07Smoke That Puffs Outward in a Burst When a Button Is Pressed

<main class="stage">
<div class="smk is-demo" id="smkRoot">
  <canvas class="smk__canvas" id="smkCanvas" width="480" height="300"></canvas>
  <p class="smk__caption">The instant the button is pressed, one particle cluster forms and bursts outward in every direction before quickly fading.</p>
  <button class="smk__btn" id="smkBtn" type="button">Puff smoke</button>
</div>
</main>

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

.smk {
  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;
}

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

.smk__caption {
  position: absolute;
  left: $sp-3;
  top: $sp-3;
  max-width: 66%;
  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;
}

.smk__btn {
  position: absolute;
  left: 50%;
  bottom: $sp-4;
  transform: translateX(-50%);
  border: none;
  border-radius: $r-control;
  padding: $sp-2 $sp-6;
  font-weight: 700;
  font-size: 13px;
  color: $stage-paper;
  background: $subject-ink;
  box-shadow: $shadow-press;
  cursor: pointer;
}

.smk__btn:focus-visible {
  outline: 2px solid $stage-paper;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .smk__caption { font-size: 10px; padding: $sp-1 $sp-2; }
  .smk__btn { font-size: 12px; padding: $sp-1 $sp-4; }
}

@media (prefers-reduced-motion: reduce) {
  .smk { 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);
}

.smk {
  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;
}

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

.smk__caption {
  position: absolute;
  left: 12px;
  top: 12px;
  max-width: 66%;
  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;
}

.smk__btn {
  position: absolute;
  left: 50%;
  bottom: 16px;
  transform: translateX(-50%);
  border: none;
  border-radius: 12px;
  padding: 8px 24px;
  font-weight: 700;
  font-size: 13px;
  color: #ffffff;
  background: #17141a;
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
  cursor: pointer;
}

.smk__btn:focus-visible {
  outline: 2px solid #ffffff;
  outline-offset: 2px;
}

@media (max-width: 340px) {
  .smk__caption {
    font-size: 10px;
    padding: 4px 8px;
  }
  .smk__btn {
    font-size: 12px;
    padding: 4px 16px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .smk {
    cursor: default;
  }
}

(function () {
  // 기법: 누르는 순간 원점 한 곳에서 SMOKE_BURST_COUNT 개 입자를 방사형으로 한 번에
  // 만들어 서로 다른 각도·속도로 사방에 흩뿌리고, 수명을 짧게 잡아(SMOKE_BURST_LIFE_MS)
  // 빠르게 옅어지게 한다. 자동 시연은 루프마다 두 번 같은 burst() 함수를 그대로 호출한다.
  var root = document.getElementById('smkRoot');
  var canvas = document.getElementById('smkCanvas');
  var ctx = canvas.getContext('2d');
  var wrap = canvas.parentElement;
  var btn = document.getElementById('smkBtn');

  var CALC_W = 160, CALC_H = 100;
  var SMOKE_BURST_COUNT = 34;
  var SMOKE_BURST_SPEED_PX_S = 60;
  var SMOKE_BURST_LIFE_MS = 620;
  var ORIGIN_X = CALC_W * 0.5, ORIGIN_Y = CALC_H * 0.56;

  function seedRand(seed) {
    var s = seed >>> 0;
    return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
  }
  var pRand = seedRand(423071);
  var particles = [];

  function burst(bornMs) {
    for (var i = 0; i < SMOKE_BURST_COUNT; i += 1) {
      var ang = pRand() * Math.PI * 2;
      var speed = SMOKE_BURST_SPEED_PX_S * (0.4 + pRand() * 0.9);
      particles.push({
        x: ORIGIN_X, y: ORIGIN_Y,
        vx: Math.cos(ang) * speed,
        vy: Math.sin(ang) * speed,
        born: bornMs
      });
    }
  }

  function stepSim(dtMs, nowMs) {
    var dtS = dtMs / 1000;
    var alive = [];
    for (var i = 0; i < particles.length; i += 1) {
      var p = particles[i];
      p.x += p.vx * dtS;
      p.y += p.vy * dtS;
      p.vy -= 8 * dtS;
      if (nowMs - p.born < SMOKE_BURST_LIFE_MS) alive.push(p);
    }
    particles = alive;
  }

  function drawSmoke(nowMs) {
    var sx = cw / CALC_W, sy = ch / CALC_H;
    ctx.clearRect(0, 0, cw, ch);
    for (var i = 0; i < particles.length; i += 1) {
      var p = particles[i];
      var f = Math.max(0, Math.min(1, (nowMs - p.born) / SMOKE_BURST_LIFE_MS));
      var r = 4 + f * 15;
      var alpha = (1 - f) * 0.55;
      if (alpha <= 0.01) continue;
      var dx = p.x * sx, dy = p.y * sy, dr = r * ((sx + sy) / 2);
      var g = ctx.createRadialGradient(dx, dy, 0, dx, dy, dr);
      g.addColorStop(0, 'rgba(28,24,20,' + alpha + ')');
      g.addColorStop(1, 'rgba(28,24,20,0)');
      ctx.fillStyle = g;
      ctx.beginPath();
      ctx.arc(dx, dy, dr, 0, Math.PI * 2);
      ctx.fill();
    }
  }

  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;
    drawSmoke(elapsed);
  }

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

  btn.addEventListener('pointerdown', function () {
    burst(elapsed);
    if (reduce) drawSmoke(elapsed);
  });
  btn.addEventListener('keydown', function (e) {
    if (e.key === 'Enter' || e.key === ' ') {
      e.preventDefault();
      burst(elapsed);
      if (reduce) drawSmoke(elapsed);
    }
  });

  var PUFF_LOOP_MS = 2000;
  var PUFF_TIME_1 = 260;
  var PUFF_TIME_2 = 1300;
  var lastCycle = -1;
  var triggered1 = false, triggered2 = false;

  var lastTs = null;
  function tick(ts) {
    if (lastTs === null) lastTs = ts;
    var dt = Math.min(ts - lastTs, 48);
    lastTs = ts;
    if (!reduce) {
      elapsed += dt;
      if (root.classList.contains('is-demo')) {
        var cycle = Math.floor(elapsed / PUFF_LOOP_MS);
        var phase = elapsed % PUFF_LOOP_MS;
        if (cycle !== lastCycle) { lastCycle = cycle; triggered1 = false; triggered2 = false; }
        if (!triggered1 && phase >= PUFF_TIME_1) { triggered1 = true; burst(elapsed); }
        if (!triggered2 && phase >= PUFF_TIME_2) { triggered2 = true; burst(elapsed); }
      }
      stepSim(dt, elapsed);
      drawSmoke(elapsed);
    }
    requestAnimationFrame(tick);
  }
  fit();
  window.addEventListener('resize', fit);
  drawSmoke(elapsed);
  requestAnimationFrame(tick);
})();

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

type Particle = { x: number; y: number; vx: number; vy: number; born: number };

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

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

    const CALC_W = 160, CALC_H = 100;
    const SMOKE_BURST_COUNT = 34;
    const SMOKE_BURST_SPEED_PX_S = 60;
    const SMOKE_BURST_LIFE_MS = 620;
    const ORIGIN_X = CALC_W * 0.5, ORIGIN_Y = CALC_H * 0.56;

    function seedRand(seed: number) {
      let s = seed >>> 0;
      return function () { s = (s * 1664525 + 1013904223) >>> 0; return s / 4294967296; };
    }
    const pRand = seedRand(423071);
    let particles: Particle[] = [];

    function burst(bornMs: number) {
      for (let i = 0; i < SMOKE_BURST_COUNT; i += 1) {
        const ang = pRand() * Math.PI * 2;
        const speed = SMOKE_BURST_SPEED_PX_S * (0.4 + pRand() * 0.9);
        particles.push({
          x: ORIGIN_X, y: ORIGIN_Y,
          vx: Math.cos(ang) * speed,
          vy: Math.sin(ang) * speed,
          born: bornMs
        });
      }
    }

    function stepSim(dtMs: number, nowMs: number) {
      const dtS = dtMs / 1000;
      const alive: Particle[] = [];
      for (let i = 0; i < particles.length; i += 1) {
        const p = particles[i];
        p.x += p.vx * dtS;
        p.y += p.vy * dtS;
        p.vy -= 8 * dtS;
        if (nowMs - p.born < SMOKE_BURST_LIFE_MS) alive.push(p);
      }
      particles = alive;
    }

    let cw = 480, ch = 300;
    function drawSmoke(nowMs: number) {
      const sx = cw / CALC_W, sy = ch / CALC_H;
      ctx!.clearRect(0, 0, cw, ch);
      for (let i = 0; i < particles.length; i += 1) {
        const p = particles[i];
        const f = Math.max(0, Math.min(1, (nowMs - p.born) / SMOKE_BURST_LIFE_MS));
        const r = 4 + f * 15;
        const alpha = (1 - f) * 0.55;
        if (alpha <= 0.01) continue;
        const dx = p.x * sx, dy = p.y * sy, dr = r * ((sx + sy) / 2);
        const g = ctx!.createRadialGradient(dx, dy, 0, dx, dy, dr);
        g.addColorStop(0, "rgba(28,24,20," + alpha + ")");
        g.addColorStop(1, "rgba(28,24,20,0)");
        ctx!.fillStyle = g;
        ctx!.beginPath();
        ctx!.arc(dx, dy, dr, 0, Math.PI * 2);
        ctx!.fill();
      }
    }

    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;
      drawSmoke(elapsed);
    }

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

    function onPointerDown() {
      burst(elapsed);
      if (reduce) drawSmoke(elapsed);
    }
    function onKeydown(e: KeyboardEvent) {
      if (e.key === "Enter" || e.key === " ") {
        e.preventDefault();
        burst(elapsed);
        if (reduce) drawSmoke(elapsed);
      }
    }
    btn.addEventListener("pointerdown", onPointerDown);
    btn.addEventListener("keydown", onKeydown);

    const PUFF_LOOP_MS = 2000;
    const PUFF_TIME_1 = 260;
    const PUFF_TIME_2 = 1300;
    let lastCycle = -1;
    let triggered1 = false, triggered2 = false;

    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;
        if (root!.classList.contains("is-demo")) {
          const cycle = Math.floor(elapsed / PUFF_LOOP_MS);
          const phase = elapsed % PUFF_LOOP_MS;
          if (cycle !== lastCycle) { lastCycle = cycle; triggered1 = false; triggered2 = false; }
          if (!triggered1 && phase >= PUFF_TIME_1) { triggered1 = true; burst(elapsed); }
          if (!triggered2 && phase >= PUFF_TIME_2) { triggered2 = true; burst(elapsed); }
        }
        stepSim(dt, elapsed);
        drawSmoke(elapsed);
      }
      raf = requestAnimationFrame(tick);
    }
    fit();
    window.addEventListener("resize", fit);
    drawSmoke(elapsed);
    raf = requestAnimationFrame(tick);

    return () => {
      cancelAnimationFrame(raf);
      window.removeEventListener("resize", fit);
      btn.removeEventListener("pointerdown", onPointerDown);
      btn.removeEventListener("keydown", onKeydown);
    };
  }, []);

  return (
    <main className={styles.stage}>
      <div className={`${styles.smk} is-demo`} ref={rootRef}>
        <canvas className={styles.smk__canvas} ref={canvasRef} width={480} height={300} />
        <p className={styles.smk__caption}>버튼이 눌린 순간 입자 뭉치 하나가 생겨 짧은 시간 안에 사방으로 퍼지다가 빠르게 옅어진다</p>
        <button className={styles.smk__btn} ref={btnRef} type="button">연기 뿜기</button>
      </div>
    </main>
  );
}