Compare Crack Seam

1"use client";
2 
3import { useEffect, useRef, type ReactNode } from "react";
4 
5type Pt = { x: number; y: number };
6type Fissure = {
7  /** origin x relative to the handle (seam offset at spawn) */
8  ox: number;
9  /** origin y in pane coordinates */
10  oy: number;
11  /** polyline relative to the origin */
12  pts: Pt[];
13  len: number;
14  alpha: number;
15  born: number;
16  /** timestamp retraction started; 0 while still held open */
17  retract: number;
18};
19 
20const HANDLE_W = 40;
21const GROW_MS = 90;
22const RETRACT_MS = 300;
23const GLINT_MS = 450;
24const GLINT_LEN = 56;
25const SPRING_K = 170; // s^-2
26const SPRING_C = 2 * 0.85 * Math.sqrt(SPRING_K); // zeta 0.85 — taut, no wobble
27 
28const clamp = (v: number, lo: number, hi: number) => Math.min(hi, Math.max(lo, v));
29const easeOut = (t: number) => 1 - (1 - t) ** 3;
30 
31function parseColor(raw: string): { r: number; g: number; b: number } | null {
32  const v = raw.trim();
33  if (v.startsWith("#")) {
34    const hex = v.slice(1);
35    if (hex.length === 3) {
36      const r = parseInt(hex[0] + hex[0], 16);
37      const g = parseInt(hex[1] + hex[1], 16);
38      const b = parseInt(hex[2] + hex[2], 16);
39      if (Number.isNaN(r) || Number.isNaN(g) || Number.isNaN(b)) return null;
40      return { r, g, b };
41    }
42    if (hex.length >= 6) {
43      const r = parseInt(hex.slice(0, 2), 16);
44      const g = parseInt(hex.slice(2, 4), 16);
45      const b = parseInt(hex.slice(4, 6), 16);
46      if (Number.isNaN(r) || Number.isNaN(g) || Number.isNaN(b)) return null;
47      return { r, g, b };
48    }
49    return null;
50  }
51  const m = v.match(/rgba?\(\s*([\d.]+)[,\s]+([\d.]+)[,\s]+([\d.]+)/i);
52  if (!m) return null;
53  return { r: Number(m[1]), g: Number(m[2]), b: Number(m[3]) };
54}
55 
56/** dart-throwing Poisson disc — relaxes min distance if the pane is crowded */
57function poissonPoints(w: number, h: number, count: number, minDist: number): Pt[] {
58  const pts: Pt[] = [];
59  let d = minDist;
60  let attempts = 0;
61  while (pts.length < count && attempts < 6000) {
62    attempts++;
63    const c = { x: Math.random() * w, y: Math.random() * h };
64    let ok = true;
65    for (const q of pts) {
66      const dx = q.x - c.x;
67      const dy = q.y - c.y;
68      if (dx * dx + dy * dy < d * d) {
69        ok = false;
70        break;
71      }
72    }
73    if (ok) pts.push(c);
74    if (attempts % 1500 === 0) d *= 0.85;
75  }
76  return pts;
77}
78 
79/**
80 * Nearest and second-nearest seeds to (x, y). Their perpendicular bisector is
81 * the half-plane boundary between the two Voronoi cells — the exact wall the
82// … truncated