09Loader a Survival-rule Value Fills via Cellular Automaton

<main class="stage">
<div class="ld" id="ld">
  <p class="ld__hint">
    <svg class="ld__ico" viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M232 56v56a8 8 0 0 1-16 0V91.3l-25.6 25.7A80 80 0 1 1 174 60a8 8 0 1 1-9 13.2A64 64 0 1 0 179.7 128H216a8 8 0 0 1 0 16h-56a8 8 0 0 1-8-8V80a8 8 0 0 1 16 0v20.7L192.7 76A80.1 80.1 0 0 0 64 128a8 8 0 0 1-16 0a96 96 0 0 1 163.6-68.3L224 71.3V56a8 8 0 0 1 8 8" opacity=".2"/><path d="M224 48a8 8 0 0 0-8 8v15.3l-11.7-11.6a96 96 0 1 0 27.6 51.6a8 8 0 0 0-15.8 2.5a80 80 0 1 1-23-43l-25.7 25.7A8 8 0 0 0 173 112h56a8 8 0 0 0 8-8V56a8 8 0 0 0-13-8"/></g></svg>
    <span>Click or press the space bar to pause or restart</span>
  </p>
  <div class="ld__field" id="field" role="application" aria-label="Cellular automaton fill test panel" tabindex="0">
    <canvas class="ld__cv" id="cv"></canvas>
    <b class="ld__badge" aria-hidden="true"><span class="ld__badgeNum" id="pct">0%</span><span class="ld__badgeUnit">Fill</span></b>
  </div>
</div>
</main>

@use "../../../../site/static/demo-tokens" as *;

// 셀룰러 오토마타 로더 — 씨앗 몇 개에서 "이웃 3개 이상이면 태어나고 한 번 살면 계속 산다"는
// 생존 규칙 하나로 세대를 진행시킨다. 움직임은 전부 캔버스 rAF 루프 안에 있다(@keyframes 0개 — 077 선례).

$duration: $dur-loop;
$easing: $ease-pop;
$color: $subject-mint;

@include stage($stage-ink);

.ld {
  --paper: #{$subject-ink};
  --cell1: #{$subject-mint};
  --cell2: #{$subject-blue-light};

  display: flex; flex-direction: column; gap: $sp-2;
  width: 100%; max-width: 424px;
}

.ld__hint {
  display: flex; align-items: center; gap: $sp-1; margin: 0;
  font-weight: 700; font-size: clamp(10px, 2.8vw, 12px); line-height: 1.35;
  color: $subject-cream;
}
.ld__ico { width: 16px; height: 16px; flex: 0 0 auto; color: $subject-mint; }

.ld__field {
  position: relative; height: 208px;
  border-radius: $r-card; overflow: hidden;
  background: $subject-ink;
  box-shadow: inset 0 0 0 1px rgba($subject-cream, .16);
  cursor: pointer;
}
.ld__field:focus-visible { outline: 2px solid $subject-mint; outline-offset: 2px; }

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

.ld__badge {
  position: absolute; right: $sp-2; top: $sp-2;
  display: flex; align-items: baseline; gap: $sp-1;
  padding: $sp-1 $sp-2; border-radius: $r-pill;
  background: rgba($subject-cream, .14);
  color: $subject-cream; font-weight: 700; font-size: 11px;
}
.ld__badgeNum { font-size: 13px; color: $subject-mint; }
.ld__badgeUnit { font-weight: 700; }

@media (max-width: 340px) {
  .ld { gap: $sp-1; }
  .ld__field { height: 124px; }
  .ld__badge { font-size: 10px; padding: 0 $sp-1; }
  .ld__badgeNum { font-size: 11px; }
}

// reduce — 루프를 시작하지 않고 진행률 62% 언저리에서 멈춘 한 장만 그린다.
@media (prefers-reduced-motion: reduce) {
  .ld.is-still .ld__field { cursor: default !important; }
  .ld.is-still .ld__badge { opacity: .92 !important; }
}

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);
}

.ld {
  --paper: #17141a;
  --cell1: #4cd4a6;
  --cell2: #5b8cf8;
  display: flex;
  flex-direction: column;
  gap: 8px;
  width: 100%;
  max-width: 424px;
}

.ld__hint {
  display: flex;
  align-items: center;
  gap: 4px;
  margin: 0;
  font-weight: 700;
  font-size: clamp(10px, 2.8vw, 12px);
  line-height: 1.35;
  color: #fff7e6;
}

.ld__ico {
  width: 16px;
  height: 16px;
  flex: 0 0 auto;
  color: #4cd4a6;
}

.ld__field {
  position: relative;
  height: 208px;
  border-radius: 16px;
  overflow: hidden;
  background: #17141a;
  box-shadow: inset 0 0 0 1px rgba(255, 247, 230, 0.16);
  cursor: pointer;
}

.ld__field:focus-visible {
  outline: 2px solid #4cd4a6;
  outline-offset: 2px;
}

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

.ld__badge {
  position: absolute;
  right: 8px;
  top: 8px;
  display: flex;
  align-items: baseline;
  gap: 4px;
  padding: 4px 8px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.14);
  color: #fff7e6;
  font-weight: 700;
  font-size: 11px;
}

.ld__badgeNum {
  font-size: 13px;
  color: #4cd4a6;
}

.ld__badgeUnit {
  font-weight: 700;
}

@media (max-width: 340px) {
  .ld {
    gap: 4px;
  }
  .ld__field {
    height: 124px;
  }
  .ld__badge {
    font-size: 10px;
    padding: 0 4px;
  }
  .ld__badgeNum {
    font-size: 11px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .ld.is-still .ld__field {
    cursor: default !important;
  }
  .ld.is-still .ld__badge {
    opacity: 0.92 !important;
  }
}

// 셀룰러 오토마타 로더 — 씨앗 몇 개에서 시작해 "이웃 3개 이상이면 태어나고, 한 번 살면 계속 산다"는
// 생존 규칙 하나로 세대를 진행시킨다. 그 세대의 살아있는 칸 비율(채워진 칸/전체 칸)이 곧 진행률이다.
var root = document.getElementById('ld');
var field = document.getElementById('field');
var cv = document.getElementById('cv');
var ctx = cv.getContext('2d');
var pctEl = document.getElementById('pct');

var css = getComputedStyle(root);
var PAPER = css.getPropertyValue('--paper').trim();
var CELL1 = css.getPropertyValue('--cell1').trim();
var CELL2 = css.getPropertyValue('--cell2').trim();

function makeRng(seed) {
  var s = seed >>> 0;
  return function () {
    s = (1103515245 * s + 12345) >>> 0;
    return (s >>> 8) / 16777216;
  };
}

var GX = 26, GY = 16;
var TOTAL = GX * GY;
var BIRTH = 3;                       // 생존(탄생) 규칙 상수(훅 고정값) — cellular-automaton-fill-percent, 이웃 수가 이 이상이면 태어난다
var INIT_SEEDS = 5;
var GENS = 16;
var STEP_INTERVAL = 0.15;
var LOOP = GENS * STEP_INTERVAL;

var rng = makeRng(20260927);
function setAlive(g, x, y) {
  if (x < 0 || y < 0 || x >= GX || y >= GY) return;
  g[y * GX + x] = 1;
}
function makeSeedGrid() {
  var g = new Uint8Array(TOTAL);
  for (var i = 0; i < INIT_SEEDS; i++) {
    var x = Math.floor(rng() * GX), y = Math.floor(rng() * GY);
    // 씨앗마다 L자 3칸 뭉치 — 홀로 떨어진 1칸은 이웃 3개 조건을 영영 못 채워 자라지 않는다
    setAlive(g, x, y);
    setAlive(g, x + 1, y);
    setAlive(g, x, y + 1);
  }
  return g;
}
function neighborCount(g, x, y) {
  var c = 0;
  for (var dy = -1; dy <= 1; dy++) {
    for (var dx = -1; dx <= 1; dx++) {
      if (dx === 0 && dy === 0) continue;
      var nx = x + dx, ny = y + dy;
      if (nx < 0 || ny < 0 || nx >= GX || ny >= GY) continue;
      if (g[ny * GX + nx]) c++;
    }
  }
  return c;
}
function stepGen(prev) {
  var next = new Uint8Array(TOTAL);
  for (var y = 0; y < GY; y++) {
    for (var x = 0; x < GX; x++) {
      var idx = y * GX + x;
      if (prev[idx]) { next[idx] = 1; continue; }
      next[idx] = neighborCount(prev, x, y) >= BIRTH ? 1 : 0;
    }
  }
  return next;
}

var generations = [makeSeedGrid()];
for (var gi = 1; gi <= GENS; gi++) generations.push(stepGen(generations[gi - 1]));

var shimF = new Float32Array(TOTAL), shimP = new Float32Array(TOTAL);
(function () {
  var srng = makeRng(778899);
  for (var i = 0; i < TOTAL; i++) { shimF[i] = 1.4 + srng() * 2.2; shimP[i] = srng() * Math.PI * 2; }
})();

var W = 0, H = 0, dpr = 1, cw = 0, ch = 0, ox = 0, oy = 0;

function fit() {
  var r = field.getBoundingClientRect();
  dpr = window.devicePixelRatio || 1;
  W = r.width; H = r.height;
  cv.width = Math.round(W * dpr); cv.height = Math.round(H * dpr);
  ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
  cw = W / GX; ch = H / GY;
}

function draw(sec) {
  var t = sec % LOOP;
  var gen = Math.min(GENS, Math.floor(t / STEP_INTERVAL));
  var grid = generations[gen];

  ctx.fillStyle = PAPER;
  ctx.fillRect(0, 0, W, H);

  var alive = 0;
  for (var y = 0; y < GY; y++) {
    for (var x = 0; x < GX; x++) {
      var idx = y * GX + x;
      if (!grid[idx]) continue;
      alive++;
      var shim = 0.58 + 0.42 * Math.sin(sec * shimF[idx] + shimP[idx]);
      ctx.fillStyle = (idx % 2 === 0) ? CELL1 : CELL2;
      ctx.globalAlpha = shim;
      ctx.fillRect(x * cw + 1, y * ch + 1, cw - 2, ch - 2);
    }
  }
  ctx.globalAlpha = 1;

  pctEl.textContent = Math.round(alive / TOTAL * 100) + '%';
}

var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
var paused = false;
var t0 = 0;
var raf = 0;

function togglePause() {
  paused = !paused;
  root.classList.toggle('is-paused', paused);
}
function restart() {
  t0 = performance.now();
  draw(0);
}

field.addEventListener('click', function () { togglePause(); });
field.addEventListener('keydown', function (e) {
  if (e.key === ' ' || e.key === 'Enter') { e.preventDefault(); togglePause(); }
  else if (e.key === 'r' || e.key === 'R') { e.preventDefault(); restart(); }
});
window.addEventListener('resize', function () {
  fit();
  if (paused || reduce) draw(((performance.now() - t0) / 1000));
});

function frame(now) {
  if (!paused) draw((now - t0) / 1000);
  raf = requestAnimationFrame(frame);
}

t0 = performance.now();
fit();
if (reduce) {
  root.classList.add('is-still');
  draw(LOOP * 0.62);
} else {
  raf = requestAnimationFrame(frame);
}

// CellAutomaton — vanilla 판(run/395/demo/09-canvas-loader-cellular-automaton-fill-percent/index.html) 의 React 포트.
// 씨앗 몇 개에서 시작해 "이웃 3개 이상이면 태어나고, 한 번 살면 계속 산다"는 생존 규칙 하나로
// 세대를 진행시킨다. 그 세대의 살아있는 칸 비율(채워진 칸/전체 칸)이 곧 진행률이다.
import { useEffect, useRef } from "react";
import type { CSSProperties } from "react";
import styles from "./CellAutomaton.module.scss";

export type CellAutomatonProps = {
  duration?: string;
  easing?: string;
  color?: string;
};

type Vars = CSSProperties & { "--duration"?: string; "--easing"?: string; "--color"?: string };
type Box<T> = { current: T };
type KeyEvt = { key: string; preventDefault(): void };

function makeRng(seed: number) {
  let s = seed >>> 0;
  return function () {
    s = (1103515245 * s + 12345) >>> 0;
    return (s >>> 8) / 16777216;
  };
}

const GX = 26, GY = 16;
const TOTAL = GX * GY;
const BIRTH = 3;              // 생존(탄생) 규칙 상수(훅 고정값) — cellular-automaton-fill-percent, 이웃 수가 이 이상이면 태어난다
const INIT_SEEDS = 5;
const GENS = 16;
const STEP_INTERVAL = 0.15;
const LOOP = GENS * STEP_INTERVAL;
const FIELD_LABEL = "셀룰러 오토마타 채움 실험판";

function setAlive(g: Uint8Array, x: number, y: number): void {
  if (x < 0 || y < 0 || x >= GX || y >= GY) return;
  g[y * GX + x] = 1;
}
function makeSeedGrid(): Uint8Array {
  const rng = makeRng(20260927);
  const g = new Uint8Array(TOTAL);
  for (let i = 0; i < INIT_SEEDS; i++) {
    const x = Math.floor(rng() * GX), y = Math.floor(rng() * GY);
    // 씨앗마다 L자 3칸 뭉치 — 홀로 떨어진 1칸은 이웃 3개 조건을 영영 못 채워 자라지 않는다
    setAlive(g, x, y);
    setAlive(g, x + 1, y);
    setAlive(g, x, y + 1);
  }
  return g;
}
function neighborCount(g: Uint8Array, x: number, y: number): number {
  let c = 0;
  for (let dy = -1; dy <= 1; dy++) {
    for (let dx = -1; dx <= 1; dx++) {
      if (dx === 0 && dy === 0) continue;
      const nx = x + dx, ny = y + dy;
      if (nx < 0 || ny < 0 || nx >= GX || ny >= GY) continue;
      if (g[ny * GX + nx]) c++;
    }
  }
  return c;
}
function stepGen(prev: Uint8Array): Uint8Array {
  const next = new Uint8Array(TOTAL);
  for (let y = 0; y < GY; y++) {
    for (let x = 0; x < GX; x++) {
      const idx = y * GX + x;
      if (prev[idx]) { next[idx] = 1; continue; }
      next[idx] = neighborCount(prev, x, y) >= BIRTH ? 1 : 0;
    }
  }
  return next;
}
function makeGenerations(): Uint8Array[] {
  const gens = [makeSeedGrid()];
  for (let gi = 1; gi <= GENS; gi++) gens.push(stepGen(gens[gi - 1]));
  return gens;
}
function makeShimmer(): { f: Float32Array; p: Float32Array } {
  const rng = makeRng(778899);
  const f = new Float32Array(TOTAL), p = new Float32Array(TOTAL);
  for (let i = 0; i < TOTAL; i++) { f[i] = 1.4 + rng() * 2.2; p[i] = rng() * Math.PI * 2; }
  return { f, p };
}

export default function CellAutomaton({
  duration = "2.4s",
  easing = "cubic-bezier(.2, 1.4, .4, 1)",   // vanilla $easing: $ease-pop
  color = "#7de0c2",                          // vanilla $color: $subject-mint
}: CellAutomatonProps) {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const fieldRef = useRef<HTMLDivElement | null>(null);
  const cvRef = useRef<HTMLCanvasElement | null>(null);
  const ctxRef = useRef<CanvasRenderingContext2D | null>(null);
  const pctRef = useRef<HTMLSpanElement | null>(null);
  const sizeRef = useRef({ w: 0, h: 0, dpr: 1, cw: 0, ch: 0 }) as Box<{ w: number; h: number; dpr: number; cw: number; ch: number }>;
  const gensRef = useRef<Uint8Array[]>([]) as Box<Uint8Array[]>;
  const shimRef = useRef<{ f: Float32Array; p: Float32Array } | null>(null) as Box<{ f: Float32Array; p: Float32Array } | null>;
  const pausedRef = useRef(false) as Box<boolean>;
  const t0Ref = useRef(0) as Box<number>;
  const rafRef = useRef(0) as Box<number>;
  const vars: Vars = { "--duration": duration, "--easing": easing, "--color": color };

  function reduced(): boolean {
    return window.matchMedia("(prefers-reduced-motion: reduce)").matches;
  }

  function fit(): void {
    const field = fieldRef.current;
    const cv = cvRef.current;
    const ctx = ctxRef.current;
    if (!field || !cv || !ctx) return;
    const r = field.getBoundingClientRect();
    const dpr = window.devicePixelRatio || 1;
    const size = sizeRef.current;
    size.w = r.width; size.h = r.height; size.dpr = dpr;
    cv.width = Math.round(r.width * dpr);
    cv.height = Math.round(r.height * dpr);
    ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
    size.cw = r.width / GX; size.ch = r.height / GY;
  }

  function draw(sec: number): void {
    const ctx = ctxRef.current;
    const root = rootRef.current;
    const shim = shimRef.current;
    if (!ctx || !root || !shim) return;
    const size = sizeRef.current;
    const W = size.w, H = size.h;
    const t = sec % LOOP;
    const gen = Math.min(GENS, Math.floor(t / STEP_INTERVAL));
    const grid = gensRef.current[gen];

    const cssv = (n: string) => getComputedStyle(root).getPropertyValue(n).trim();
    const PAPER = cssv("--paper"), CELL1 = cssv("--cell1"), CELL2 = cssv("--cell2");

    ctx.fillStyle = PAPER;
    ctx.fillRect(0, 0, W, H);

    let alive = 0;
    for (let y = 0; y < GY; y++) {
      for (let x = 0; x < GX; x++) {
        const idx = y * GX + x;
        if (!grid[idx]) continue;
        alive++;
        const s = 0.58 + 0.42 * Math.sin(sec * shim.f[idx] + shim.p[idx]);
        ctx.fillStyle = idx % 2 === 0 ? CELL1 : CELL2;
        ctx.globalAlpha = s;
        ctx.fillRect(x * size.cw + 1, y * size.ch + 1, size.cw - 2, size.ch - 2);
      }
    }
    ctx.globalAlpha = 1;

    if (pctRef.current) pctRef.current.textContent = Math.round((alive / TOTAL) * 100) + "%";
  }

  function togglePause(): void {
    pausedRef.current = !pausedRef.current;
    const root = rootRef.current;
    if (root) root.classList.toggle("is-paused", pausedRef.current);
  }

  function restart(): void {
    t0Ref.current = performance.now();
    draw(0);
  }

  function onKey(e: KeyEvt): void {
    if (e.key === " " || e.key === "Enter") { e.preventDefault(); togglePause(); }
    else if (e.key === "r" || e.key === "R") { e.preventDefault(); restart(); }
  }

  function onClick(): void {
    togglePause();
  }

  function onResize(): void {
    fit();
    if (pausedRef.current || reduced()) draw((performance.now() - t0Ref.current) / 1000);
  }

  function frame(now: number): void {
    if (!pausedRef.current) draw((now - t0Ref.current) / 1000);
    rafRef.current = requestAnimationFrame(frame);
  }

  useEffect(() => {
    const cv = cvRef.current;
    if (!cv) return;
    ctxRef.current = cv.getContext("2d");
    if (!ctxRef.current) return;
    gensRef.current = makeGenerations();
    shimRef.current = makeShimmer();
    t0Ref.current = performance.now();
    fit();
    window.addEventListener("resize", onResize);
    if (reduced()) {
      const root = rootRef.current;
      if (root) root.classList.add("is-still");
      draw(LOOP * 0.62);
    } else {
      rafRef.current = requestAnimationFrame(frame);
    }
    return () => {
      window.removeEventListener("resize", onResize);
      cancelAnimationFrame(rafRef.current);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={styles.root} ref={rootRef} style={vars}>
        <p className={styles.hint}>
          <svg className={styles.ico} viewBox="0 0 256 256" aria-hidden="true"><g fill="currentColor"><path d="M232 56v56a8 8 0 0 1-16 0V91.3l-25.6 25.7A80 80 0 1 1 174 60a8 8 0 1 1-9 13.2A64 64 0 1 0 179.7 128H216a8 8 0 0 1 0 16h-56a8 8 0 0 1-8-8V80a8 8 0 0 1 16 0v20.7L192.7 76A80.1 80.1 0 0 0 64 128a8 8 0 0 1-16 0a96 96 0 0 1 163.6-68.3L224 71.3V56a8 8 0 0 1 8 8" opacity=".2"/><path d="M224 48a8 8 0 0 0-8 8v15.3l-11.7-11.6a96 96 0 1 0 27.6 51.6a8 8 0 0 0-15.8 2.5a80 80 0 1 1-23-43l-25.7 25.7A8 8 0 0 0 173 112h56a8 8 0 0 0 8-8V56a8 8 0 0 0-13-8"/></g></svg>
          <span>클릭하거나 스페이스바를 누르면 멈추거나 다시 갑니다</span>
        </p>
        <div
          className={styles.field}
          ref={fieldRef}
          role="application"
          aria-label={FIELD_LABEL}
          tabIndex={0}
          onClick={onClick}
          onKeyDown={onKey}
        >
          <canvas className={styles.cv} ref={cvRef}></canvas>
          <b className={styles.badge} aria-hidden="true"><span className={styles.badgeNum} ref={pctRef}>0%</span><span className={styles.badgeUnit}>채움</span></b>
        </div>
      </div>
    </main>
  );
}