: 0, y: 0, w: W, h: H, phase: .17, palette: MONET_COOL.concat(MONET_LIGHT), paletteAmount: .42, paletteJitter: .10, length: [28, 78], width: [6, 15], opacity: [.20, .36], angleJitter: 22, bend: 9, spread: 2, distanceScale: [1.15, .72] });
    opticalField({ layer: "breathing-sky", type: "curved-sky-bristle", calls: 28000, bristles: 3, x: 0, y: 0, w: W, h: 470, phase: .31, accept: blueAir, palette: MONET_LIGHT.concat(MONET_COOL), paletteAmount: .30, paletteJitter: .11, length: [24, 66], width: [2.6, 8], opacity: [.13, .29], angle: function(x,y){ return -12 + Math.sin(x * .006 + y * .013) * 9; }, angleJitter: 13, bend: 10, spread: 4.2, distanceScale: [1.1, .88] });
    opticalField({ layer: "stone-mass", type: "facade-broken-color", calls: 25000, bristles: 3, x: 170, y: 135, w: 1630, h: 695, phase: .47, accept: observedStone, palette: MONET_STONE.concat(MONET_STONE).concat(MONET_COOL), paletteAmount: .48, paletteJitter: .10, length: [9, 31], width: [1.5, 5.2], opacity: [.30, .58], angleJitter: 16, bend: 5.5, spread: 2.4, distanceScale: [.82, 1.08] });
    opticalField({ layer: "architecture-turning", type: "form-following-bristle", calls: 35000, bristles: 2, x: 180, y: 135, w: 1600, h: 695, phase: .63, accept: observedStone, palette: MONET_STONE.concat(MONET_DARK).concat(MONET_LIGHT), paletteAmount: .32, paletteJitter: .08, length: [5, 18], width: [.8, 3.2], opacity: [.32, .66], angleJitter: 9, bend: 3.2, spread: 1.5, distanceScale: [.72, 1.04] });
    opticalField({ layer: "wet-reflection", type: "vertical-reflection-bristle", calls: 17000, bristles: 2, x: 0, y: 680, w: W, h: 400, phase: .79, palette: MONET_COOL.concat(MONET_STONE).concat(MONET_ROSE).concat(MONET_DARK), paletteAmount: .46, paletteJitter: .14, length: function(x){ var focus = 1 - Math.min(1, Math.abs(x - 980) / 980); return [16 + focus * 16, 45 + focus * 48]; }, width: function(x){ var focus = 1 - Math.min(1, Math.abs(x - 980) / 980); return [1.1 + focus * .5, 4.2 + focus * 2.4]; }, opacity: function(x){ var focus = 1 - Math.min(1, Math.abs(x - 980) / 980); return [.12 + focus * .08, .28 + focus * .22]; }, angle: function(x,y,g,i){ return 88 + Math.sin(x * .014 + i * .03) * 9; }, angleJitter: 13, bend: 12, spread: 3.2, distanceScale: [.68, 1.18] });
    opticalField({ layer: "wet-glints", type: "broken-piazza-glint", calls: 19000, bristles: 2, x: 0, y: 720, w: W, h: 360, phase: .91, palette: MONET_LIGHT.concat(MONET_ROSE).concat(MONET_COOL), paletteAmount: .68, paletteJitter: .18, length: [4, 22], width: [.7, 3.4], opacity: [.15, .44], angle: function(){ return 2; }, angleJitter: 18, bend: 4, spread: 1.8, distanceScale: [.62, 1.28] });
    opticalField({ layer: "facade-anchors", type: "selective-dark-stone", calls: 2500, bristles: 1, x: 260, y: 235, w: 1420, h: 525, phase: .103, accept: observedStone, palette: MONET_DARK.concat(MONET_STONE), paletteAmount: .62, paletteJitter: .06, length: [3, 11], width: [.7, 2.4], opacity: [.28, .58], angleJitter: 7, bend: 2.2, spread: 1.1, distanceScale: [.78, 1] });
    opticalField({ layer: "waterline", type: "broken-waterline", calls: 1500, bristles: 1, x: 70, y: 660, w: 1780, h: 82, phase: .119, palette: MONET_DARK.concat(MONET_STONE), paletteAmount: .48, paletteJitter: .08, length: [8, 36], width: [.8, 2.8], opacity: [.22, .48], angle: function(){ return 1; }, angleJitter: 9, bend: 3, spread: 1, distanceScale: [1, 1] });
    opticalField({ layer: "central-reflection", type: "luminous-central-reflection", calls: 1000, bristles: 2, x: 610, y: 690, w: 740, h: 390, phase: .137, palette: MONET_LIGHT.concat(MONET_STONE).concat(MONET_ROSE), paletteAmount: .66, paletteJitter: .1, length: [14, 58], width: [2.2, 8.2], opacity: [.14, .31], angle: function(x,y,g,i){ return 90 + Math.sin(i * .17) * 5; }, angleJitter: 9, bend: 7, spread: 3.2, distanceScale: [.7, 1.18] });

    if (impressionist.report().marks !== TARGET) throw new Error("exact mark target failed: " + impressionist.report().marks);
    // Transparent optical glazes unify the marks without adding synthetic
    // geometry or inflating the semantic stroke ledger.
    ctx.save();
    ctx.globalCompositeOperation = "multiply";
    var depth = ctx.createLinearGradient(0, 650, 0, H);
    depth.addColorStop(0, "rgba(72,91,108,0)");
    depth.addColorStop(1, "rgba(72,91,108,.18)");
    ctx.fillStyle = depth; ctx.fillRect(0, 640, W, H - 640);
    var lateral = ctx.createLinearGradient(0, 0, W, 0);
    lateral.addColorStop(0, "rgba(64,82,103,.12)");
    lateral.addColorStop(.32, "rgba(64,82,103,0)");
    lateral.addColorStop(.68, "rgba(64,82,103,0)");
    lateral.addColorStop(1, "rgba(64,82,103,.12)");
    ctx.fillStyle = lateral; ctx.fillRect(0, 650, W, H - 650);
    ctx.globalCompositeOperation = "soft-light";
    glow(ctx, 760, 470, 720, "rgba(221,173,102,.18)", "rgba(221,173,102,0)");
    glow(ctx, 980, 820, 480, "rgba(226,186,118,.20)", "rgba(226,186,118,0)");
    ctx.globalCompositeOperation = "screen";
    var leftAir = ctx.createLinearGradient(0, 0, 280, 0);
    leftAir.addColorStop(0, "rgba(179,195,203,.28)"); leftAir.addColorStop(1, "rgba(179,195,203,0)");
    ctx.fillStyle = leftAir; ctx.fillRect(0, 170, 300, 540);
    var rightAir = ctx.createLinearGradient(W, 0, W - 260, 0);
    rightAir.addColorStop(0, "rgba(181,190,193,.25)"); rightAir.addColorStop(1, "rgba(181,190,193,0)");
    ctx.fillStyle = rightAir; ctx.fillRect(W - 300, 170, 300, 540);
    ctx.restore();
    image(paintLayer, -W / 2, -H / 2, W, H);
    window.__impressionistReport = impressionist.report();
    window.__impressionistSamplerReport = impressionistSampler.report();
  }

  function setup() {
    createCanvas(W, H, WEBGL);
    photoLayer = createGraphics(W, H);
    sourceLayer = createGraphics(W, H);
    paintLayer = createGraphics(W, H);
    buildReference();
    noLoop();
  }
  function draw() {
    if (painted) return;
    painted = true;
    paint();
  }

  window.setup = setup;
  window.draw = draw;
  window.__saintPetersScene = {
    title: "Saint Peter's Basilica After Rain — Optical Facade Study",
    width: W, height: H, targetMarks: TARGET,
    engine: "impressionist-v1.3",
    reference: "CC0 architectural geometry; no ImageGen"
  };
}());