04Overheal shield-cap toggle — when a value exceeds its ceiling, the excess appears as a translucent layer over the bar

<main class="stage">
<div class="gb is-demo" id="gb">
  <div class="gb__head">
    <span class="gb__label">HP</span>
    <span class="gb__value" id="gbValue">55 / 100</span>
  </div>
  <div class="gb__track" role="progressbar" aria-label="HP" aria-valuemin="0" aria-valuemax="100" aria-valuenow="55" id="gbTrack">
    <div class="gb__fill" id="gbFill"></div>
    <div class="gb__shield" id="gbShield"></div>
  </div>
  <button type="button" class="gb__hit" id="gbHeal">Add Overheal</button>
</div>
</main>

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

// 계산 겹: index.html loop() 이 매 프레임 상한 위 초과분을 exp(-DECAY_RATE*dt) 로
// 스스로 줄이고, 그 값에서 쉴드 겹의 폭·투명도를 다시 계산해 그린다.
@include stage($stage-paper);

.gb { width: 100%; max-width: 260px; background: $subject-cream; border-radius: $r-card; padding: $sp-5; box-shadow: $shadow-raised; box-sizing: border-box; }
.gb__head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: $sp-3; }
.gb__label { font-size: 12px; font-weight: 700; letter-spacing: .04em; color: rgba($subject-ink, .72); text-transform: uppercase; }
.gb__value { font-size: 15px; font-weight: 700; color: $subject-ink; }

.gb__track { position: relative; height: 18px; border-radius: $r-pill; background: rgba($subject-ink, .1); overflow: hidden; }
.gb__fill { position: absolute; left: 0; top: 0; height: 100%; width: 55%; border-radius: $r-pill; background: $subject-blue-deep; will-change: width; }
.gb__shield {
  position: absolute; left: 0; top: 0; height: 100%; width: 0%;
  border-radius: $r-pill; background: $subject-sky; opacity: 0; z-index: 1;
  will-change: width, opacity;
}

.gb__hit {
  margin-top: $sp-4; width: 100%; border: none; border-radius: $r-control;
  background: $subject-blue; color: $subject-cream;
  font-weight: 700; font-size: 13px; line-height: 1;
  padding: $sp-3 0; cursor: pointer;
}
.gb__hit:active { box-shadow: $shadow-press; }

@media (max-width: 340px) {
  .gb { max-width: 220px; padding: $sp-4; }
  .gb__track { height: 15px; }
  .gb__value { font-size: 13px; }
}

@media (prefers-reduced-motion: reduce) {
  .gb__shield { display: none; }
}

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

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

.gb {
  width: 100%;
  max-width: 260px;
  background: #fff7e6;
  border-radius: 16px;
  padding: 20px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  box-sizing: border-box;
}

.gb__head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 12px;
}

.gb__label {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: rgba(23, 20, 26, 0.72);
  text-transform: uppercase;
}

.gb__value {
  font-size: 15px;
  font-weight: 700;
  color: #17141a;
}

.gb__track {
  position: relative;
  height: 18px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.1);
  overflow: hidden;
}

.gb__fill {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 55%;
  border-radius: 999px;
  background: #0a4fe8;
  will-change: width;
}

.gb__shield {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 0%;
  border-radius: 999px;
  background: #6ec8ff;
  opacity: 0;
  z-index: 1;
  will-change: width, opacity;
}

.gb__hit {
  margin-top: 16px;
  width: 100%;
  border: none;
  border-radius: 12px;
  background: #2f6df6;
  color: #fff7e6;
  font-weight: 700;
  font-size: 13px;
  line-height: 1;
  padding: 12px 0;
  cursor: pointer;
}

.gb__hit:active {
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}

@media (max-width: 340px) {
  .gb {
    max-width: 220px;
    padding: 16px;
  }
  .gb__track {
    height: 15px;
  }
  .gb__value {
    font-size: 13px;
  }
}
@media (prefers-reduced-motion: reduce) {
  .gb__shield {
    display: none;
  }
}

(function () {
  var HP_MAX = 100; // 상한
  var OVERHEAL_CAP = 50; // 계산 겹 상수: 상한 위로 표시되는 쉴드 겹의 최대 폭 기준값
  var START = 55;
  var EVENTS = [[300, 45], [1300, 55], [2300, -25], [3200, -15]]; // ms, 값 변화(+회복/-피해)
  var DECAY_RATE = 0.00065; // 계산 겹: 상한 위 초과분이 계속 스스로 줄어드는 비율(ms 당)
  var reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  var gb = document.getElementById('gb');
  var track = document.getElementById('gbTrack');
  var fill = document.getElementById('gbFill');
  var shield = document.getElementById('gbShield');
  var valueEl = document.getElementById('gbValue');
  var healBtn = document.getElementById('gbHeal');

  var isDemo = true;
  var value = START;
  var appliedIdx = 0;
  var cycleStart = 0;
  var lastTs = 0;

  function render() {
    var base = Math.min(value, HP_MAX);
    var excess = Math.max(0, value - HP_MAX);
    var shieldRatio = Math.min(1, excess / OVERHEAL_CAP);
    fill.style.width = base.toFixed(2) + '%';
    // 계산 겹: 초과분 폭 = 상한 위 값 / 쉴드 표시 기준값 — 반투명 겹의 폭·투명도를 함께 구동
    shield.style.width = (shieldRatio * 100).toFixed(2) + '%';
    shield.style.opacity = shieldRatio < 0.02 ? '0' : (0.4 + shieldRatio * 0.5).toFixed(3);
    track.setAttribute('aria-valuenow', String(Math.round(base)));
    valueEl.textContent = Math.round(value) + ' / ' + HP_MAX;
  }

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

  healBtn.addEventListener('click', function () {
    human();
    value = Math.max(0, Math.min(HP_MAX + OVERHEAL_CAP, value + 30));
    render();
  });
  healBtn.addEventListener('keydown', function (ev) {
    if (ev.key !== 'Enter' && ev.key !== ' ') return;
    ev.preventDefault();
    healBtn.click();
  });

  function loop(ts) {
    if (!cycleStart) { cycleStart = ts; lastTs = ts; }
    var dt = ts - lastTs;
    lastTs = ts;
    var elapsed = ts - cycleStart;

    if (isDemo) {
      if (elapsed >= EVENTS[EVENTS.length - 1][0] + 700) {
        cycleStart = ts; elapsed = 0; appliedIdx = 0; value = START;
      }
      while (appliedIdx < EVENTS.length && elapsed >= EVENTS[appliedIdx][0]) {
        value = Math.max(0, Math.min(HP_MAX + OVERHEAL_CAP, value + EVENTS[appliedIdx][1]));
        appliedIdx++;
      }
    }

    if (value > HP_MAX) {
      value = HP_MAX + (value - HP_MAX) * Math.exp(-DECAY_RATE * dt);
    }

    render();
    requestAnimationFrame(loop);
  }

  if (!reduce) {
    requestAnimationFrame(loop);
  } else {
    render();
  }
})();

import { useEffect, useRef, useState } from 'react';
import styles from './GaugeBarOverhealShieldCap.module.scss';

type Box<T> = { current: T };

const HP_MAX = 100; // 상한
const OVERHEAL_CAP = 50; // 계산 겹 상수: 상한 위로 표시되는 쉴드 겹의 최대 폭 기준값
const START = 55;
const EVENTS: [number, number][] = [[300, 45], [1300, 55], [2300, -25], [3200, -15]]; // ms, 값 변화(+회복/-피해)
const DECAY_RATE = 0.00065; // 계산 겹: 상한 위 초과분이 계속 스스로 줄어드는 비율(ms 당)

export default function GaugeBarOverhealShieldCap() {
  const fillRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const shieldRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const trackRef = useRef(null) as unknown as Box<HTMLDivElement>;
  const isDemoRef = useRef(true) as unknown as Box<boolean>;
  const [isDemo, setIsDemo] = useState(true);
  const [value, setValue] = useState(START);

  const valueRef = useRef(START) as unknown as Box<number>;

  function human() {
    isDemoRef.current = false;
    setIsDemo(false);
  }

  function render() {
    const v = valueRef.current;
    const base = Math.min(v, HP_MAX);
    const excess = Math.max(0, v - HP_MAX);
    const shieldRatio = Math.min(1, excess / OVERHEAL_CAP);
    const fill = fillRef.current;
    const shield = shieldRef.current;
    const track = trackRef.current;
    if (fill) fill.style.width = base.toFixed(2) + '%';
    // 계산 겹: 초과분 폭 = 상한 위 값 / 쉴드 표시 기준값 — 반투명 겹의 폭·투명도를 함께 구동
    if (shield) {
      shield.style.width = (shieldRatio * 100).toFixed(2) + '%';
      shield.style.opacity = shieldRatio < 0.02 ? '0' : (0.4 + shieldRatio * 0.5).toFixed(3);
    }
    if (track) track.setAttribute('aria-valuenow', String(Math.round(base)));
    setValue(Math.round(v));
  }

  useEffect(() => {
    const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
    let cycleStart = 0;
    let lastTs = 0;
    let appliedIdx = 0;
    let rafId = 0;

    function loop(ts: number) {
      if (!cycleStart) { cycleStart = ts; lastTs = ts; }
      const dt = ts - lastTs;
      lastTs = ts;
      let elapsed = ts - cycleStart;

      if (isDemoRef.current) {
        if (elapsed >= EVENTS[EVENTS.length - 1][0] + 700) {
          cycleStart = ts; elapsed = 0; appliedIdx = 0; valueRef.current = START;
        }
        while (appliedIdx < EVENTS.length && elapsed >= EVENTS[appliedIdx][0]) {
          valueRef.current = Math.max(0, Math.min(HP_MAX + OVERHEAL_CAP, valueRef.current + EVENTS[appliedIdx][1]));
          appliedIdx++;
        }
      }

      if (valueRef.current > HP_MAX) {
        valueRef.current = HP_MAX + (valueRef.current - HP_MAX) * Math.exp(-DECAY_RATE * dt);
      }

      render();
      rafId = requestAnimationFrame(loop);
    }

    if (!reduce) {
      rafId = requestAnimationFrame(loop);
    } else {
      render();
    }
    return () => cancelAnimationFrame(rafId);
  }, []);

  function onHeal() {
    human();
    valueRef.current = Math.max(0, Math.min(HP_MAX + OVERHEAL_CAP, valueRef.current + 30));
    render();
  }

  function onKeyDown(e: { key: string; preventDefault: () => void }) {
    if (e.key !== 'Enter' && e.key !== ' ') return;
    e.preventDefault();
    onHeal();
  }

  return (
    <div className={`${styles.gb} ${isDemo ? styles.isDemo : ''}`}>
      <div className={styles.gbHead}>
        <span className={styles.gbLabel}>HP</span>
        <span className={styles.gbValue}>{value} / {HP_MAX}</span>
      </div>
      <div
        className={styles.gbTrack}
        role="progressbar"
        aria-label="HP"
        aria-valuemin={0}
        aria-valuemax={100}
        aria-valuenow={Math.min(value, HP_MAX)}
        ref={trackRef}
      >
        <div className={styles.gbFill} ref={fillRef} />
        <div className={styles.gbShield} ref={shieldRef} />
      </div>
      <button type="button" className={styles.gbHit} onClick={onHeal} onKeyDown={onKeyDown}>
        회복 얹기
      </button>
    </div>
  );
}