01A Signal Cycling Green, Yellow and Red on a Fixed Timetable
The signal runs on 100 green, 30 yellow and 100 red frames, and each lens brightness chases its target by 0.16 per frame, so the glow radius (78) and alpha (brightness to the 1.6 power) swell as a lamp turns on and fade as it turns off.
Best forA signal explainer or guide screen
PHASE_FRAMESYELLOW_FRAMESBLOOM_RADIUSLENS_GAMMA
<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 Signal Cycling Green, Yellow and Red on a Fixed Timetable"></canvas>
<p class="sc__status" id="scStatus" aria-live="polite">Green — go</p>
<button class="sc__btn" id="scBtn" type="button">Pause</button>
<p class="sc__caption">A Signal Cycling Green, Yellow and Red on a Fixed Timetable</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 = 1200;
const KEY_STEP = 12;
const FONT = '-apple-system, "Segoe UI", "Noto Sans KR", sans-serif';
const SIG_GREEN = 0;
const SIG_YELLOW = 1;
const SIG_RED = 2;
const GREEN_RGB = [61, 214, 140];
const YELLOW_RGB = [255, 200, 64];
const RED_RGB = [255, 92, 102];
const SIGNAL_RGBS = [GREEN_RGB, YELLOW_RGB, RED_RGB];
const SKY_RGB = [226, 238, 252];
const GRASS_RGB = [206, 236, 214];
const ROAD_RGB = [188, 192, 212];
const ROAD_EDGE_RGB = [162, 166, 192];
const MARK_RGB = [250, 250, 255];
const INK_RGB = [58, 52, 84];
const CAR_RGBS = [[255, 184, 196], [170, 208, 255], [196, 176, 255], [158, 232, 200], [255, 222, 150], [255, 196, 224]];
const TXT_GO = 'Green — go';
const TXT_READY = 'Yellow — get ready to stop';
const TXT_STOP = 'Red — stop';
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;
};
}
// 격자 점의 값 — 정수 두 개를 섞어 0..1 로 (같은 입력은 언제나 같은 값)
function hash2(ix, iy) {
let h = Math.imul(ix | 0, 374761393) + Math.imul(iy | 0, 668265263);
h = Math.imul(h ^ (h >>> 13), 1274126177);
return ((h ^ (h >>> 16)) >>> 0) / 4294967296;
}
// 2차원 값 잡음 — 네 격자 점을 부드럽게 보간
function vnoise(x, y) {
const ix = Math.floor(x);
const iy = Math.floor(y);
const fx = smooth(x - ix);
const fy = smooth(y - iy);
return lerp(lerp(hash2(ix, iy), hash2(ix + 1, iy), fx), lerp(hash2(ix, iy + 1), hash2(ix + 1, iy + 1), fx), fy);
}
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 rrect(ctx, x, y, w, h, r) {
const rr = Math.min(r, w / 2, h / 2);
ctx.beginPath();
ctx.moveTo(x + rr, y);
ctx.arcTo(x + w, y, x + w, y + h, rr);
ctx.arcTo(x + w, y + h, x, y + h, rr);
ctx.arcTo(x, y + h, x, y, rr);
ctx.arcTo(x, y, x + w, y, rr);
ctx.closePath();
}
// 주기 [초록, 노랑, 빨강] 프레임 수에서 프레임 f 의 신호 상태
function phaseAt(f, g, y, r) {
const total = g + y + r;
const m = ((f % total) + total) % total;
return m < g ? SIG_GREEN : (m < g + y ? SIG_YELLOW : SIG_RED);
}
function stateText(state) {
return state === SIG_GREEN ? TXT_GO : (state === SIG_YELLOW ? TXT_READY : TXT_STOP);
}
// 신호 상태 -> 빨강·노랑·초록 렌즈 밝기 (위에서 아래)
function litOf(state) {
return [state === SIG_RED ? 1 : 0, state === SIG_YELLOW ? 1 : 0, state === SIG_GREEN ? 1 : 0];
}
const LENS_RGBS = [RED_RGB, YELLOW_RGB, GREEN_RGB];
// 세로 신호등 머리 — 렌즈 세 개와 켜진 렌즈의 빛 번짐
function drawHead(ctx, cx, cy, r, lit) {
const step = r * 2.5;
rrect(ctx, cx - r * 1.45, cy - step - r * 1.45, r * 2.9, step * 2 + r * 2.9, r * 0.9);
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fill();
for (let i = 0; i < 3; i += 1) {
const ly = cy + (i - 1) * step;
ctx.beginPath();
ctx.arc(cx, ly, r, 0, PI2);
ctx.fillStyle = rgba(LENS_RGBS[i], 0.2 + 0.8 * lit[i]);
ctx.fill();
if (lit[i] > 0.02) {
glow(ctx, cx, ly, r * 3.2, LENS_RGBS[i], 0.55 * lit[i]);
}
}
}
// 위에서 본 차 — 앞 범퍼가 x, 가운데가 y. 제동 중이면 뒷등이 켜진다
function drawCar(ctx, x, y, len, wid, rgb, braking) {
const x0 = x - len;
rrect(ctx, x0, y - wid / 2, len, wid, 6);
ctx.fillStyle = rgba(rgb, 1);
ctx.fill();
rrect(ctx, x - len * 0.62, y - wid / 2 + 3, len * 0.34, wid - 6, 3);
ctx.fillStyle = 'rgba(255,255,255,0.62)';
ctx.fill();
ctx.fillStyle = 'rgba(255,248,214,1)';
ctx.fillRect(x - 3, y - wid / 2 + 2, 3, 4);
ctx.fillRect(x - 3, y + wid / 2 - 6, 3, 4);
ctx.fillStyle = braking ? rgba(RED_RGB, 1) : 'rgba(150,120,150,0.8)';
ctx.fillRect(x0, y - wid / 2 + 2, 3, 4);
ctx.fillRect(x0, y + wid / 2 - 6, 3, 4);
if (braking) {
glow(ctx, x0, y, 12, RED_RGB, 0.45);
}
}
// 한 줄 도로 장면의 바탕 — 잔디 위에 도로띠 하나, 정지선과 횡단보도
function drawLaneBackdrop(ctx, roadY, roadH, stopX, seedTrees) {
ctx.fillStyle = rgba(GRASS_RGB, 1);
ctx.fillRect(0, 0, W, H);
const rnd = mulberry32(seedTrees);
for (let i = 0; i < 14; i += 1) {
const tx = 16 + rnd() * (W - 32);
const up = rnd() < 0.5;
const ty = up ? roadY - roadH / 2 - 22 - rnd() * 26 : roadY + roadH / 2 + 22 + rnd() * 26;
ctx.beginPath();
ctx.arc(tx, ty, 9 + rnd() * 6, 0, PI2);
ctx.fillStyle = 'rgba(160,214,184,0.9)';
ctx.fill();
}
ctx.fillStyle = rgba(ROAD_RGB, 1);
ctx.fillRect(0, roadY - roadH / 2, W, roadH);
ctx.fillStyle = rgba(ROAD_EDGE_RGB, 1);
ctx.fillRect(0, roadY - roadH / 2, W, 2);
ctx.fillRect(0, roadY + roadH / 2 - 2, W, 2);
ctx.fillStyle = rgba(MARK_RGB, 0.8);
for (let x = 6; x < W; x += 36) {
ctx.fillRect(x, roadY - 1, 18, 2);
}
for (let k = 0; k < 5; k += 1) {
ctx.fillRect(stopX + 5, roadY - roadH / 2 + 3 + k * (roadH - 6) / 5, 12, (roadH - 6) / 5 - 3);
}
ctx.fillRect(stopX - 2, roadY - roadH / 2, 3, roadH);
}
// 한 줄 차량 흐름 — 앞차 간격(IDM)과 정지선을 같은 식으로 다룬다. 차는 앞쪽부터 0번이다
class Lane {
constructor(seed, p) {
this.cars = [];
this.nextAt = 0;
this.made = 0;
this.p = p;
this.rnd = mulberry32(seed);
}
accelFor(v, s, vL, g0) {
const p = this.p;
const sStar = g0 + Math.max(0, v * p.headway + v * (v - vL) / (2 * Math.sqrt(p.accel * p.brake)));
return p.accel * (1 - Math.pow(v / p.vmax, p.delta) - Math.pow(sStar / Math.max(s, 0.5), 2));
}
// f 프레임에, 뒤쪽이 비어 있고 때가 됐으면 한 대 들여보낸다
maybeSpawn(f, minGap, maxGap, v0) {
if (f < this.nextAt) {
return false;
}
const last = this.cars.length > 0 ? this.cars[this.cars.length - 1] : null;
if (last && last.x - last.len < this.p.gap + 10) {
return false;
}
const rgb = CAR_RGBS[this.made % CAR_RGBS.length];
this.cars.push({ x: -2, v: v0, len: this.p.len, rgb: rgb, go: false, decided: false, sigK: -1, brake: false, id: this.made });
this.made += 1;
this.nextAt = f + minGap + Math.floor(this.rnd() * (maxGap - minGap + 1));
return true;
}
// 신호 목록은 x 오름차순. 한 번 호출 = 한 프레임. 정지선을 넘은 차(detect 용) id 를 돌려준다
step(sigs, onCross, watchX) {
const p = this.p;
for (let i = 0; i < this.cars.length; i += 1) {
const c = this.cars[i];
let acc = this.accelFor(c.v, 1e6, c.v, p.gap);
if (i > 0) {
const L = this.cars[i - 1];
acc = Math.min(acc, this.accelFor(c.v, (L.x - L.len) - c.x, L.v, p.gap));
}
let k = -1;
for (let j = 0; j < sigs.length; j += 1) {
if (sigs[j].x >= c.x) {
k = j;
break;
}
}
let clampX = 1e9;
if (k >= 0) {
const sg = sigs[k];
if (c.sigK !== k) {
c.sigK = k;
c.decided = false;
c.go = false;
}
if (sg.state === SIG_GREEN) {
c.decided = false;
c.go = false;
}
else {
if (!c.decided) {
c.decided = true;
c.go = c.v * c.v / (2 * p.brake) > sg.x - c.x;
}
if (!c.go) {
acc = Math.min(acc, this.accelFor(c.v, sg.x - c.x - 2, 0, p.lineGap));
clampX = sg.x - 1.5;
}
}
}
acc = Math.max(acc, -p.brake * 3);
const prevX = c.x;
c.v = Math.max(0, c.v + acc);
c.x += c.v;
if (c.x > clampX && prevX <= clampX) {
c.x = clampX;
c.v = 0;
}
c.brake = acc < -0.012 || c.v < 0.05;
if (prevX < watchX && c.x >= watchX) {
onCross(c, watchX);
}
}
while (this.cars.length > 0 && this.cars[0].x - this.cars[0].len > W + 20) {
this.cars.shift();
}
}
// 정지선 뒤에서 서 있는 차 수
waiting(stopX) {
let n = 0;
for (let i = 0; i < this.cars.length; i += 1) {
const c = this.cars[i];
if (c.v < 0.25 && c.x < stopX + 2 && c.x > stopX - 260) {
n += 1;
}
}
return n;
}
}
function main(rootEl, canvas, statusEl, btnEl) {
const ctx0 = canvas.getContext('2d');
if (!ctx0) {
return function () { return; };
}
canvas.width = W;
canvas.height = H;
const reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const scene = makeScene(ctx0, reduce);
if (reduce) {
rootEl.classList.remove('is-demo');
}
let paused = false;
let rafId = 0;
let lastTs = null;
let accMs = 0;
let lastLabel = '';
let px = W / 2;
let py = H / 2;
const cleaners = [];
function listen(target, type, fn) {
target.addEventListener(type, fn);
cleaners.push(function () { target.removeEventListener(type, fn); });
}
function show() {
scene.draw();
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) {
scene.step();
}
}
function setButton() {
btnEl.textContent = reduce ? 'Next scene' : (paused ? 'Play' : 'Pause');
}
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 moved() {
if (scene.point) {
scene.point(px, py);
}
if (reduce) {
show();
}
}
function onButton() {
if (reduce) {
advance(REDUCE_STEP_MS);
show();
return;
}
paused = !paused;
if (paused) {
rootEl.classList.remove('is-demo');
}
else {
rootEl.classList.add('is-demo');
}
setButton();
}
function onAction() {
if (scene.tap) {
scene.tap();
if (reduce) {
show();
}
return;
}
onButton();
}
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) {
scene.step();
accMs -= FIXED_DT;
}
show();
}
rafId = requestAnimationFrame(tick);
}
listen(btnEl, 'click', function () { onButton(); });
listen(canvas, 'pointerdown', function (e) {
const p = toLocal(e);
px = p[0];
py = p[1];
moved();
if (scene.tap) {
scene.tap();
if (reduce) {
show();
}
}
});
listen(canvas, 'pointermove', function (e) {
const p = toLocal(e);
px = p[0];
py = p[1];
moved();
});
listen(canvas, 'keydown', function (e) {
const k = e.key;
if (k === 'Enter' || k === ' ') {
e.preventDefault();
onAction();
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();
px = clamp(px + dx, 0, W);
py = clamp(py + dy, 0, H);
moved();
});
advance(REDUCE_START_MS);
setButton();
show();
if (!reduce) {
rafId = requestAnimationFrame(tick);
}
function destroy() {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) {
cleaners[i]();
}
}
return destroy;
}
const PHASE_FRAMES = 100;
const YELLOW_FRAMES = 30;
const BLOOM_RADIUS = 78;
const LENS_GAMMA = 1.6;
const LIT_RISE = 0.16;
const START_FRAME = 70;
const HEAD_X = 240;
const HEAD_Y = 112;
const LENS_R = 21;
const BAR_X = 60;
const BAR_W = 360;
const BAR_Y = 238;
function makeScene(ctx, reduce) {
const cycle = PHASE_FRAMES * 2 + YELLOW_FRAMES;
let f = START_FRAME;
const lit = [0, 0, 1];
if (reduce) {
lit[0] = 0;
}
function state() { return phaseAt(f, PHASE_FRAMES, YELLOW_FRAMES, PHASE_FRAMES); }
// 켜지는 쪽은 부풀고 꺼지는 쪽은 잦아든다 — 목표 밝기를 향해 한 프레임에 LIT_RISE 만큼
function relax() {
const t = litOf(state());
for (let i = 0; i < 3; i += 1) {
lit[i] += (t[i] - lit[i]) * (reduce ? 1 : LIT_RISE);
}
}
function segX(frame) { return BAR_X + BAR_W * frame / cycle; }
const scene = {
step: function () {
f += 1;
relax();
},
label: function () { return stateText(state()); },
draw: function () {
ctx.fillStyle = rgba(SKY_RGB, 1);
ctx.fillRect(0, 0, W, H);
for (let i = 0; i < 3; i += 1) {
glow(ctx, HEAD_X, HEAD_Y + (i - 1) * LENS_R * 2.5, 260, LENS_RGBS[i], 0.26 * lit[i]);
}
ctx.fillStyle = rgba(GRASS_RGB, 1);
ctx.fillRect(0, 214, W, 86);
ctx.fillStyle = rgba(ROAD_RGB, 1);
ctx.fillRect(0, 214, W, 14);
// 기둥
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fillRect(HEAD_X - 4, HEAD_Y + LENS_R * 3.6, 8, 214 - (HEAD_Y + LENS_R * 3.6));
// 바닥에 떨어지는 빛 웅덩이 — 켜진 렌즈 색이 번진다
for (let i = 0; i < 3; i += 1) {
if (lit[i] > 0.02) {
ctx.save();
ctx.translate(HEAD_X, 221);
ctx.scale(2.6, 0.3);
glow(ctx, 0, 0, 60, LENS_RGBS[i], 0.8 * lit[i]);
ctx.restore();
}
}
// 렌즈 — 알파는 밝기^LENS_GAMMA, 번짐 반경은 켜진 정도에 따라 자란다
rrect(ctx, HEAD_X - LENS_R * 1.45, HEAD_Y - LENS_R * 2.5 - LENS_R * 1.45, LENS_R * 2.9, LENS_R * 5 + LENS_R * 2.9, LENS_R * 0.9);
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fill();
for (let i = 0; i < 3; i += 1) {
const ly = HEAD_Y + (i - 1) * LENS_R * 2.5;
const a = Math.pow(lit[i], LENS_GAMMA);
ctx.beginPath();
ctx.arc(HEAD_X, ly, LENS_R, 0, PI2);
ctx.fillStyle = rgba(LENS_RGBS[i], 0.2 + 0.8 * a);
ctx.fill();
if (lit[i] > 0.02) {
glow(ctx, HEAD_X, ly, BLOOM_RADIUS * (0.35 + 0.65 * lit[i]), LENS_RGBS[i], 0.78 * a);
glow(ctx, HEAD_X - 6, ly - 6, LENS_R * 0.8, [255, 255, 255], 0.7 * a);
}
}
// 시간표 막대 — 초록 · 노랑 · 빨강 구간과 지금 위치
const g1 = segX(PHASE_FRAMES);
const y1 = segX(PHASE_FRAMES + YELLOW_FRAMES);
ctx.fillStyle = rgba(GREEN_RGB, 1);
rrect(ctx, BAR_X, BAR_Y, g1 - BAR_X, 12, 4);
ctx.fill();
ctx.fillStyle = rgba(YELLOW_RGB, 1);
ctx.fillRect(g1, BAR_Y, y1 - g1, 12);
ctx.fillStyle = rgba(RED_RGB, 1);
rrect(ctx, y1, BAR_Y, BAR_X + BAR_W - y1, 12, 4);
ctx.fill();
const m = ((f % cycle) + cycle) % cycle;
const cx = segX(m);
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fillRect(cx - 2, BAR_Y - 8, 4, 28);
ctx.beginPath();
ctx.arc(cx, BAR_Y - 8, 5, 0, PI2);
ctx.fill();
}
};
for (let i = 0; i < 40; i += 1) {
relax();
}
return scene;
}
main(document.getElementById('scRoot'), document.getElementById('scCanvas'), document.getElementById('scStatus'), document.getElementById('scBtn'));
})();import { useEffect, useRef } from "react";
import styles from "./TlSignalPhaseTimelineBloom.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 = 1200;
const KEY_STEP = 12;
const FONT = '-apple-system, "Segoe UI", "Noto Sans KR", sans-serif';
const SIG_GREEN = 0;
const SIG_YELLOW = 1;
const SIG_RED = 2;
const GREEN_RGB = [61, 214, 140];
const YELLOW_RGB = [255, 200, 64];
const RED_RGB = [255, 92, 102];
const SIGNAL_RGBS = [GREEN_RGB, YELLOW_RGB, RED_RGB];
const SKY_RGB = [226, 238, 252];
const GRASS_RGB = [206, 236, 214];
const ROAD_RGB = [188, 192, 212];
const ROAD_EDGE_RGB = [162, 166, 192];
const MARK_RGB = [250, 250, 255];
const INK_RGB = [58, 52, 84];
const CAR_RGBS = [[255, 184, 196], [170, 208, 255], [196, 176, 255], [158, 232, 200], [255, 222, 150], [255, 196, 224]];
const TXT_GO = '초록불 — 진행';
const TXT_READY = '노란불 — 정지 준비';
const TXT_STOP = '빨간불 — 정지';
type Pt = [number, number];
interface Scene {
step(): void;
draw(): void;
label(): string;
point?(x: number, y: number): void;
tap?(): 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;
};
}
// 격자 점의 값 — 정수 두 개를 섞어 0..1 로 (같은 입력은 언제나 같은 값)
function hash2(ix: number, iy: number): number {
let h = Math.imul(ix | 0, 374761393) + Math.imul(iy | 0, 668265263);
h = Math.imul(h ^ (h >>> 13), 1274126177);
return ((h ^ (h >>> 16)) >>> 0) / 4294967296;
}
// 2차원 값 잡음 — 네 격자 점을 부드럽게 보간
function vnoise(x: number, y: number): number {
const ix = Math.floor(x);
const iy = Math.floor(y);
const fx = smooth(x - ix);
const fy = smooth(y - iy);
return lerp(lerp(hash2(ix, iy), hash2(ix + 1, iy), fx), lerp(hash2(ix, iy + 1), hash2(ix + 1, iy + 1), fx), fy);
}
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 rrect(ctx: CanvasRenderingContext2D, x: number, y: number, w: number, h: number, r: number): void {
const rr = Math.min(r, w / 2, h / 2);
ctx.beginPath();
ctx.moveTo(x + rr, y);
ctx.arcTo(x + w, y, x + w, y + h, rr);
ctx.arcTo(x + w, y + h, x, y + h, rr);
ctx.arcTo(x, y + h, x, y, rr);
ctx.arcTo(x, y, x + w, y, rr);
ctx.closePath();
}
// 주기 [초록, 노랑, 빨강] 프레임 수에서 프레임 f 의 신호 상태
function phaseAt(f: number, g: number, y: number, r: number): number {
const total = g + y + r;
const m = ((f % total) + total) % total;
return m < g ? SIG_GREEN : (m < g + y ? SIG_YELLOW : SIG_RED);
}
function stateText(state: number): string {
return state === SIG_GREEN ? TXT_GO : (state === SIG_YELLOW ? TXT_READY : TXT_STOP);
}
// 신호 상태 -> 빨강·노랑·초록 렌즈 밝기 (위에서 아래)
function litOf(state: number): number[] {
return [state === SIG_RED ? 1 : 0, state === SIG_YELLOW ? 1 : 0, state === SIG_GREEN ? 1 : 0];
}
const LENS_RGBS = [RED_RGB, YELLOW_RGB, GREEN_RGB];
// 세로 신호등 머리 — 렌즈 세 개와 켜진 렌즈의 빛 번짐
function drawHead(ctx: CanvasRenderingContext2D, cx: number, cy: number, r: number, lit: number[]): void {
const step = r * 2.5;
rrect(ctx, cx - r * 1.45, cy - step - r * 1.45, r * 2.9, step * 2 + r * 2.9, r * 0.9);
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fill();
for (let i = 0; i < 3; i += 1) {
const ly = cy + (i - 1) * step;
ctx.beginPath();
ctx.arc(cx, ly, r, 0, PI2);
ctx.fillStyle = rgba(LENS_RGBS[i], 0.2 + 0.8 * lit[i]);
ctx.fill();
if (lit[i] > 0.02) {
glow(ctx, cx, ly, r * 3.2, LENS_RGBS[i], 0.55 * lit[i]);
}
}
}
// 위에서 본 차 — 앞 범퍼가 x, 가운데가 y. 제동 중이면 뒷등이 켜진다
function drawCar(ctx: CanvasRenderingContext2D, x: number, y: number, len: number, wid: number, rgb: number[], braking: boolean): void {
const x0 = x - len;
rrect(ctx, x0, y - wid / 2, len, wid, 6);
ctx.fillStyle = rgba(rgb, 1);
ctx.fill();
rrect(ctx, x - len * 0.62, y - wid / 2 + 3, len * 0.34, wid - 6, 3);
ctx.fillStyle = 'rgba(255,255,255,0.62)';
ctx.fill();
ctx.fillStyle = 'rgba(255,248,214,1)';
ctx.fillRect(x - 3, y - wid / 2 + 2, 3, 4);
ctx.fillRect(x - 3, y + wid / 2 - 6, 3, 4);
ctx.fillStyle = braking ? rgba(RED_RGB, 1) : 'rgba(150,120,150,0.8)';
ctx.fillRect(x0, y - wid / 2 + 2, 3, 4);
ctx.fillRect(x0, y + wid / 2 - 6, 3, 4);
if (braking) {
glow(ctx, x0, y, 12, RED_RGB, 0.45);
}
}
// 한 줄 도로 장면의 바탕 — 잔디 위에 도로띠 하나, 정지선과 횡단보도
function drawLaneBackdrop(ctx: CanvasRenderingContext2D, roadY: number, roadH: number, stopX: number, seedTrees: number): void {
ctx.fillStyle = rgba(GRASS_RGB, 1);
ctx.fillRect(0, 0, W, H);
const rnd = mulberry32(seedTrees);
for (let i = 0; i < 14; i += 1) {
const tx = 16 + rnd() * (W - 32);
const up = rnd() < 0.5;
const ty = up ? roadY - roadH / 2 - 22 - rnd() * 26 : roadY + roadH / 2 + 22 + rnd() * 26;
ctx.beginPath();
ctx.arc(tx, ty, 9 + rnd() * 6, 0, PI2);
ctx.fillStyle = 'rgba(160,214,184,0.9)';
ctx.fill();
}
ctx.fillStyle = rgba(ROAD_RGB, 1);
ctx.fillRect(0, roadY - roadH / 2, W, roadH);
ctx.fillStyle = rgba(ROAD_EDGE_RGB, 1);
ctx.fillRect(0, roadY - roadH / 2, W, 2);
ctx.fillRect(0, roadY + roadH / 2 - 2, W, 2);
ctx.fillStyle = rgba(MARK_RGB, 0.8);
for (let x = 6; x < W; x += 36) {
ctx.fillRect(x, roadY - 1, 18, 2);
}
for (let k = 0; k < 5; k += 1) {
ctx.fillRect(stopX + 5, roadY - roadH / 2 + 3 + k * (roadH - 6) / 5, 12, (roadH - 6) / 5 - 3);
}
ctx.fillRect(stopX - 2, roadY - roadH / 2, 3, roadH);
}
interface Car { x: number; v: number; len: number; rgb: number[]; go: boolean; decided: boolean; sigK: number; brake: boolean; id: number; }
interface Sig { x: number; state: number; }
interface LaneParams { accel: number; brake: number; gap: number; lineGap: number; vmax: number; headway: number; delta: number; len: number; }
// 한 줄 차량 흐름 — 앞차 간격(IDM)과 정지선을 같은 식으로 다룬다. 차는 앞쪽부터 0번이다
class Lane {
cars: Car[] = [];
p: LaneParams;
rnd: () => number;
nextAt = 0;
made = 0;
constructor(seed: number, p: LaneParams) {
this.p = p;
this.rnd = mulberry32(seed);
}
accelFor(v: number, s: number, vL: number, g0: number): number {
const p = this.p;
const sStar = g0 + Math.max(0, v * p.headway + v * (v - vL) / (2 * Math.sqrt(p.accel * p.brake)));
return p.accel * (1 - Math.pow(v / p.vmax, p.delta) - Math.pow(sStar / Math.max(s, 0.5), 2));
}
// f 프레임에, 뒤쪽이 비어 있고 때가 됐으면 한 대 들여보낸다
maybeSpawn(f: number, minGap: number, maxGap: number, v0: number): boolean {
if (f < this.nextAt) { return false; }
const last = this.cars.length > 0 ? this.cars[this.cars.length - 1] : null;
if (last && last.x - last.len < this.p.gap + 10) { return false; }
const rgb = CAR_RGBS[this.made % CAR_RGBS.length];
this.cars.push({ x: -2, v: v0, len: this.p.len, rgb: rgb, go: false, decided: false, sigK: -1, brake: false, id: this.made });
this.made += 1;
this.nextAt = f + minGap + Math.floor(this.rnd() * (maxGap - minGap + 1));
return true;
}
// 신호 목록은 x 오름차순. 한 번 호출 = 한 프레임. 정지선을 넘은 차(detect 용) id 를 돌려준다
step(sigs: Sig[], onCross: (c: Car, x: number) => void, watchX: number): void {
const p = this.p;
for (let i = 0; i < this.cars.length; i += 1) {
const c = this.cars[i];
let acc = this.accelFor(c.v, 1e6, c.v, p.gap);
if (i > 0) {
const L = this.cars[i - 1];
acc = Math.min(acc, this.accelFor(c.v, (L.x - L.len) - c.x, L.v, p.gap));
}
let k = -1;
for (let j = 0; j < sigs.length; j += 1) {
if (sigs[j].x >= c.x) { k = j; break; }
}
let clampX = 1e9;
if (k >= 0) {
const sg = sigs[k];
if (c.sigK !== k) { c.sigK = k; c.decided = false; c.go = false; }
if (sg.state === SIG_GREEN) {
c.decided = false;
c.go = false;
} else {
if (!c.decided) {
c.decided = true;
c.go = c.v * c.v / (2 * p.brake) > sg.x - c.x;
}
if (!c.go) {
acc = Math.min(acc, this.accelFor(c.v, sg.x - c.x - 2, 0, p.lineGap));
clampX = sg.x - 1.5;
}
}
}
acc = Math.max(acc, -p.brake * 3);
const prevX = c.x;
c.v = Math.max(0, c.v + acc);
c.x += c.v;
if (c.x > clampX && prevX <= clampX) {
c.x = clampX;
c.v = 0;
}
c.brake = acc < -0.012 || c.v < 0.05;
if (prevX < watchX && c.x >= watchX) { onCross(c, watchX); }
}
while (this.cars.length > 0 && this.cars[0].x - this.cars[0].len > W + 20) {
this.cars.shift();
}
}
// 정지선 뒤에서 서 있는 차 수
waiting(stopX: number): number {
let n = 0;
for (let i = 0; i < this.cars.length; i += 1) {
const c = this.cars[i];
if (c.v < 0.25 && c.x < stopX + 2 && c.x > stopX - 260) { n += 1; }
}
return n;
}
}
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 reduce = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
const scene = makeScene(ctx0, reduce);
if (reduce) { rootEl.classList.remove('is-demo'); }
let paused = false;
let rafId = 0;
let lastTs: number | null = null;
let accMs = 0;
let lastLabel = '';
let px = W / 2;
let py = H / 2;
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();
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) { scene.step(); }
}
function setButton(): void {
btnEl.textContent = reduce ? '다음 장면' : (paused ? '재생' : '멈춤');
}
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 moved(): void {
if (scene.point) { scene.point(px, py); }
if (reduce) { show(); }
}
function onButton(): void {
if (reduce) {
advance(REDUCE_STEP_MS);
show();
return;
}
paused = !paused;
if (paused) { rootEl.classList.remove('is-demo'); } else { rootEl.classList.add('is-demo'); }
setButton();
}
function onAction(): void {
if (scene.tap) {
scene.tap();
if (reduce) { show(); }
return;
}
onButton();
}
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) {
scene.step();
accMs -= FIXED_DT;
}
show();
}
rafId = requestAnimationFrame(tick);
}
listen(btnEl, 'click', function (): void { onButton(); });
listen(canvas, 'pointerdown', function (e: Event): void {
const p = toLocal(e as PointerEvent);
px = p[0];
py = p[1];
moved();
if (scene.tap) {
scene.tap();
if (reduce) { show(); }
}
});
listen(canvas, 'pointermove', function (e: Event): void {
const p = toLocal(e as PointerEvent);
px = p[0];
py = p[1];
moved();
});
listen(canvas, 'keydown', function (e: Event): void {
const k = (e as KeyboardEvent).key;
if (k === 'Enter' || k === ' ') {
e.preventDefault();
onAction();
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();
px = clamp(px + dx, 0, W);
py = clamp(py + dy, 0, H);
moved();
});
advance(REDUCE_START_MS);
setButton();
show();
if (!reduce) {
rafId = requestAnimationFrame(tick);
}
function destroy(): void {
cancelAnimationFrame(rafId);
for (let i = 0; i < cleaners.length; i += 1) { cleaners[i](); }
}
return destroy;
}
const PHASE_FRAMES = 100;
const YELLOW_FRAMES = 30;
const BLOOM_RADIUS = 78;
const LENS_GAMMA = 1.6;
const LIT_RISE = 0.16;
const START_FRAME = 70;
const HEAD_X = 240;
const HEAD_Y = 112;
const LENS_R = 21;
const BAR_X = 60;
const BAR_W = 360;
const BAR_Y = 238;
function makeScene(ctx: CanvasRenderingContext2D, reduce: boolean): Scene {
const cycle = PHASE_FRAMES * 2 + YELLOW_FRAMES;
let f = START_FRAME;
const lit = [0, 0, 1];
if (reduce) { lit[0] = 0; }
function state(): number { return phaseAt(f, PHASE_FRAMES, YELLOW_FRAMES, PHASE_FRAMES); }
// 켜지는 쪽은 부풀고 꺼지는 쪽은 잦아든다 — 목표 밝기를 향해 한 프레임에 LIT_RISE 만큼
function relax(): void {
const t = litOf(state());
for (let i = 0; i < 3; i += 1) {
lit[i] += (t[i] - lit[i]) * (reduce ? 1 : LIT_RISE);
}
}
function segX(frame: number): number { return BAR_X + BAR_W * frame / cycle; }
const scene: Scene = {
step: function (): void {
f += 1;
relax();
},
label: function (): string { return stateText(state()); },
draw: function (): void {
ctx.fillStyle = rgba(SKY_RGB, 1);
ctx.fillRect(0, 0, W, H);
for (let i = 0; i < 3; i += 1) {
glow(ctx, HEAD_X, HEAD_Y + (i - 1) * LENS_R * 2.5, 260, LENS_RGBS[i], 0.26 * lit[i]);
}
ctx.fillStyle = rgba(GRASS_RGB, 1);
ctx.fillRect(0, 214, W, 86);
ctx.fillStyle = rgba(ROAD_RGB, 1);
ctx.fillRect(0, 214, W, 14);
// 기둥
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fillRect(HEAD_X - 4, HEAD_Y + LENS_R * 3.6, 8, 214 - (HEAD_Y + LENS_R * 3.6));
// 바닥에 떨어지는 빛 웅덩이 — 켜진 렌즈 색이 번진다
for (let i = 0; i < 3; i += 1) {
if (lit[i] > 0.02) {
ctx.save();
ctx.translate(HEAD_X, 221);
ctx.scale(2.6, 0.3);
glow(ctx, 0, 0, 60, LENS_RGBS[i], 0.8 * lit[i]);
ctx.restore();
}
}
// 렌즈 — 알파는 밝기^LENS_GAMMA, 번짐 반경은 켜진 정도에 따라 자란다
rrect(ctx, HEAD_X - LENS_R * 1.45, HEAD_Y - LENS_R * 2.5 - LENS_R * 1.45, LENS_R * 2.9, LENS_R * 5 + LENS_R * 2.9, LENS_R * 0.9);
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fill();
for (let i = 0; i < 3; i += 1) {
const ly = HEAD_Y + (i - 1) * LENS_R * 2.5;
const a = Math.pow(lit[i], LENS_GAMMA);
ctx.beginPath();
ctx.arc(HEAD_X, ly, LENS_R, 0, PI2);
ctx.fillStyle = rgba(LENS_RGBS[i], 0.2 + 0.8 * a);
ctx.fill();
if (lit[i] > 0.02) {
glow(ctx, HEAD_X, ly, BLOOM_RADIUS * (0.35 + 0.65 * lit[i]), LENS_RGBS[i], 0.78 * a);
glow(ctx, HEAD_X - 6, ly - 6, LENS_R * 0.8, [255, 255, 255], 0.7 * a);
}
}
// 시간표 막대 — 초록 · 노랑 · 빨강 구간과 지금 위치
const g1 = segX(PHASE_FRAMES);
const y1 = segX(PHASE_FRAMES + YELLOW_FRAMES);
ctx.fillStyle = rgba(GREEN_RGB, 1);
rrect(ctx, BAR_X, BAR_Y, g1 - BAR_X, 12, 4);
ctx.fill();
ctx.fillStyle = rgba(YELLOW_RGB, 1);
ctx.fillRect(g1, BAR_Y, y1 - g1, 12);
ctx.fillStyle = rgba(RED_RGB, 1);
rrect(ctx, y1, BAR_Y, BAR_X + BAR_W - y1, 12, 4);
ctx.fill();
const m = ((f % cycle) + cycle) % cycle;
const cx = segX(m);
ctx.fillStyle = rgba(INK_RGB, 1);
ctx.fillRect(cx - 2, BAR_Y - 8, 4, 28);
ctx.beginPath();
ctx.arc(cx, BAR_Y - 8, 5, 0, PI2);
ctx.fill();
}
};
for (let i = 0; i < 40; i += 1) { relax(); }
return scene;
}
export default function TlSignalPhaseTimelineBloom() {
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="녹색·황색·적색이 시간표대로 넘어가는 신호등" />
<p className={styles.sc__status} ref={statusRef} aria-live="polite">초록불 — 진행</p>
<button className={styles.sc__btn} ref={btnRef} type="button">멈춤</button>
<p className={styles.sc__caption}>녹색·황색·적색이 시간표대로 넘어가는 신호등</p>
</div>
</main>
);
}01 A Signal Cycling Green, Yellow and Red on a Fixed Timetable — Measured area 45.421% · moving frames 23/23Original by GODRICH · SCSS and React ship in the zip · Traffic Light CSS: 9 Demos With Queues and Waves
The post this demo lives in
Traffic Light CSS: 9 Demos With Queues and WavesA traffic light css built as a color-swapping timer lets cars roll through red, signals drift out of step and pedestrian See all demos in this post
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