05Cells Whose Boundary the Pointer Pushes as an Extra Seed

<main class="stage">
<div class="vd is-demo" id="vdRoot">
  <canvas class="vd__canvas" id="vdCanvas" width="480" height="300"></canvas>
  <p class="vd__caption">Cells Whose Boundary the Pointer Pushes as an Extra Seed</p>
</div>
</main>

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

.vd {
  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;
}

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

.vd__caption {
  position: absolute;
  left: $sp-3;
  bottom: $sp-3;
  max-width: 72%;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 247, 230, .85);
  color: $subject-ink;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  pointer-events: none;
}

.vd__step {
  position: absolute;
  right: $sp-3;
  top: $sp-3;
  margin: 0;
  padding: $sp-1 $sp-3;
  border-radius: $r-pill;
  background: rgba(255, 247, 230, .85);
  color: $subject-ink;
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  pointer-events: none;
}

@media (max-width: 340px) {
  .vd__caption, .vd__step { font-size: 10px; padding: $sp-1 $sp-2; }
}

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

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);
}

.vd {
  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);
}

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

.vd__caption {
  position: absolute;
  left: 12px;
  bottom: 12px;
  max-width: 72%;
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.85);
  color: #17141a;
  font-weight: 500;
  font-size: 12px;
  line-height: 1.4;
  pointer-events: none;
}

.vd__step {
  position: absolute;
  right: 12px;
  top: 12px;
  margin: 0;
  padding: 4px 12px;
  border-radius: 999px;
  background: rgba(255, 247, 230, 0.85);
  color: #17141a;
  font-weight: 700;
  font-size: 11px;
  font-variant-numeric: tabular-nums;
  pointer-events: none;
}

@media (max-width: 340px) {
  .vd__caption, .vd__step {
    font-size: 10px;
    padding: 4px 8px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .vd {
    cursor: default;
  }
}

(function () {
  var root = document.getElementById('vdRoot');
  var canvas = document.getElementById('vdCanvas');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;

  var CALC_W = 160, CALC_H = 100;
  var LOOP_MS = 2000;
  var SEED_REPEL_RADIUS_PX = 120;
  var ORBIT_FREQ = Math.PI * 2 / LOOP_MS;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var rand = seedRand(409051);

  var off = document.createElement('canvas');
  off.width = CALC_W; off.height = CALC_H;
  var octx = off.getContext('2d');
  var offImg = octx.createImageData(CALC_W, CALC_H);
  var offBuf = offImg.data;

  function hexToRgb(hex) {
    var v = parseInt(hex.slice(1), 16);
    return [(v >> 16) & 255, (v >> 8) & 255, v & 255];
  }

  var NEI = -1, ND = 0, ND2 = 0;
  function nearestTwo(px, py, arr) {
    var bd = Infinity, bd2 = Infinity, bi = -1;
    for (var i = 0; i < arr.length; i += 1) {
      var dx = px - arr[i].x, dy = py - arr[i].y, d = dx * dx + dy * dy;
      if (d < bd) { bd2 = bd; bd = d; bi = i; } else if (d < bd2) { bd2 = d; }
    }
    NEI = bi; ND = Math.sqrt(bd); ND2 = Math.sqrt(bd2);
  }

  var repelPalette = ['#2f6df6', '#ff9ebb', '#4cd4a6', '#b9a0ff', '#6ec8ff', '#fff7e6'];
  var paletteRgb = {};
  repelPalette.forEach(function (h) { paletteRgb[h] = hexToRgb(h); });
  var SEED_COUNT05 = 26;
  var seeds = [];
  for (var i5 = 0; i5 < SEED_COUNT05; i5 += 1) {
    seeds.push({ bx: rand() * CALC_W, by: rand() * CALC_H, x: 0, y: 0, c: repelPalette[i5 % repelPalette.length] });
  }
  var pointerActive = false;
  var realPointer = { x: CALC_W / 2, y: CALC_H / 2 };

  function virtualPointerOrbit(t) {
    var cx = CALC_W / 2, cy = CALC_H / 2;
    var orbR = Math.min(CALC_W, CALC_H) * 0.4;
    return { x: cx + Math.cos(t * ORBIT_FREQ) * orbR, y: cy + Math.sin(t * ORBIT_FREQ * 1.3) * orbR * 0.7 };
  }

  function repelSeeds(pointerCalc) {
    var radiusCalc = SEED_REPEL_RADIUS_PX * (CALC_W / cw);
    seeds.forEach(function (s) {
      var dx = s.bx - pointerCalc.x, dy = s.by - pointerCalc.y;
      var dist = Math.sqrt(dx * dx + dy * dy) || 0.0001;
      if (dist < radiusCalc) {
        var push = (radiusCalc - dist) / radiusCalc;
        var k = push * push * 0.95;
        s.x = s.bx + (dx / dist) * k * radiusCalc;
        s.y = s.by + (dy / dist) * k * radiusCalc;
      } else {
        s.x = s.bx; s.y = s.by;
      }
    });
  }

  function renderField(t) {
    var pointerCalc = pointerActive ? realPointer : (reduce ? { x: -999, y: -999 } : virtualPointerOrbit(t));
    repelSeeds(pointerCalc);
    var idx = 0;
    for (var y = 0; y < CALC_H; y += 1) {
      for (var x = 0; x < CALC_W; x += 1) {
        nearestTwo(x + 0.5, y + 0.5, seeds);
        var rgb = paletteRgb[seeds[NEI].c];
        var edge = ND2 - ND;
        var dark = edge < 1.5 ? 0.5 + edge / 3 : 1;
        offBuf[idx] = rgb[0] * dark; offBuf[idx + 1] = rgb[1] * dark; offBuf[idx + 2] = rgb[2] * dark; offBuf[idx + 3] = 255;
        idx += 4;
      }
    }
  }

  var cw = 480, ch = 300;
  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;
    draw(lastElapsed);
  }

  var lastElapsed = 0;
  function draw(elapsed) {
    lastElapsed = elapsed;
    renderField(elapsed);
    octx.putImageData(offImg, 0, 0);
    ctx.imageSmoothingEnabled = false;
    ctx.clearRect(0, 0, cw, ch);
    ctx.drawImage(off, 0, 0, CALC_W, CALC_H, 0, 0, cw, ch);

  }

  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
  var playing = !reduce;
  var elapsed = reduce ? 0 : 0;
  if (reduce) { root.classList.remove('is-demo'); }

  function calcFromEvent(e) {
    var r = wrap.getBoundingClientRect();
    var t0 = (e.touches && e.touches[0]) ? e.touches[0] : e;
    var relX = (t0.clientX - r.left) / r.width * cw;
    var relY = (t0.clientY - r.top) / r.height * ch;
    realPointer.x = relX * (CALC_W / cw);
    realPointer.y = relY * (CALC_H / ch);
  }
  wrap.addEventListener('pointermove', function (e) {
    pointerActive = true;
    calcFromEvent(e);
    draw(lastElapsed);
  });
  wrap.addEventListener('pointerleave', function () {
    pointerActive = false;
    draw(lastElapsed);
  });

  var lastTs = null;
  function tick(ts) {
    if (lastTs === null) lastTs = ts;
    var dt = ts - lastTs;
    lastTs = ts;
    if (playing) {
      elapsed += dt;
      if (elapsed >= LOOP_MS) elapsed -= LOOP_MS;
    }
    draw(elapsed);
    requestAnimationFrame(tick);
  }
  fit();
  window.addEventListener('resize', fit);
  draw(elapsed);
  requestAnimationFrame(tick);
})();

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

export default function VoronoiPointerSeedRepel() {
  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 LOOP_MS = 2000;
    const SEED_REPEL_RADIUS_PX = 120;
    const ORBIT_FREQ = (Math.PI * 2) / LOOP_MS;

    function seedRand(seed: number) {
      let s = seed >>> 0;
      return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
    }
    const rand = seedRand(409051);

    const off = document.createElement("canvas");
    off.width = CALC_W; off.height = CALC_H;
    const octx = off.getContext("2d") as CanvasRenderingContext2D;
    const offImg = octx.createImageData(CALC_W, CALC_H);
    const offBuf = offImg.data;

    function hexToRgb(hex: string): [number, number, number] {
      const v = parseInt(hex.slice(1), 16);
      return [(v >> 16) & 255, (v >> 8) & 255, v & 255];
    }

    type Vec = { x: number; y: number };
    let NEI = -1, ND = 0, ND2 = 0;
    function nearestTwo<T extends Vec>(px: number, py: number, arr: T[]): void {
      let bd = Infinity, bd2 = Infinity, bi = -1;
      for (let i = 0; i < arr.length; i += 1) {
        const dx = px - arr[i].x, dy = py - arr[i].y, d = dx * dx + dy * dy;
        if (d < bd) { bd2 = bd; bd = d; bi = i; } else if (d < bd2) { bd2 = d; }
      }
      NEI = bi; ND = Math.sqrt(bd); ND2 = Math.sqrt(bd2);
    }

    type Seed = { bx: number; by: number; x: number; y: number; c: string };
    const repelPalette = ["#2f6df6", "#ff9ebb", "#4cd4a6", "#b9a0ff", "#6ec8ff", "#fff7e6"];
    const paletteRgb: Record<string, [number, number, number]> = {};
    repelPalette.forEach((h) => { paletteRgb[h] = hexToRgb(h); });
    const SEED_COUNT05 = 26;
    const seeds: Seed[] = [];
    for (let i5 = 0; i5 < SEED_COUNT05; i5 += 1) {
      seeds.push({ bx: rand() * CALC_W, by: rand() * CALC_H, x: 0, y: 0, c: repelPalette[i5 % repelPalette.length] });
    }
    let pointerActive = false;
    const realPointer = { x: CALC_W / 2, y: CALC_H / 2 };

    function virtualPointerOrbit(t: number): Vec {
      const cx = CALC_W / 2, cy = CALC_H / 2;
      const orbR = Math.min(CALC_W, CALC_H) * 0.4;
      return { x: cx + Math.cos(t * ORBIT_FREQ) * orbR, y: cy + Math.sin(t * ORBIT_FREQ * 1.3) * orbR * 0.7 };
    }

    function repelSeeds(pointerCalc: Vec) {
      const radiusCalc = SEED_REPEL_RADIUS_PX * (CALC_W / cw);
      seeds.forEach((s) => {
        const dx = s.bx - pointerCalc.x, dy = s.by - pointerCalc.y;
        const dist = Math.sqrt(dx * dx + dy * dy) || 0.0001;
        if (dist < radiusCalc) {
          const push = (radiusCalc - dist) / radiusCalc;
          const k = push * push * 0.95;
          s.x = s.bx + (dx / dist) * k * radiusCalc;
          s.y = s.by + (dy / dist) * k * radiusCalc;
        } else {
          s.x = s.bx; s.y = s.by;
        }
      });
    }

    function renderField(t: number) {
      const pointerCalc = pointerActive ? realPointer : (reduce ? { x: -999, y: -999 } : virtualPointerOrbit(t));
      repelSeeds(pointerCalc);
      let idx = 0;
      for (let y = 0; y < CALC_H; y += 1) {
        for (let x = 0; x < CALC_W; x += 1) {
          nearestTwo(x + 0.5, y + 0.5, seeds);
          const rgb = paletteRgb[seeds[NEI].c];
          const edge = ND2 - ND;
          const dark = edge < 1.5 ? 0.5 + edge / 3 : 1;
          offBuf[idx] = rgb[0] * dark; offBuf[idx + 1] = rgb[1] * dark; offBuf[idx + 2] = rgb[2] * dark; offBuf[idx + 3] = 255;
          idx += 4;
        }
      }
    }

    let cw = 480, ch = 300;
    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;
      draw(lastElapsed);
    }

    let lastElapsed = 0;
    function draw(elapsed: number) {
      lastElapsed = elapsed;
      renderField(elapsed);
      octx.putImageData(offImg, 0, 0);
      ctx!.imageSmoothingEnabled = false;
      ctx!.clearRect(0, 0, cw, ch);
      ctx!.drawImage(off, 0, 0, CALC_W, CALC_H, 0, 0, cw, ch);

    }

    const reduce = window.matchMedia("(prefers-reduced-motion: reduce)").matches;
    let playing = !reduce;
    let elapsed = reduce ? 0 : 0;
    if (reduce) { root.classList.remove("is-demo"); }

    function calcFromEvent(e: PointerEvent) {
      const r = wrap.getBoundingClientRect();
      const relX = ((e.clientX - r.left) / r.width) * cw;
      const relY = ((e.clientY - r.top) / r.height) * ch;
      realPointer.x = relX * (CALC_W / cw);
      realPointer.y = relY * (CALC_H / ch);
    }
    function onPointerMove(e: PointerEvent) {
      pointerActive = true;
      calcFromEvent(e);
      draw(lastElapsed);
    }
    function onPointerLeave() {
      pointerActive = false;
      draw(lastElapsed);
    }
    wrap.addEventListener("pointermove", onPointerMove);
    wrap.addEventListener("pointerleave", onPointerLeave);


    let lastTs: number | null = null;
    let raf = 0;
    function tick(ts: number) {
      if (lastTs === null) lastTs = ts;
      const dt = ts - lastTs;
      lastTs = ts;
      if (playing) {
        elapsed += dt;
        if (elapsed >= LOOP_MS) elapsed -= LOOP_MS;
      }
      draw(elapsed);
      raf = requestAnimationFrame(tick);
    }
    fit();
    window.addEventListener("resize", fit);
    draw(elapsed);
    raf = requestAnimationFrame(tick);

    return () => {
      cancelAnimationFrame(raf);
      window.removeEventListener("resize", fit);
      wrap.removeEventListener("pointermove", onPointerMove);
      wrap.removeEventListener("pointerleave", onPointerLeave);

    };

  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.vd} is-demo`} ref={rootRef}>
        <canvas className={styles.vd__canvas} ref={canvasRef} width={480} height={300} />
        <p className={styles.vd__caption}>포인터가 하나의 시드가 되어 경계를 미는 셀</p>

      </div>
    </main>
  );
}