bubblechambersimart/src/render/canvasPhoto.js

/* ============================================================
   canvasPhoto.js — the photographic raster renderer.
   A multi-pass compositor that turns the pure scene model into
   something that reads as a worn bubble-chamber plate:
     paper + gas-glow → tonal mottle → ink (soft blooming
     bubbles that merge into lines) → halation → shock disk →
     plate damage → vignette → film grain.
   Geometry is identical to the vector renderer; only the look
   differs. Same code path serves the live preview and the
   high-resolution print render (effect radii scale with size).
   ============================================================ */
import { makeRng } from '../rng.js';
import { sampleBubbles, trackInkWeight } from '../scene/bubbles.js';
import { mottleCanvas, grainCanvas } from './noise.js';

const MARGIN = 0.02;

/* ---- palettes ---- */
function palette(inv) {
  return inv
    ? { paperFlat: '#d3ccb8', glowIn: '#e4ddc9', glowOut: '#b3aa92',
        ink: [28, 24, 19], inkBlend: 'multiply',
        lift: 'screen', vign: [56, 46, 32] }
    : { paperFlat: '#0e0d0b', glowIn: '#211e18', glowOut: '#070605',
        ink: [233, 228, 214], inkBlend: 'screen',
        lift: 'multiply', vign: [0, 0, 0] };
}

/* cached noise canvases (rebuilt only when seed/size change) */
const noiseCache = { key: '', mottleA: null, mottleB: null, grain: null, sprite: null, spriteKey: '' };

function softDotSprite(inkRGB) {
  const key = inkRGB.join(',');
  if (noiseCache.sprite && noiseCache.spriteKey === key) return noiseCache.sprite;
  const S = 64;
  const c = document.createElement('canvas');
  c.width = c.height = S;
  const g = c.getContext('2d');
  const grad = g.createRadialGradient(S / 2, S / 2, 0, S / 2, S / 2, S / 2);
  const [r, gr, b] = inkRGB;
  grad.addColorStop(0.0, `rgba(${r},${gr},${b},1)`);
  grad.addColorStop(0.30, `rgba(${r},${gr},${b},0.92)`);
  grad.addColorStop(0.62, `rgba(${r},${gr},${b},0.40)`);
  grad.addColorStop(1.0, `rgba(${r},${gr},${b},0)`);
  g.fillStyle = grad;
  g.fillRect(0, 0, S, S);
  noiseCache.sprite = c; noiseCache.spriteKey = key;
  return c;
}

export function renderCanvasPhoto(ctx, w, h, scene, params, opts = {}) {
  const pre = opts.preview !== false;
  const inv = params.invert;
  const P = palette(inv);
  const scale = (w / 2) * (1 - MARGIN);
  const cx = w / 2, cy = h / 2;
  const tx = (x) => cx + x * scale;
  const ty = (y) => cy + y * scale;
  const u = w / 1000;                 // unit scale relative to a 1000px render
  const blur = (px) => `blur(${(px * u).toFixed(2)}px)`;

  // ---- noise cache key ----
  const nKey = `${params.seed}|${w}`;
  if (noiseCache.key !== nKey) {
    noiseCache.key = nKey;
    noiseCache.mottleA = mottleCanvas(params.seed, Math.min(512, w), 4, 4);   // broad blotches
    noiseCache.mottleB = mottleCanvas(params.seed + '#b', Math.min(512, w), 14, 4); // medium
    noiseCache.grain = grainCanvas(params.seed, Math.max(256, Math.round(w / 2.2)), 1.15);
  }

  /* ---------- Pass 1: paper + gas glow ---------- */
  ctx.globalCompositeOperation = 'source-over';
  ctx.globalAlpha = 1;
  ctx.fillStyle = P.paperFlat;
  ctx.fillRect(0, 0, w, h);
  const glow = ctx.createRadialGradient(w * 0.5, h * 0.42, 0, w * 0.5, h * 0.5, w * 0.72);
  glow.addColorStop(0, P.glowIn);
  glow.addColorStop(1, P.glowOut);
  ctx.fillStyle = glow;
  ctx.fillRect(0, 0, w, h);

  /* ---------- Pass 2: tonal mottle (uneven development) ---------- */
  if (params.mottle > 0) {
    ctx.save();
    ctx.globalCompositeOperation = inv ? 'multiply' : 'screen';
    ctx.globalAlpha = params.mottle * 0.5;
    ctx.drawImage(noiseCache.mottleA, 0, 0, w, h);
    ctx.globalAlpha = params.mottle * 0.28;
    ctx.drawImage(noiseCache.mottleB, 0, 0, w, h);
    ctx.restore();
  }

  /* ---------- Pass 2.5: chamber optics / structural geometry ---------- */
  if (scene.instrument) drawInstrument(ctx, scene.instrument, tx, ty, scale, u, P, inv);

  /* ---------- Pass 3: ink layer (offscreen, transparent) ---------- */
  const ink = document.createElement('canvas');
  ink.width = w; ink.height = h;
  const ic = ink.getContext('2d');
  const [ir, ig, ib] = P.ink;
  const sprite = softDotSprite(P.ink);

  // NOTE: never set ic.filter here — a filter set before the bubble loop is
  // re-applied to every single drawImage stamp (tens of thousands), which is
  // catastrophically slow and scales with size. Softness is the sprite's job,
  // plus one whole-layer blur at composite time (Pass 5).

  // 3a. continuity under-stroke beneath each track
  ic.lineCap = 'round'; ic.lineJoin = 'round';
  for (const track of scene.tracks) {
    if (track.pts.length < 2) continue;
    const iw = trackInkWeight(track);
    const wgt = track.weight;
    const lw = Math.min(2.6, (0.25 + Math.sqrt(iw) * 0.12)) * u * params.size * wgt;
    if (lw < 0.2 * u) continue;
    ic.strokeStyle = `rgba(${ir},${ig},${ib},${0.14 * wgt})`;
    ic.lineWidth = lw;
    ic.beginPath();
    ic.moveTo(tx(track.pts[0].x), ty(track.pts[0].y));
    for (let i = 1; i < track.pts.length; i++) ic.lineTo(tx(track.pts[i].x), ty(track.pts[i].y));
    ic.stroke();
  }

  // 3b. soft blooming bubbles (stamped sprite; overlaps merge into lines)
  const bubbleRng = makeRng(params.seed, 'bubbles');
  for (const track of scene.tracks) {
    const bubs = sampleBubbles(track, params, bubbleRng);
    ic.globalAlpha = Math.min(1, 0.45 + track.weight * 0.5);
    for (const b of bubs) {
      const rr = Math.max(b.r * scale, 0.45);
      const d = rr * 2.4;            // sprite footprint a touch larger than core
      ic.drawImage(sprite, tx(b.x) - d / 2, ty(b.y) - d / 2, d, d);
    }
  }
  ic.globalAlpha = 1;

  // 3c. shock disk drawn into the ink layer so bloom catches it
  if (scene.shock) drawShock(ic, scene.shock, tx, ty, scale, u, P, params, sprite);

  /* ---------- Pass 4: halation / bloom ---------- */
  // composite a blurred copy of the ink under the sharp ink for soft spread
  if (params.bloom > 0) {
    ctx.save();
    ctx.globalCompositeOperation = P.inkBlend;
    ctx.globalAlpha = Math.min(0.9, params.bloom * 0.7);
    ctx.filter = blur(pre ? 2.4 : 3.0);
    ctx.drawImage(ink, 0, 0);
    ctx.filter = 'none';
    ctx.restore();
  }

  /* ---------- Pass 5: composite sharp ink onto paper (one soft-focus blur) ---------- */
  ctx.save();
  ctx.globalCompositeOperation = P.inkBlend;
  ctx.globalAlpha = 1;
  ctx.filter = blur(pre ? 0.5 : 0.7);   // single whole-layer blur, not per-stamp
  ctx.drawImage(ink, 0, 0);
  ctx.filter = 'none';
  ctx.restore();

  /* ---------- Pass 6: plate damage ---------- */
  drawDamage(ctx, scene.artifacts, tx, ty, scale, u, P, inv);

  /* ---------- Pass 7: fiducials, boundary & archival header ---------- */
  drawFiducialsBoundary(ctx, w, h, params, scale, cx, cy, tx, ty, u, P, inv);
  if (params.showHeader) drawHeader(ctx, w, h, scene, params, u, P);

  /* ---------- Pass 8: vignette ---------- */
  if (params.vign > 0) {
    const vg = ctx.createRadialGradient(w / 2, h / 2, w * 0.28, w / 2, h / 2, w * 0.72);
    const [vr, vgc, vb] = P.vign;
    vg.addColorStop(0, `rgba(${vr},${vgc},${vb},0)`);
    vg.addColorStop(1, `rgba(${vr},${vgc},${vb},${params.vign * (inv ? 0.5 : 0.85)})`);
    ctx.fillStyle = vg;
    ctx.fillRect(0, 0, w, h);
  }

  /* ---------- Pass 9: film grain ---------- */
  if (params.grain > 0) {
    ctx.save();
    ctx.globalCompositeOperation = 'overlay';
    ctx.globalAlpha = Math.min(0.85, params.grain * 0.7);
    // tile the grain canvas across at ~1:1.6 so clumps are supra-pixel
    const gsz = noiseCache.grain.width;
    const tile = gsz * 1.6;
    for (let gy = 0; gy < h; gy += tile) {
      for (let gx = 0; gx < w; gx += tile) {
        ctx.drawImage(noiseCache.grain, gx, gy, tile, tile);
      }
    }
    ctx.restore();
  }
  ctx.globalCompositeOperation = 'source-over';
  ctx.globalAlpha = 1;
}

/* ---- shock disk ---- */
function drawShock(c, shock, tx, ty, scale, u, P, params, sprite) {
  const [r, g, b] = P.ink;
  const px = tx(shock.x), py = ty(shock.y), R = shock.r * scale;
  const useBubbles = params.diskBubbles !== false;

  // when softening, draw the whole disk to its own offscreen and composite it
  // back through a single Gaussian blur — softens just this layer's edges.
  const soften = (params.diskSoften || 0) * u;
  let T = c, tmp = null;
  if (soften > 0) {
    tmp = document.createElement('canvas');
    tmp.width = c.canvas.width; tmp.height = c.canvas.height;
    T = tmp.getContext('2d');
  }

  // disk body: dark annulus that keeps a lighter, detailed centre.
  // softer when the line work is bubbles (the bubbles carry the density).
  const bodyK = useBubbles ? 0.6 : 1.0;
  const core = T.createRadialGradient(px, py, 0, px, py, R);
  core.addColorStop(0.0, `rgba(${r},${g},${b},${0.06 * shock.intensity * bodyK})`);
  core.addColorStop(0.35, `rgba(${r},${g},${b},${0.18 * shock.intensity * bodyK})`);
  core.addColorStop(0.72, `rgba(${r},${g},${b},${0.38 * shock.intensity * bodyK})`);
  core.addColorStop(0.94, `rgba(${r},${g},${b},${0.34 * shock.intensity * bodyK})`);
  core.addColorStop(1, `rgba(${r},${g},${b},0)`);
  T.fillStyle = core;
  T.beginPath(); T.arc(px, py, R, 0, Math.PI * 2); T.fill();

  if (useBubbles && shock.bubbleStrokes) {
    // describe striations / rings / rim / core with the particle method
    const dRng = makeRng(params.seed, 'diskbubbles');
    for (const stroke of shock.bubbleStrokes) {
      const bubs = sampleBubbles(stroke, params, dRng);
      T.globalAlpha = Math.min(1, 0.45 + stroke.weight * 0.5);
      for (const bb of bubs) {
        const rr = Math.max(bb.r * scale, 0.45);
        const d = rr * 2.4;
        T.drawImage(sprite, tx(bb.x) - d / 2, ty(bb.y) - d / 2, d, d);
      }
    }
    T.globalAlpha = 1;
  } else {
    // clean vector strokes
    T.lineCap = 'round';
    for (const s of shock.striations) {
      const ix = px + Math.cos(s.a) * s.inner * scale, iy = py + Math.sin(s.a) * s.inner * scale;
      const ox = px + Math.cos(s.a) * s.outer * scale, oy = py + Math.sin(s.a) * s.outer * scale;
      const mx = (ix + ox) / 2 + Math.cos(s.a + Math.PI / 2) * s.wobble * scale;
      const my = (iy + oy) / 2 + Math.sin(s.a + Math.PI / 2) * s.wobble * scale;
      T.strokeStyle = `rgba(${r},${g},${b},${s.opacity})`;
      T.lineWidth = s.width * u;
      T.beginPath(); T.moveTo(ix, iy); T.quadraticCurveTo(mx, my, ox, oy); T.stroke();
    }
    for (const ring of shock.rings) {
      T.strokeStyle = `rgba(${r},${g},${b},${ring.opacity})`;
      T.lineWidth = ring.width * u;
      T.beginPath(); T.arc(px, py, ring.rr * scale, 0, Math.PI * 2); T.stroke();
    }
    for (const seg of (shock.rimSegs || [])) {
      T.strokeStyle = `rgba(${r},${g},${b},${seg.opacity})`;
      T.lineWidth = seg.width * u;
      T.beginPath(); T.arc(px, py, shock.r * scale, seg.a0, seg.a1); T.stroke();
    }
    for (const k of shock.core) {
      T.strokeStyle = `rgba(${r},${g},${b},${k.opacity})`;
      T.lineWidth = k.width * u;
      T.beginPath(); T.moveTo(tx(k.x1), ty(k.y1)); T.lineTo(tx(k.x2), ty(k.y2)); T.stroke();
    }
  }

  // staining blotches: dark = grime, light = lifted/washed clean spots
  if (shock.stains) {
    for (const st of shock.stains) {
      const sr = st.r * scale;
      const grad = T.createRadialGradient(tx(st.x), ty(st.y), 0, tx(st.x), ty(st.y), sr);
      if (st.dark) {
        T.globalCompositeOperation = 'source-over';
        grad.addColorStop(0, `rgba(${r},${g},${b},${st.opacity})`);
        grad.addColorStop(1, `rgba(${r},${g},${b},0)`);
        T.fillStyle = grad;
      } else {
        T.globalCompositeOperation = 'destination-out';
        grad.addColorStop(0, `rgba(0,0,0,${st.opacity * 1.4})`);
        grad.addColorStop(1, 'rgba(0,0,0,0)');
        T.fillStyle = grad;
      }
      T.beginPath(); T.arc(tx(st.x), ty(st.y), sr, 0, Math.PI * 2); T.fill();
    }
    T.globalCompositeOperation = 'source-over';
  }

  // keep a bright, detailed centre by clearing a soft hole
  if (shock.bright) {
    T.save();
    T.globalCompositeOperation = 'destination-out';
    const hole = T.createRadialGradient(px, py, 0, px, py, shock.bright * scale);
    hole.addColorStop(0, 'rgba(0,0,0,0.85)');
    hole.addColorStop(1, 'rgba(0,0,0,0)');
    T.fillStyle = hole;
    T.beginPath(); T.arc(px, py, shock.bright * scale, 0, Math.PI * 2); T.fill();
    T.restore();
  }

  // composite the (optionally blurred) disk back onto the ink layer
  if (tmp) {
    c.save();
    c.filter = `blur(${soften.toFixed(2)}px)`;
    c.drawImage(tmp, 0, 0);
    c.filter = 'none';
    c.restore();
  }
}

/* ---- plate damage ---- */
function drawDamage(ctx, A, tx, ty, scale, u, P, inv) {
  if (!A) return;
  const [r, g, b] = P.ink;
  ctx.save();

  // water rings (faint, under)
  ctx.globalCompositeOperation = inv ? 'multiply' : 'screen';
  for (const ring of A.rings) {
    ctx.strokeStyle = `rgba(${r},${g},${b},${ring.opacity})`;
    ctx.lineWidth = ring.width * u;
    ctx.beginPath(); ctx.arc(tx(ring.x), ty(ring.y), ring.r * scale, 0, Math.PI * 2); ctx.stroke();
  }

  // fingerprints
  for (const fp of A.fingerprints) {
    ctx.strokeStyle = `rgba(${r},${g},${b},${fp.opacity})`;
    ctx.lineWidth = 0.7 * u;
    for (const lp of fp.loops) {
      ctx.save();
      ctx.translate(tx(fp.x), ty(fp.y));
      ctx.rotate(lp.rot);
      ctx.scale(1, lp.squash);
      ctx.beginPath(); ctx.arc(0, 0, lp.rr * scale, 0, Math.PI * 2); ctx.stroke();
      ctx.restore();
    }
  }

  // scratches: dark (multiply) and bright (lift)
  for (const s of A.scratches) {
    ctx.globalCompositeOperation = s.bright ? P.lift : (inv ? 'multiply' : 'screen');
    const col = s.bright ? (inv ? '245,242,232' : '0,0,0') : `${r},${g},${b}`;
    ctx.strokeStyle = `rgba(${col},${s.opacity})`;
    ctx.lineWidth = s.width * u;
    ctx.beginPath(); ctx.moveTo(tx(s.x1), ty(s.y1)); ctx.lineTo(tx(s.x2), ty(s.y2)); ctx.stroke();
  }

  // hairs
  ctx.globalCompositeOperation = inv ? 'multiply' : 'screen';
  for (const hair of A.hairs) {
    ctx.strokeStyle = `rgba(${r},${g},${b},${hair.opacity})`;
    ctx.lineWidth = hair.width * u;
    ctx.beginPath();
    ctx.moveTo(tx(hair.pts[0].x), ty(hair.pts[0].y));
    for (let i = 1; i < hair.pts.length; i++) ctx.lineTo(tx(hair.pts[i].x), ty(hair.pts[i].y));
    ctx.stroke();
  }

  // dust specks (over)
  for (const sp of A.specks) {
    ctx.fillStyle = `rgba(${r},${g},${b},${sp.opacity})`;
    ctx.beginPath(); ctx.arc(tx(sp.x), ty(sp.y), Math.max(sp.r * scale, 0.4), 0, Math.PI * 2); ctx.fill();
  }
  ctx.restore();
}

/* ---- chamber optics / structural geometry ---- */
function drawInstrument(ctx, inst, tx, ty, scale, u, P, inv) {
  const [r, g, b] = P.ink;
  ctx.save();
  ctx.globalCompositeOperation = inv ? 'multiply' : 'screen';
  ctx.lineCap = 'round';
  ctx.filter = `blur(${(0.4 * u).toFixed(2)}px)`;
  for (const l of inst.lines) {
    ctx.strokeStyle = `rgba(${r},${g},${b},${l.opacity})`;
    ctx.lineWidth = l.width * u;
    ctx.beginPath(); ctx.moveTo(tx(l.x1), ty(l.y1)); ctx.lineTo(tx(l.x2), ty(l.y2)); ctx.stroke();
  }
  for (const a of inst.arcs) {
    ctx.strokeStyle = `rgba(${r},${g},${b},${a.opacity})`;
    ctx.lineWidth = a.width * u;
    ctx.beginPath();
    ctx.moveTo(tx(a.pts[0].x), ty(a.pts[0].y));
    for (let i = 1; i < a.pts.length; i++) ctx.lineTo(tx(a.pts[i].x), ty(a.pts[i].y));
    ctx.stroke();
  }
  ctx.restore();
}

/* ---- archival header (rendered text, baked into the plate) ---- */
function drawHeader(ctx, w, h, scene, params, u, P) {
  const [r, g, b] = P.ink;
  ctx.save();
  ctx.globalCompositeOperation = params.invert ? 'multiply' : 'screen';
  ctx.fillStyle = `rgba(${r},${g},${b},0.62)`;
  const pad = 26 * u;
  ctx.font = `${11 * u}px 'JetBrains Mono', ui-monospace, monospace`;
  ctx.textBaseline = 'top';
  ctx.fillText(scene.lab.toUpperCase(), pad, pad);
  ctx.font = `${9 * u}px 'JetBrains Mono', ui-monospace, monospace`;
  ctx.fillStyle = `rgba(${r},${g},${b},0.5)`;
  ctx.fillText(`SEED ${params.seed}`, pad, pad + 16 * u);

  ctx.textAlign = 'right';
  ctx.textBaseline = 'bottom';
  ctx.font = `${10 * u}px 'JetBrains Mono', ui-monospace, monospace`;
  ctx.fillStyle = `rgba(${r},${g},${b},0.58)`;
  ctx.fillText(`PLATE ${scene.plate}`, w - pad, h - pad - 13 * u);
  ctx.fillText(`EXPOSED ${scene.exposure}`, w - pad, h - pad);
  ctx.restore();
}

/* ---- fiducials & chamber boundary ---- */
function drawFiducialsBoundary(ctx, w, h, params, scale, cx, cy, tx, ty, u, P, inv) {
  const [r, g, b] = P.ink;
  if (params.showBoundary) {
    ctx.strokeStyle = `rgba(${r},${g},${b},0.4)`;
    ctx.lineWidth = 1.4 * u;
    ctx.beginPath();
    ctx.arc(cx, cy + h * 0.35, w * 0.45, Math.PI * 0.15, Math.PI - Math.PI * 0.15, false);
    ctx.stroke();
  }
  if (params.showFiducials) {
    ctx.strokeStyle = `rgba(${r},${g},${b},0.55)`;
    ctx.lineWidth = 1 * u;
    const fids = [[-0.85, -0.85], [0.85, -0.85], [-0.85, 0.85], [0.85, 0.85], [0, -0.85], [-0.85, 0], [0.85, 0]];
    const s = 6 * u;
    for (const [fx, fy] of fids) {
      const px = tx(fx), py = ty(fy);
      ctx.beginPath();
      ctx.moveTo(px - s, py); ctx.lineTo(px + s, py);
      ctx.moveTo(px, py - s); ctx.lineTo(px, py + s);
      ctx.stroke();
    }
  }
}