04シードで同じ順番を繰り返すサイコロ

<main class="stage">
<div class="bp is-demo" id="bpRoot">
  <canvas class="bp__canvas" id="bpCanvas" width="480" height="300" role="img" aria-label="線形合同法の数列で投げるたびの初期回転と速度を決め、同じシードなら同じ目が同じ順に出ることを、先に計算しておいた上の列と今転がしている下の列の目の履歴で見比べる。"></canvas>
  <output class="bp__status" aria-live="polite"><span id="bpLabel">転がり中</span> <b id="bpNum"></b></output>
  <button type="button" class="bp__btn" id="bpBtn">振る</button>
  <p class="bp__caption">線形合同法の数列で投げるたびの初期回転と速度を決め、同じシードなら同じ目が同じ順に出ることを、先に計算しておいた上の列と今転がしている下の列の目の履歴で見比べる。</p>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);

.bp {
  position: relative;
  width: min(92vw, calc(160vh - 12.8vw));
  aspect-ratio: 480 / 300;
  margin: 0 auto;
  border-radius: $r-card;
  overflow: hidden;
  box-shadow: $shadow-raised;
  background: $stage-ink;
}

.bp__canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.bp__status {
  position: absolute;
  left: $sp-3;
  top: $sp-3;
  display: flex;
  align-items: baseline;
  gap: $sp-2;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
}

.bp__status b {
  min-width: 1ch;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.bp__btn {
  position: absolute;
  right: $sp-3;
  top: $sp-3;
  min-height: $sp-8;
  padding: 0 $sp-4;
  border: 0;
  border-radius: $r-control;
  background: $subject-cream;
  color: $subject-ink;
  font-weight: 700;
  font-size: 13px;
  line-height: 1;
  cursor: pointer;
  box-shadow: $shadow-press;
  transition: transform $dur-instant $ease-out;
}

.bp__btn:hover { transform: translateY(-1px); }
.bp__btn:active { transform: translateY(1px); }

.bp__btn:focus-visible {
  outline: 2px solid rgba(255, 255, 255, .9);
  outline-offset: 2px;
}

.bp__canvas:focus-visible {
  outline: 2px solid rgba(255, 255, 255, .85);
  outline-offset: -6px;
}

.bp__caption {
  position: absolute;
  left: $sp-3;
  bottom: $sp-3;
  max-width: 80%;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .85);
  color: $subject-ink;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  pointer-events: none;
}

@media (max-width: 340px) {
  .bp__caption { font-size: 10px; padding: $sp-1 $sp-2; }
  .bp__status { font-size: 10px; padding: $sp-1 $sp-2; }
  .bp__btn { font-size: 11px; padding: 0 $sp-3; }
}

@media (prefers-reduced-motion: reduce) {
  .bp { cursor: default; }
  .bp__btn { transition: none; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.bp {
  position: relative;
  width: min(92vw, 160vh - 12.8vw);
  aspect-ratio: 480/300;
  margin: 0 auto;
  border-radius: 16px;
  overflow: hidden;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: #17141a;
}

.bp__canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.bp__status {
  position: absolute;
  left: 12px;
  top: 12px;
  display: flex;
  align-items: baseline;
  gap: 8px;
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
}

.bp__status b {
  min-width: 1ch;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.bp__btn {
  position: absolute;
  right: 12px;
  top: 12px;
  min-height: 32px;
  padding: 0 16px;
  border: 0;
  border-radius: 12px;
  background: #fff7e6;
  color: #17141a;
  font-weight: 700;
  font-size: 13px;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  transition: transform 140ms ease-out;
}

.bp__btn:hover {
  transform: translateY(-1px);
}

.bp__btn:active {
  transform: translateY(1px);
}

.bp__btn:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.9);
  outline-offset: 2px;
}

.bp__canvas:focus-visible {
  outline: 2px solid rgba(255, 255, 255, 0.85);
  outline-offset: -6px;
}

.bp__caption {
  position: absolute;
  left: 12px;
  bottom: 12px;
  max-width: 80%;
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #17141a;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  pointer-events: none;
}

@media (max-width: 340px) {
  .bp__caption {
    font-size: 10px;
    padding: 4px 8px;
  }
  .bp__status {
    font-size: 10px;
    padding: 4px 8px;
  }
  .bp__btn {
    font-size: 11px;
    padding: 0 12px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .bp {
    cursor: default;
  }
  .bp__btn {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('bpRoot');
  var canvas = document.getElementById('bpCanvas');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;
  var labelEl = document.getElementById('bpLabel');
  var numEl = document.getElementById('bpNum');
  var btn = document.getElementById('bpBtn');

  var CALC_W = 320, CALC_H = 200;
  var FIXED_DT = 16;
  var dtS = FIXED_DT / 1000;
  var DICE_RESTITUTION = 0.45;
  var SPIN_DAMPING = 0.985;
  var DICE_SEED = 7;
  var GRAVITY = 22;
  var DIE_HALF = 1;
  var INERTIA = 2 * DIE_HALF * DIE_HALF / 3;
  var FLOOR_FRICTION = 0.35;
  var SETTLE_AFTER_MS = 2000;
  var SETTLE_RATE = 0.16;
  var HOLD_MS = 700;
  var CAM_Y = 5.6, CAM_BACK = 12, FOCAL = 275, VIEW_CX = 160, VIEW_CY = 82;
  var TABLE_X = 4.4, TABLE_Z0 = -3, TABLE_Z1 = 5;
  var PH_FLY = 0, PH_SETTLE = 1, PH_HOLD = 2, PH_IDLE = 3;
  var STRIP_BASE = 128;
  var BAR_MAX = 18;
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var demo = !reduce;
  if (!demo) root.classList.remove('is-demo');
  function stopDemo() { demo = false; root.classList.remove('is-demo'); }

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  function clamp(v, lo, hi) { return v < lo ? lo : (v > hi ? hi : v); }
  function lerp(a, b, t) { return a + (b - a) * t; }
  function dot(a, b) { return a[0] * b[0] + a[1] * b[1] + a[2] * b[2]; }
  function cross(a, b) { return [a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]]; }
  function unit(a) { var l = Math.hypot(a[0], a[1], a[2]) || 1; return [a[0] / l, a[1] / l, a[2] / l]; }
  function matMul(a, b) {
    var o = [0, 0, 0, 0, 0, 0, 0, 0, 0];
    for (var i = 0; i < 3; i += 1) {
      for (var j = 0; j < 3; j += 1) o[i * 3 + j] = a[i * 3] * b[j] + a[i * 3 + 1] * b[3 + j] + a[i * 3 + 2] * b[6 + j];
    }
    return o;
  }
  function matVec(m, v) {
    return [m[0] * v[0] + m[1] * v[1] + m[2] * v[2], m[3] * v[0] + m[4] * v[1] + m[5] * v[2], m[6] * v[0] + m[7] * v[1] + m[8] * v[2]];
  }
  // 로드리게스 공식: 단위 축 ax 둘레로 ang 만큼 도는 회전 행렬
  function rotAxis(ax, ang) {
    var c = Math.cos(ang), s = Math.sin(ang), t = 1 - c, x = ax[0], y = ax[1], z = ax[2];
    return [t * x * x + c, t * x * y - s * z, t * x * z + s * y,
      t * x * y + s * z, t * y * y + c, t * y * z - s * x,
      t * x * z - s * y, t * y * z + s * x, t * z * z + c];
  }
  function orthonormalize(m) {
    var a = unit([m[0], m[1], m[2]]);
    var k = a[0] * m[3] + a[1] * m[4] + a[2] * m[5];
    var b = unit([m[3] - a[0] * k, m[4] - a[1] * k, m[5] - a[2] * k]);
    var c = cross(a, b);
    return [a[0], a[1], a[2], b[0], b[1], b[2], c[0], c[1], c[2]];
  }
  function randAxis(rnd) { return unit([rnd() * 2 - 1, rnd() * 2 - 1, rnd() * 2 - 1]); }

  var PITCH = Math.atan2(CAM_Y, CAM_BACK);
  var CAM_S = Math.sin(PITCH), CAM_C = Math.cos(PITCH);
  function camPoint(p) {
    var qy = p[1] - CAM_Y, qz = p[2] + CAM_BACK;
    return [p[0], qy * CAM_C + qz * CAM_S, -qy * CAM_S + qz * CAM_C];
  }
  function camDir(v) { return [v[0], v[1] * CAM_C + v[2] * CAM_S, -v[1] * CAM_S + v[2] * CAM_C]; }
  function scr(p) {
    var c = camPoint(p);
    var k = FOCAL / c[2];
    return [VIEW_CX + c[0] * k, VIEW_CY - c[1] * k, k];
  }

  var FACE_N = [[0, 1, 0], [0, -1, 0], [1, 0, 0], [-1, 0, 0], [0, 0, 1], [0, 0, -1]];
  var FACE_U = [[1, 0, 0], [1, 0, 0], [0, 1, 0], [0, 1, 0], [1, 0, 0], [1, 0, 0]];
  var FACE_V = [[0, 0, 1], [0, 0, 1], [0, 0, 1], [0, 0, 1], [0, 1, 0], [0, 1, 0]];
  var FACE_VAL = [1, 6, 2, 5, 3, 4];
  var PIPS = [[], [[0, 0]], [[-1, -1], [1, 1]], [[-1, -1], [0, 0], [1, 1]],
    [[-1, -1], [1, -1], [-1, 1], [1, 1]], [[-1, -1], [1, -1], [0, 0], [-1, 1], [1, 1]],
    [[-1, -1], [-1, 0], [-1, 1], [1, -1], [1, 0], [1, 1]]];
  var DICE_PAL = [
    { face: [255, 214, 226], edge: [240, 160, 186], pip: '#4b3a63' },
    { face: [200, 232, 255], edge: [140, 190, 236], pip: '#3b4a6b' },
    { face: [224, 212, 255], edge: [170, 150, 232], pip: '#46386b' },
    { face: [255, 240, 196], edge: [236, 206, 120], pip: '#5a4636' }
  ];
  var LIGHT = unit([-0.45, 0.85, -0.35]);

  function newDie(pal, xmin, xmax, zmin, zmax) {
    return { p: [0, DIE_HALF, 0], v: [0, 0, 0], R: [1, 0, 0, 0, 1, 0, 0, 0, 1], w: [0, 0, 0], pal: pal, phase: PH_IDLE, t: 0, hold: 0,
      bounces: 0, result: 0, top: 1, hit: 0, hx: 0, hz: 0, xmin: xmin, xmax: xmax, zmin: zmin, zmax: zmax };
  }
  function topIndex(d) {
    var best = 0, by = -9;
    for (var f = 0; f < 6; f += 1) {
      var ny = d.R[3] * FACE_N[f][0] + d.R[4] * FACE_N[f][1] + d.R[5] * FACE_N[f][2];
      if (ny > by) { by = ny; best = f; }
    }
    return best;
  }
  // 던지기: 시작 위치·속도·회전을 시드 수열에서 순서대로 뽑는다 (뽑는 순서가 곧 재현 규칙)
  function launch(d, rnd, x, z, vx, vz, vy0, spin) {
    d.p = [x, 2.4, z];
    d.v = [vx + (rnd() - 0.5) * 1.6, vy0 + rnd() * 2.2, vz + (rnd() - 0.5) * 1.6];
    var ax = randAxis(rnd);
    var s = spin * (0.6 + rnd() * 0.8);
    d.w = [ax[0] * s, ax[1] * s, ax[2] * s];
    d.R = rotAxis(randAxis(rnd), rnd() * 6.283);
    d.phase = PH_FLY; d.t = 0; d.hold = 0; d.bounces = 0; d.result = 0; d.hit = 0;
  }
  function spinStep(d, dt) {
    var wl = Math.hypot(d.w[0], d.w[1], d.w[2]);
    if (wl > 1e-5) d.R = matMul(rotAxis([d.w[0] / wl, d.w[1] / wl, d.w[2] / wl], wl * dt), d.R);
  }
  function floorStep(d) {
    var mi = 0, my = 99;
    var rx = 0, ry = 0, rz = 0;
    for (var i = 0; i < 8; i += 1) {
      var lx = (i & 1) ? DIE_HALF : -DIE_HALF, ly = (i & 2) ? DIE_HALF : -DIE_HALF, lz = (i & 4) ? DIE_HALF : -DIE_HALF;
      var wy = d.R[3] * lx + d.R[4] * ly + d.R[5] * lz;
      if (wy < my) { my = wy; mi = i; rx = d.R[0] * lx + d.R[1] * ly + d.R[2] * lz; ry = wy; rz = d.R[6] * lx + d.R[7] * ly + d.R[8] * lz; }
    }
    var low = d.p[1] + my;
    if (low >= 0) return;
    d.p[1] -= low;
    var cvx = d.v[0] + d.w[1] * rz - d.w[2] * ry;
    var cvy = d.v[1] + d.w[2] * rx - d.w[0] * rz;
    var cvz = d.v[2] + d.w[0] * ry - d.w[1] * rx;
    if (cvy >= 0) return;
    var j = -(1 + DICE_RESTITUTION) * cvy / (1 + (rx * rx + rz * rz) / INERTIA);
    d.v[1] += j;
    d.w[0] += -rz * j / INERTIA; d.w[2] += rx * j / INERTIA;
    var tl = Math.hypot(cvx, cvz);
    if (tl > 1e-4) {
      var jt = Math.min(FLOOR_FRICTION * j, tl * 0.5);
      var tx = -cvx / tl * jt, tz = -cvz / tl * jt;
      d.v[0] += tx; d.v[2] += tz;
      d.w[0] += ry * tz / INERTIA; d.w[1] += (rz * tx - rx * tz) / INERTIA; d.w[2] += -ry * tx / INERTIA;
    }
    if (cvy < -1.2) { d.bounces += 1; d.hit = -cvy; d.hx = d.p[0] + rx; d.hz = d.p[2] + rz; }
  }
  function wallStep(d) {
    if (d.p[0] < d.xmin) { d.p[0] = d.xmin; d.v[0] = Math.abs(d.v[0]) * 0.5; }
    if (d.p[0] > d.xmax) { d.p[0] = d.xmax; d.v[0] = -Math.abs(d.v[0]) * 0.5; }
    if (d.p[2] < d.zmin) { d.p[2] = d.zmin; d.v[2] = Math.abs(d.v[2]) * 0.5; }
    if (d.p[2] > d.zmax) { d.p[2] = d.zmax; d.v[2] = -Math.abs(d.v[2]) * 0.5; }
  }
  // 멈추기: 법선 y 가 가장 큰 면을 윗면으로 읽고, 그 면이 정확히 위를 보도록 남은 각도의 SETTLE_RATE 만큼씩 돌린다
  function settleStep(d) {
    var k = topIndex(d);
    d.top = FACE_VAL[k];
    var nw = matVec(d.R, FACE_N[k]);
    var ang = Math.acos(clamp(nw[1], -1, 1));
    if (ang > 1e-4) {
      var ax = unit(cross(nw, [0, 1, 0]));
      d.R = orthonormalize(matMul(rotAxis(ax, ang * SETTLE_RATE), d.R));
    }
    d.R = orthonormalize(matMul(rotAxis([0, 1, 0], d.w[1] * dtS), d.R));
    d.w[1] *= 0.88;
    d.v[0] *= 0.86; d.v[2] *= 0.86; d.v[1] = 0;
    d.p[0] += d.v[0] * dtS; d.p[2] += d.v[2] * dtS;
    d.p[1] += (DIE_HALF - d.p[1]) * 0.22;
    wallStep(d);
    if (ang < 0.004 && Math.abs(d.p[1] - DIE_HALF) < 0.01) {
      d.p[1] = DIE_HALF;
      var q = topIndex(d);
      d.R = orthonormalize(matMul(rotAxis(unit(cross(matVec(d.R, FACE_N[q]), [0, 1, 0])), Math.acos(clamp(matVec(d.R, FACE_N[q])[1], -1, 1))), d.R));
      d.phase = PH_HOLD; d.hold = 0; d.result = FACE_VAL[q]; d.top = d.result;
    }
  }
  function stepDie(d) {
    if (d.phase === PH_FLY) {
      d.t += FIXED_DT;
      d.v[1] -= GRAVITY * dtS;
      d.p[0] += d.v[0] * dtS; d.p[1] += d.v[1] * dtS; d.p[2] += d.v[2] * dtS;
      spinStep(d, dtS);
      d.w[0] *= SPIN_DAMPING; d.w[1] *= SPIN_DAMPING; d.w[2] *= SPIN_DAMPING;
      wallStep(d);
      floorStep(d);
      var sp = Math.hypot(d.v[0], d.v[1], d.v[2]);
      if (d.t > SETTLE_AFTER_MS || (d.bounces >= 3 && sp < 1.6)) d.phase = PH_SETTLE;
    } else if (d.phase === PH_SETTLE) {
      d.t += FIXED_DT;
      settleStep(d);
    } else if (d.phase === PH_HOLD) {
      d.hold += FIXED_DT;
    }
  }
  function runUntilHold(d) {
    for (var i = 0; i < 1200 && d.phase !== PH_HOLD; i += 1) stepDie(d);
    return d.result;
  }

  // ── 그리기 ──
  function rgb(c, k) {
    return 'rgb(' + Math.min(255, Math.round(c[0] * k)) + ',' + Math.min(255, Math.round(c[1] * k)) + ',' + Math.min(255, Math.round(c[2] * k)) + ')';
  }
  function quad(c, u, v, s) {
    var o = [];
    var sg = [[-1, -1], [1, -1], [1, 1], [-1, 1]];
    for (var i = 0; i < 4; i += 1) {
      o.push(scr([c[0] + (u[0] * sg[i][0] + v[0] * sg[i][1]) * s * DIE_HALF, c[1] + (u[1] * sg[i][0] + v[1] * sg[i][1]) * s * DIE_HALF, c[2] + (u[2] * sg[i][0] + v[2] * sg[i][1]) * s * DIE_HALF]));
    }
    return o;
  }
  function fillPoly(pts, color, edge) {
    ctx.beginPath();
    ctx.moveTo(pts[0][0], pts[0][1]);
    for (var i = 1; i < pts.length; i += 1) ctx.lineTo(pts[i][0], pts[i][1]);
    ctx.closePath();
    ctx.fillStyle = color;
    ctx.fill();
    if (edge > 0) { ctx.strokeStyle = color; ctx.lineWidth = edge; ctx.stroke(); }
  }
  function drawDie(d, hi, alpha) {
    var pal = DICE_PAL[d.pal % DICE_PAL.length];
    ctx.globalAlpha = alpha;
    ctx.lineJoin = 'round';
    for (var f = 0; f < 6; f += 1) {
      var nw = matVec(d.R, FACE_N[f]);
      var cw = [d.p[0] + nw[0] * DIE_HALF, d.p[1] + nw[1] * DIE_HALF, d.p[2] + nw[2] * DIE_HALF];
      var cc = camPoint(cw), nc = camDir(nw);
      if (nc[0] * cc[0] + nc[1] * cc[1] + nc[2] * cc[2] >= 0) continue;
      var uw = matVec(d.R, FACE_U[f]), vw = matVec(d.R, FACE_V[f]);
      var lit = 0.66 + 0.34 * Math.max(0, dot(nw, LIGHT));
      var k0 = scr(cw)[2];
      fillPoly(quad(cw, uw, vw, 1), rgb(pal.edge, lit), k0 * 0.1);
      fillPoly(quad(cw, uw, vw, 0.84), rgb(pal.face, lit), k0 * 0.16);
      if (f === hi) fillPoly(quad(cw, uw, vw, 0.84), 'rgba(255,255,255,0.4)', 0);
      var val = FACE_VAL[f];
      for (var pi = 0; pi < PIPS[val].length; pi += 1) {
        var a = PIPS[val][pi][0] * 0.5 * DIE_HALF, b = PIPS[val][pi][1] * 0.5 * DIE_HALF;
        var ring = [];
        for (var j = 0; j < 10; j += 1) {
          var an = j * 0.62832, rr = 0.17 * DIE_HALF;
          var ca = Math.cos(an) * rr, sa = Math.sin(an) * rr;
          ring.push(scr([cw[0] + uw[0] * (a + ca) + vw[0] * (b + sa) + nw[0] * 0.004, cw[1] + uw[1] * (a + ca) + vw[1] * (b + sa) + nw[1] * 0.004, cw[2] + uw[2] * (a + ca) + vw[2] * (b + sa) + nw[2] * 0.004]));
        }
        fillPoly(ring, pal.pip, 0);
      }
    }
    ctx.globalAlpha = 1;
  }
  function drawShadow(d, alpha) {
    var s = scr([d.p[0], 0, d.p[2]]);
    var h = Math.max(0, d.p[1] - DIE_HALF);
    var r = DIE_HALF * s[2] * (1.2 + h * 0.18);
    ctx.save();
    ctx.translate(s[0], s[1]);
    ctx.scale(1, 0.42);
    ctx.beginPath();
    ctx.arc(0, 0, r, 0, 6.2832);
    ctx.fillStyle = 'rgba(30,60,60,' + (0.34 * alpha / (1 + h * 0.7)) + ')';
    ctx.fill();
    ctx.restore();
  }
  var FELT_DOTS = [];
  (function () {
    var fr = seedRand(99);
    for (var i = 0; i < 70; i += 1) FELT_DOTS.push([(fr() * 2 - 1) * TABLE_X, TABLE_Z0 + fr() * (TABLE_Z1 - TABLE_Z0), 0.04 + fr() * 0.08]);
  })();
  function tablePts(m) {
    return [scr([-TABLE_X - m, 0, TABLE_Z0 - m]), scr([TABLE_X + m, 0, TABLE_Z0 - m]), scr([TABLE_X + m, 0, TABLE_Z1 + m]), scr([-TABLE_X - m, 0, TABLE_Z1 + m])];
  }
  function drawStage(lightX, lightK) {
    ctx.setTransform(1, 0, 0, 1, 0, 0);
    ctx.fillStyle = '#1d1a2b';
    ctx.fillRect(0, 0, cw, ch);
    ctx.setTransform(sc, 0, 0, sc, 0, 0);
    var bg = ctx.createRadialGradient(160, 80, 10, 160, 80, 210);
    bg.addColorStop(0, '#3f3764');
    bg.addColorStop(1, '#221d36');
    ctx.fillStyle = bg;
    ctx.fillRect(0, 0, CALC_W, CALC_H);
    fillPoly(tablePts(0.5), '#8e80c8', 0);
    var tp = tablePts(0);
    var g = ctx.createLinearGradient(0, tp[0][1], 0, tp[2][1]);
    g.addColorStop(0, '#9fdcc3');
    g.addColorStop(1, '#78c8aa');
    fillPoly(tp, g, 0);
    for (var i = 0; i < FELT_DOTS.length; i += 1) {
      var s = scr([FELT_DOTS[i][0], 0, FELT_DOTS[i][1]]);
      ctx.beginPath();
      ctx.arc(s[0], s[1], FELT_DOTS[i][2] * s[2], 0, 6.2832);
      ctx.fillStyle = 'rgba(40,110,90,0.12)';
      ctx.fill();
    }
    var lp = scr([lightX, 0, 1]);
    var lg = ctx.createRadialGradient(lp[0], lp[1], 4, lp[0], lp[1], 120);
    lg.addColorStop(0, 'rgba(255,255,255,' + (0.3 * lightK) + ')');
    lg.addColorStop(1, 'rgba(255,255,255,0)');
    ctx.save();
    ctx.beginPath();
    ctx.moveTo(tp[0][0], tp[0][1]); ctx.lineTo(tp[1][0], tp[1][1]); ctx.lineTo(tp[2][0], tp[2][1]); ctx.lineTo(tp[3][0], tp[3][1]);
    ctx.closePath();
    ctx.clip();
    ctx.fillStyle = lg;
    ctx.fillRect(0, 0, CALC_W, CALC_H);
    ctx.restore();
  }
  function drawChip(x, y, s, value, pal, mark) {
    var p = DICE_PAL[pal % DICE_PAL.length];
    ctx.fillStyle = value > 0 ? rgb(p.face, 1) : 'rgba(255,255,255,0.18)';
    ctx.strokeStyle = mark ? '#7fe3bd' : rgb(p.edge, 1);
    ctx.lineWidth = mark ? 1.8 : 1;
    ctx.fillRect(x, y, s, s);
    ctx.strokeRect(x, y, s, s);
    for (var i = 0; i < PIPS[value].length; i += 1) {
      ctx.beginPath();
      ctx.arc(x + s / 2 + PIPS[value][i][0] * s * 0.26, y + s / 2 + PIPS[value][i][1] * s * 0.26, s * 0.1, 0, 6.2832);
      ctx.fillStyle = p.pip;
      ctx.fill();
    }
  }

  // ── 상태 줄 (aria-live) ──
  var stLabel = '', stNum = '', stAt = -9999;
  function setStatus(label, num, force) {
    if (label === stLabel && num === stNum) return;
    if (!force && label === stLabel && elapsed - stAt < 450) return;
    stLabel = label; stNum = num; stAt = elapsed;
    labelEl.textContent = label;
    numEl.textContent = num;
  }
  var cw = 480, ch = 300, sc = 1.5, elapsed = 0;
  var rafId = 0;
  var cleaners = [];

  // 기법: 선형 합동 수열 s = s * 1664525 + 1013904223 (mod 2^32) 이 던질 때마다의 각도·속도·회전을 순서대로 뽑는다.
  // 같은 DICE_SEED 로 다시 시작하면 같은 수열이 나오므로, 먼저 한 바퀴를 보이지 않게 계산해 위 줄에 깔아 두고 아래 줄과 견준다.
  var T_RESULT = '結果';
  var T_ROLLING = '転がり中';
  var SEQ_LEN = 6;
  var die = newDie(2, -3.0, 3.0, -1.6, 2.4);
  var rng = seedRand(DICE_SEED);
  var throwNo = 0;
  var prevRun = [];
  var curRun = [];

  function seqThrow(d, rnd) {
    launch(d, rnd, -2.8, rnd() * 2.4 - 0.8, 3.2, 0.1, 3.0, 14);
  }
  function sceneInit() {
    var r2 = seedRand(DICE_SEED);
    var tmp = newDie(2, -3.0, 3.0, -1.6, 2.4);
    for (var k = 0; k < SEQ_LEN; k += 1) { seqThrow(tmp, r2); prevRun.push(runUntilHold(tmp)); }
    die.phase = PH_IDLE;
  }
  function sceneRoll(manual) {
    if (throwNo % SEQ_LEN === 0) { rng = seedRand(DICE_SEED); curRun = []; }
    throwNo += 1;
    seqThrow(die, rng);
    setStatus(T_ROLLING, '', true);
  }
  function sceneDone() { return die.phase === PH_HOLD; }
  function sceneFinish() { setStatus(T_RESULT, String(die.result), true); }
  var recorded = -1;
  function stepWorld() {
    if (die.phase === PH_IDLE) return;
    stepDie(die);
    if (die.phase === PH_HOLD && recorded !== throwNo) {
      recorded = throwNo;
      curRun.push(die.result);
      setStatus(T_RESULT, String(die.result), true);
    }
    if (die.phase === PH_HOLD && demo && die.hold >= HOLD_MS) sceneRoll(false);
  }
  function drawWorld() {
    drawStage(die.p[0], 0.8);
    if (die.phase !== PH_IDLE) { drawShadow(die, 1); drawDie(die, -1, 1); }
    for (var k = 0; k < SEQ_LEN; k += 1) {
      var x = 104 + k * 17;
      drawChip(x, STRIP_BASE - 22, 12, prevRun[k] || 0, 3, false);
      var got = curRun[k] || 0;
      drawChip(x, STRIP_BASE - 8, 12, got, 2, got > 0 && got === prevRun[k]);
    }
  }

  function fit() {
    var r = wrap.getBoundingClientRect();
    cw = Math.max(1, Math.round(r.width));
    ch = Math.max(1, Math.round(r.height));
    canvas.width = cw; canvas.height = ch;
    sc = cw / CALC_W;
    drawWorld();
  }
  var lastTs = -1;
  var acc = 0;
  function tick(ts) {
    if (lastTs < 0) lastTs = ts;
    var frameDt = Math.min(ts - lastTs, 48);
    lastTs = ts;
    acc += frameDt;
    while (acc >= FIXED_DT) { elapsed += FIXED_DT; stepWorld(); acc -= FIXED_DT; }
    drawWorld();
    rafId = requestAnimationFrame(tick);
  }
  // 모션 줄이기: 애니메이션 없이 결과가 나올 때까지 같은 계산을 한 번에 돌려 최종 장면만 그린다
  function runToDone() {
    var i = 0;
    do { elapsed += FIXED_DT; stepWorld(); i += 1; } while (i < 1500 && !sceneDone());
    sceneFinish();
    drawWorld();
  }
  function onRollClick() {
    stopDemo();
    sceneRoll(true);
    if (reduce) runToDone();
  }
  sceneInit();
  sceneRoll(false);
  if (reduce) {
    runToDone();
  } else {
    for (var w0 = 0; w0 < 8; w0 += 1) { elapsed += FIXED_DT; stepWorld(); }
  }
  btn.addEventListener('click', onRollClick);
  cleaners.push(function () { btn.removeEventListener('click', onRollClick); });
  fit();
  window.addEventListener('resize', fit);
  cleaners.push(function () { window.removeEventListener('resize', fit); });
  if (!reduce) rafId = requestAnimationFrame(tick);

  function destroy() {
    cancelAnimationFrame(rafId);
    for (var i = 0; i < cleaners.length; i += 1) cleaners[i]();
  }

})();

import { useEffect, useRef } from "react";
import styles from "./SpinDiceSceneSeededSequence.module.scss";

export default function SpinDiceSceneSeededSequence() {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const canvasRef = useRef<HTMLCanvasElement | null>(null);
  const labelRef = useRef<HTMLSpanElement | null>(null);
  const numRef = useRef<HTMLElement | null>(null);
  const btnRef = useRef<HTMLButtonElement | null>(null);

  useEffect(() => {
    const rootEl = rootRef.current, canvasEl = canvasRef.current, l0 = labelRef.current, n0 = numRef.current, b0 = btnRef.current;
    if (!rootEl || !canvasEl || !l0 || !n0 || !b0) return;
    const root: HTMLDivElement = rootEl;
    const canvas: HTMLCanvasElement = canvasEl;
    const ctx0 = canvas.getContext("2d");
    if (!ctx0) return;
    const ctx: CanvasRenderingContext2D = ctx0;
    const wrap: HTMLElement = canvas.parentElement ?? root;
    const labelEl: HTMLElement = l0;
    const numEl: HTMLElement = n0;
    const btn: HTMLButtonElement = b0;

    type Vec = number[];
    type Mat = number[];
    type RandFn = () => number;
    type Fn = () => void;
    type Paint = string | CanvasGradient;
    type Pal = { face: number[]; edge: number[]; pip: string };
    type Die = { p: Vec; v: Vec; R: Mat; w: Vec; pal: number; phase: number; t: number; hold: number; bounces: number; result: number; top: number; hit: number; hx: number; hz: number; xmin: number; xmax: number; zmin: number; zmax: number };

    var CALC_W = 320, CALC_H = 200;
    var FIXED_DT = 16;
    var dtS = FIXED_DT / 1000;
    var DICE_RESTITUTION = 0.45;
    var SPIN_DAMPING = 0.985;
    var DICE_SEED = 7;
    var GRAVITY = 22;
    var DIE_HALF = 1;
    var INERTIA = 2 * DIE_HALF * DIE_HALF / 3;
    var FLOOR_FRICTION = 0.35;
    var SETTLE_AFTER_MS = 2000;
    var SETTLE_RATE = 0.16;
    var HOLD_MS = 700;
    var CAM_Y = 5.6, CAM_BACK = 12, FOCAL = 275, VIEW_CX = 160, VIEW_CY = 82;
    var TABLE_X = 4.4, TABLE_Z0 = -3, TABLE_Z1 = 5;
    var PH_FLY = 0, PH_SETTLE = 1, PH_HOLD = 2, PH_IDLE = 3;
    var STRIP_BASE = 128;
    var BAR_MAX = 18;
    var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    var demo = !reduce;
    if (!demo) root.classList.remove('is-demo');
    function stopDemo(): void { demo = false; root.classList.remove('is-demo'); }

    function seedRand(seed: number): RandFn {
      var s = seed >>> 0;
      return function (): number { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
    }
    function clamp(v: number, lo: number, hi: number): number { return v < lo ? lo : (v > hi ? hi : v); }
    function lerp(a: number, b: number, t: number): number { return a + (b - a) * t; }
    function dot(a: Vec, b: Vec): number { return a[0] * b[0] + a[1] * b[1] + a[2] * b[2]; }
    function cross(a: Vec, b: Vec): Vec { return [a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]]; }
    function unit(a: Vec): Vec { var l = Math.hypot(a[0], a[1], a[2]) || 1; return [a[0] / l, a[1] / l, a[2] / l]; }
    function matMul(a: Mat, b: Mat): Mat {
      var o: Mat = [0, 0, 0, 0, 0, 0, 0, 0, 0];
      for (var i = 0; i < 3; i += 1) {
        for (var j = 0; j < 3; j += 1) o[i * 3 + j] = a[i * 3] * b[j] + a[i * 3 + 1] * b[3 + j] + a[i * 3 + 2] * b[6 + j];
      }
      return o;
    }
    function matVec(m: Mat, v: Vec): Vec {
      return [m[0] * v[0] + m[1] * v[1] + m[2] * v[2], m[3] * v[0] + m[4] * v[1] + m[5] * v[2], m[6] * v[0] + m[7] * v[1] + m[8] * v[2]];
    }
    // 로드리게스 공식: 단위 축 ax 둘레로 ang 만큼 도는 회전 행렬
    function rotAxis(ax: Vec, ang: number): Mat {
      var c = Math.cos(ang), s = Math.sin(ang), t = 1 - c, x = ax[0], y = ax[1], z = ax[2];
      return [t * x * x + c, t * x * y - s * z, t * x * z + s * y,
        t * x * y + s * z, t * y * y + c, t * y * z - s * x,
        t * x * z - s * y, t * y * z + s * x, t * z * z + c];
    }
    function orthonormalize(m: Mat): Mat {
      var a = unit([m[0], m[1], m[2]]);
      var k = a[0] * m[3] + a[1] * m[4] + a[2] * m[5];
      var b = unit([m[3] - a[0] * k, m[4] - a[1] * k, m[5] - a[2] * k]);
      var c = cross(a, b);
      return [a[0], a[1], a[2], b[0], b[1], b[2], c[0], c[1], c[2]];
    }
    function randAxis(rnd: RandFn): Vec { return unit([rnd() * 2 - 1, rnd() * 2 - 1, rnd() * 2 - 1]); }

    var PITCH = Math.atan2(CAM_Y, CAM_BACK);
    var CAM_S = Math.sin(PITCH), CAM_C = Math.cos(PITCH);
    function camPoint(p: Vec): Vec {
      var qy = p[1] - CAM_Y, qz = p[2] + CAM_BACK;
      return [p[0], qy * CAM_C + qz * CAM_S, -qy * CAM_S + qz * CAM_C];
    }
    function camDir(v: Vec): Vec { return [v[0], v[1] * CAM_C + v[2] * CAM_S, -v[1] * CAM_S + v[2] * CAM_C]; }
    function scr(p: Vec): Vec {
      var c = camPoint(p);
      var k = FOCAL / c[2];
      return [VIEW_CX + c[0] * k, VIEW_CY - c[1] * k, k];
    }

    var FACE_N: Vec[] = [[0, 1, 0], [0, -1, 0], [1, 0, 0], [-1, 0, 0], [0, 0, 1], [0, 0, -1]];
    var FACE_U: Vec[] = [[1, 0, 0], [1, 0, 0], [0, 1, 0], [0, 1, 0], [1, 0, 0], [1, 0, 0]];
    var FACE_V: Vec[] = [[0, 0, 1], [0, 0, 1], [0, 0, 1], [0, 0, 1], [0, 1, 0], [0, 1, 0]];
    var FACE_VAL: number[] = [1, 6, 2, 5, 3, 4];
    var PIPS: number[][][] = [[], [[0, 0]], [[-1, -1], [1, 1]], [[-1, -1], [0, 0], [1, 1]],
      [[-1, -1], [1, -1], [-1, 1], [1, 1]], [[-1, -1], [1, -1], [0, 0], [-1, 1], [1, 1]],
      [[-1, -1], [-1, 0], [-1, 1], [1, -1], [1, 0], [1, 1]]];
    var DICE_PAL: Pal[] = [
      { face: [255, 214, 226], edge: [240, 160, 186], pip: '#4b3a63' },
      { face: [200, 232, 255], edge: [140, 190, 236], pip: '#3b4a6b' },
      { face: [224, 212, 255], edge: [170, 150, 232], pip: '#46386b' },
      { face: [255, 240, 196], edge: [236, 206, 120], pip: '#5a4636' }
    ];
    var LIGHT: Vec = unit([-0.45, 0.85, -0.35]);

    function newDie(pal: number, xmin: number, xmax: number, zmin: number, zmax: number): Die {
      return { p: [0, DIE_HALF, 0], v: [0, 0, 0], R: [1, 0, 0, 0, 1, 0, 0, 0, 1], w: [0, 0, 0], pal: pal, phase: PH_IDLE, t: 0, hold: 0,
        bounces: 0, result: 0, top: 1, hit: 0, hx: 0, hz: 0, xmin: xmin, xmax: xmax, zmin: zmin, zmax: zmax };
    }
    function topIndex(d: Die): number {
      var best = 0, by = -9;
      for (var f = 0; f < 6; f += 1) {
        var ny = d.R[3] * FACE_N[f][0] + d.R[4] * FACE_N[f][1] + d.R[5] * FACE_N[f][2];
        if (ny > by) { by = ny; best = f; }
      }
      return best;
    }
    // 던지기: 시작 위치·속도·회전을 시드 수열에서 순서대로 뽑는다 (뽑는 순서가 곧 재현 규칙)
    function launch(d: Die, rnd: RandFn, x: number, z: number, vx: number, vz: number, vy0: number, spin: number): void {
      d.p = [x, 2.4, z];
      d.v = [vx + (rnd() - 0.5) * 1.6, vy0 + rnd() * 2.2, vz + (rnd() - 0.5) * 1.6];
      var ax = randAxis(rnd);
      var s = spin * (0.6 + rnd() * 0.8);
      d.w = [ax[0] * s, ax[1] * s, ax[2] * s];
      d.R = rotAxis(randAxis(rnd), rnd() * 6.283);
      d.phase = PH_FLY; d.t = 0; d.hold = 0; d.bounces = 0; d.result = 0; d.hit = 0;
    }
    function spinStep(d: Die, dt: number): void {
      var wl = Math.hypot(d.w[0], d.w[1], d.w[2]);
      if (wl > 1e-5) d.R = matMul(rotAxis([d.w[0] / wl, d.w[1] / wl, d.w[2] / wl], wl * dt), d.R);
    }
    function floorStep(d: Die): void {
      var mi = 0, my = 99;
      var rx = 0, ry = 0, rz = 0;
      for (var i = 0; i < 8; i += 1) {
        var lx = (i & 1) ? DIE_HALF : -DIE_HALF, ly = (i & 2) ? DIE_HALF : -DIE_HALF, lz = (i & 4) ? DIE_HALF : -DIE_HALF;
        var wy = d.R[3] * lx + d.R[4] * ly + d.R[5] * lz;
        if (wy < my) { my = wy; mi = i; rx = d.R[0] * lx + d.R[1] * ly + d.R[2] * lz; ry = wy; rz = d.R[6] * lx + d.R[7] * ly + d.R[8] * lz; }
      }
      var low = d.p[1] + my;
      if (low >= 0) return;
      d.p[1] -= low;
      var cvx = d.v[0] + d.w[1] * rz - d.w[2] * ry;
      var cvy = d.v[1] + d.w[2] * rx - d.w[0] * rz;
      var cvz = d.v[2] + d.w[0] * ry - d.w[1] * rx;
      if (cvy >= 0) return;
      var j = -(1 + DICE_RESTITUTION) * cvy / (1 + (rx * rx + rz * rz) / INERTIA);
      d.v[1] += j;
      d.w[0] += -rz * j / INERTIA; d.w[2] += rx * j / INERTIA;
      var tl = Math.hypot(cvx, cvz);
      if (tl > 1e-4) {
        var jt = Math.min(FLOOR_FRICTION * j, tl * 0.5);
        var tx = -cvx / tl * jt, tz = -cvz / tl * jt;
        d.v[0] += tx; d.v[2] += tz;
        d.w[0] += ry * tz / INERTIA; d.w[1] += (rz * tx - rx * tz) / INERTIA; d.w[2] += -ry * tx / INERTIA;
      }
      if (cvy < -1.2) { d.bounces += 1; d.hit = -cvy; d.hx = d.p[0] + rx; d.hz = d.p[2] + rz; }
    }
    function wallStep(d: Die): void {
      if (d.p[0] < d.xmin) { d.p[0] = d.xmin; d.v[0] = Math.abs(d.v[0]) * 0.5; }
      if (d.p[0] > d.xmax) { d.p[0] = d.xmax; d.v[0] = -Math.abs(d.v[0]) * 0.5; }
      if (d.p[2] < d.zmin) { d.p[2] = d.zmin; d.v[2] = Math.abs(d.v[2]) * 0.5; }
      if (d.p[2] > d.zmax) { d.p[2] = d.zmax; d.v[2] = -Math.abs(d.v[2]) * 0.5; }
    }
    // 멈추기: 법선 y 가 가장 큰 면을 윗면으로 읽고, 그 면이 정확히 위를 보도록 남은 각도의 SETTLE_RATE 만큼씩 돌린다
    function settleStep(d: Die): void {
      var k = topIndex(d);
      d.top = FACE_VAL[k];
      var nw = matVec(d.R, FACE_N[k]);
      var ang = Math.acos(clamp(nw[1], -1, 1));
      if (ang > 1e-4) {
        var ax = unit(cross(nw, [0, 1, 0]));
        d.R = orthonormalize(matMul(rotAxis(ax, ang * SETTLE_RATE), d.R));
      }
      d.R = orthonormalize(matMul(rotAxis([0, 1, 0], d.w[1] * dtS), d.R));
      d.w[1] *= 0.88;
      d.v[0] *= 0.86; d.v[2] *= 0.86; d.v[1] = 0;
      d.p[0] += d.v[0] * dtS; d.p[2] += d.v[2] * dtS;
      d.p[1] += (DIE_HALF - d.p[1]) * 0.22;
      wallStep(d);
      if (ang < 0.004 && Math.abs(d.p[1] - DIE_HALF) < 0.01) {
        d.p[1] = DIE_HALF;
        var q = topIndex(d);
        d.R = orthonormalize(matMul(rotAxis(unit(cross(matVec(d.R, FACE_N[q]), [0, 1, 0])), Math.acos(clamp(matVec(d.R, FACE_N[q])[1], -1, 1))), d.R));
        d.phase = PH_HOLD; d.hold = 0; d.result = FACE_VAL[q]; d.top = d.result;
      }
    }
    function stepDie(d: Die): void {
      if (d.phase === PH_FLY) {
        d.t += FIXED_DT;
        d.v[1] -= GRAVITY * dtS;
        d.p[0] += d.v[0] * dtS; d.p[1] += d.v[1] * dtS; d.p[2] += d.v[2] * dtS;
        spinStep(d, dtS);
        d.w[0] *= SPIN_DAMPING; d.w[1] *= SPIN_DAMPING; d.w[2] *= SPIN_DAMPING;
        wallStep(d);
        floorStep(d);
        var sp = Math.hypot(d.v[0], d.v[1], d.v[2]);
        if (d.t > SETTLE_AFTER_MS || (d.bounces >= 3 && sp < 1.6)) d.phase = PH_SETTLE;
      } else if (d.phase === PH_SETTLE) {
        d.t += FIXED_DT;
        settleStep(d);
      } else if (d.phase === PH_HOLD) {
        d.hold += FIXED_DT;
      }
    }
    function runUntilHold(d: Die): number {
      for (var i = 0; i < 1200 && d.phase !== PH_HOLD; i += 1) stepDie(d);
      return d.result;
    }

    // ── 그리기 ──
    function rgb(c: number[], k: number): string {
      return 'rgb(' + Math.min(255, Math.round(c[0] * k)) + ',' + Math.min(255, Math.round(c[1] * k)) + ',' + Math.min(255, Math.round(c[2] * k)) + ')';
    }
    function quad(c: Vec, u: Vec, v: Vec, s: number): number[][] {
      var o: number[][] = [];
      var sg = [[-1, -1], [1, -1], [1, 1], [-1, 1]];
      for (var i = 0; i < 4; i += 1) {
        o.push(scr([c[0] + (u[0] * sg[i][0] + v[0] * sg[i][1]) * s * DIE_HALF, c[1] + (u[1] * sg[i][0] + v[1] * sg[i][1]) * s * DIE_HALF, c[2] + (u[2] * sg[i][0] + v[2] * sg[i][1]) * s * DIE_HALF]));
      }
      return o;
    }
    function fillPoly(pts: number[][], color: Paint, edge: number): void {
      ctx.beginPath();
      ctx.moveTo(pts[0][0], pts[0][1]);
      for (var i = 1; i < pts.length; i += 1) ctx.lineTo(pts[i][0], pts[i][1]);
      ctx.closePath();
      ctx.fillStyle = color;
      ctx.fill();
      if (edge > 0) { ctx.strokeStyle = color; ctx.lineWidth = edge; ctx.stroke(); }
    }
    function drawDie(d: Die, hi: number, alpha: number): void {
      var pal = DICE_PAL[d.pal % DICE_PAL.length];
      ctx.globalAlpha = alpha;
      ctx.lineJoin = 'round';
      for (var f = 0; f < 6; f += 1) {
        var nw = matVec(d.R, FACE_N[f]);
        var cw: Vec = [d.p[0] + nw[0] * DIE_HALF, d.p[1] + nw[1] * DIE_HALF, d.p[2] + nw[2] * DIE_HALF];
        var cc = camPoint(cw), nc = camDir(nw);
        if (nc[0] * cc[0] + nc[1] * cc[1] + nc[2] * cc[2] >= 0) continue;
        var uw = matVec(d.R, FACE_U[f]), vw = matVec(d.R, FACE_V[f]);
        var lit = 0.66 + 0.34 * Math.max(0, dot(nw, LIGHT));
        var k0 = scr(cw)[2];
        fillPoly(quad(cw, uw, vw, 1), rgb(pal.edge, lit), k0 * 0.1);
        fillPoly(quad(cw, uw, vw, 0.84), rgb(pal.face, lit), k0 * 0.16);
        if (f === hi) fillPoly(quad(cw, uw, vw, 0.84), 'rgba(255,255,255,0.4)', 0);
        var val = FACE_VAL[f];
        for (var pi = 0; pi < PIPS[val].length; pi += 1) {
          var a = PIPS[val][pi][0] * 0.5 * DIE_HALF, b = PIPS[val][pi][1] * 0.5 * DIE_HALF;
          var ring: number[][] = [];
          for (var j = 0; j < 10; j += 1) {
            var an = j * 0.62832, rr = 0.17 * DIE_HALF;
            var ca = Math.cos(an) * rr, sa = Math.sin(an) * rr;
            ring.push(scr([cw[0] + uw[0] * (a + ca) + vw[0] * (b + sa) + nw[0] * 0.004, cw[1] + uw[1] * (a + ca) + vw[1] * (b + sa) + nw[1] * 0.004, cw[2] + uw[2] * (a + ca) + vw[2] * (b + sa) + nw[2] * 0.004]));
          }
          fillPoly(ring, pal.pip, 0);
        }
      }
      ctx.globalAlpha = 1;
    }
    function drawShadow(d: Die, alpha: number): void {
      var s = scr([d.p[0], 0, d.p[2]]);
      var h = Math.max(0, d.p[1] - DIE_HALF);
      var r = DIE_HALF * s[2] * (1.2 + h * 0.18);
      ctx.save();
      ctx.translate(s[0], s[1]);
      ctx.scale(1, 0.42);
      ctx.beginPath();
      ctx.arc(0, 0, r, 0, 6.2832);
      ctx.fillStyle = 'rgba(30,60,60,' + (0.34 * alpha / (1 + h * 0.7)) + ')';
      ctx.fill();
      ctx.restore();
    }
    var FELT_DOTS: number[][] = [];
    (function (): void {
      var fr = seedRand(99);
      for (var i = 0; i < 70; i += 1) FELT_DOTS.push([(fr() * 2 - 1) * TABLE_X, TABLE_Z0 + fr() * (TABLE_Z1 - TABLE_Z0), 0.04 + fr() * 0.08]);
    })();
    function tablePts(m: number): number[][] {
      return [scr([-TABLE_X - m, 0, TABLE_Z0 - m]), scr([TABLE_X + m, 0, TABLE_Z0 - m]), scr([TABLE_X + m, 0, TABLE_Z1 + m]), scr([-TABLE_X - m, 0, TABLE_Z1 + m])];
    }
    function drawStage(lightX: number, lightK: number): void {
      ctx.setTransform(1, 0, 0, 1, 0, 0);
      ctx.fillStyle = '#1d1a2b';
      ctx.fillRect(0, 0, cw, ch);
      ctx.setTransform(sc, 0, 0, sc, 0, 0);
      var bg = ctx.createRadialGradient(160, 80, 10, 160, 80, 210);
      bg.addColorStop(0, '#3f3764');
      bg.addColorStop(1, '#221d36');
      ctx.fillStyle = bg;
      ctx.fillRect(0, 0, CALC_W, CALC_H);
      fillPoly(tablePts(0.5), '#8e80c8', 0);
      var tp = tablePts(0);
      var g = ctx.createLinearGradient(0, tp[0][1], 0, tp[2][1]);
      g.addColorStop(0, '#9fdcc3');
      g.addColorStop(1, '#78c8aa');
      fillPoly(tp, g, 0);
      for (var i = 0; i < FELT_DOTS.length; i += 1) {
        var s = scr([FELT_DOTS[i][0], 0, FELT_DOTS[i][1]]);
        ctx.beginPath();
        ctx.arc(s[0], s[1], FELT_DOTS[i][2] * s[2], 0, 6.2832);
        ctx.fillStyle = 'rgba(40,110,90,0.12)';
        ctx.fill();
      }
      var lp = scr([lightX, 0, 1]);
      var lg = ctx.createRadialGradient(lp[0], lp[1], 4, lp[0], lp[1], 120);
      lg.addColorStop(0, 'rgba(255,255,255,' + (0.3 * lightK) + ')');
      lg.addColorStop(1, 'rgba(255,255,255,0)');
      ctx.save();
      ctx.beginPath();
      ctx.moveTo(tp[0][0], tp[0][1]); ctx.lineTo(tp[1][0], tp[1][1]); ctx.lineTo(tp[2][0], tp[2][1]); ctx.lineTo(tp[3][0], tp[3][1]);
      ctx.closePath();
      ctx.clip();
      ctx.fillStyle = lg;
      ctx.fillRect(0, 0, CALC_W, CALC_H);
      ctx.restore();
    }
    function drawChip(x: number, y: number, s: number, value: number, pal: number, mark: boolean): void {
      var p = DICE_PAL[pal % DICE_PAL.length];
      ctx.fillStyle = value > 0 ? rgb(p.face, 1) : 'rgba(255,255,255,0.18)';
      ctx.strokeStyle = mark ? '#7fe3bd' : rgb(p.edge, 1);
      ctx.lineWidth = mark ? 1.8 : 1;
      ctx.fillRect(x, y, s, s);
      ctx.strokeRect(x, y, s, s);
      for (var i = 0; i < PIPS[value].length; i += 1) {
        ctx.beginPath();
        ctx.arc(x + s / 2 + PIPS[value][i][0] * s * 0.26, y + s / 2 + PIPS[value][i][1] * s * 0.26, s * 0.1, 0, 6.2832);
        ctx.fillStyle = p.pip;
        ctx.fill();
      }
    }

    // ── 상태 줄 (aria-live) ──
    var stLabel = '', stNum = '', stAt = -9999;
    function setStatus(label: string, num: string, force: boolean): void {
      if (label === stLabel && num === stNum) return;
      if (!force && label === stLabel && elapsed - stAt < 450) return;
      stLabel = label; stNum = num; stAt = elapsed;
      labelEl.textContent = label;
      numEl.textContent = num;
    }
    var cw = 480, ch = 300, sc = 1.5, elapsed = 0;
    var rafId = 0;
    var cleaners: Fn[] = [];

    // 기법: 선형 합동 수열 s = s * 1664525 + 1013904223 (mod 2^32) 이 던질 때마다의 각도·속도·회전을 순서대로 뽑는다.
    // 같은 DICE_SEED 로 다시 시작하면 같은 수열이 나오므로, 먼저 한 바퀴를 보이지 않게 계산해 위 줄에 깔아 두고 아래 줄과 견준다.
    var T_RESULT = '결과';
    var T_ROLLING = '굴리는 중';
    var SEQ_LEN = 6;
    var die: Die = newDie(2, -3.0, 3.0, -1.6, 2.4);
    var rng: RandFn = seedRand(DICE_SEED);
    var throwNo = 0;
    var prevRun: number[] = [];
    var curRun: number[] = [];

    function seqThrow(d: Die, rnd: RandFn): void {
      launch(d, rnd, -2.8, rnd() * 2.4 - 0.8, 3.2, 0.1, 3.0, 14);
    }
    function sceneInit(): void {
      var r2: RandFn = seedRand(DICE_SEED);
      var tmp: Die = newDie(2, -3.0, 3.0, -1.6, 2.4);
      for (var k = 0; k < SEQ_LEN; k += 1) { seqThrow(tmp, r2); prevRun.push(runUntilHold(tmp)); }
      die.phase = PH_IDLE;
    }
    function sceneRoll(manual: boolean): void {
      if (throwNo % SEQ_LEN === 0) { rng = seedRand(DICE_SEED); curRun = []; }
      throwNo += 1;
      seqThrow(die, rng);
      setStatus(T_ROLLING, '', true);
    }
    function sceneDone(): boolean { return die.phase === PH_HOLD; }
    function sceneFinish(): void { setStatus(T_RESULT, String(die.result), true); }
    var recorded = -1;
    function stepWorld(): void {
      if (die.phase === PH_IDLE) return;
      stepDie(die);
      if (die.phase === PH_HOLD && recorded !== throwNo) {
        recorded = throwNo;
        curRun.push(die.result);
        setStatus(T_RESULT, String(die.result), true);
      }
      if (die.phase === PH_HOLD && demo && die.hold >= HOLD_MS) sceneRoll(false);
    }
    function drawWorld(): void {
      drawStage(die.p[0], 0.8);
      if (die.phase !== PH_IDLE) { drawShadow(die, 1); drawDie(die, -1, 1); }
      for (var k = 0; k < SEQ_LEN; k += 1) {
        var x = 104 + k * 17;
        drawChip(x, STRIP_BASE - 22, 12, prevRun[k] || 0, 3, false);
        var got = curRun[k] || 0;
        drawChip(x, STRIP_BASE - 8, 12, got, 2, got > 0 && got === prevRun[k]);
      }
    }

    function fit(): void {
      var r = wrap.getBoundingClientRect();
      cw = Math.max(1, Math.round(r.width));
      ch = Math.max(1, Math.round(r.height));
      canvas.width = cw; canvas.height = ch;
      sc = cw / CALC_W;
      drawWorld();
    }
    var lastTs = -1;
    var acc = 0;
    function tick(ts: number): void {
      if (lastTs < 0) lastTs = ts;
      var frameDt = Math.min(ts - lastTs, 48);
      lastTs = ts;
      acc += frameDt;
      while (acc >= FIXED_DT) { elapsed += FIXED_DT; stepWorld(); acc -= FIXED_DT; }
      drawWorld();
      rafId = requestAnimationFrame(tick);
    }
    // 모션 줄이기: 애니메이션 없이 결과가 나올 때까지 같은 계산을 한 번에 돌려 최종 장면만 그린다
    function runToDone(): void {
      var i = 0;
      do { elapsed += FIXED_DT; stepWorld(); i += 1; } while (i < 1500 && !sceneDone());
      sceneFinish();
      drawWorld();
    }
    function onRollClick(): void {
      stopDemo();
      sceneRoll(true);
      if (reduce) runToDone();
    }
    sceneInit();
    sceneRoll(false);
    if (reduce) {
      runToDone();
    } else {
      for (var w0 = 0; w0 < 8; w0 += 1) { elapsed += FIXED_DT; stepWorld(); }
    }
    btn.addEventListener('click', onRollClick);
    cleaners.push(function (): void { btn.removeEventListener('click', onRollClick); });
    fit();
    window.addEventListener('resize', fit);
    cleaners.push(function (): void { window.removeEventListener('resize', fit); });
    if (!reduce) rafId = requestAnimationFrame(tick);

    function destroy(): void {
      cancelAnimationFrame(rafId);
      for (var i = 0; i < cleaners.length; i += 1) cleaners[i]();
    }


    return destroy;
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.bp} is-demo`} ref={rootRef}>
        <canvas className={styles.bp__canvas} ref={canvasRef} width={480} height={300} role="img" aria-label="선형 합동 수열로 던질 때마다의 초기 회전과 속도를 정해, 같은 시드면 같은 눈이 같은 순서로 나오는 것을 미리 계산해 둔 윗줄과 지금 굴리는 아랫줄의 눈 이력으로 견줘 보인다." />
        <output className={styles.bp__status} aria-live="polite"><span ref={labelRef}>굴리는 중</span> <b ref={numRef} /></output>
        <button type="button" className={styles.bp__btn} ref={btnRef}>굴리기</button>
        <p className={styles.bp__caption}>선형 합동 수열로 던질 때마다의 초기 회전과 속도를 정해, 같은 시드면 같은 눈이 같은 순서로 나오는 것을 미리 계산해 둔 윗줄과 지금 굴리는 아랫줄의 눈 이력으로 견줘 보인다.</p>
      </div>
    </main>
  );
}