05A Maze Where a Spreading Wave Computes the Distance to Every Cell
Starting at the entrance it spreads one ring of neighbors at a time, writing the arrival count as each cell's distance. The whole board becomes a heat map of distance, and the largest value marks the farthest room.
Best forDifficulty maps and stats widgets
FLOOD_STEP_MSHEAT_MAX_DRING_ALPHA
<main class="stage">
<div class="hs is-demo" id="hs">
<canvas class="hs__canvas" data-role="canvas" width="480" height="300" tabindex="0" aria-label="A maze where a wave spreading one ring at a time from the entrance writes each cell's distance as a heat map and marks the farthest room. Press a cell to spread from there"></canvas>
<p class="hs__status" data-role="status" aria-live="off">Spreading from the entrance one ring at a time</p>
<div class="hs__tools">
<button class="hs__btn" data-role="far" type="button">From farthest room</button>
<button class="hs__btn" data-role="new" type="button">New maze</button>
</div>
</div>
</main>@use "../../../../site/static/demo-tokens" as *;
@include stage($stage-ink);
.hs {
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;
}
.hs__canvas {
display: block;
width: 100%;
height: 100%;
cursor: crosshair;
}
.hs__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, .85);
outline-offset: -6px;
}
.hs__status {
position: absolute;
left: $sp-3;
bottom: $sp-3;
box-sizing: border-box;
max-width: 34%;
margin: 0;
padding: $sp-1 $sp-3;
border-radius: $r-control;
background: rgba(255, 255, 255, .85);
color: $subject-ink;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
// 판은 오른쪽에 있다 — 버튼은 왼쪽 위 칸에 두고, 좁으면 줄을 바꿔 판을 덮지 않는다
.hs__tools {
position: absolute;
left: $sp-3;
top: $sp-3;
box-sizing: border-box;
max-width: 34%;
display: flex;
flex-wrap: wrap;
gap: $sp-2;
}
.hs__btn {
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;
transition: background-color $dur-quick ease-out;
}
.hs__btn:hover {
background: $subject-cream;
}
.hs__btn[aria-pressed="true"] {
background: $subject-mint;
}
.hs__btn:focus-visible {
outline: 2px solid rgba(255, 255, 255, .95);
outline-offset: 2px;
}
// 손가락 가로 끌기는 이 캔버스가 받고, 세로 쓸기는 브라우저에 남겨 페이지 스크롤이 막히지 않게 한다
.hs__canvas { touch-action: pan-y; }
@media (max-width: 340px) {
.hs__btn { font-size: 10px; padding: $sp-1 $sp-2; }
.hs__status { font-size: 10px; padding: $sp-1 $sp-2; }
}
@media (prefers-reduced-motion: reduce) {
.hs__btn { transition: none; }
}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);
}
.hs {
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;
}
.hs__canvas {
display: block;
width: 100%;
height: 100%;
cursor: crosshair;
}
.hs__canvas:focus-visible {
outline: 2px solid rgba(255, 255, 255, 0.85);
outline-offset: -6px;
}
.hs__status {
position: absolute;
left: 12px;
bottom: 12px;
box-sizing: border-box;
max-width: 34%;
margin: 0;
padding: 4px 12px;
border-radius: 12px;
background: rgba(255, 255, 255, 0.85);
color: #17141a;
font-weight: 500;
font-size: 11px;
line-height: 1.4;
pointer-events: none;
}
.hs__tools {
position: absolute;
left: 12px;
top: 12px;
box-sizing: border-box;
max-width: 34%;
display: flex;
flex-wrap: wrap;
gap: 8px;
}
.hs__btn {
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;
transition: background-color 220ms ease-out;
}
.hs__btn:hover {
background: #fff7e6;
}
.hs__btn[aria-pressed=true] {
background: #4cd4a6;
}
.hs__btn:focus-visible {
outline: 2px solid rgba(255, 255, 255, 0.95);
outline-offset: 2px;
}
.hs__canvas {
touch-action: pan-y;
}
@media (max-width: 340px) {
.hs__btn {
font-size: 10px;
padding: 4px 8px;
}
.hs__status {
font-size: 10px;
padding: 4px 8px;
}
}
@media (prefers-reduced-motion: reduce) {
.hs__btn {
transition: none;
}
}(function () {
const root = document.getElementById("hs");
if (!root) return;
const W = 480;
const H = 300;
const FIXED_DT = 16;
// 파스텔 팔레트 — 어두운 무대 위에 밝은 바닥을 얹어 명도 차로 길이 읽힌다
const BG = [29, 26, 44];
const ROCK = [44, 39, 64];
const PAPER = [255, 248, 234];
const INK = [58, 48, 76];
const MINT = [126, 226, 192];
const SKY = [124, 196, 255];
const LILAC = [190, 164, 255];
const PINK = [255, 160, 190];
const PEACH = [255, 208, 168];
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)]; }
const canvasEl = root.querySelector('[data-role="canvas"]');
const statusEl = root.querySelector('[data-role="status"]');
const ctxRaw = canvasEl ? canvasEl.getContext('2d') : null;
if (!canvasEl || !ctxRaw || !statusEl) {
return;
}
const cv = canvasEl;
const ctx = ctxRaw;
const status = statusEl;
const reduceQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
const still = reduceQuery.matches;
// 자동 시연 중인가 — 사람이 처음 만지는 순간 시연을 멈추고 상태 줄을 읽어 주기 시작한다
let demo = root.classList.contains('is-demo');
function wake() {
if (!demo) {
return;
}
demo = false;
root.classList.remove('is-demo');
status.setAttribute('aria-live', 'polite');
}
function say(text) {
if (status.textContent !== text) {
status.textContent = text;
}
}
function fitCanvas() {
// 배율은 2 에서 자른다 — 배율 3 기기에서 화소가 2.25배로 늘어 프레임마다 일이 그만큼 커지지 않게
const dpr = Math.min(window.devicePixelRatio || 1, 2);
cv.width = Math.round(W * dpr);
cv.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
}
function onResize() {
fitCanvas();
draw();
}
fitCanvas();
window.addEventListener('resize', onResize);
// 화면 좌표(CSS px) → 장면 좌표(480x300). 리사이즈 뒤에도 늘 현재 크기로 다시 잰다
function toScene(ev) {
const r = cv.getBoundingClientRect();
return [((ev.clientX - r.left) / r.width) * W, ((ev.clientY - r.top) / r.height) * H];
}
// 시드 고정 난수 — 같은 시드면 같은 미로가 다시 나온다 (32비트 정수 섞기)
function makeRng(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 — 31×31 칸, 칸마다 벽 네 장을 비트 하나씩으로 든다
const GRID_N = 31;
const CELL_N = GRID_N * GRID_N;
const CS = 9;
const BOARD = GRID_N * CS;
let BX = W - 12 - BOARD;
const BY = (H - BOARD) / 2;
const ENTRY = 0;
const EXIT = CELL_N - 1;
// 방향 0 북 · 1 동 · 2 남 · 3 서 — 시계 방향 순서라 +1 이 오른쪽으로 돌기, +3 이 왼쪽으로 돌기
const DX = [0, 1, 0, -1];
const DY = [-1, 0, 1, 0];
const BIT = [1, 2, 4, 8];
const ALL_WALLS = 15;
function neighbor(i, d) {
const x = (i % GRID_N) + DX[d];
const y = Math.floor(i / GRID_N) + DY[d];
return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
}
function isOpen(walls, i, d) {
return (walls[i] & BIT[d]) === 0 && neighbor(i, d) >= 0;
}
// 벽 한 장 걷기 — 양쪽 칸의 비트를 함께 지운다 (한쪽만 지우면 길이 일방통행이 된다)
function knock(walls, i, d) {
const n = neighbor(i, d);
walls[i] &= ~BIT[d];
walls[n] &= ~BIT[(d + 2) % 4];
return n;
}
function openCount(walls, i) {
let c = 0;
for (let d = 0; d < 4; d += 1) {
if (isOpen(walls, i, d)) {
c += 1;
}
}
return c;
}
function cellX(i) { return BX + (i % GRID_N) * CS; }
function cellY(i) { return BY + Math.floor(i / GRID_N) * CS; }
function cellAt(sx, sy) {
const x = Math.floor((sx - BX) / CS);
const y = Math.floor((sy - BY) / CS);
return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
}
function fillCell(i, c, a) {
ctx.fillStyle = rgba(c, a);
ctx.fillRect(cellX(i), cellY(i), CS, CS);
}
// 벽 비트를 선분으로 — 칸마다 동·남 벽만 긋고 맨 윗줄·맨 왼줄만 북·서 벽을 더 긋는다 (같은 벽을 두 번 긋지 않는다)
function strokeWalls(walls, color, lw) {
ctx.beginPath();
for (let i = 0; i < CELL_N; i += 1) {
const x = cellX(i);
const y = cellY(i);
const w = walls[i];
if ((w & 2) !== 0) {
ctx.moveTo(x + CS, y);
ctx.lineTo(x + CS, y + CS);
}
if ((w & 4) !== 0) {
ctx.moveTo(x, y + CS);
ctx.lineTo(x + CS, y + CS);
}
if (i < GRID_N && (w & 1) !== 0) {
ctx.moveTo(x, y);
ctx.lineTo(x + CS, y);
}
if (i % GRID_N === 0 && (w & 8) !== 0) {
ctx.moveTo(x, y);
ctx.lineTo(x, y + CS);
}
}
ctx.strokeStyle = color;
ctx.lineWidth = lw;
ctx.lineCap = 'square';
ctx.stroke();
}
// 입구(왼쪽 위)·출구(오른쪽 아래) 표시 — 바깥 벽 밖에 작은 삼각형
function drawGates() {
ctx.fillStyle = rgba(MINT, 0.95);
ctx.beginPath();
ctx.moveTo(BX - 9, BY + 1);
ctx.lineTo(BX - 2, BY + CS / 2);
ctx.lineTo(BX - 9, BY + CS - 1);
ctx.closePath();
ctx.fill();
ctx.fillStyle = rgba(PINK, 0.95);
ctx.beginPath();
ctx.moveTo(BX + BOARD + 2, BY + BOARD - CS + 1);
ctx.lineTo(BX + BOARD + 9, BY + BOARD - CS / 2);
ctx.lineTo(BX + BOARD + 2, BY + BOARD - 1);
ctx.closePath();
ctx.fill();
}
// 왼쪽 칸의 수치 — 이름표 한 줄 + 값 한 줄
function panelRow(row, label, value) {
const y = 104 + row * 34;
ctx.textAlign = 'left';
ctx.textBaseline = 'alphabetic';
ctx.fillStyle = rgba(PAPER, 0.62);
ctx.font = '500 11px sans-serif';
ctx.fillText(label, 16, y);
ctx.fillStyle = rgba(PAPER, 0.96);
ctx.font = '700 15px sans-serif';
ctx.fillText(value, 16, y + 18);
}
function clearStage() {
ctx.fillStyle = rgba(BG, 1);
ctx.fillRect(0, 0, W, H);
}
function addFront(g, c) {
for (let d = 0; d < 4; d += 1) {
const n = neighbor(c, d);
if (n < 0 || g.inMaze[n] === 1 || g.inFront[n] === 1) {
continue;
}
g.inFront[n] = 1;
g.front.push(n);
}
}
function growStart(seed, start) {
const g = { walls: new Uint8Array(CELL_N).fill(ALL_WALLS), inMaze: new Uint8Array(CELL_N), inFront: new Uint8Array(CELL_N), front: [], order: new Int32Array(CELL_N).fill(-1), count: 0, last: start, rnd: makeRng(seed) };
g.inMaze[start] = 1;
g.order[start] = 0;
g.count = 1;
addFront(g, start);
return g;
}
// Frontier(판 영역에 닿은 안 Carved cells)에서 하나를 골라 이미 판 이웃 하나와 벽 한 장으로 잇는다
function growOne(g, mode) {
const len = g.front.length;
if (len === 0) {
return -1;
}
let c = 0;
if (mode === 'newest') {
c = g.front.pop();
}
else if (mode === 'oldest') {
c = g.front.shift();
}
else {
const k = Math.floor(g.rnd() * len);
c = g.front[k];
g.front[k] = g.front[len - 1];
g.front.pop();
}
g.inFront[c] = 0;
const links = [];
for (let d = 0; d < 4; d += 1) {
const n = neighbor(c, d);
if (n >= 0 && g.inMaze[n] === 1) {
links.push(d);
}
}
knock(g.walls, c, links[Math.floor(g.rnd() * links.length)]);
g.inMaze[c] = 1;
g.order[c] = g.count;
g.count += 1;
g.last = c;
addFront(g, c);
return c;
}
function growAll(seed, start, mode) {
const g = growStart(seed, start);
while (growOne(g, mode) >= 0) { /* 프론티어가 빌 때까지 */ }
return g.walls;
}
// 한 겹(같은 거리의 칸들)을 번지는 데 쓰는 시간
const FLOOD_STEP_MS = 20;
// 열지도 눈금의 바닥 — 파도가 이 거리를 넘기 전까지는 눈금을 이 값으로 고정해 초반 색이 출렁이지 않게 한다
const HEAT_MAX_D = 60;
// 지금 막 닿은 겹(파도 앞머리)을 덮는 밝기
const RING_ALPHA = 0.85;
const SEED = 464;
const HOLD_MS = 1400;
const GAP_MS = 500;
const HEAT_RAMP = [SKY, MINT, PEACH, PINK];
const TXT_FLOOD = 'Spreading from the entrance one ring at a time';
const TXT_FLOOD2 = 'Spreading again from the farthest room';
const TXT_DONE1 = 'Done — found the farthest room';
const TXT_DONE2 = 'Done — found the two rooms farthest apart';
const farBtn = root.querySelector('[data-role="far"]');
const newBtn = root.querySelector('[data-role="new"]');
let pass = 0;
let walls = growAll(SEED, Math.floor(CELL_N / 2), 'random');
let dist = new Int32Array(CELL_N).fill(-1);
let layer = [];
let front = 0;
let reached = 0;
let src = ENTRY;
let farCell = ENTRY;
let sweep = 1;
let longest = -1;
let longEnd = -1;
let stepAcc = 0;
let holdLeft = 0;
function startFlood(s, sw) {
src = s;
sweep = sw;
dist = new Int32Array(CELL_N).fill(-1);
dist[s] = 0;
layer = [s];
front = 0;
reached = 1;
farCell = s;
stepAcc = 0;
holdLeft = 0;
}
// 한 겹 번지기 — 지금 겹의 칸마다 열린 이웃 중 아직 거리가 없는 칸에 거리+1 을 적어 다음 겹을 만든다
function floodStep() {
if (layer.length === 0) {
return;
}
const next = [];
for (const c of layer) {
for (let d = 0; d < 4; d += 1) {
if (!isOpen(walls, c, d)) {
continue;
}
const n = neighbor(c, d);
if (dist[n] >= 0) {
continue;
}
dist[n] = front + 1;
next.push(n);
}
}
if (next.length === 0) {
layer = [];
if (sweep === 2) {
longest = front;
longEnd = farCell;
}
return;
}
front += 1;
layer = next;
reached += next.length;
farCell = next[next.length - 1];
}
function flooding() { return layer.length > 0; }
function report() {
if (flooding()) {
say(sweep === 2 ? TXT_FLOOD2 : TXT_FLOOD);
}
else {
say(sweep === 2 ? TXT_DONE2 : TXT_DONE1);
}
}
function flood(n) {
for (let k = 0; k < n && flooding(); k += 1) {
floodStep();
}
}
function step() {
if (!flooding()) {
return;
}
stepAcc += FIXED_DT;
while (stepAcc >= FLOOD_STEP_MS && flooding()) {
stepAcc -= FLOOD_STEP_MS;
floodStep();
}
report();
}
function settle() {
flood(CELL_N);
report();
}
// 시연 — 입구에서 번진 뒤 From farthest room 한 번 더 번진다 (가지 없는 길이 하나뿐인 미로에서 두 번째 끝이 가장 긴 길의 양 끝)
function demoTick(t) {
if (flooding() || t < 0) {
return;
}
holdLeft += FIXED_DT;
if (sweep === 1 && holdLeft >= GAP_MS) {
startFlood(farCell, 2);
}
else if (sweep === 2 && holdLeft >= HOLD_MS) {
newMaze();
}
}
function heat(t) {
const x = clamp(t, 0, 1) * (HEAT_RAMP.length - 1);
const i = Math.min(Math.floor(x), HEAT_RAMP.length - 2);
return mix(HEAT_RAMP[i], HEAT_RAMP[i + 1], x - i);
}
function ringAt(c, col, r) {
ctx.strokeStyle = rgba(col, 1);
ctx.lineWidth = 2;
ctx.beginPath();
ctx.arc(cellX(c) + CS / 2, cellY(c) + CS / 2, r, 0, Math.PI * 2);
ctx.stroke();
}
const UNREACHED = mix(ROCK, PAPER, 0.12);
function draw() {
clearStage();
const scale = Math.max(front, HEAT_MAX_D);
for (let i = 0; i < CELL_N; i += 1) {
const d = dist[i];
if (d < 0) {
fillCell(i, UNREACHED, 1);
continue;
}
fillCell(i, mix(heat(d / scale), PAPER, 0.18), 1);
if (flooding() && d === front) {
fillCell(i, PAPER, RING_ALPHA);
}
}
strokeWalls(walls, rgba(INK, 1), 2);
ringAt(src, PAPER, 5);
ringAt(farCell, PAPER, 6.5);
drawGates();
panelRow(0, 'Distance ring', String(front));
panelRow(1, 'Cells reached', String(reached) + ' / ' + String(CELL_N));
panelRow(2, 'To farthest room', String(dist[farCell]));
panelRow(3, 'Longest path', longest >= 0 ? String(longest) : '—');
}
function after() {
if (still) {
settle();
}
report();
draw();
}
function newMaze() {
pass += 1;
walls = growAll(SEED + pass, Math.floor(CELL_N / 2), 'random');
longest = -1;
longEnd = -1;
startFlood(ENTRY, 1);
after();
}
function fromFar() {
if (flooding()) {
settle();
}
startFlood(farCell, 2);
after();
}
cv.addEventListener('pointerdown', function (ev) {
wake();
const p = toScene(ev);
const c = cellAt(p[0], p[1]);
if (c < 0) {
return;
}
longest = -1;
startFlood(c, 1);
after();
});
cv.addEventListener('keydown', function (ev) {
if (ev.key === 'Enter') {
ev.preventDefault();
wake();
fromFar();
}
else if (ev.key === 'ArrowRight') {
ev.preventDefault();
wake();
flood(5);
after();
}
else if (ev.key === 'Home') {
ev.preventDefault();
wake();
newMaze();
}
});
if (farBtn) {
farBtn.addEventListener('click', function () { wake(); fromFar(); });
}
if (newBtn) {
newBtn.addEventListener('click', function () { wake(); newMaze(); });
}
startFlood(ENTRY, 1);
report();
let rafId = 0;
let lastTs = -1;
let acc = 0;
let clock = 0;
function frame(ts) {
if (lastTs < 0) {
lastTs = ts;
}
// 탭이 숨었다 돌아와도 한 번에 100ms 까지만 따라잡는다 — 순간이동 대신 이어서 움직인다
acc += Math.min(ts - lastTs, 100);
lastTs = ts;
let n = 0;
while (acc >= FIXED_DT && n < 6) {
clock += FIXED_DT;
if (demo) {
demoTick(clock);
}
step();
acc -= FIXED_DT;
n += 1;
}
draw();
rafId = window.requestAnimationFrame(frame);
}
if (still) {
settle();
draw();
}
else {
rafId = window.requestAnimationFrame(frame);
}
return function () {
window.cancelAnimationFrame(rafId);
window.removeEventListener('resize', onResize);
};
})();// MzDistanceBfsFloodHeat - vanilla 판(05-mz-distance-bfs-flood-heat) 의 React 포트. 같은 계산을 useEffect 안에서 돌린다.
import { useEffect, useRef } from "react";
import styles from "./MzDistanceBfsFloodHeat.module.scss";
const cx = (s: string): string => s.split(" ").map((n) => styles[n] ?? n).join(" ");
export default function MzDistanceBfsFloodHeat() {
const rootRef = useRef<HTMLDivElement | null>(null);
useEffect(() => {
const rootEl = rootRef.current;
if (!rootEl) return;
const root: HTMLElement = rootEl;
type RGB = [number, number, number];
const W = 480;
const H = 300;
const FIXED_DT = 16;
// 파스텔 팔레트 — 어두운 무대 위에 밝은 바닥을 얹어 명도 차로 길이 읽힌다
const BG: RGB = [29, 26, 44];
const ROCK: RGB = [44, 39, 64];
const PAPER: RGB = [255, 248, 234];
const INK: RGB = [58, 48, 76];
const MINT: RGB = [126, 226, 192];
const SKY: RGB = [124, 196, 255];
const LILAC: RGB = [190, 164, 255];
const PINK: RGB = [255, 160, 190];
const PEACH: RGB = [255, 208, 168];
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)]; }
const canvasEl = root.querySelector('[data-role="canvas"]') as HTMLCanvasElement | null;
const statusEl = root.querySelector('[data-role="status"]') as HTMLElement | null;
const ctxRaw = canvasEl ? canvasEl.getContext('2d') : null;
if (!canvasEl || !ctxRaw || !statusEl) { return; }
const cv: HTMLCanvasElement = canvasEl;
const ctx: CanvasRenderingContext2D = ctxRaw;
const status: HTMLElement = statusEl;
const reduceQuery = window.matchMedia('(prefers-reduced-motion: reduce)');
const still = reduceQuery.matches;
// 자동 시연 중인가 — 사람이 처음 만지는 순간 시연을 멈추고 상태 줄을 읽어 주기 시작한다
let demo = root.classList.contains('is-demo');
function wake(): void {
if (!demo) { return; }
demo = false;
root.classList.remove('is-demo');
status.setAttribute('aria-live', 'polite');
}
function say(text: string): void {
if (status.textContent !== text) { status.textContent = text; }
}
function fitCanvas(): void {
// 배율은 2 에서 자른다 — 배율 3 기기에서 화소가 2.25배로 늘어 프레임마다 일이 그만큼 커지지 않게
const dpr = Math.min(window.devicePixelRatio || 1, 2);
cv.width = Math.round(W * dpr);
cv.height = Math.round(H * dpr);
ctx.setTransform(dpr, 0, 0, dpr, 0, 0);
}
function onResize(): void {
fitCanvas();
draw();
}
fitCanvas();
window.addEventListener('resize', onResize);
// 화면 좌표(CSS px) → 장면 좌표(480x300). 리사이즈 뒤에도 늘 현재 크기로 다시 잰다
function toScene(ev: PointerEvent): [number, number] {
const r = cv.getBoundingClientRect();
return [((ev.clientX - r.left) / r.width) * W, ((ev.clientY - r.top) / r.height) * H];
}
// 시드 고정 난수 — 같은 시드면 같은 미로가 다시 나온다 (32비트 정수 섞기)
function makeRng(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 — 31×31 칸, 칸마다 벽 네 장을 비트 하나씩으로 든다
const GRID_N = 31;
const CELL_N = GRID_N * GRID_N;
const CS = 9;
const BOARD = GRID_N * CS;
let BX = W - 12 - BOARD;
const BY = (H - BOARD) / 2;
const ENTRY = 0;
const EXIT = CELL_N - 1;
// 방향 0 북 · 1 동 · 2 남 · 3 서 — 시계 방향 순서라 +1 이 오른쪽으로 돌기, +3 이 왼쪽으로 돌기
const DX = [0, 1, 0, -1];
const DY = [-1, 0, 1, 0];
const BIT = [1, 2, 4, 8];
const ALL_WALLS = 15;
function neighbor(i: number, d: number): number {
const x = (i % GRID_N) + DX[d];
const y = Math.floor(i / GRID_N) + DY[d];
return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
}
function isOpen(walls: Uint8Array, i: number, d: number): boolean {
return (walls[i] & BIT[d]) === 0 && neighbor(i, d) >= 0;
}
// 벽 한 장 걷기 — 양쪽 칸의 비트를 함께 지운다 (한쪽만 지우면 길이 일방통행이 된다)
function knock(walls: Uint8Array, i: number, d: number): number {
const n = neighbor(i, d);
walls[i] &= ~BIT[d];
walls[n] &= ~BIT[(d + 2) % 4];
return n;
}
function openCount(walls: Uint8Array, i: number): number {
let c = 0;
for (let d = 0; d < 4; d += 1) { if (isOpen(walls, i, d)) { c += 1; } }
return c;
}
function cellX(i: number): number { return BX + (i % GRID_N) * CS; }
function cellY(i: number): number { return BY + Math.floor(i / GRID_N) * CS; }
function cellAt(sx: number, sy: number): number {
const x = Math.floor((sx - BX) / CS);
const y = Math.floor((sy - BY) / CS);
return x < 0 || y < 0 || x >= GRID_N || y >= GRID_N ? -1 : y * GRID_N + x;
}
function fillCell(i: number, c: RGB, a: number): void {
ctx.fillStyle = rgba(c, a);
ctx.fillRect(cellX(i), cellY(i), CS, CS);
}
// 벽 비트를 선분으로 — 칸마다 동·남 벽만 긋고 맨 윗줄·맨 왼줄만 북·서 벽을 더 긋는다 (같은 벽을 두 번 긋지 않는다)
function strokeWalls(walls: Uint8Array, color: string, lw: number): void {
ctx.beginPath();
for (let i = 0; i < CELL_N; i += 1) {
const x = cellX(i);
const y = cellY(i);
const w = walls[i];
if ((w & 2) !== 0) { ctx.moveTo(x + CS, y); ctx.lineTo(x + CS, y + CS); }
if ((w & 4) !== 0) { ctx.moveTo(x, y + CS); ctx.lineTo(x + CS, y + CS); }
if (i < GRID_N && (w & 1) !== 0) { ctx.moveTo(x, y); ctx.lineTo(x + CS, y); }
if (i % GRID_N === 0 && (w & 8) !== 0) { ctx.moveTo(x, y); ctx.lineTo(x, y + CS); }
}
ctx.strokeStyle = color;
ctx.lineWidth = lw;
ctx.lineCap = 'square';
ctx.stroke();
}
// 입구(왼쪽 위)·출구(오른쪽 아래) 표시 — 바깥 벽 밖에 작은 삼각형
function drawGates(): void {
ctx.fillStyle = rgba(MINT, 0.95);
ctx.beginPath();
ctx.moveTo(BX - 9, BY + 1);
ctx.lineTo(BX - 2, BY + CS / 2);
ctx.lineTo(BX - 9, BY + CS - 1);
ctx.closePath();
ctx.fill();
ctx.fillStyle = rgba(PINK, 0.95);
ctx.beginPath();
ctx.moveTo(BX + BOARD + 2, BY + BOARD - CS + 1);
ctx.lineTo(BX + BOARD + 9, BY + BOARD - CS / 2);
ctx.lineTo(BX + BOARD + 2, BY + BOARD - 1);
ctx.closePath();
ctx.fill();
}
// 왼쪽 칸의 수치 — 이름표 한 줄 + 값 한 줄
function panelRow(row: number, label: string, value: string): void {
const y = 104 + row * 34;
ctx.textAlign = 'left';
ctx.textBaseline = 'alphabetic';
ctx.fillStyle = rgba(PAPER, 0.62);
ctx.font = '500 11px sans-serif';
ctx.fillText(label, 16, y);
ctx.fillStyle = rgba(PAPER, 0.96);
ctx.font = '700 15px sans-serif';
ctx.fillText(value, 16, y + 18);
}
function clearStage(): void {
ctx.fillStyle = rgba(BG, 1);
ctx.fillRect(0, 0, W, H);
}
type PickMode = 'random' | 'newest' | 'oldest';
type Grower = { walls: Uint8Array; inMaze: Uint8Array; inFront: Uint8Array; front: number[]; order: Int32Array; count: number; last: number; rnd: () => number };
function addFront(g: Grower, c: number): void {
for (let d = 0; d < 4; d += 1) {
const n = neighbor(c, d);
if (n < 0 || g.inMaze[n] === 1 || g.inFront[n] === 1) { continue; }
g.inFront[n] = 1;
g.front.push(n);
}
}
function growStart(seed: number, start: number): Grower {
const g: Grower = { walls: new Uint8Array(CELL_N).fill(ALL_WALLS), inMaze: new Uint8Array(CELL_N), inFront: new Uint8Array(CELL_N), front: [], order: new Int32Array(CELL_N).fill(-1), count: 0, last: start, rnd: makeRng(seed) };
g.inMaze[start] = 1;
g.order[start] = 0;
g.count = 1;
addFront(g, start);
return g;
}
// 프론티어(판 영역에 닿은 안 판 칸)에서 하나를 골라 이미 판 이웃 하나와 벽 한 장으로 잇는다
function growOne(g: Grower, mode: PickMode): number {
const len = g.front.length;
if (len === 0) { return -1; }
let c = 0;
if (mode === 'newest') {
c = g.front.pop() as number;
} else if (mode === 'oldest') {
c = g.front.shift() as number;
} else {
const k = Math.floor(g.rnd() * len);
c = g.front[k];
g.front[k] = g.front[len - 1];
g.front.pop();
}
g.inFront[c] = 0;
const links: number[] = [];
for (let d = 0; d < 4; d += 1) {
const n = neighbor(c, d);
if (n >= 0 && g.inMaze[n] === 1) { links.push(d); }
}
knock(g.walls, c, links[Math.floor(g.rnd() * links.length)]);
g.inMaze[c] = 1;
g.order[c] = g.count;
g.count += 1;
g.last = c;
addFront(g, c);
return c;
}
function growAll(seed: number, start: number, mode: PickMode): Uint8Array {
const g = growStart(seed, start);
while (growOne(g, mode) >= 0) { /* 프론티어가 빌 때까지 */ }
return g.walls;
}
// 한 겹(같은 거리의 칸들)을 번지는 데 쓰는 시간
const FLOOD_STEP_MS = 20;
// 열지도 눈금의 바닥 — 파도가 이 거리를 넘기 전까지는 눈금을 이 값으로 고정해 초반 색이 출렁이지 않게 한다
const HEAT_MAX_D = 60;
// 지금 막 닿은 겹(파도 앞머리)을 덮는 밝기
const RING_ALPHA = 0.85;
const SEED = 464;
const HOLD_MS = 1400;
const GAP_MS = 500;
const HEAT_RAMP: RGB[] = [SKY, MINT, PEACH, PINK];
const TXT_FLOOD = '입구에서 한 겹씩 번지는 중';
const TXT_FLOOD2 = '가장 먼 방에서 다시 번지는 중';
const TXT_DONE1 = '끝 — 가장 먼 방을 찾음';
const TXT_DONE2 = '끝 — 서로 가장 먼 두 방을 찾음';
const farBtn = root.querySelector('[data-role="far"]') as HTMLButtonElement | null;
const newBtn = root.querySelector('[data-role="new"]') as HTMLButtonElement | null;
let pass = 0;
let walls = growAll(SEED, Math.floor(CELL_N / 2), 'random');
let dist = new Int32Array(CELL_N).fill(-1);
let layer: number[] = [];
let front = 0;
let reached = 0;
let src = ENTRY;
let farCell = ENTRY;
let sweep = 1;
let longest = -1;
let longEnd = -1;
let stepAcc = 0;
let holdLeft = 0;
function startFlood(s: number, sw: number): void {
src = s;
sweep = sw;
dist = new Int32Array(CELL_N).fill(-1);
dist[s] = 0;
layer = [s];
front = 0;
reached = 1;
farCell = s;
stepAcc = 0;
holdLeft = 0;
}
// 한 겹 번지기 — 지금 겹의 칸마다 열린 이웃 중 아직 거리가 없는 칸에 거리+1 을 적어 다음 겹을 만든다
function floodStep(): void {
if (layer.length === 0) { return; }
const next: number[] = [];
for (const c of layer) {
for (let d = 0; d < 4; d += 1) {
if (!isOpen(walls, c, d)) { continue; }
const n = neighbor(c, d);
if (dist[n] >= 0) { continue; }
dist[n] = front + 1;
next.push(n);
}
}
if (next.length === 0) {
layer = [];
if (sweep === 2) { longest = front; longEnd = farCell; }
return;
}
front += 1;
layer = next;
reached += next.length;
farCell = next[next.length - 1];
}
function flooding(): boolean { return layer.length > 0; }
function report(): void {
if (flooding()) { say(sweep === 2 ? TXT_FLOOD2 : TXT_FLOOD); }
else { say(sweep === 2 ? TXT_DONE2 : TXT_DONE1); }
}
function flood(n: number): void {
for (let k = 0; k < n && flooding(); k += 1) { floodStep(); }
}
function step(): void {
if (!flooding()) { return; }
stepAcc += FIXED_DT;
while (stepAcc >= FLOOD_STEP_MS && flooding()) {
stepAcc -= FLOOD_STEP_MS;
floodStep();
}
report();
}
function settle(): void {
flood(CELL_N);
report();
}
// 시연 — 입구에서 번진 뒤 가장 먼 방에서 한 번 더 번진다 (가지 없는 길이 하나뿐인 미로에서 두 번째 끝이 가장 긴 길의 양 끝)
function demoTick(t: number): void {
if (flooding() || t < 0) { return; }
holdLeft += FIXED_DT;
if (sweep === 1 && holdLeft >= GAP_MS) { startFlood(farCell, 2); }
else if (sweep === 2 && holdLeft >= HOLD_MS) { newMaze(); }
}
function heat(t: number): RGB {
const x = clamp(t, 0, 1) * (HEAT_RAMP.length - 1);
const i = Math.min(Math.floor(x), HEAT_RAMP.length - 2);
return mix(HEAT_RAMP[i], HEAT_RAMP[i + 1], x - i);
}
function ringAt(c: number, col: RGB, r: number): void {
ctx.strokeStyle = rgba(col, 1);
ctx.lineWidth = 2;
ctx.beginPath();
ctx.arc(cellX(c) + CS / 2, cellY(c) + CS / 2, r, 0, Math.PI * 2);
ctx.stroke();
}
const UNREACHED = mix(ROCK, PAPER, 0.12);
function draw(): void {
clearStage();
const scale = Math.max(front, HEAT_MAX_D);
for (let i = 0; i < CELL_N; i += 1) {
const d = dist[i];
if (d < 0) { fillCell(i, UNREACHED, 1); continue; }
fillCell(i, mix(heat(d / scale), PAPER, 0.18), 1);
if (flooding() && d === front) { fillCell(i, PAPER, RING_ALPHA); }
}
strokeWalls(walls, rgba(INK, 1), 2);
ringAt(src, PAPER, 5);
ringAt(farCell, PAPER, 6.5);
drawGates();
panelRow(0, '거리 겹', String(front));
panelRow(1, '닿은 칸', String(reached) + ' / ' + String(CELL_N));
panelRow(2, '가장 먼 방까지', String(dist[farCell]));
panelRow(3, '가장 긴 길', longest >= 0 ? String(longest) : '—');
}
function after(): void {
if (still) { settle(); }
report();
draw();
}
function newMaze(): void {
pass += 1;
walls = growAll(SEED + pass, Math.floor(CELL_N / 2), 'random');
longest = -1;
longEnd = -1;
startFlood(ENTRY, 1);
after();
}
function fromFar(): void {
if (flooding()) { settle(); }
startFlood(farCell, 2);
after();
}
cv.addEventListener('pointerdown', function (ev: PointerEvent): void {
wake();
const p = toScene(ev);
const c = cellAt(p[0], p[1]);
if (c < 0) { return; }
longest = -1;
startFlood(c, 1);
after();
});
cv.addEventListener('keydown', function (ev: KeyboardEvent): void {
if (ev.key === 'Enter') { ev.preventDefault(); wake(); fromFar(); }
else if (ev.key === 'ArrowRight') { ev.preventDefault(); wake(); flood(5); after(); }
else if (ev.key === 'Home') { ev.preventDefault(); wake(); newMaze(); }
});
if (farBtn) { farBtn.addEventListener('click', function (): void { wake(); fromFar(); }); }
if (newBtn) { newBtn.addEventListener('click', function (): void { wake(); newMaze(); }); }
startFlood(ENTRY, 1);
report();
let rafId = 0;
let lastTs = -1;
let acc = 0;
let clock = 0;
function frame(ts: number): void {
if (lastTs < 0) { lastTs = ts; }
// 탭이 숨었다 돌아와도 한 번에 100ms 까지만 따라잡는다 — 순간이동 대신 이어서 움직인다
acc += Math.min(ts - lastTs, 100);
lastTs = ts;
let n = 0;
while (acc >= FIXED_DT && n < 6) {
clock += FIXED_DT;
if (demo) { demoTick(clock); }
step();
acc -= FIXED_DT;
n += 1;
}
draw();
rafId = window.requestAnimationFrame(frame);
}
if (still) {
settle();
draw();
} else {
rafId = window.requestAnimationFrame(frame);
}
return function (): void {
window.cancelAnimationFrame(rafId);
window.removeEventListener('resize', onResize);
};
}, []);
return (
<div className={cx("hs") + " is-demo"} ref={rootRef}>
<canvas className={cx("hs__canvas")} data-role="canvas" width={480} height={300} tabIndex={0} aria-label="입구에서 한 겹씩 번지는 파도가 칸마다 거리를 적어 열지도로 물들이고 가장 먼 방을 표시하는 미로. 칸을 누르면 그 칸에서 번진다"></canvas>
<p className={cx("hs__status")} data-role="status" aria-live="off">입구에서 한 겹씩 번지는 중</p>
<div className={cx("hs__tools")}>
<button className={cx("hs__btn")} data-role="far" type="button">가장 먼 방에서</button>
<button className={cx("hs__btn")} data-role="new" type="button">새 미로</button>
</div>
</div>
);
}05 A Maze Where a Spreading Wave Computes the Distance to Every Cell — Measured area 41.073% · moving frames 19/23Original by GODRICH · SCSS and React ship in the zip · Maze Generator: 9 Carve-and-Solve Scenes
The post this demo lives in
Maze Generator: 9 Carve-and-Solve ScenesIn this maze generator set, mazes are carved, not drawn — 02 reads carve order from a random frontier's ripple bands, 06 See all demos in this post
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