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Added vibe coded Delaunay solver

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Mikael Lövqvist
2025-12-29 23:19:39 +01:00
parent 43b7a5f2c9
commit a7396a100a
2 changed files with 517 additions and 0 deletions
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index.html
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<ul> <ul>
<li><a href="standalone/gradient_editor.html">Gradient editor</a></li> <li><a href="standalone/gradient_editor.html">Gradient editor</a></li>
<li><a href="standalone/imu-1/3d.html">3D view using GravitySensor</a></li> <li><a href="standalone/imu-1/3d.html">3D view using GravitySensor</a></li>
<li><a href="standalone/delaunay.html">Delaunay dataset</a></li>
</ul> </ul>
</li> </li>

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standalone/delaunay.html Normal file
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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width,initial-scale=1" />
<title>Delaunay (Bowyer–Watson) on Canvas</title>
<style>
html, body {
height: 100%;
margin: 0;
background: #111;
color: #ddd;
font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
}
#wrap {
display: grid;
grid-template-rows: auto 1fr;
height: 100%;
}
#bar {
display: flex;
flex-wrap: wrap;
gap: 10px;
align-items: center;
padding: 10px 12px;
background: #1a1a1a;
border-bottom: 1px solid #2a2a2a;
}
#bar > * { margin: 0; }
label {
display: inline-flex;
align-items: center;
gap: 6px;
white-space: nowrap;
}
input[type="range"] { width: 220px; }
button {
background: #2a2a2a;
color: #ddd;
border: 1px solid #3a3a3a;
padding: 7px 10px;
border-radius: 6px;
cursor: pointer;
}
button:hover { background: #333; }
button:disabled { opacity: .5; cursor: default; }
.small {
font-size: 12px;
opacity: .85;
}
#c {
display: block;
width: 100%;
height: 100%;
}
</style>
</head>
<body>
<div id="wrap">
<div id="bar">
<label>
N
<input id="n" type="range" min="10" max="600" value="120" />
<span id="nVal">120</span>
</label>
<button id="regen">Regenerate points</button>
<button id="solve">Solve (one go)</button>
<label>
<input id="animate" type="checkbox" checked />
Animate
</label>
<label>
Step ms
<input id="stepMs" type="range" min="0" max="200" value="12" />
<span id="stepMsVal">12</span>
</label>
<button id="run" title="Start/stop animation">Start</button>
<span class="small" id="status"></span>
</div>
<canvas id="c"></canvas>
</div>
<script>
(() => {
"use strict";
// ----------------------------
// Canvas + UI
// ----------------------------
const canvas = document.getElementById("c");
const ctx = canvas.getContext("2d", { alpha: false });
const nSlider = document.getElementById("n");
const nVal = document.getElementById("nVal");
const regenBtn = document.getElementById("regen");
const solveBtn = document.getElementById("solve");
const animateChk = document.getElementById("animate");
const stepMs = document.getElementById("stepMs");
const stepMsVal = document.getElementById("stepMsVal");
const runBtn = document.getElementById("run");
const statusEl = document.getElementById("status");
let W = 0, H = 0, DPR = 1;
function resize() {
const rect = canvas.getBoundingClientRect();
DPR = Math.max(1, Math.floor(window.devicePixelRatio || 1));
W = Math.max(1, Math.floor(rect.width));
H = Math.max(1, Math.floor(rect.height));
canvas.width = W * DPR;
canvas.height = H * DPR;
ctx.setTransform(DPR, 0, 0, DPR, 0, 0);
draw();
}
window.addEventListener("resize", resize);
nSlider.addEventListener("input", () => {
nVal.textContent = nSlider.value;
});
stepMs.addEventListener("input", () => {
stepMsVal.textContent = stepMs.value;
});
// ----------------------------
// Geometry helpers
// ----------------------------
function orient2d(a, b, c) {
// Positive if a->b->c is counter-clockwise
return (b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x);
}
function circumcircleContains(a, b, c, p) {
// Robust-enough incircle test for typical canvas demos:
// Uses determinant form; assumes triangle (a,b,c) is CCW.
const ax = a.x - p.x;
const ay = a.y - p.y;
const bx = b.x - p.x;
const by = b.y - p.y;
const cx = c.x - p.x;
const cy = c.y - p.y;
const a2 = ax * ax + ay * ay;
const b2 = bx * bx + by * by;
const c2 = cx * cx + cy * cy;
const det =
ax * (by * c2 - b2 * cy) -
ay * (bx * c2 - b2 * cx) +
a2 * (bx * cy - by * cx);
// For CCW triangle, det > 0 means p is inside circumcircle.
// Small epsilon to reduce flicker on nearly co-circular sets.
return det > 1e-10;
}
function triKey(i, j) {
return i < j ? (i + "," + j) : (j + "," + i);
}
// ----------------------------
// Bowyer–Watson incremental state
// ----------------------------
let points = [];
let triangles = []; // each {a,b,c} indices into points
let superIds = null; // [sa,sb,sc]
let insertOrder = [];
let insertIndex = 0;
let isRunning = false;
let lastStepTime = 0;
function makeRandomPoints(n) {
const margin = 24;
const pts = [];
for (let i = 0; i < n; i++) {
pts.push({
x: margin + Math.random() * (W - 2 * margin),
y: margin + Math.random() * (H - 2 * margin),
isSuper: false
});
}
return pts;
}
function initTriangulation() {
const n = Number(nSlider.value);
points = makeRandomPoints(n);
// Build a super-triangle that contains the canvas comfortably.
// Big triangle around center, scaled by max dimension.
const cx = W * 0.5;
const cy = H * 0.5;
const s = Math.max(W, H) * 10;
const sa = points.length;
points.push({ x: cx - 2 * s, y: cy + s, isSuper: true });
const sb = points.length;
points.push({ x: cx, y: cy - 2 * s, isSuper: true });
const sc = points.length;
points.push({ x: cx + 2 * s, y: cy + s, isSuper: true });
superIds = [sa, sb, sc];
// Ensure CCW order for the super triangle
if (orient2d(points[sa], points[sb], points[sc]) < 0) {
// swap sb and sc
superIds = [sa, sc, sb];
}
triangles = [{
a: superIds[0],
b: superIds[1],
c: superIds[2]
}];
// Insert points in random order for a nicer incremental animation
insertOrder = [];
for (let i = 0; i < n; i++) insertOrder.push(i);
for (let i = insertOrder.length - 1; i > 0; i--) {
const j = (Math.random() * (i + 1)) | 0;
const t = insertOrder[i];
insertOrder[i] = insertOrder[j];
insertOrder[j] = t;
}
insertIndex = 0;
updateStatus();
draw();
}
function stepInsertOnePoint() {
if (insertIndex >= insertOrder.length) return false;
const pIndex = insertOrder[insertIndex++];
const p = points[pIndex];
// 1) Find "bad" triangles whose circumcircle contains p
const bad = [];
for (let t = 0; t < triangles.length; t++) {
const tri = triangles[t];
const a = points[tri.a], b = points[tri.b], c = points[tri.c];
// Ensure CCW for the incircle test
let ia = tri.a, ib = tri.b, ic = tri.c;
if (orient2d(a, b, c) < 0) {
// Swap two vertices to make it CCW
ib = tri.c;
ic = tri.b;
}
const aa = points[ia], bb = points[ib], cc = points[ic];
if (circumcircleContains(aa, bb, cc, p)) {
bad.push(t);
}
}
// 2) Find boundary edges of the polygonal hole
// Count edges from bad triangles; boundary edges are those that appear once.
const edgeCount = new Map(); // key "i,j" -> {i,j,count}
for (let k = 0; k < bad.length; k++) {
const tri = triangles[bad[k]];
const e1 = triKey(tri.a, tri.b);
const e2 = triKey(tri.b, tri.c);
const e3 = triKey(tri.c, tri.a);
for (const [key, i, j] of [
[e1, tri.a, tri.b],
[e2, tri.b, tri.c],
[e3, tri.c, tri.a]
]) {
const cur = edgeCount.get(key);
if (cur) cur.count++;
else edgeCount.set(key, { i, j, count: 1 });
}
}
const boundaryEdges = [];
for (const e of edgeCount.values()) {
if (e.count === 1) boundaryEdges.push({ i: e.i, j: e.j });
}
// 3) Remove bad triangles (remove in descending index order)
bad.sort((x, y) => y - x);
for (let k = 0; k < bad.length; k++) {
triangles.splice(bad[k], 1);
}
// 4) Re-triangulate the hole by connecting p to each boundary edge
for (let e = 0; e < boundaryEdges.length; e++) {
const i = boundaryEdges[e].i;
const j = boundaryEdges[e].j;
// Make triangle (i, j, pIndex) CCW
const A = points[i], B = points[j], C = p;
if (orient2d(A, B, C) > 0) {
triangles.push({ a: i, b: j, c: pIndex });
} else {
triangles.push({ a: j, b: i, c: pIndex });
}
}
return true;
}
function finalizeRemoveSuperTriangle() {
if (!superIds) return;
const s0 = superIds[0], s1 = superIds[1], s2 = superIds[2];
triangles = triangles.filter(t => t.a !== s0 && t.a !== s1 && t.a !== s2 &&
t.b !== s0 && t.b !== s1 && t.b !== s2 &&
t.c !== s0 && t.c !== s1 && t.c !== s2);
updateStatus();
draw();
}
function solveAll() {
while (insertIndex < insertOrder.length) {
stepInsertOnePoint();
}
finalizeRemoveSuperTriangle();
}
// ----------------------------
// Drawing
// ----------------------------
function draw() {
// Background
ctx.fillStyle = "#111";
ctx.fillRect(0, 0, W, H);
// Triangles
ctx.lineWidth = 1;
ctx.strokeStyle = "rgba(190,190,190,0.65)";
ctx.beginPath();
for (let t = 0; t < triangles.length; t++) {
const tri = triangles[t];
const a = points[tri.a];
const b = points[tri.b];
const c = points[tri.c];
// Optionally hide super triangle edges during build for clarity
if (a.isSuper || b.isSuper || c.isSuper) continue;
ctx.moveTo(a.x, a.y);
ctx.lineTo(b.x, b.y);
ctx.lineTo(c.x, c.y);
ctx.lineTo(a.x, a.y);
}
ctx.stroke();
// Points
for (let i = 0; i < points.length; i++) {
const p = points[i];
if (p.isSuper) continue;
ctx.fillStyle = "#ddd";
ctx.beginPath();
ctx.arc(p.x, p.y, 2.2, 0, Math.PI * 2);
ctx.fill();
}
// Current insertion point highlight
if (insertIndex < insertOrder.length) {
const idx = insertOrder[insertIndex];
const p = points[idx];
ctx.strokeStyle = "rgba(255,255,255,0.9)";
ctx.lineWidth = 2;
ctx.beginPath();
ctx.arc(p.x, p.y, 6, 0, Math.PI * 2);
ctx.stroke();
ctx.lineWidth = 1;
}
}
function updateStatus() {
const n = Number(nSlider.value);
const inserted = Math.min(insertIndex, n);
const done = (insertIndex >= n);
statusEl.textContent = done
? `done: points ${n}, triangles ${triangles.length}`
: `inserting: ${inserted}/${n}, triangles ${triangles.length}`;
}
// ----------------------------
// Animation loop
// ----------------------------
function tick(ts) {
if (!isRunning) return;
const ms = Number(stepMs.value);
const ready = (ms === 0) ? true : (ts - lastStepTime >= ms);
if (ready) {
lastStepTime = ts;
const progressed = stepInsertOnePoint();
updateStatus();
draw();
if (!progressed) {
finalizeRemoveSuperTriangle();
isRunning = false;
runBtn.textContent = "Start";
solveBtn.disabled = false;
regenBtn.disabled = false;
nSlider.disabled = false;
animateChk.disabled = false;
}
}
requestAnimationFrame(tick);
}
function startStop() {
if (!animateChk.checked) return;
if (!isRunning) {
isRunning = true;
lastStepTime = 0;
runBtn.textContent = "Stop";
solveBtn.disabled = true;
regenBtn.disabled = true;
nSlider.disabled = true;
animateChk.disabled = true;
requestAnimationFrame(tick);
} else {
isRunning = false;
runBtn.textContent = "Start";
solveBtn.disabled = false;
regenBtn.disabled = false;
nSlider.disabled = false;
animateChk.disabled = false;
updateStatus();
draw();
}
}
// ----------------------------
// UI handlers
// ----------------------------
regenBtn.addEventListener("click", () => {
isRunning = false;
runBtn.textContent = "Start";
solveBtn.disabled = false;
regenBtn.disabled = false;
nSlider.disabled = false;
animateChk.disabled = false;
initTriangulation();
});
solveBtn.addEventListener("click", () => {
isRunning = false;
runBtn.textContent = "Start";
solveAll();
});
runBtn.addEventListener("click", () => {
startStop();
});
animateChk.addEventListener("change", () => {
if (!animateChk.checked) {
isRunning = false;
runBtn.textContent = "Start";
runBtn.disabled = true;
} else {
runBtn.disabled = false;
}
});
// Click to add a point (optional quick test)
canvas.addEventListener("pointerdown", (e) => {
// Only allow adding points when not running and before solving is complete.
if (isRunning) return;
const n = Number(nSlider.value);
if (insertIndex >= insertOrder.length) return;
const rect = canvas.getBoundingClientRect();
const x = e.clientX - rect.left;
const y = e.clientY - rect.top;
// Replace next-to-insert random point with clicked position for quick experimentation
const idx = insertOrder[insertIndex];
points[idx].x = x;
points[idx].y = y;
draw();
});
function boot() {
nVal.textContent = nSlider.value;
stepMsVal.textContent = stepMs.value;
runBtn.disabled = !animateChk.checked;
resize();
initTriangulation();
updateStatus();
draw();
}
boot();
})();
</script>
</body>
</html>