03高さに応じてぼやける影
片端だけ浮いた板で、床からの高さに比例して影のぼかしと濃さを帯ごとに計算し、接する所と離れた所の見え方を変える。
使いどころ浮いたカードとフローティングボタン
BLUR_PER_HEIGHTCONTACT_ALPHALIFT_MAX
<main class="stage">
<div class="sc is-demo" id="scRoot">
<canvas class="sc__canvas" id="scCanvas" width="480" height="300" tabindex="0" aria-label="片端だけ浮いた板で、床からの高さに比例して影のぼかしと濃さを帯ごとに計算し、接する所と離れた所の見え方を変える。"></canvas>
<p class="sc__status" id="scStatus" aria-live="polite">デモ実行中</p>
<button class="sc__btn" id="scBtn" type="button">一時停止</button>
<p class="sc__caption">片端だけ浮いた板で、床からの高さに比例して影のぼかしと濃さを帯ごとに計算し、接する所と離れた所の見え方を変える。</p>
</div>
</main>@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);
.sc {
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: $subject-ink;
}
.sc__canvas {
display: block;
width: 100%;
height: 100%;
touch-action: none;
}
.sc__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, .85);
outline-offset: -6px;
}
.sc__status {
position: absolute;
left: $sp-3;
top: $sp-3;
max-width: 62%;
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: 11px;
line-height: 1.4;
pointer-events: none;
}
.sc__btn {
position: absolute;
right: $sp-3;
bottom: $sp-3;
margin: 0;
padding: $sp-1 $sp-3;
border: 0;
border-radius: $r-pill;
background: rgba(255, 255, 255, .85);
color: $subject-ink;
font: inherit;
font-weight: 500;
font-size: 12px;
line-height: 1.4;
cursor: pointer;
}
.sc__btn:focus-visible {
outline: 2px solid #ffffff;
outline-offset: 2px;
}
.sc__caption {
position: absolute;
left: $sp-3;
bottom: $sp-3;
max-width: 68%;
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) {
.sc__caption, .sc__btn { font-size: 10px; padding: $sp-1 $sp-2; }
.sc__status { font-size: 10px; }
}
@media (prefers-reduced-motion: reduce) {
.sc { 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);
}
.sc {
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: #17141a;
}
.sc__canvas {
display: block;
width: 100%;
height: 100%;
touch-action: none;
}
.sc__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, 0.85);
outline-offset: -6px;
}
.sc__status {
position: absolute;
left: 12px;
top: 12px;
max-width: 62%;
margin: 0;
padding: 4px 12px;
border-radius: 999px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
.sc__btn {
position: absolute;
right: 12px;
bottom: 12px;
margin: 0;
padding: 4px 12px;
border: 0;
border-radius: 999px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font: inherit;
font-weight: 500;
font-size: 12px;
line-height: 1.4;
cursor: pointer;
}
.sc__btn:focus-visible {
outline: 2px solid #ffffff;
outline-offset: 2px;
}
.sc__caption {
position: absolute;
left: 12px;
bottom: 12px;
max-width: 68%;
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) {
.sc__caption, .sc__btn {
font-size: 10px;
padding: 4px 8px;
}
.sc__status {
font-size: 10px;
}
}
@media (prefers-reduced-motion: reduce) {
.sc {
cursor: default;
}
}(function () {
const W = 480;
const H = 300;
const PI2 = Math.PI * 2;
const FIXED_DT = 16;
const REDUCE_STEP_MS = 900;
const REDUCE_START_MS = 1000;
const PERIOD_MS = 4000;
const KEY_STEP = 12;
const FONT = '-apple-system, "Segoe UI", "Noto Sans KR", sans-serif';
function clamp(v, lo, hi) { return v < lo ? lo : (v > hi ? hi : v); }
function lerp(a, b, k) { return a + (b - a) * k; }
function smooth(x) { const c = clamp(x, 0, 1); return c * c * (3 - 2 * c); }
function rgba(c, a) {
return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + a.toFixed(3) + ')';
}
// 시드 고정 난수 — 같은 시드면 언제나 같은 수열
function mulberry32(seed) {
let s = seed >>> 0;
return function () {
s = (s + 0x6D2B79F5) >>> 0;
let t = s;
t = Math.imul(t ^ (t >>> 15), t | 1);
t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
};
}
function glow(ctx, x, y, r, c, a) {
const g = ctx.createRadialGradient(x, y, 0, x, y, r);
g.addColorStop(0, rgba(c, a));
g.addColorStop(1, rgba(c, 0));
ctx.fillStyle = g;
ctx.fillRect(x - r, y - r, r * 2, r * 2);
}
function polyPath(ctx, poly) {
ctx.beginPath();
for (let i = 0; i < poly.length; i += 1) {
if (i === 0) {
ctx.moveTo(poly[i][0], poly[i][1]);
}
else {
ctx.lineTo(poly[i][0], poly[i][1]);
}
}
ctx.closePath();
}
const BLUR_PER_HEIGHT = 0.2;
const CONTACT_ALPHA = 0.62;
const LIFT_MAX = 110;
const LIGHT_LERP = 0.16;
const PLANK_LEFT = 80;
const PLANK_LEN = 320;
const PLANK_THICK = 14;
const STRIPS = 64;
const BASE_Y = 168;
const WALL_RGB = [255, 244, 214];
const FLOOR_RGB = [236, 228, 250];
const SHADOW_RGB = [70, 54, 116];
const PLANK_TOP = [150, 206, 255];
const PLANK_EDGE = [96, 160, 226];
function makeScene(ctx) {
let px = 240;
let py = 160;
function lift() { return LIFT_MAX * clamp((py - 30) / 240, 0, 1); }
// 가로 위치 u (0 은 닿은 쪽, 1 은 뜬 쪽) 에서 판의 높이
function heightAt(u, total) { return total * u; }
const scene = {
path: function (t) {
const a = PI2 * t / PERIOD_MS;
return [240 + 170 * Math.sin(a * 2), 150 + 130 * Math.sin(a - 1.2)];
},
pos: function () { return [px, py]; },
update: function (tx, ty) {
px = lerp(px, tx, LIGHT_LERP);
py = lerp(py, ty, LIGHT_LERP);
},
snap: function (tx, ty) { px = tx; py = ty; },
draw: function () {
const total = lift();
const slide = (px - 240) / 240;
ctx.fillStyle = rgba(WALL_RGB, 1);
ctx.fillRect(0, 0, W, BASE_Y - 20);
ctx.fillStyle = rgba(FLOOR_RGB, 1);
ctx.fillRect(0, BASE_Y - 20, W, H - BASE_Y + 20);
// 그림자 띠 — 띠마다 높이로 번짐과 농도를 따로 계산한다
for (let i = 0; i < STRIPS; i += 1) {
const h0 = heightAt(i / STRIPS, total);
const h1 = heightAt((i + 1) / STRIPS, total);
const hm = (h0 + h1) / 2;
const xa = Math.round(PLANK_LEFT + (PLANK_LEN * i) / STRIPS + h0 * slide * 0.9);
const xb = Math.round(PLANK_LEFT + (PLANK_LEN * (i + 1)) / STRIPS + h1 * slide * 0.9);
const blur = 2 + hm * BLUR_PER_HEIGHT;
const alpha = CONTACT_ALPHA / (1 + hm * 0.03);
const yTop = BASE_Y - 2;
const yBot = BASE_Y + 16 + hm * 0.5;
const g = ctx.createLinearGradient(0, yTop - blur, 0, yBot + blur);
const span = yBot - yTop + 2 * blur;
g.addColorStop(0, rgba(SHADOW_RGB, 0));
g.addColorStop(clamp(blur * 1.2 / span, 0, 0.45), rgba(SHADOW_RGB, alpha));
g.addColorStop(clamp(1 - blur * 1.2 / span, 0.55, 1), rgba(SHADOW_RGB, alpha * 0.85));
g.addColorStop(1, rgba(SHADOW_RGB, 0));
ctx.fillStyle = g;
ctx.fillRect(xa, yTop - blur, xb - xa, span);
}
// 판 — 왼쪽 끝은 바닥에 닿고 오른쪽 끝만 들린다
ctx.beginPath();
for (let i = 0; i <= STRIPS; i += 1) {
const hh = heightAt(i / STRIPS, total);
const x = PLANK_LEFT + (PLANK_LEN * i) / STRIPS;
const y = BASE_Y - hh * 0.7 - PLANK_THICK;
if (i === 0) {
ctx.moveTo(x, y);
}
else {
ctx.lineTo(x, y);
}
}
for (let i = STRIPS; i >= 0; i -= 1) {
const hh = heightAt(i / STRIPS, total);
ctx.lineTo(PLANK_LEFT + (PLANK_LEN * i) / STRIPS, BASE_Y - hh * 0.7);
}
ctx.closePath();
ctx.fillStyle = rgba(PLANK_TOP, 1);
ctx.fill();
ctx.lineWidth = 2;
ctx.strokeStyle = rgba(PLANK_EDGE, 1);
ctx.stroke();
ctx.beginPath();
ctx.arc(PLANK_LEFT, BASE_Y - PLANK_THICK / 2, 5, 0, PI2);
ctx.fillStyle = rgba(PLANK_EDGE, 1);
ctx.fill();
// 광원 표시 — 가로 위치가 그림자가 쏠리는 쪽을 정한다
glow(ctx, px, 30, 46, [255, 220, 120], 0.9);
ctx.beginPath();
ctx.arc(px, 30, 8, 0, PI2);
ctx.fillStyle = 'rgba(255,246,208,1)';
ctx.fill();
ctx.lineWidth = 2;
ctx.strokeStyle = 'rgba(214,170,70,0.9)';
ctx.stroke();
}
};
return scene;
}
function main(rootEl, canvas, statusEl, btnEl) {
const ctx0 = canvas.getContext('2d');
if (!ctx0) {
return function () { return; };
}
canvas.width = W;
canvas.height = H;
const scene = makeScene(ctx0);
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
if (reduce) {
rootEl.classList.remove('is-demo');
}
let paused = false;
let autoplay = !reduce;
let elapsed = reduce ? REDUCE_START_MS : 0;
let rafId = 0;
let lastTs = null;
let accMs = 0;
let tgt = scene.path(elapsed);
const cleaners = [];
function listen(target, type, fn) {
target.addEventListener(type, fn);
cleaners.push(function () { target.removeEventListener(type, fn); });
}
function setMode() {
if (reduce) {
statusEl.textContent = '一場面ずつ送っています';
btnEl.textContent = '次の場面';
return;
}
statusEl.textContent = !autoplay ? '手動操作中' : (paused ? '一時停止中' : 'デモ実行中');
btnEl.textContent = (autoplay && !paused) ? '一時停止' : '再生';
}
function toLocal(e) {
const r = canvas.getBoundingClientRect();
return [clamp((e.clientX - r.left) * W / r.width, 0, W), clamp((e.clientY - r.top) * H / r.height, 0, H)];
}
function takeOver() {
if (reduce || !autoplay) {
return;
}
autoplay = false;
paused = false;
rootEl.classList.remove('is-demo');
const p = scene.pos();
tgt = [p[0], p[1]];
setMode();
}
function afterInput() {
if (reduce) {
scene.snap(tgt[0], tgt[1]);
scene.draw(elapsed);
}
}
function onButton() {
if (reduce) {
elapsed += REDUCE_STEP_MS;
tgt = scene.path(elapsed);
scene.snap(tgt[0], tgt[1]);
scene.draw(elapsed);
return;
}
if (autoplay && !paused) {
paused = true;
}
else {
paused = false;
autoplay = true;
rootEl.classList.add('is-demo');
}
setMode();
}
function tick(ts) {
if (lastTs === null) {
lastTs = ts;
}
const frameDt = Math.min(ts - lastTs, 160);
lastTs = ts;
if (!paused) {
accMs += frameDt;
while (accMs >= FIXED_DT) {
elapsed += FIXED_DT;
accMs -= FIXED_DT;
if (autoplay) {
tgt = scene.path(elapsed);
}
scene.update(tgt[0], tgt[1]);
}
scene.draw(elapsed);
}
rafId = requestAnimationFrame(tick);
}
listen(btnEl, 'click', function () { onButton(); });
listen(canvas, 'pointerdown', function (e) {
takeOver();
tgt = toLocal(e);
afterInput();
});
listen(canvas, 'pointermove', function (e) {
if (autoplay && !reduce) {
return;
}
tgt = toLocal(e);
afterInput();
});
listen(canvas, 'keydown', function (e) {
const k = e.key;
if (k === 'Enter' || k === ' ') {
e.preventDefault();
onButton();
return;
}
let dx = 0;
let dy = 0;
if (k === 'ArrowLeft') {
dx = -KEY_STEP;
}
else if (k === 'ArrowRight') {
dx = KEY_STEP;
}
else if (k === 'ArrowUp') {
dy = -KEY_STEP;
}
else if (k === 'ArrowDown') {
dy = KEY_STEP;
}
else {
return;
}
e.preventDefault();
takeOver();
tgt = [clamp(tgt[0] + dx, 0, W), clamp(tgt[1] + dy, 0, H)];
afterInput();
});
if (reduce) {
scene.snap(tgt[0], tgt[1]);
scene.draw(elapsed);
setMode();
}
else {
scene.draw(elapsed);
setMode();
rafId = requestAnimationFrame(tick);
}
function destroy() {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) {
cleaners[i]();
}
}
return destroy;
}
main(document.getElementById('scRoot'), document.getElementById('scCanvas'), document.getElementById('scStatus'), document.getElementById('scBtn'));
})();import { useEffect, useRef } from "react";
import styles from "./ShcastHeightPenumbraBlur.module.scss";
const W = 480;
const H = 300;
const PI2 = Math.PI * 2;
const FIXED_DT = 16;
const REDUCE_STEP_MS = 900;
const REDUCE_START_MS = 1000;
const PERIOD_MS = 4000;
const KEY_STEP = 12;
const FONT = '-apple-system, "Segoe UI", "Noto Sans KR", sans-serif';
type Pt = [number, number];
interface Scene {
path(t: number): Pt;
pos(): Pt;
update(tx: number, ty: number): void;
snap(tx: number, ty: number): void;
draw(t: number): void;
}
function clamp(v: number, lo: number, hi: number): number { return v < lo ? lo : (v > hi ? hi : v); }
function lerp(a: number, b: number, k: number): number { return a + (b - a) * k; }
function smooth(x: number): number { const c = clamp(x, 0, 1); return c * c * (3 - 2 * c); }
function rgba(c: number[], a: number): string {
return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + a.toFixed(3) + ')';
}
// 시드 고정 난수 — 같은 시드면 언제나 같은 수열
function mulberry32(seed: number): () => number {
let s = seed >>> 0;
return function (): number {
s = (s + 0x6D2B79F5) >>> 0;
let t = s;
t = Math.imul(t ^ (t >>> 15), t | 1);
t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
};
}
function glow(ctx: CanvasRenderingContext2D, x: number, y: number, r: number, c: number[], a: number): void {
const g = ctx.createRadialGradient(x, y, 0, x, y, r);
g.addColorStop(0, rgba(c, a));
g.addColorStop(1, rgba(c, 0));
ctx.fillStyle = g;
ctx.fillRect(x - r, y - r, r * 2, r * 2);
}
function polyPath(ctx: CanvasRenderingContext2D, poly: Pt[]): void {
ctx.beginPath();
for (let i = 0; i < poly.length; i += 1) {
if (i === 0) { ctx.moveTo(poly[i][0], poly[i][1]); } else { ctx.lineTo(poly[i][0], poly[i][1]); }
}
ctx.closePath();
}
const BLUR_PER_HEIGHT = 0.2;
const CONTACT_ALPHA = 0.62;
const LIFT_MAX = 110;
const LIGHT_LERP = 0.16;
const PLANK_LEFT = 80;
const PLANK_LEN = 320;
const PLANK_THICK = 14;
const STRIPS = 64;
const BASE_Y = 168;
const WALL_RGB = [255, 244, 214];
const FLOOR_RGB = [236, 228, 250];
const SHADOW_RGB = [70, 54, 116];
const PLANK_TOP = [150, 206, 255];
const PLANK_EDGE = [96, 160, 226];
function makeScene(ctx: CanvasRenderingContext2D): Scene {
let px = 240;
let py = 160;
function lift(): number { return LIFT_MAX * clamp((py - 30) / 240, 0, 1); }
// 가로 위치 u (0 은 닿은 쪽, 1 은 뜬 쪽) 에서 판의 높이
function heightAt(u: number, total: number): number { return total * u; }
const scene: Scene = {
path: function (t: number): Pt {
const a = PI2 * t / PERIOD_MS;
return [240 + 170 * Math.sin(a * 2), 150 + 130 * Math.sin(a - 1.2)];
},
pos: function (): Pt { return [px, py]; },
update: function (tx: number, ty: number): void {
px = lerp(px, tx, LIGHT_LERP);
py = lerp(py, ty, LIGHT_LERP);
},
snap: function (tx: number, ty: number): void { px = tx; py = ty; },
draw: function (): void {
const total = lift();
const slide = (px - 240) / 240;
ctx.fillStyle = rgba(WALL_RGB, 1);
ctx.fillRect(0, 0, W, BASE_Y - 20);
ctx.fillStyle = rgba(FLOOR_RGB, 1);
ctx.fillRect(0, BASE_Y - 20, W, H - BASE_Y + 20);
// 그림자 띠 — 띠마다 높이로 번짐과 농도를 따로 계산한다
for (let i = 0; i < STRIPS; i += 1) {
const h0 = heightAt(i / STRIPS, total);
const h1 = heightAt((i + 1) / STRIPS, total);
const hm = (h0 + h1) / 2;
const xa = Math.round(PLANK_LEFT + (PLANK_LEN * i) / STRIPS + h0 * slide * 0.9);
const xb = Math.round(PLANK_LEFT + (PLANK_LEN * (i + 1)) / STRIPS + h1 * slide * 0.9);
const blur = 2 + hm * BLUR_PER_HEIGHT;
const alpha = CONTACT_ALPHA / (1 + hm * 0.03);
const yTop = BASE_Y - 2;
const yBot = BASE_Y + 16 + hm * 0.5;
const g = ctx.createLinearGradient(0, yTop - blur, 0, yBot + blur);
const span = yBot - yTop + 2 * blur;
g.addColorStop(0, rgba(SHADOW_RGB, 0));
g.addColorStop(clamp(blur * 1.2 / span, 0, 0.45), rgba(SHADOW_RGB, alpha));
g.addColorStop(clamp(1 - blur * 1.2 / span, 0.55, 1), rgba(SHADOW_RGB, alpha * 0.85));
g.addColorStop(1, rgba(SHADOW_RGB, 0));
ctx.fillStyle = g;
ctx.fillRect(xa, yTop - blur, xb - xa, span);
}
// 판 — 왼쪽 끝은 바닥에 닿고 오른쪽 끝만 들린다
ctx.beginPath();
for (let i = 0; i <= STRIPS; i += 1) {
const hh = heightAt(i / STRIPS, total);
const x = PLANK_LEFT + (PLANK_LEN * i) / STRIPS;
const y = BASE_Y - hh * 0.7 - PLANK_THICK;
if (i === 0) { ctx.moveTo(x, y); } else { ctx.lineTo(x, y); }
}
for (let i = STRIPS; i >= 0; i -= 1) {
const hh = heightAt(i / STRIPS, total);
ctx.lineTo(PLANK_LEFT + (PLANK_LEN * i) / STRIPS, BASE_Y - hh * 0.7);
}
ctx.closePath();
ctx.fillStyle = rgba(PLANK_TOP, 1);
ctx.fill();
ctx.lineWidth = 2;
ctx.strokeStyle = rgba(PLANK_EDGE, 1);
ctx.stroke();
ctx.beginPath();
ctx.arc(PLANK_LEFT, BASE_Y - PLANK_THICK / 2, 5, 0, PI2);
ctx.fillStyle = rgba(PLANK_EDGE, 1);
ctx.fill();
// 광원 표시 — 가로 위치가 그림자가 쏠리는 쪽을 정한다
glow(ctx, px, 30, 46, [255, 220, 120], 0.9);
ctx.beginPath();
ctx.arc(px, 30, 8, 0, PI2);
ctx.fillStyle = 'rgba(255,246,208,1)';
ctx.fill();
ctx.lineWidth = 2;
ctx.strokeStyle = 'rgba(214,170,70,0.9)';
ctx.stroke();
}
};
return scene;
}
function main(rootEl: HTMLElement, canvas: HTMLCanvasElement, statusEl: HTMLElement, btnEl: HTMLButtonElement): () => void {
const ctx0 = canvas.getContext('2d');
if (!ctx0) { return function (): void { return; }; }
canvas.width = W;
canvas.height = H;
const scene: Scene = makeScene(ctx0);
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
if (reduce) { rootEl.classList.remove('is-demo'); }
let paused = false;
let autoplay = !reduce;
let elapsed = reduce ? REDUCE_START_MS : 0;
let rafId = 0;
let lastTs: number | null = null;
let accMs = 0;
let tgt: Pt = scene.path(elapsed);
const cleaners: Array<() => void> = [];
function listen(target: EventTarget, type: string, fn: (e: Event) => void): void {
target.addEventListener(type, fn);
cleaners.push(function (): void { target.removeEventListener(type, fn); });
}
function setMode(): void {
if (reduce) {
statusEl.textContent = '한 장면씩 넘기는 중';
btnEl.textContent = '다음 장면';
return;
}
statusEl.textContent = !autoplay ? '직접 조작 중' : (paused ? '일시정지됨' : '시연 중');
btnEl.textContent = (autoplay && !paused) ? '멈춤' : '재생';
}
function toLocal(e: PointerEvent): Pt {
const r = canvas.getBoundingClientRect();
return [clamp((e.clientX - r.left) * W / r.width, 0, W), clamp((e.clientY - r.top) * H / r.height, 0, H)];
}
function takeOver(): void {
if (reduce || !autoplay) { return; }
autoplay = false;
paused = false;
rootEl.classList.remove('is-demo');
const p = scene.pos();
tgt = [p[0], p[1]];
setMode();
}
function afterInput(): void {
if (reduce) {
scene.snap(tgt[0], tgt[1]);
scene.draw(elapsed);
}
}
function onButton(): void {
if (reduce) {
elapsed += REDUCE_STEP_MS;
tgt = scene.path(elapsed);
scene.snap(tgt[0], tgt[1]);
scene.draw(elapsed);
return;
}
if (autoplay && !paused) {
paused = true;
} else {
paused = false;
autoplay = true;
rootEl.classList.add('is-demo');
}
setMode();
}
function tick(ts: number): void {
if (lastTs === null) { lastTs = ts; }
const frameDt = Math.min(ts - lastTs, 160);
lastTs = ts;
if (!paused) {
accMs += frameDt;
while (accMs >= FIXED_DT) {
elapsed += FIXED_DT;
accMs -= FIXED_DT;
if (autoplay) { tgt = scene.path(elapsed); }
scene.update(tgt[0], tgt[1]);
}
scene.draw(elapsed);
}
rafId = requestAnimationFrame(tick);
}
listen(btnEl, 'click', function (): void { onButton(); });
listen(canvas, 'pointerdown', function (e: Event): void {
takeOver();
tgt = toLocal(e as PointerEvent);
afterInput();
});
listen(canvas, 'pointermove', function (e: Event): void {
if (autoplay && !reduce) { return; }
tgt = toLocal(e as PointerEvent);
afterInput();
});
listen(canvas, 'keydown', function (e: Event): void {
const k = (e as KeyboardEvent).key;
if (k === 'Enter' || k === ' ') {
e.preventDefault();
onButton();
return;
}
let dx = 0;
let dy = 0;
if (k === 'ArrowLeft') { dx = -KEY_STEP; } else if (k === 'ArrowRight') { dx = KEY_STEP; }
else if (k === 'ArrowUp') { dy = -KEY_STEP; } else if (k === 'ArrowDown') { dy = KEY_STEP; }
else { return; }
e.preventDefault();
takeOver();
tgt = [clamp(tgt[0] + dx, 0, W), clamp(tgt[1] + dy, 0, H)];
afterInput();
});
if (reduce) {
scene.snap(tgt[0], tgt[1]);
scene.draw(elapsed);
setMode();
} else {
scene.draw(elapsed);
setMode();
rafId = requestAnimationFrame(tick);
}
function destroy(): void {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) { cleaners[i](); }
}
return destroy;
}
export default function ShcastHeightPenumbraBlur() {
const rootRef = useRef<HTMLDivElement | null>(null);
const canvasRef = useRef<HTMLCanvasElement | null>(null);
const statusRef = useRef<HTMLParagraphElement | null>(null);
const btnRef = useRef<HTMLButtonElement | null>(null);
useEffect(() => {
const root = rootRef.current;
const canvas = canvasRef.current;
const statusEl = statusRef.current;
const btnEl = btnRef.current;
if (!root || !canvas || !statusEl || !btnEl) return;
return main(root, canvas, statusEl, btnEl);
}, []);
return (
<main className={styles.stage}>
<div className={`${styles.sc} is-demo`} ref={rootRef}>
<canvas className={styles.sc__canvas} ref={canvasRef} width={480} height={300} tabIndex={0} aria-label="한쪽 끝만 뜬 판에서 바닥 높이에 비례해 그림자의 흐림과 농도를 띠마다 계산해, 맞닿은 곳과 떨어진 곳이 다르게 보인다." />
<p className={styles.sc__status} ref={statusRef} aria-live="polite">시연 중</p>
<button className={styles.sc__btn} ref={btnRef} type="button">멈춤</button>
<p className={styles.sc__caption}>한쪽 끝만 뜬 판에서 바닥 높이에 비례해 그림자의 흐림과 농도를 띠마다 계산해, 맞닿은 곳과 떨어진 곳이 다르게 보인다.</p>
</div>
</main>
);
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