07トラッキング揺れ値が安定する画面の切り替え

<main class="stage">
<div class="tw is-demo" id="tw">
  <p class="tw__hint"><span>クリックまたはEnterキーを押すと、トラッキングの揺れ値が大きく揺れてから収まり画面が落ち着きます</span></p>
  <div class="tw__panel" id="panel" tabindex="0" role="button" aria-label="テープトラッキングの揺れ値が落ち着くイントロ転換をもう一度再生">
    <canvas class="tw__cv" id="cv" aria-hidden="true"></canvas>
  </div>
</div>
</main>

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

// 계산 겹(테이프 트래킹 렌더)은 index.html 의 PRECOMPUTE()/RENDER() 에 있다. 여기는 무대·레이아웃만.
$duration: $dur-loop;
$easing:   $ease-out;
$color:    $subject-ink;

@include stage($stage-orange);

.tw {
  --scene-tile1: #{$subject-orange-deep};
  --scene-tile2: #{$subject-cream};
  --scene-tile3: #{$subject-blue};
  --accent: #{$color};
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: $sp-2;
  width: min(400px, 92vw);
}

.tw__hint {
  margin: 0;
  color: $subject-ink;
  font-size: 12px;
  font-weight: 500;
  line-height: 1.35;
  text-align: center;
}

.tw__panel {
  position: relative;
  width: 100%;
  height: 176px;
  border-radius: $r-card;
  overflow: hidden;
  cursor: pointer;
  box-shadow: 0 0 0 1px rgba($subject-ink, .14);
  transition: box-shadow $duration $easing;
}

.tw__panel:hover {
  box-shadow: 0 0 0 1px $color;
}

.tw__panel:focus-visible {
  outline: 2px solid $color;
  outline-offset: 2px;
}

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

@media (max-width: 340px) {
  .tw__hint { font-size: 11px; }
  .tw__panel, .tw__cv { height: 120px; }
}

@media (prefers-reduced-motion: reduce) {
  .tw__panel { transition: none; }
}

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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.tw {
  --scene-tile1: #c93000;
  --scene-tile2: #fff7e6;
  --scene-tile3: #2f6df6;
  --accent: #17141a;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  width: min(400px, 92vw);
}

.tw__hint {
  margin: 0;
  color: #17141a;
  font-size: 12px;
  font-weight: 500;
  line-height: 1.35;
  text-align: center;
}

.tw__panel {
  position: relative;
  width: 100%;
  height: 176px;
  border-radius: 16px;
  overflow: hidden;
  cursor: pointer;
  box-shadow: 0 0 0 1px rgba(23, 20, 26, 0.14);
  transition: box-shadow 2s ease-out;
}

.tw__panel:hover {
  box-shadow: 0 0 0 1px #17141a;
}

.tw__panel:focus-visible {
  outline: 2px solid #17141a;
  outline-offset: 2px;
}

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

@media (max-width: 340px) {
  .tw__hint {
    font-size: 11px;
  }
  .tw__panel, .tw__cv {
    height: 120px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .tw__panel {
    transition: none;
  }
}

(function () {
  var root = document.getElementById('tw');
  var panel = document.getElementById('panel');
  var cv = document.getElementById('cv');
  var ctx = cv.getContext('2d');
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var isDemo = true;

  // 결정론 난수 — Math.random 을 쓰지 않는다. LCG(선형합동생성기) 하나로 장면을 만든다.
  function makeLcg(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }

  var css = getComputedStyle(root);
  function tok(name, fb) { var v = css.getPropertyValue(name); return v ? (v.trim() || fb) : fb; }
  var TILE1 = tok('--scene-tile1', '#f4a340');
  var TILE2 = tok('--scene-tile2', '#fff7e6');
  var TILE3 = tok('--scene-tile3', '#2f6df6');

  var W = 0, H = 0, dpr = 1;
  var buf = document.createElement('canvas');
  var bctx = buf.getContext('2d');

  // 장면(레트로 인트로 타이틀 카드 자리) — 격자 타일로 가로·세로 흔들림이 모두 드러나게 한다.
  function paintScene(bc, w, h, seed) {
    var rng = makeLcg(seed);
    var cols = 8, rows = 6;
    var tw = w / cols, th = h / rows;
    for (var r = 0; r < rows; r++) {
      for (var c = 0; c < cols; c++) {
        var v = rng();
        bc.fillStyle = v < 0.34 ? TILE1 : (v < 0.67 ? TILE2 : TILE3);
        bc.fillRect(c * tw, r * th, tw + 1, th + 1);
      }
    }
  }

  var SEED = 919;
  var TAPE_WOBBLE_AMPLITUDE = 40;
  var TAPE_JITTER_AMPLITUDE = 16;
  var data, outImg, iw, ih;

  function PRECOMPUTE() {
    iw = cv.width; ih = cv.height;
    data = bctx.getImageData(0, 0, iw, ih).data;
    outImg = ctx.createImageData(iw, ih);
  }

  function hash01(n) {
    n = (n ^ 61) ^ (n >>> 16);
    n = (n + (n << 3)) | 0;
    n = n ^ (n >>> 4);
    n = Math.imul(n, 0x27d4eb2d);
    n = n ^ (n >>> 15);
    return (n >>> 0) / 4294967295;
  }

  function clampI(v, lo, hi) { return v < lo ? lo : (v > hi ? hi : v); }
  function wrap(v, m) { var r = v % m; return r < 0 ? r + m : r; }

  var PLAY_MS = 640;
  var phaseRoll = 0;
  var frameCounter = 0;

  function RENDER(p) {
    phaseRoll += 0.33;
    frameCounter = (frameCounter + 1) >>> 0;
    var rollY = Math.round(TAPE_WOBBLE_AMPLITUDE * dpr * p * Math.sin(phaseRoll));
    var fSalt = Math.imul(frameCounter, 2246822519) >>> 0;
    var o = outImg.data;
    for (var y = 0; y < ih; y++) {
      var srcY = wrap(y - rollY, ih);
      var jh = hash01((Math.imul(srcY, 668265263) ^ fSalt) >>> 0);
      var jitterX = Math.round(TAPE_JITTER_AMPLITUDE * dpr * p * (jh * 2 - 1));
      var base = y * iw;
      var srcBase = srcY * iw;
      for (var x = 0; x < iw; x++) {
        var sx = clampI(x - jitterX, 0, iw - 1);
        var k = (base + x) * 4;
        var sk = (srcBase + sx) * 4;
        o[k] = data[sk]; o[k + 1] = data[sk + 1]; o[k + 2] = data[sk + 2]; o[k + 3] = 255;
      }
    }
    ctx.putImageData(outImg, 0, 0);
  }

  function fit() {
    var r = panel.getBoundingClientRect();
    dpr = window.devicePixelRatio || 1;
    W = r.width; H = r.height;
    cv.width = Math.round(W * dpr); cv.height = Math.round(H * dpr);
    buf.width = cv.width; buf.height = cv.height;
    paintScene(bctx, buf.width, buf.height, SEED);
    PRECOMPUTE();
  }

  function human() { if (isDemo) { root.classList.remove('is-demo'); isDemo = false; } }

  var progress = 0, target = 0, playT0 = 0, playFrom = 0, playing = false;

  function easeInOut(t) { return t < 0.5 ? 2 * t * t : 1 - Math.pow(-2 * t + 2, 2) / 2; }

  function play() {
    human();
    playFrom = progress; target = progress < 0.5 ? 1 : 0;
    playT0 = 0; playing = true;
  }

  function stepPlay(now) {
    if (!playing) return;
    if (!playT0) playT0 = now;
    var t = Math.min(1, (now - playT0) / PLAY_MS);
    progress = playFrom + (target - playFrom) * easeInOut(t);
    if (t >= 1) { playing = false; progress = target; }
  }

  var DRIVE_PERIOD_MS = 2000;
  var driveStart = 0;
  function triangle(frac) { return frac < 0.5 ? frac * 2 : 2 - frac * 2; }
  function driveTick(now) {
    if (!driveStart) driveStart = now;
    if (isDemo) {
      var frac = ((now - driveStart) % DRIVE_PERIOD_MS) / DRIVE_PERIOD_MS;
      progress = triangle(frac);
    }
    requestAnimationFrame(driveTick);
  }

  function frame(now) {
    stepPlay(now);
    RENDER(progress);
    requestAnimationFrame(frame);
  }

  window.addEventListener('resize', fit);
  fit();

  if (reduce) {
    root.classList.add('is-still');
    progress = 0; RENDER(progress);
    panel.addEventListener('click', function () { human(); progress = progress < 0.5 ? 1 : 0; RENDER(progress); });
    panel.addEventListener('keydown', function (e) {
      if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); human(); progress = progress < 0.5 ? 1 : 0; RENDER(progress); }
    });
  } else {
    panel.addEventListener('click', play);
    panel.addEventListener('keydown', function (e) {
      if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); play(); }
    });
    requestAnimationFrame(frame);
    requestAnimationFrame(driveTick);
  }
})();

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

export default function TapeTrackingWobble() {
  const rootRef = useRef<HTMLDivElement | null>(null);
  const panelRef = useRef<HTMLDivElement | null>(null);
  const cvRef = useRef<HTMLCanvasElement | null>(null);

  useEffect(() => {
    const root = rootRef.current;
    const panel = panelRef.current;
    const cv = cvRef.current;
    if (!root || !panel || !cv) return;
    const ctx = cv.getContext("2d");
    if (!ctx) return;
    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let isDemo = true;

    // 결정론 난수 — Math.random 을 쓰지 않는다. LCG(선형합동생성기) 하나로 장면을 만든다.
    function makeLcg(seed: number) {
      let s = seed >>> 0;
      return function () {
        s = (s * 1664525 + 1013904223) >>> 0;
        return s / 4294967296;
      };
    }

    const css = getComputedStyle(root);
    function tok(name: string, fb: string) {
      const v = css.getPropertyValue(name);
      return v ? v.trim() || fb : fb;
    }
    const TILE1 = tok("--scene-tile1", "#f4a340");
    const TILE2 = tok("--scene-tile2", "#fff7e6");
    const TILE3 = tok("--scene-tile3", "#2f6df6");

    let W = 0;
    let H = 0;
    let dpr = 1;
    const buf = document.createElement("canvas");
    const bctx = buf.getContext("2d");
    if (!bctx) return;

    // 장면(레트로 인트로 타이틀 카드 자리) — 격자 타일로 가로·세로 흔들림이 모두 드러나게 한다.
    function paintScene(bc: CanvasRenderingContext2D, w: number, h: number, seed: number) {
      const rng = makeLcg(seed);
      const cols = 8;
      const rows = 6;
      const tw = w / cols;
      const th = h / rows;
      for (let r = 0; r < rows; r++) {
        for (let c = 0; c < cols; c++) {
          const v = rng();
          bc.fillStyle = v < 0.34 ? TILE1 : v < 0.67 ? TILE2 : TILE3;
          bc.fillRect(c * tw, r * th, tw + 1, th + 1);
        }
      }
    }

    const SEED = 919;
    const TAPE_WOBBLE_AMPLITUDE = 40;
    const TAPE_JITTER_AMPLITUDE = 16;
    let data: Uint8ClampedArray | null = null;
    let outImg: ImageData | null = null;
    let iw = 0;
    let ih = 0;

    function PRECOMPUTE() {
      iw = cv!.width;
      ih = cv!.height;
      data = bctx!.getImageData(0, 0, iw, ih).data;
      outImg = ctx!.createImageData(iw, ih);
    }

    function hash01(n: number) {
      n = (n ^ 61) ^ (n >>> 16);
      n = (n + (n << 3)) | 0;
      n = n ^ (n >>> 4);
      n = Math.imul(n, 0x27d4eb2d);
      n = n ^ (n >>> 15);
      return (n >>> 0) / 4294967295;
    }

    function clampI(v: number, lo: number, hi: number) {
      return v < lo ? lo : v > hi ? hi : v;
    }
    function wrap(v: number, m: number) {
      const r = v % m;
      return r < 0 ? r + m : r;
    }

    const PLAY_MS = 640;
    let phaseRoll = 0;
    let frameCounter = 0;

    function RENDER(p: number) {
      phaseRoll += 0.33;
      frameCounter = (frameCounter + 1) >>> 0;
      const rollY = Math.round(TAPE_WOBBLE_AMPLITUDE * dpr * p * Math.sin(phaseRoll));
      const fSalt = Math.imul(frameCounter, 2246822519) >>> 0;
      const o = outImg!.data;
      const d = data!;
      for (let y = 0; y < ih; y++) {
        const srcY = wrap(y - rollY, ih);
        const jh = hash01((Math.imul(srcY, 668265263) ^ fSalt) >>> 0);
        const jitterX = Math.round(TAPE_JITTER_AMPLITUDE * dpr * p * (jh * 2 - 1));
        const base = y * iw;
        const srcBase = srcY * iw;
        for (let x = 0; x < iw; x++) {
          const sx = clampI(x - jitterX, 0, iw - 1);
          const k = (base + x) * 4;
          const sk = (srcBase + sx) * 4;
          o[k] = d[sk];
          o[k + 1] = d[sk + 1];
          o[k + 2] = d[sk + 2];
          o[k + 3] = 255;
        }
      }
      ctx!.putImageData(outImg!, 0, 0);
    }

    function fit() {
      const r = panel!.getBoundingClientRect();
      dpr = window.devicePixelRatio || 1;
      W = r.width;
      H = r.height;
      cv!.width = Math.round(W * dpr);
      cv!.height = Math.round(H * dpr);
      buf.width = cv!.width;
      buf.height = cv!.height;
      paintScene(bctx!, buf.width, buf.height, SEED);
      PRECOMPUTE();
    }

    function human() {
      if (isDemo) {
        root!.classList.remove("is-demo");
        isDemo = false;
      }
    }

    let progress = 0;
    let target = 0;
    let playT0 = 0;
    let playFrom = 0;
    let playing = false;

    function easeInOut(t: number) {
      return t < 0.5 ? 2 * t * t : 1 - Math.pow(-2 * t + 2, 2) / 2;
    }

    function play() {
      human();
      playFrom = progress;
      target = progress < 0.5 ? 1 : 0;
      playT0 = 0;
      playing = true;
    }

    function stepPlay(now: number) {
      if (!playing) return;
      if (!playT0) playT0 = now;
      const t = Math.min(1, (now - playT0) / PLAY_MS);
      progress = playFrom + (target - playFrom) * easeInOut(t);
      if (t >= 1) {
        playing = false;
        progress = target;
      }
    }

    const DRIVE_PERIOD_MS = 2000;
    let driveStart = 0;
    let rafFrame = 0;
    let rafDrive = 0;

    function triangle(frac: number) {
      return frac < 0.5 ? frac * 2 : 2 - frac * 2;
    }

    function driveTick(now: number) {
      if (!driveStart) driveStart = now;
      if (isDemo) {
        const frac = ((now - driveStart) % DRIVE_PERIOD_MS) / DRIVE_PERIOD_MS;
        progress = triangle(frac);
      }
      rafDrive = requestAnimationFrame(driveTick);
    }

    function frame(now: number) {
      stepPlay(now);
      RENDER(progress);
      rafFrame = requestAnimationFrame(frame);
    }

    function onClick() {
      play();
    }
    function onKeyDown(e: Event) {
      const ke = e as KeyboardEvent;
      if (ke.key === "Enter" || ke.key === " ") {
        ke.preventDefault();
        play();
      }
    }
    function onClickReduce() {
      human();
      progress = progress < 0.5 ? 1 : 0;
      RENDER(progress);
    }
    function onKeyDownReduce(e: Event) {
      const ke = e as KeyboardEvent;
      if (ke.key === "Enter" || ke.key === " ") {
        ke.preventDefault();
        human();
        progress = progress < 0.5 ? 1 : 0;
        RENDER(progress);
      }
    }

    window.addEventListener("resize", fit);
    fit();

    if (reduce) {
      root.classList.add("is-still");
      progress = 0;
      RENDER(progress);
      panel.addEventListener("click", onClickReduce);
      panel.addEventListener("keydown", onKeyDownReduce);
    } else {
      panel.addEventListener("click", onClick);
      panel.addEventListener("keydown", onKeyDown);
      rafFrame = requestAnimationFrame(frame);
      rafDrive = requestAnimationFrame(driveTick);
    }

    return () => {
      window.removeEventListener("resize", fit);
      cancelAnimationFrame(rafFrame);
      cancelAnimationFrame(rafDrive);
      if (reduce) {
        panel.removeEventListener("click", onClickReduce);
        panel.removeEventListener("keydown", onKeyDownReduce);
      } else {
        panel.removeEventListener("click", onClick);
        panel.removeEventListener("keydown", onKeyDown);
      }
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.root} is-demo`} ref={rootRef}>
        <p className={styles.hint}>
          <span>클릭하거나 Enter 를 누르면 트래킹 흔들림 값이 크게 흔들리다가 잦아들며 화면이 정착합니다</span>
        </p>
        <div
          className={styles.panel}
          ref={panelRef}
          tabIndex={0}
          role="button"
          aria-label="테이프 트래킹 흔들림 값이 정착하는 인트로 전환 다시 재생"
        >
          <canvas className={styles.cv} ref={cvRef} aria-hidden="true" />
        </div>
      </div>
    </main>
  );
}