09A Dither Hero Where Only the Area Around the Pointer Gets Dense
A Gaussian of pointer distance is added to a noise-driven background brightness, making a hero where only the cursor's surroundings are stamped bright and dense.
Best forHero focal scenes
HALO_RHALO_GAINNOISE_SCALELERP
<main class="stage">
<div class="sc is-demo" id="scRoot">
<canvas class="sc__canvas" id="scCanvas" width="480" height="300" tabindex="0" aria-label="A Dither Hero Where Only the Area Around the Pointer Gets Dense"></canvas>
<p class="sc__status" id="scStatus" aria-live="polite">The halo drifts by itself</p>
<button class="sc__btn" id="scBtn" type="button">Pause</button>
<p class="sc__caption">A Dither Hero Where Only the Area Around the Pointer Gets Dense</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;
image-rendering: pixelated;
}
.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;
image-rendering: pixelated;
}
.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 KEY_STEP = 14;
const IDLE_TICKS = 150;
const BTN_PAUSE = 'Pause';
const BTN_PLAY = 'Play';
const BTN_NEXT = 'Next scene';
// 점을 찍는 작은 격자 — 화면에는 3배로 확대해 올린다
const GW = 160;
const GH = 100;
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 frac(x) { return x - Math.floor(x); }
// 시드 고정 난수 — 같은 시드면 언제나 같은 수열 (선형 합동 방식)
function lcg(seed) {
let s = seed >>> 0;
return function () {
s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
return s / 4294967296;
};
}
// 좌표 두 개와 시드로 0 이상 1 미만의 값을 만드는 정수 해시 (난수 함수 없이도 같은 좌표는 늘 같은 값)
function hash2(x, y, seed) {
let h = (Math.imul(x | 0, 374761393) + Math.imul(y | 0, 668265263) + Math.imul(seed | 0, 1442695041)) | 0;
h = Math.imul(h ^ (h >>> 13), 1274126177);
h ^= h >>> 16;
return (h >>> 0) / 4294967296;
}
// 격자 네 점의 해시를 smooth 로 이어 붙인 값 노이즈
function vnoise(x, y, seed) {
const xi = Math.floor(x);
const yi = Math.floor(y);
const fx = smooth(x - xi);
const fy = smooth(y - yi);
const a = lerp(hash2(xi, yi, seed), hash2(xi + 1, yi, seed), fx);
const b = lerp(hash2(xi, yi + 1, seed), hash2(xi + 1, yi + 1, seed), fx);
return lerp(a, b, fy);
}
// 베이어 임계 행렬 — n 은 2 의 거듭제곱. 값은 0 초과 1 미만으로 맞춘다
function makeBayer(n) {
let size = 2;
let m = [0, 2, 3, 1];
const quad = [0, 2, 3, 1];
while (size < n) {
const s2 = size * 2;
const next = [];
for (let y = 0; y < s2; y += 1) {
for (let x = 0; x < s2; x += 1) {
const q = (y >= size ? 2 : 0) + (x >= size ? 1 : 0);
next.push(4 * m[(y % size) * size + (x % size)] + quad[q]);
}
}
m = next;
size = s2;
}
const out = new Float32Array(n * n);
for (let i = 0; i < out.length; i += 1) {
out[i] = (m[i] + 0.5) / (n * n);
}
return out;
}
// 색 하나를 캔버스 픽셀 한 개(리틀 엔디언 RGBA)로 묶는다
function pack(c) {
return ((255 << 24) | (Math.round(c[2]) << 16) | (Math.round(c[1]) << 8) | Math.round(c[0])) >>> 0;
}
function mixPack(a, b, k) {
return pack([lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)]);
}
function makeBuf() {
const off = document.createElement('canvas');
off.width = GW;
off.height = GH;
const octx = off.getContext('2d');
if (!octx) {
throw new Error('2d context unavailable');
}
const img = octx.createImageData(GW, GH);
return { off: off, octx: octx, img: img, px: new Uint32Array(img.data.buffer) };
}
// 작은 격자를 큰 캔버스에 보간 없이 확대해 올린다
function flush(ctx, b) {
b.octx.putImageData(b.img, 0, 0);
ctx.imageSmoothingEnabled = false;
ctx.drawImage(b.off, 0, 0, W, H);
}
function start(root, canvas, statusEl, btnEl, make) {
const ctx0 = canvas.getContext('2d');
if (!ctx0) {
return function () { return; };
}
const ctx = ctx0;
const dpr = Math.min(window.devicePixelRatio || 1, 2);
canvas.width = Math.round(W * dpr);
canvas.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const inp = { x: W / 2, y: H / 2, idle: 99999 };
const scene = make(inp, reduce);
let paused = false;
let rafId = 0;
let lastTs = -1;
let accMs = 0;
let lastLabel = '';
const cleaners = [];
function listen(target, type, fn) {
target.addEventListener(type, fn);
cleaners.push(function () { target.removeEventListener(type, fn); });
}
function show() {
scene.draw(ctx);
const t = scene.label();
if (t !== lastLabel) {
lastLabel = t;
statusEl.textContent = t;
}
}
function advance(ms) {
const n = Math.round(ms / FIXED_DT);
for (let i = 0; i < n; i += 1) {
inp.idle += 1;
scene.step();
}
}
function refresh() {
if (reduce) {
advance(FIXED_DT * 6);
show();
}
}
function toLocal(e) {
const r = canvas.getBoundingClientRect();
inp.x = clamp((e.clientX - r.left) * W / r.width, 0, W);
inp.y = clamp((e.clientY - r.top) * H / r.height, 0, H);
inp.idle = 0;
}
function tick(ts) {
if (lastTs < 0) {
lastTs = ts;
}
const frameDt = Math.min(ts - lastTs, 160);
lastTs = ts;
if (!paused) {
accMs += frameDt;
while (accMs >= FIXED_DT) {
inp.idle += 1;
scene.step();
accMs -= FIXED_DT;
}
show();
}
rafId = requestAnimationFrame(tick);
}
btnEl.textContent = reduce ? BTN_NEXT : BTN_PAUSE;
if (reduce) {
root.classList.remove('is-demo');
advance(1400);
show();
}
listen(btnEl, 'click', function () {
if (reduce) {
advance(REDUCE_STEP_MS);
show();
return;
}
paused = !paused;
if (paused) {
root.classList.remove('is-demo');
}
else {
root.classList.add('is-demo');
}
btnEl.textContent = paused ? BTN_PLAY : BTN_PAUSE;
});
listen(canvas, 'pointermove', function (e) {
toLocal(e);
refresh();
});
listen(canvas, 'pointerdown', function (e) {
toLocal(e);
scene.tap();
refresh();
});
listen(canvas, 'keydown', function (e) {
const k = e.key;
let dx = 0;
let dy = 0;
if (k === 'Enter' || k === ' ') {
e.preventDefault();
scene.tap();
refresh();
return;
}
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();
inp.x = clamp(inp.x + dx, 0, W);
inp.y = clamp(inp.y + dy, 0, H);
inp.idle = 0;
refresh();
});
if (!reduce) {
rafId = requestAnimationFrame(tick);
}
return function () {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) {
cleaners[i]();
}
};
}
const HALO_R = 34;
const HALO_GAIN = 0.85;
const NOISE_SCALE = 0.05;
const LERP = 0.12;
const NOISE_SEED = 9;
const PULSE_TICKS = 40;
const DARK_09 = [34, 31, 58];
const LIGHT_BASE = [160, 196, 255];
const LIGHT_HALO = [255, 196, 222];
const TXT_AUTO = 'The halo drifts by itself';
const TXT_FOLLOW = 'The halo trails the pointer with a lag';
const TXT_PULSE = 'Press and the halo swells once, then settles';
function makeScene(inp, reduce) {
const buf = makeBuf();
const matrix = makeBayer(8);
const dark = pack(DARK_09);
// 후광 세기 0~1 을 32 단계 색으로 미리 만들어 둔다
const tint = [];
for (let k = 0; k < 32; k += 1) {
tint.push(mixPack(LIGHT_BASE, LIGHT_HALO, k / 31));
}
let t = 0;
let hx = GW * 0.5;
let hy = GH * 0.5;
let pulse = 0;
const scene = {
step() {
t += 1;
let tx = GW * (0.5 + 0.32 * Math.sin(t * 0.021));
let ty = GH * (0.5 + 0.28 * Math.sin(t * 0.033 + 1));
if (inp.idle < IDLE_TICKS) {
tx = inp.x * GW / W;
ty = inp.y * GH / H;
}
hx = lerp(hx, tx, LERP);
hy = lerp(hy, ty, LERP);
if (pulse > 0) {
pulse -= 1;
}
},
draw(ctx) {
const breathe = 1 + 0.12 * Math.sin(t * 0.07) + 0.6 * smooth(pulse / PULSE_TICKS);
const sigma = (HALO_R / 1.6) * breathe;
const inv = 1 / (2 * sigma * sigma);
for (let y = 0; y < GH; y += 1) {
for (let x = 0; x < GW; x += 1) {
const nx = x * NOISE_SCALE + t * 0.012;
const ny = y * NOISE_SCALE - t * 0.007;
const n = vnoise(nx, ny, NOISE_SEED) * 0.65 + vnoise(nx * 2.1 + 7, ny * 2.1 + 3, NOISE_SEED) * 0.35;
const dx = x - hx;
const dy = y - hy;
const halo = Math.exp(-(dx * dx + dy * dy) * inv);
const v = 0.05 + 0.5 * n + halo * HALO_GAIN;
const i = y * GW + x;
buf.px[i] = v > matrix[(y & 7) * 8 + (x & 7)] ? tint[Math.min(31, Math.floor(halo * 31))] : dark;
}
}
flush(ctx, buf);
},
label() {
if (pulse > 0) {
return TXT_PULSE;
}
return inp.idle < IDLE_TICKS ? TXT_FOLLOW : TXT_AUTO;
},
tap() {
pulse = PULSE_TICKS;
}
};
if (reduce) {
for (let i = 0; i < 40; i += 1) {
scene.step();
}
}
return scene;
}
start(document.getElementById('scRoot'), document.getElementById('scCanvas'), document.getElementById('scStatus'), document.getElementById('scBtn'), makeScene);
})();import { useEffect, useRef } from "react";
import styles from "./DtPointerHaloHero.module.scss";
const W = 480;
const H = 300;
const PI2 = Math.PI * 2;
const FIXED_DT = 16;
const REDUCE_STEP_MS = 900;
const KEY_STEP = 14;
const IDLE_TICKS = 150;
const BTN_PAUSE = '멈춤';
const BTN_PLAY = '재생';
const BTN_NEXT = '다음 장면';
// 점을 찍는 작은 격자 — 화면에는 3배로 확대해 올린다
const GW = 160;
const GH = 100;
type RGB = [number, number, number];
interface Input { x: number; y: number; idle: number; }
interface Scene {
step(): void;
draw(ctx: CanvasRenderingContext2D): void;
label(): string;
tap(): void;
}
type Maker = (inp: Input, reduce: boolean) => Scene;
interface Buf {
off: HTMLCanvasElement;
octx: CanvasRenderingContext2D;
img: ImageData;
px: Uint32Array;
}
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 frac(x: number): number { return x - Math.floor(x); }
// 시드 고정 난수 — 같은 시드면 언제나 같은 수열 (선형 합동 방식)
function lcg(seed: number): () => number {
let s = seed >>> 0;
return function (): number {
s = (Math.imul(s, 1664525) + 1013904223) >>> 0;
return s / 4294967296;
};
}
// 좌표 두 개와 시드로 0 이상 1 미만의 값을 만드는 정수 해시 (난수 함수 없이도 같은 좌표는 늘 같은 값)
function hash2(x: number, y: number, seed: number): number {
let h = (Math.imul(x | 0, 374761393) + Math.imul(y | 0, 668265263) + Math.imul(seed | 0, 1442695041)) | 0;
h = Math.imul(h ^ (h >>> 13), 1274126177);
h ^= h >>> 16;
return (h >>> 0) / 4294967296;
}
// 격자 네 점의 해시를 smooth 로 이어 붙인 값 노이즈
function vnoise(x: number, y: number, seed: number): number {
const xi = Math.floor(x);
const yi = Math.floor(y);
const fx = smooth(x - xi);
const fy = smooth(y - yi);
const a = lerp(hash2(xi, yi, seed), hash2(xi + 1, yi, seed), fx);
const b = lerp(hash2(xi, yi + 1, seed), hash2(xi + 1, yi + 1, seed), fx);
return lerp(a, b, fy);
}
// 베이어 임계 행렬 — n 은 2 의 거듭제곱. 값은 0 초과 1 미만으로 맞춘다
function makeBayer(n: number): Float32Array {
let size = 2;
let m: number[] = [0, 2, 3, 1];
const quad = [0, 2, 3, 1];
while (size < n) {
const s2 = size * 2;
const next: number[] = [];
for (let y = 0; y < s2; y += 1) {
for (let x = 0; x < s2; x += 1) {
const q = (y >= size ? 2 : 0) + (x >= size ? 1 : 0);
next.push(4 * m[(y % size) * size + (x % size)] + quad[q]);
}
}
m = next;
size = s2;
}
const out = new Float32Array(n * n);
for (let i = 0; i < out.length; i += 1) {
out[i] = (m[i] + 0.5) / (n * n);
}
return out;
}
// 색 하나를 캔버스 픽셀 한 개(리틀 엔디언 RGBA)로 묶는다
function pack(c: RGB): number {
return ((255 << 24) | (Math.round(c[2]) << 16) | (Math.round(c[1]) << 8) | Math.round(c[0])) >>> 0;
}
function mixPack(a: RGB, b: RGB, k: number): number {
return pack([lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)]);
}
function makeBuf(): Buf {
const off = document.createElement('canvas');
off.width = GW;
off.height = GH;
const octx = off.getContext('2d');
if (!octx) {
throw new Error('2d context unavailable');
}
const img = octx.createImageData(GW, GH);
return { off: off, octx: octx, img: img, px: new Uint32Array(img.data.buffer) };
}
// 작은 격자를 큰 캔버스에 보간 없이 확대해 올린다
function flush(ctx: CanvasRenderingContext2D, b: Buf): void {
b.octx.putImageData(b.img, 0, 0);
ctx.imageSmoothingEnabled = false;
ctx.drawImage(b.off, 0, 0, W, H);
}
function start(root: HTMLElement, canvas: HTMLCanvasElement, statusEl: HTMLElement, btnEl: HTMLButtonElement, make: Maker): () => void {
const ctx0 = canvas.getContext('2d');
if (!ctx0) {
return function (): void { return; };
}
const ctx: CanvasRenderingContext2D = ctx0;
const dpr = Math.min(window.devicePixelRatio || 1, 2);
canvas.width = Math.round(W * dpr);
canvas.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const inp: Input = { x: W / 2, y: H / 2, idle: 99999 };
const scene = make(inp, reduce);
let paused = false;
let rafId = 0;
let lastTs = -1;
let accMs = 0;
let lastLabel = '';
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 show(): void {
scene.draw(ctx);
const t = scene.label();
if (t !== lastLabel) {
lastLabel = t;
statusEl.textContent = t;
}
}
function advance(ms: number): void {
const n = Math.round(ms / FIXED_DT);
for (let i = 0; i < n; i += 1) {
inp.idle += 1;
scene.step();
}
}
function refresh(): void {
if (reduce) {
advance(FIXED_DT * 6);
show();
}
}
function toLocal(e: PointerEvent): void {
const r = canvas.getBoundingClientRect();
inp.x = clamp((e.clientX - r.left) * W / r.width, 0, W);
inp.y = clamp((e.clientY - r.top) * H / r.height, 0, H);
inp.idle = 0;
}
function tick(ts: number): void {
if (lastTs < 0) {
lastTs = ts;
}
const frameDt = Math.min(ts - lastTs, 160);
lastTs = ts;
if (!paused) {
accMs += frameDt;
while (accMs >= FIXED_DT) {
inp.idle += 1;
scene.step();
accMs -= FIXED_DT;
}
show();
}
rafId = requestAnimationFrame(tick);
}
btnEl.textContent = reduce ? BTN_NEXT : BTN_PAUSE;
if (reduce) {
root.classList.remove('is-demo');
advance(1400);
show();
}
listen(btnEl, 'click', function (): void {
if (reduce) {
advance(REDUCE_STEP_MS);
show();
return;
}
paused = !paused;
if (paused) {
root.classList.remove('is-demo');
} else {
root.classList.add('is-demo');
}
btnEl.textContent = paused ? BTN_PLAY : BTN_PAUSE;
});
listen(canvas, 'pointermove', function (e: Event): void {
toLocal(e as PointerEvent);
refresh();
});
listen(canvas, 'pointerdown', function (e: Event): void {
toLocal(e as PointerEvent);
scene.tap();
refresh();
});
listen(canvas, 'keydown', function (e: Event): void {
const k = (e as KeyboardEvent).key;
let dx = 0;
let dy = 0;
if (k === 'Enter' || k === ' ') {
e.preventDefault();
scene.tap();
refresh();
return;
}
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();
inp.x = clamp(inp.x + dx, 0, W);
inp.y = clamp(inp.y + dy, 0, H);
inp.idle = 0;
refresh();
});
if (!reduce) {
rafId = requestAnimationFrame(tick);
}
return function (): void {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) {
cleaners[i]();
}
};
}
const HALO_R = 34;
const HALO_GAIN = 0.85;
const NOISE_SCALE = 0.05;
const LERP = 0.12;
const NOISE_SEED = 9;
const PULSE_TICKS = 40;
const DARK_09: RGB = [34, 31, 58];
const LIGHT_BASE: RGB = [160, 196, 255];
const LIGHT_HALO: RGB = [255, 196, 222];
const TXT_AUTO = '빛무리가 스스로 떠돈다';
const TXT_FOLLOW = '빛무리가 포인터를 늦게 따라온다';
const TXT_PULSE = '누르면 빛무리가 한 번 부풀었다 가라앉는다';
function makeScene(inp: Input, reduce: boolean): Scene {
const buf = makeBuf();
const matrix = makeBayer(8);
const dark = pack(DARK_09);
// 후광 세기 0~1 을 32 단계 색으로 미리 만들어 둔다
const tint: number[] = [];
for (let k = 0; k < 32; k += 1) {
tint.push(mixPack(LIGHT_BASE, LIGHT_HALO, k / 31));
}
let t = 0;
let hx = GW * 0.5;
let hy = GH * 0.5;
let pulse = 0;
const scene: Scene = {
step(): void {
t += 1;
let tx = GW * (0.5 + 0.32 * Math.sin(t * 0.021));
let ty = GH * (0.5 + 0.28 * Math.sin(t * 0.033 + 1));
if (inp.idle < IDLE_TICKS) {
tx = inp.x * GW / W;
ty = inp.y * GH / H;
}
hx = lerp(hx, tx, LERP);
hy = lerp(hy, ty, LERP);
if (pulse > 0) {
pulse -= 1;
}
},
draw(ctx: CanvasRenderingContext2D): void {
const breathe = 1 + 0.12 * Math.sin(t * 0.07) + 0.6 * smooth(pulse / PULSE_TICKS);
const sigma = (HALO_R / 1.6) * breathe;
const inv = 1 / (2 * sigma * sigma);
for (let y = 0; y < GH; y += 1) {
for (let x = 0; x < GW; x += 1) {
const nx = x * NOISE_SCALE + t * 0.012;
const ny = y * NOISE_SCALE - t * 0.007;
const n = vnoise(nx, ny, NOISE_SEED) * 0.65 + vnoise(nx * 2.1 + 7, ny * 2.1 + 3, NOISE_SEED) * 0.35;
const dx = x - hx;
const dy = y - hy;
const halo = Math.exp(-(dx * dx + dy * dy) * inv);
const v = 0.05 + 0.5 * n + halo * HALO_GAIN;
const i = y * GW + x;
buf.px[i] = v > matrix[(y & 7) * 8 + (x & 7)] ? tint[Math.min(31, Math.floor(halo * 31))] : dark;
}
}
flush(ctx, buf);
},
label(): string {
if (pulse > 0) {
return TXT_PULSE;
}
return inp.idle < IDLE_TICKS ? TXT_FOLLOW : TXT_AUTO;
},
tap(): void {
pulse = PULSE_TICKS;
}
};
if (reduce) {
for (let i = 0; i < 40; i += 1) {
scene.step();
}
}
return scene;
}
export default function DtPointerHaloHero() {
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 start(root, canvas, statusEl, btnEl, makeScene);
}, []);
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="포인터 둘레만 촘촘해지는 빛무리 디더 히어로" />
<p className={styles.sc__status} ref={statusRef} aria-live="polite">빛무리가 스스로 떠돈다</p>
<button className={styles.sc__btn} ref={btnRef} type="button">멈춤</button>
<p className={styles.sc__caption}>포인터 둘레만 촘촘해지는 빛무리 디더 히어로</p>
</div>
</main>
);
}09 A Dither Hero Where Only the Area Around the Pointer Gets Dense — Measured area 50.6% · moving frames 23/23Original by GODRICH · SCSS and React ship in the zip · CSS Dither: 9 Scenes Drawn by Threshold Math
The post this demo lives in
CSS Dither: 9 Scenes Drawn by Threshold MathA css dither throws away every color but two, so why does the gradient look smoother? Scene 01's threshold matrix and sc See all demos in this post
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