06A Sky Dome of Stars on a Sphere Turned by a Rotation Matrix
Stars sit as points on a sphere, get multiplied by yaw and pitch rotation matrices and projected with a field of view, so the whole sky turns about one point.
Best forPlanetarium and hero scenes
YAW_RATEPITCHFOVSTAR_COUNT
<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 Sky Dome of Stars on a Sphere Turned by a Rotation Matrix"></canvas>
<p class="sc__status" id="scStatus" aria-live="polite">The sky dome turns slowly</p>
<button class="sc__btn" id="scBtn" type="button">Pause</button>
<p class="sc__caption">A Sky Dome of Stars on a Sphere Turned by a Rotation Matrix</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 KEY_STEP = 14;
const IDLE_TICKS = 150;
const BTN_PAUSE = 'Pause';
const BTN_PLAY = 'Play';
const BTN_NEXT = 'Next scene';
const BG = [14, 12, 32];
const STAR_RGBS = [[226, 238, 255], [255, 222, 196], [208, 196, 255], [196, 240, 228], [255, 206, 226]];
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]) + ',' + clamp(a, 0, 1).toFixed(3) + ')';
}
function mix(a, b, k) {
return [lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)];
}
// 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;
};
}
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 paintBg(ctx, alpha) {
ctx.fillStyle = rgba(BG, alpha);
ctx.fillRect(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 YAW_RATE = 0.012;
const PITCH = 0.38;
const FOV = 150;
const STAR_COUNT = 900;
const BAND_STARS = 520;
const GRID_STEP = 72;
const NEAR_CUT = 0.08;
const TXT_AUTO = 'The sky dome turns slowly';
const TXT_LOOK = 'Turn your head toward the pointer';
function makeScene(inp, reduce) {
const rnd = lcg(450606);
const stars = [];
// 구면 위 고른 분포 — 높이 z 를 -1 이상 1 이하에서 고르게, 방위각도 고르게
for (let i = 0; i < STAR_COUNT; i += 1) {
const zz = rnd() * 2 - 1;
const ph = rnd() * PI2;
const rr = Math.sqrt(1 - zz * zz);
stars.push({ x: rr * Math.cos(ph), y: zz, z: rr * Math.sin(ph), m: rnd(), c: STAR_RGBS[i % STAR_RGBS.length] });
}
// 은하수 띠 — 기울어진 큰 원 둘레에 좁게 모은 별
const tilt = 0.6;
for (let i = 0; i < BAND_STARS; i += 1) {
const ph = rnd() * PI2;
const lat = (rnd() + rnd() + rnd() - 1.5) * 0.2;
const bx = Math.cos(lat) * Math.cos(ph);
const by = Math.sin(lat);
const bz = Math.cos(lat) * Math.sin(ph);
stars.push({ x: bx, y: by * Math.cos(tilt) - bz * Math.sin(tilt), z: by * Math.sin(tilt) + bz * Math.cos(tilt), m: rnd() * 0.5, c: STAR_RGBS[2] });
}
let yaw = 0;
let pitch = PITCH;
let t = 0;
let look = 0;
let lookP = 0;
function project(x, y, z, cy, sy, cp, sp) {
const x1 = x * cy + z * sy;
const z1 = -x * sy + z * cy;
const y2 = y * cp - z1 * sp;
const z2 = y * sp + z1 * cp;
return [W / 2 + FOV * x1 / z2, H / 2 - FOV * y2 / z2, z2];
}
const scene = {
step() {
t += 1;
let ly = 0;
let lp = 0.22 * Math.sin(t * 0.008);
if (inp.idle < IDLE_TICKS) {
ly = (inp.x - W / 2) / W * 1.6;
lp = (H / 2 - inp.y) / H * 0.9;
}
look = lerp(look, ly, 0.06);
lookP = lerp(lookP, lp, 0.06);
yaw += YAW_RATE;
pitch = PITCH + lookP;
},
draw(ctx) {
paintBg(ctx, 1);
const cyw = Math.cos(yaw + look);
const syw = Math.sin(yaw + look);
const cp = Math.cos(pitch);
const sp = Math.sin(pitch);
// 위도선과 경선 — 점으로만 그려 돌아가는 방향이 보이게
ctx.fillStyle = rgba([208, 196, 255], 0.55);
for (let la = -60; la <= 60; la += 30) {
const rl = Math.cos(la * Math.PI / 180);
const yl = Math.sin(la * Math.PI / 180);
for (let a = 0; a < 360; a += 5) {
const p = project(rl * Math.cos(a * Math.PI / 180), yl, rl * Math.sin(a * Math.PI / 180), cyw, syw, cp, sp);
if (p[2] > NEAR_CUT) {
ctx.fillRect(p[0] - 0.9, p[1] - 0.9, 1.9, 1.9);
}
}
}
for (let me = 0; me < 360; me += GRID_STEP / 2) {
for (let a = -80; a <= 80; a += 5) {
const rl = Math.cos(a * Math.PI / 180);
const p = project(rl * Math.cos(me * Math.PI / 180), Math.sin(a * Math.PI / 180), rl * Math.sin(me * Math.PI / 180), cyw, syw, cp, sp);
if (p[2] > NEAR_CUT) {
ctx.fillRect(p[0] - 0.9, p[1] - 0.9, 1.9, 1.9);
}
}
}
for (let i = 0; i < stars.length; i += 1) {
const s = stars[i];
const p = project(s.x, s.y, s.z, cyw, syw, cp, sp);
if (p[2] <= NEAR_CUT || p[0] < -6 || p[0] > W + 6 || p[1] < -6 || p[1] > H + 6) {
continue;
}
const r = 0.5 + 1.9 * s.m * s.m * s.m + (i < STAR_COUNT ? 0.3 : 0);
const a = 0.35 + 0.65 * clamp(p[2] * 1.2, 0, 1);
if (r > 1.5) {
glow(ctx, p[0], p[1], r * 5, s.c, 0.35 * a);
}
ctx.fillStyle = rgba(s.c, a);
ctx.beginPath();
ctx.arc(p[0], p[1], r, 0, PI2);
ctx.fill();
}
},
label() {
return inp.idle < IDLE_TICKS ? TXT_LOOK : TXT_AUTO;
},
tap() {
yaw += Math.PI / 3;
}
};
if (reduce) {
for (let i = 0; i < 60; 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 "./SfRotatingSkyDome.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';
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;
const BG: RGB = [14, 12, 32];
const STAR_RGBS: RGB[] = [[226, 238, 255], [255, 222, 196], [208, 196, 255], [196, 240, 228], [255, 206, 226]];
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: RGB, a: number): string {
return 'rgba(' + Math.round(c[0]) + ',' + Math.round(c[1]) + ',' + Math.round(c[2]) + ',' + clamp(a, 0, 1).toFixed(3) + ')';
}
function mix(a: RGB, b: RGB, k: number): RGB {
return [lerp(a[0], b[0], k), lerp(a[1], b[1], k), lerp(a[2], b[2], k)];
}
// 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;
};
}
function glow(ctx: CanvasRenderingContext2D, x: number, y: number, r: number, c: RGB, 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 paintBg(ctx: CanvasRenderingContext2D, alpha: number): void {
ctx.fillStyle = rgba(BG, alpha);
ctx.fillRect(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 YAW_RATE = 0.012;
const PITCH = 0.38;
const FOV = 150;
const STAR_COUNT = 900;
const BAND_STARS = 520;
const GRID_STEP = 72;
const NEAR_CUT = 0.08;
const TXT_AUTO = '하늘 돔이 천천히 돈다';
const TXT_LOOK = '포인터 방향으로 고개를 돌린다';
interface Sky { x: number; y: number; z: number; m: number; c: RGB; }
function makeScene(inp: Input, reduce: boolean): Scene {
const rnd = lcg(450606);
const stars: Sky[] = [];
// 구면 위 고른 분포 — 높이 z 를 -1 이상 1 이하에서 고르게, 방위각도 고르게
for (let i = 0; i < STAR_COUNT; i += 1) {
const zz = rnd() * 2 - 1;
const ph = rnd() * PI2;
const rr = Math.sqrt(1 - zz * zz);
stars.push({ x: rr * Math.cos(ph), y: zz, z: rr * Math.sin(ph), m: rnd(), c: STAR_RGBS[i % STAR_RGBS.length] });
}
// 은하수 띠 — 기울어진 큰 원 둘레에 좁게 모은 별
const tilt = 0.6;
for (let i = 0; i < BAND_STARS; i += 1) {
const ph = rnd() * PI2;
const lat = (rnd() + rnd() + rnd() - 1.5) * 0.2;
const bx = Math.cos(lat) * Math.cos(ph);
const by = Math.sin(lat);
const bz = Math.cos(lat) * Math.sin(ph);
stars.push({ x: bx, y: by * Math.cos(tilt) - bz * Math.sin(tilt), z: by * Math.sin(tilt) + bz * Math.cos(tilt), m: rnd() * 0.5, c: STAR_RGBS[2] });
}
let yaw = 0;
let pitch = PITCH;
let t = 0;
let look = 0;
let lookP = 0;
function project(x: number, y: number, z: number, cy: number, sy: number, cp: number, sp: number): [number, number, number] {
const x1 = x * cy + z * sy;
const z1 = -x * sy + z * cy;
const y2 = y * cp - z1 * sp;
const z2 = y * sp + z1 * cp;
return [W / 2 + FOV * x1 / z2, H / 2 - FOV * y2 / z2, z2];
}
const scene: Scene = {
step(): void {
t += 1;
let ly = 0;
let lp = 0.22 * Math.sin(t * 0.008);
if (inp.idle < IDLE_TICKS) {
ly = (inp.x - W / 2) / W * 1.6;
lp = (H / 2 - inp.y) / H * 0.9;
}
look = lerp(look, ly, 0.06);
lookP = lerp(lookP, lp, 0.06);
yaw += YAW_RATE;
pitch = PITCH + lookP;
},
draw(ctx: CanvasRenderingContext2D): void {
paintBg(ctx, 1);
const cyw = Math.cos(yaw + look);
const syw = Math.sin(yaw + look);
const cp = Math.cos(pitch);
const sp = Math.sin(pitch);
// 위도선과 경선 — 점으로만 그려 돌아가는 방향이 보이게
ctx.fillStyle = rgba([208, 196, 255], 0.55);
for (let la = -60; la <= 60; la += 30) {
const rl = Math.cos(la * Math.PI / 180);
const yl = Math.sin(la * Math.PI / 180);
for (let a = 0; a < 360; a += 5) {
const p = project(rl * Math.cos(a * Math.PI / 180), yl, rl * Math.sin(a * Math.PI / 180), cyw, syw, cp, sp);
if (p[2] > NEAR_CUT) {
ctx.fillRect(p[0] - 0.9, p[1] - 0.9, 1.9, 1.9);
}
}
}
for (let me = 0; me < 360; me += GRID_STEP / 2) {
for (let a = -80; a <= 80; a += 5) {
const rl = Math.cos(a * Math.PI / 180);
const p = project(rl * Math.cos(me * Math.PI / 180), Math.sin(a * Math.PI / 180), rl * Math.sin(me * Math.PI / 180), cyw, syw, cp, sp);
if (p[2] > NEAR_CUT) {
ctx.fillRect(p[0] - 0.9, p[1] - 0.9, 1.9, 1.9);
}
}
}
for (let i = 0; i < stars.length; i += 1) {
const s = stars[i];
const p = project(s.x, s.y, s.z, cyw, syw, cp, sp);
if (p[2] <= NEAR_CUT || p[0] < -6 || p[0] > W + 6 || p[1] < -6 || p[1] > H + 6) {
continue;
}
const r = 0.5 + 1.9 * s.m * s.m * s.m + (i < STAR_COUNT ? 0.3 : 0);
const a = 0.35 + 0.65 * clamp(p[2] * 1.2, 0, 1);
if (r > 1.5) {
glow(ctx, p[0], p[1], r * 5, s.c, 0.35 * a);
}
ctx.fillStyle = rgba(s.c, a);
ctx.beginPath();
ctx.arc(p[0], p[1], r, 0, PI2);
ctx.fill();
}
},
label(): string {
return inp.idle < IDLE_TICKS ? TXT_LOOK : TXT_AUTO;
},
tap(): void {
yaw += Math.PI / 3;
}
};
if (reduce) {
for (let i = 0; i < 60; i += 1) {
scene.step();
}
}
return scene;
}
export default function SfRotatingSkyDome() {
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="구면 위의 별을 회전 행렬로 돌려 보는 하늘 돔" />
<p className={styles.sc__status} ref={statusRef} aria-live="polite">하늘 돔이 천천히 돈다</p>
<button className={styles.sc__btn} ref={btnRef} type="button">멈춤</button>
<p className={styles.sc__caption}>구면 위의 별을 회전 행렬로 돌려 보는 하늘 돔</p>
</div>
</main>
);
}06 A Sky Dome of Stars on a Sphere Turned by a Rotation Matrix — Measured area 56.859% · moving frames 23/23Original by GODRICH · SCSS and React ship in the zip · CSS Starfield: 9 Backgrounds Stars Fly Through
The post this demo lives in
CSS Starfield: 9 Backgrounds Stars Fly ThroughA css starfield of a few CSS-animated dots has no depth and a flat constant speed — scenes 01, 02 and 05 solve it with p See all demos in this post
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