03止まりながら上の目を読むサイコロ

<main class="stage">
<div class="bp is-demo" id="bpRoot">
  <canvas class="bp__canvas" id="bpCanvas" width="480" height="300" role="img" aria-label="回転が遅くなるにつれ、六つの面の法線のうち最も上を向く面を選んでその目を結果として読み、その面が真上に来るまで向きをなめらかに補正する。"></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">回転が遅くなるにつれ、六つの面の法線のうち最も上を向く面を選んでその目を結果として読み、その面が真上に来るまで向きをなめらかに補正する。</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: 여섯 면의 월드 법선 n 중 n.y 가 가장 큰 면이 윗면이다. 회전이 느려지면 그 면의 n 과 (0,1,0) 사이 각도를
  // 매 걸음 SETTLE_RATE 비율만큼 줄이는 회전을 곱해(남은 각도의 지수 보정) 면이 정확히 위를 보게 한다.
  var T_TOP = '上の面';
  var T_RESULT = '結果';
  var T_ROLLING = '転がり中';
  var die = newDie(1, -2.2, 2.2, -1.2, 2.0);
  var rng = seedRand(DICE_SEED + 3);
  var normY = [0, 0, 0, 0, 0, 0];
  var bestIdx = 0;

  function sceneInit() { die.phase = PH_IDLE; }
  function sceneRoll(manual) {
    launch(die, rng, -1.4, rng() * 1.6 - 0.2, 1.8, 0.3, 2.4, 17);
    setStatus(T_ROLLING, '', true);
  }
  function sceneDone() { return die.phase === PH_HOLD; }
  function sceneFinish() { setStatus(T_RESULT, String(die.result), true); }
  function readNormals() {
    bestIdx = 0;
    for (var f = 0; f < 6; f += 1) {
      var ny = die.R[3] * FACE_N[f][0] + die.R[4] * FACE_N[f][1] + die.R[5] * FACE_N[f][2];
      normY[FACE_VAL[f] - 1] = ny;
      if (ny > die.R[3] * FACE_N[bestIdx][0] + die.R[4] * FACE_N[bestIdx][1] + die.R[5] * FACE_N[bestIdx][2]) bestIdx = f;
    }
  }
  function stepWorld() {
    if (die.phase === PH_IDLE) return;
    stepDie(die);
    readNormals();
    if (die.phase === PH_HOLD) setStatus(T_RESULT, String(die.result), true);
    else if (die.phase === PH_SETTLE || die.bounces > 0) setStatus(T_TOP, String(FACE_VAL[bestIdx]), false);
    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) return;
    drawShadow(die, 1);
    var showHi = die.bounces > 0 || die.phase !== PH_FLY;
    drawDie(die, showHi ? bestIdx : -1, 1);
    if (showHi) {
      var nw = matVec(die.R, FACE_N[bestIdx]);
      var a = scr([die.p[0] + nw[0] * DIE_HALF, die.p[1] + nw[1] * DIE_HALF, die.p[2] + nw[2] * DIE_HALF]);
      var b = scr([die.p[0] + nw[0] * (DIE_HALF + 1.5), die.p[1] + nw[1] * (DIE_HALF + 1.5), die.p[2] + nw[2] * (DIE_HALF + 1.5)]);
      ctx.beginPath(); ctx.moveTo(a[0], a[1]); ctx.lineTo(b[0], b[1]);
      ctx.strokeStyle = '#fff4b0'; ctx.lineWidth = 2.4; ctx.lineCap = 'round'; ctx.stroke();
      ctx.beginPath(); ctx.arc(b[0], b[1], 3.4, 0, 6.2832); ctx.fillStyle = '#fff4b0'; ctx.fill();
    }
    // 여섯 면의 법선 y 막대: 가장 큰 막대가 上の面, 보정이 끝나면 1.0 에 닿는다
    ctx.fillStyle = 'rgba(255,255,255,0.14)';
    ctx.fillRect(84, STRIP_BASE - BAR_MAX - 3, 152, BAR_MAX + 17);
    ctx.font = '8px sans-serif';
    ctx.textAlign = 'center';
    for (var v = 0; v < 6; v += 1) {
      var h = Math.max(0, normY[v]) * BAR_MAX;
      ctx.fillStyle = (v + 1) === FACE_VAL[bestIdx] ? '#ff9ebb' : '#c9b8ff';
      ctx.fillRect(92 + v * 24, STRIP_BASE - h, 16, h);
      ctx.fillStyle = 'rgba(255,255,255,0.85)';
      ctx.fillText(String(v + 1), 100 + v * 24, STRIP_BASE + 9);
    }
  }

  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 "./SpinDiceSceneSettleTopFaceRead.module.scss";

export default function SpinDiceSceneSettleTopFaceRead() {
  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: 여섯 면의 월드 법선 n 중 n.y 가 가장 큰 면이 윗면이다. 회전이 느려지면 그 면의 n 과 (0,1,0) 사이 각도를
    // 매 걸음 SETTLE_RATE 비율만큼 줄이는 회전을 곱해(남은 각도의 지수 보정) 면이 정확히 위를 보게 한다.
    var T_TOP = '윗면';
    var T_RESULT = '결과';
    var T_ROLLING = '굴리는 중';
    var die: Die = newDie(1, -2.2, 2.2, -1.2, 2.0);
    var rng: RandFn = seedRand(DICE_SEED + 3);
    var normY: number[] = [0, 0, 0, 0, 0, 0];
    var bestIdx = 0;

    function sceneInit(): void { die.phase = PH_IDLE; }
    function sceneRoll(manual: boolean): void {
      launch(die, rng, -1.4, rng() * 1.6 - 0.2, 1.8, 0.3, 2.4, 17);
      setStatus(T_ROLLING, '', true);
    }
    function sceneDone(): boolean { return die.phase === PH_HOLD; }
    function sceneFinish(): void { setStatus(T_RESULT, String(die.result), true); }
    function readNormals(): void {
      bestIdx = 0;
      for (var f = 0; f < 6; f += 1) {
        var ny = die.R[3] * FACE_N[f][0] + die.R[4] * FACE_N[f][1] + die.R[5] * FACE_N[f][2];
        normY[FACE_VAL[f] - 1] = ny;
        if (ny > die.R[3] * FACE_N[bestIdx][0] + die.R[4] * FACE_N[bestIdx][1] + die.R[5] * FACE_N[bestIdx][2]) bestIdx = f;
      }
    }
    function stepWorld(): void {
      if (die.phase === PH_IDLE) return;
      stepDie(die);
      readNormals();
      if (die.phase === PH_HOLD) setStatus(T_RESULT, String(die.result), true);
      else if (die.phase === PH_SETTLE || die.bounces > 0) setStatus(T_TOP, String(FACE_VAL[bestIdx]), false);
      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) return;
      drawShadow(die, 1);
      var showHi = die.bounces > 0 || die.phase !== PH_FLY;
      drawDie(die, showHi ? bestIdx : -1, 1);
      if (showHi) {
        var nw = matVec(die.R, FACE_N[bestIdx]);
        var a = scr([die.p[0] + nw[0] * DIE_HALF, die.p[1] + nw[1] * DIE_HALF, die.p[2] + nw[2] * DIE_HALF]);
        var b = scr([die.p[0] + nw[0] * (DIE_HALF + 1.5), die.p[1] + nw[1] * (DIE_HALF + 1.5), die.p[2] + nw[2] * (DIE_HALF + 1.5)]);
        ctx.beginPath(); ctx.moveTo(a[0], a[1]); ctx.lineTo(b[0], b[1]);
        ctx.strokeStyle = '#fff4b0'; ctx.lineWidth = 2.4; ctx.lineCap = 'round'; ctx.stroke();
        ctx.beginPath(); ctx.arc(b[0], b[1], 3.4, 0, 6.2832); ctx.fillStyle = '#fff4b0'; ctx.fill();
      }
      // 여섯 면의 법선 y 막대: 가장 큰 막대가 윗면, 보정이 끝나면 1.0 에 닿는다
      ctx.fillStyle = 'rgba(255,255,255,0.14)';
      ctx.fillRect(84, STRIP_BASE - BAR_MAX - 3, 152, BAR_MAX + 17);
      ctx.font = '8px sans-serif';
      ctx.textAlign = 'center';
      for (var v = 0; v < 6; v += 1) {
        var h = Math.max(0, normY[v]) * BAR_MAX;
        ctx.fillStyle = (v + 1) === FACE_VAL[bestIdx] ? '#ff9ebb' : '#c9b8ff';
        ctx.fillRect(92 + v * 24, STRIP_BASE - h, 16, h);
        ctx.fillStyle = 'rgba(255,255,255,0.85)';
        ctx.fillText(String(v + 1), 100 + v * 24, STRIP_BASE + 9);
      }
    }

    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="회전이 느려질 때 여섯 면의 법선 중 위쪽을 가장 많이 향한 면을 골라 그 눈 수를 결과로 읽고, 방향을 그 면이 정확히 위로 오도록 서서히 보정한다." />
        <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}>회전이 느려질 때 여섯 면의 법선 중 위쪽을 가장 많이 향한 면을 골라 그 눈 수를 결과로 읽고, 방향을 그 면이 정확히 위로 오도록 서서히 보정한다.</p>
      </div>
    </main>
  );
}