03層ごとにゆっくり流れるグラデーションメッシュ背景

<main class="stage">
<div class="d3 is-demo" id="d3Root">
  <canvas class="d3__canvas" id="d3Canvas" width="480" height="300"></canvas>
  <p class="d3__caption">複数のぼかしたグラデーション塊に異なる移動周期を与えて重ねて描き、近い層ほど大きく速く、遠い層ほど小さくゆっくり流れる</p>
</div>
</main>

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

.d3 {
  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-orange;
}

.d3__canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.d3__caption {
  position: absolute;
  left: $sp-3;
  bottom: $sp-3;
  max-width: 78%;
  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) {
  .d3__caption { font-size: 10px; padding: $sp-1 $sp-2; }
}

@media (prefers-reduced-motion: reduce) {
  .d3 { cursor: default; }
}

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);
}

.d3 {
  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: #ff4d1f;
}

.d3__canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.d3__caption {
  position: absolute;
  left: 12px;
  bottom: 12px;
  max-width: 78%;
  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) {
  .d3__caption {
    font-size: 10px;
    padding: 4px 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .d3 {
    cursor: default;
  }
}

(function () {
  // 기법: meshLayers 배열의 층마다 이동 주기(period)·반경·이동 폭을 다르게 줘 Lissajous 곡선으로
  // 흐르게 한다 — 가까운 층(인덱스 0)은 MESH_DRIFT_PERIOD_BASE_MS 그대로 짧게·크게·빠르게, 먼 층일수록
  // 주기를 늘리고 반경·이동 폭을 줄여 작고 느리게 흐르는 것처럼 보이게 한다.
  var root = document.getElementById('d3Root');
  var canvas = document.getElementById('d3Canvas');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;

  var CALC_W = 160, CALC_H = 100;
  var MESH_DRIFT_PERIOD_BASE_MS = 3200;
  var MESH_LAYER_COUNT = 5;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var rnd = seedRand(429031);
  var palette = ['#ff9ebb', '#ffb37a', '#ffd23f', '#ff8a5c', '#ffcf99'];

  var meshLayers = [];
  for (var i = 0; i < MESH_LAYER_COUNT; i += 1) {
    var depthIndex = i;
    meshLayers.push({
      depthIndex: depthIndex,
      period: MESH_DRIFT_PERIOD_BASE_MS * (1 + depthIndex * 0.62),
      centerX: 20 + rnd() * (CALC_W - 40),
      centerY: 18 + rnd() * (CALC_H - 36),
      reachPx: Math.max(10, 42 - depthIndex * 6),
      radius: Math.max(14, 46 - depthIndex * 7),
      phaseX: rnd() * Math.PI * 2,
      phaseY: rnd() * Math.PI * 2,
      color: palette[i % palette.length]
    });
  }
  meshLayers.sort(function (a, b) { return b.depthIndex - a.depthIndex; });

  function blobPositionAt(layer, t) {
    var ax = Math.sin(t / layer.period * Math.PI * 2 + layer.phaseX) * layer.reachPx;
    var ay = Math.cos(t / layer.period * Math.PI * 2.3 + layer.phaseY) * layer.reachPx * 0.7;
    return { x: layer.centerX + ax, y: layer.centerY + ay };
  }

  var elapsed = 0;
  var cw = 480, ch = 300;

  function drawScene(nowMs) {
    var sx = cw / CALC_W, sy = ch / CALC_H;
    var savg = (sx + sy) / 2;
    ctx.clearRect(0, 0, cw, ch);
    ctx.globalCompositeOperation = 'lighter';
    for (var i = 0; i < meshLayers.length; i += 1) {
      var layer = meshLayers[i];
      var pos = blobPositionAt(layer, nowMs);
      var alpha = Math.max(0.3, 0.72 - layer.depthIndex * 0.1);
      var dx = pos.x * sx, dy = pos.y * sy, dr = layer.radius * savg;
      var g = ctx.createRadialGradient(dx, dy, 0, dx, dy, dr);
      g.addColorStop(0, layer.color);
      g.addColorStop(1, 'rgba(0,0,0,0)');
      ctx.globalAlpha = alpha;
      ctx.fillStyle = g;
      ctx.beginPath();
      ctx.arc(dx, dy, dr, 0, Math.PI * 2);
      ctx.fill();
    }
    ctx.globalAlpha = 1;
    ctx.globalCompositeOperation = 'source-over';
  }

  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;
    drawScene(elapsed);
  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  if (reduce) root.classList.remove('is-demo');

  var warmSteps = reduce ? 0 : 90;
  for (var w = 0; w < warmSteps; w += 1) elapsed += 20;

  var lastTs = null;
  function tick(ts) {
    if (lastTs === null) lastTs = ts;
    var dt = Math.min(ts - lastTs, 48);
    lastTs = ts;
    if (!reduce) {
      elapsed += dt;
      drawScene(elapsed);
    }
    requestAnimationFrame(tick);
  }
  fit();
  window.addEventListener('resize', fit);
  drawScene(elapsed);
  requestAnimationFrame(tick);
})();

import { useEffect, useRef } from "react";
import styles from "./Depth3dGradientMeshDrift.module.scss";

type MeshLayer = {
  depthIndex: number;
  period: number;
  centerX: number;
  centerY: number;
  reachPx: number;
  radius: number;
  phaseX: number;
  phaseY: number;
  color: string;
};

export default function Depth3dGradientMeshDrift() {
  const rootRef = useRef<HTMLDivElement>(null);
  const canvasRef = useRef<HTMLCanvasElement>(null);

  useEffect(() => {
    const root = rootRef.current;
    const canvas = canvasRef.current;
    if (!root || !canvas) return;
    const ctx = canvas.getContext("2d");
    if (!ctx) return;
    const wrap = canvas.parentElement as HTMLElement;

    const CALC_W = 160, CALC_H = 100;
    const MESH_DRIFT_PERIOD_BASE_MS = 3200;
    const MESH_LAYER_COUNT = 5;

    function seedRand(seed: number) {
      let s = seed >>> 0;
      return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
    }
    const rnd = seedRand(429031);
    const palette = ["#ff9ebb", "#ffb37a", "#ffd23f", "#ff8a5c", "#ffcf99"];

    const meshLayers: MeshLayer[] = [];
    for (let i = 0; i < MESH_LAYER_COUNT; i += 1) {
      const depthIndex = i;
      meshLayers.push({
        depthIndex,
        period: MESH_DRIFT_PERIOD_BASE_MS * (1 + depthIndex * 0.62),
        centerX: 20 + rnd() * (CALC_W - 40),
        centerY: 18 + rnd() * (CALC_H - 36),
        reachPx: Math.max(10, 42 - depthIndex * 6),
        radius: Math.max(14, 46 - depthIndex * 7),
        phaseX: rnd() * Math.PI * 2,
        phaseY: rnd() * Math.PI * 2,
        color: palette[i % palette.length]
      });
    }
    meshLayers.sort((a, b) => b.depthIndex - a.depthIndex);

    function blobPositionAt(layer: MeshLayer, t: number) {
      const ax = Math.sin(t / layer.period * Math.PI * 2 + layer.phaseX) * layer.reachPx;
      const ay = Math.cos(t / layer.period * Math.PI * 2.3 + layer.phaseY) * layer.reachPx * 0.7;
      return { x: layer.centerX + ax, y: layer.centerY + ay };
    }

    let elapsed = 0;
    let cw = 480, ch = 300;

    function drawScene(nowMs: number) {
      const sx = cw / CALC_W, sy = ch / CALC_H;
      const savg = (sx + sy) / 2;
      ctx!.clearRect(0, 0, cw, ch);
      ctx!.globalCompositeOperation = "lighter";
      for (let i = 0; i < meshLayers.length; i += 1) {
        const layer = meshLayers[i];
        const pos = blobPositionAt(layer, nowMs);
        const alpha = Math.max(0.3, 0.72 - layer.depthIndex * 0.1);
        const dx = pos.x * sx, dy = pos.y * sy, dr = layer.radius * savg;
        const g = ctx!.createRadialGradient(dx, dy, 0, dx, dy, dr);
        g.addColorStop(0, layer.color);
        g.addColorStop(1, "rgba(0,0,0,0)");
        ctx!.globalAlpha = alpha;
        ctx!.fillStyle = g;
        ctx!.beginPath();
        ctx!.arc(dx, dy, dr, 0, Math.PI * 2);
        ctx!.fill();
      }
      ctx!.globalAlpha = 1;
      ctx!.globalCompositeOperation = "source-over";
    }

    function fit() {
      const 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;
      drawScene(elapsed);
    }

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    if (reduce) root.classList.remove("is-demo");

    const warmSteps = reduce ? 0 : 90;
    for (let w = 0; w < warmSteps; w += 1) elapsed += 20;

    let lastTs: number | null = null;
    let raf = 0;
    function tick(ts: number) {
      if (lastTs === null) lastTs = ts;
      const dt = Math.min(ts - lastTs, 48);
      lastTs = ts;
      if (!reduce) {
        elapsed += dt;
        drawScene(elapsed);
      }
      raf = requestAnimationFrame(tick);
    }
    fit();
    window.addEventListener("resize", fit);
    drawScene(elapsed);
    raf = requestAnimationFrame(tick);

    return () => {
      cancelAnimationFrame(raf);
      window.removeEventListener("resize", fit);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.d3} is-demo`} ref={rootRef}>
        <canvas className={styles.d3__canvas} ref={canvasRef} width={480} height={300} />
        <p className={styles.d3__caption}>여러 겹의 흐린 그라데이션 덩어리에 서로 다른 이동 주기를 줘 겹쳐 그리고, 가까운 층일수록 더 크고 빠르게, 먼 층일수록 작고 느리게 흐른다</p>
      </div>
    </main>
  );
}