Tectum/js/core/geometry.js

/*!
 * Tectum
 * Copyright © 2026 Machiel Heinen.
 * Alle rechten voorbehouden. Gebruik uitsluitend met schriftelijke toestemming.
 * Zie LICENTIE.md.
 */
// Plain script, geen ES-module: imports breken bij file:// (CORS).

// Map van de engine (met assets/ en kosten/), afgeleid van de plek van dit script. Texturen, kleurstalen en de
// kosten-CSV's laden via tectumUrl(), zodat ze ook werken als de engine in een andere pagina staat (light-versie op
// een modelpagina van de site). Paden in de data blijven relatief.
const TECTUM_BASE = (() => {
  const s = typeof document !== 'undefined' && document.currentScript && document.currentScript.src;
  return s ? new URL('../../', s).href : '';
})();
function tectumUrl(path) {
  return path && !/^(?:[a-z][a-z0-9+.-]*:|\/)/i.test(path) ? TECTUM_BASE + path : path;
}

function calculateSegmentPositions(spanWidth, minSp, maxSp) {
  if (spanWidth <= 0) return [];
  let numBays = Math.ceil(spanWidth / maxSp);
  let spacing = spanWidth / numBays;

  if (spacing < minSp && numBays > 1) {
    numBays = Math.floor(spanWidth / minSp);
    spacing = spanWidth / numBays;
  }

  const positions = [];
  for (let i = 1; i < numBays; i++) {
    positions.push(i * spacing);
  }
  return positions;
}

function polygonArea(points) {
  let area = 0;
  for (let i = 0; i < points.length; i++) {
    const p1 = points[i];
    const p2 = points[(i + 1) % points.length];
    area += p1.x * p2.y - p2.x * p1.y;
  }
  return Math.abs(area) / 2;
}

function clipPolygonYLE(points, yLimit) {
  const result = [];
  for (let i = 0; i < points.length; i++) {
    const cur = points[i];
    const prev = points[(i - 1 + points.length) % points.length];
    const curIn = cur.y <= yLimit + 1e-12;
    const prevIn = prev.y <= yLimit + 1e-12;
    if (curIn) {
      if (!prevIn) {
        const t = (yLimit - prev.y) / (cur.y - prev.y);
        result.push({ x: prev.x + t * (cur.x - prev.x), y: yLimit });
      }
      result.push(cur);
    } else if (prevIn) {
      const t = (yLimit - prev.y) / (cur.y - prev.y);
      result.push({ x: prev.x + t * (cur.x - prev.x), y: yLimit });
    }
  }
  return result;
}
function clipPolygonYGE(points, yLimit) {
  const result = [];
  for (let i = 0; i < points.length; i++) {
    const cur = points[i];
    const prev = points[(i - 1 + points.length) % points.length];
    const curIn = cur.y >= yLimit - 1e-12;
    const prevIn = prev.y >= yLimit - 1e-12;
    if (curIn) {
      if (!prevIn) {
        const t = (yLimit - prev.y) / (cur.y - prev.y);
        result.push({ x: prev.x + t * (cur.x - prev.x), y: yLimit });
      }
      result.push(cur);
    } else if (prevIn) {
      const t = (yLimit - prev.y) / (cur.y - prev.y);
      result.push({ x: prev.x + t * (cur.x - prev.x), y: yLimit });
    }
  }
  return result;
}

function shapeAreaWithHoles(shape) {
  let area = polygonArea(shape.getPoints());
  (shape.holes || []).forEach(hole => { area -= polygonArea(hole.getPoints()); });
  return area;
}

function dist2D(a, b) {
  return Math.hypot(a.x - b.x, a.y - b.y);
}

// Zaagsnede-breedte wordt verwaarloosd.
function planStockCutting(pieceLengths, stockLengths) {
  const stocks = stockLengths.slice().sort((a, b) => a - b);
  const maxStock = stocks[stocks.length - 1];

  const parts = [];
  pieceLengths.forEach(len => {
    let rest = Math.round(len);
    while (rest > maxStock) { parts.push(maxStock); rest -= maxStock; }
    if (rest > 0) parts.push(rest);
  });
  parts.sort((a, b) => b - a);

  const bars = [];
  parts.forEach(p => {
    let best = null, bestRest = Infinity;
    bars.forEach(bar => {
      const r = maxStock - bar.used - p;
      if (r >= 0 && r < bestRest) { best = bar; bestRest = r; }
    });
    if (!best) { best = { used: 0, cuts: [] }; bars.push(best); }
    best.cuts.push(p);
    best.used += p;
  });
  bars.forEach(bar => {
    bar.stock = stocks.find(s => s >= bar.used);
    bar.waste = bar.stock - bar.used;
  });
  return bars;
}

function summarizeStockPlan(bars) {
  const byStock = new Map();
  bars.forEach(b => byStock.set(b.stock, (byStock.get(b.stock) || 0) + 1));
  return {
    perStock: Array.from(byStock.entries()).sort((a, b) => a[0] - b[0]).map(([stock, count]) => ({ stock, count })),
    stockMM: bars.reduce((a, b) => a + b.stock, 0),
    wasteMM: bars.reduce((a, b) => a + b.waste, 0)
  };
}

// Een uitsparing over de rand wordt een inkeping, geen afgekapt gat (dat liet een haarfijn
// reepje materiaal met randlijnen door de opening lopen). Schuin (y1r) alleen bovenin.
function columnMinusRects(x0, x1, yBottom, topYAt, rects, opts) {
  const eps = 1e-9;
  const yCap = (opts && opts.yCap !== undefined) ? opts.yCap : Infinity;
  const top = (x) => Math.min(yCap, topYAt(x));
  const uniq = (arr) => arr.sort((a, b) => a - b).filter((v, i, a) => i === 0 || v - a[i - 1] > eps);

  const rs = rects
    .filter(r => Math.min(x1, r.x1) - Math.max(x0, r.x0) > eps)
    .map(r => {
      const y1r = r.y1r !== undefined ? r.y1r : r.y1, s = (y1r - r.y1) / (r.x1 - r.x0);
      return { x0: Math.max(x0, r.x0), x1: Math.min(x1, r.x1), y0: r.y0, topAt: (x) => r.y1 + (x - r.x0) * s };
    });
  const inRect = (x, y) => rs.some(r => x > r.x0 && x < r.x1 && y > r.y0 && y < r.topAt(x));

  const raw = [() => yBottom, top];
  rs.forEach(r => raw.push(() => r.y0, r.topAt));
  const clamp = (f) => (x) => Math.min(top(x), Math.max(yBottom, f(x)));
  const lines = raw.map(clamp);

  let xs = uniq([x0, x1, ...((opts && opts.extraXs) || []).filter(x => x > x0 + eps && x < x1 - eps), ...rs.flatMap(r => [r.x0, r.x1])]);
  const cuts = [];
  for (let i = 0; i < xs.length - 1; i++) {
    const a = xs[i], b = xs[i + 1];
    for (let p = 0; p < raw.length; p++) {
      for (let q = p + 1; q < raw.length; q++) {
        const da = raw[p](a) - raw[q](a), db = raw[p](b) - raw[q](b);
        if ((da > eps && db < -eps) || (da < -eps && db > eps)) cuts.push(a + (b - a) * da / (da - db));
      }
    }
  }
  xs = uniq(xs.concat(cuts));

  const cols = [];
  for (let i = 0; i < xs.length - 1; i++) {
    const a = xs[i], b = xs[i + 1], m = (a + b) / 2;
    const vals = lines.map(f => ({ a: f(a), b: f(b), m: f(m) }))
      .sort((p, q) => p.m - q.m)
      .filter((v, k, arr) => k === 0 || v.m - arr[k - 1].m > eps || Math.abs(v.a - arr[k - 1].a) > eps || Math.abs(v.b - arr[k - 1].b) > eps);
    const cells = [];
    for (let k = 0; k < vals.length - 1; k++) {
      const lo = vals[k], hi = vals[k + 1];
      if (hi.m - lo.m <= eps) continue;
      cells.push({ lo, hi, filled: !inRect(m, (lo.m + hi.m) / 2) });
    }
    cols.push({ a, b, cells });
  }

  const verts = [];
  const vid = (x, y) => {
    let k = verts.findIndex(v => Math.abs(v.x - x) < 1e-7 && Math.abs(v.y - y) < 1e-7);
    if (k < 0) { k = verts.length; verts.push({ x, y }); }
    return k;
  };
  const edges = new Map();
  const addEdge = (p, q) => {
    const a = vid(p.x, p.y), b = vid(q.x, q.y);
    if (a === b) return;
    if (!edges.has(a)) edges.set(a, []);
    edges.get(a).push(b);
  };
  cols.forEach(col => col.cells.forEach((c, k) => {
    if (!c.filled) return;
    if (!(k > 0 && col.cells[k - 1].filled && col.cells[k - 1].hi === c.lo)) addEdge({ x: col.a, y: c.lo.a }, { x: col.b, y: c.lo.b });
    if (!(k < col.cells.length - 1 && col.cells[k + 1].filled && col.cells[k + 1].lo === c.hi)) addEdge({ x: col.b, y: c.hi.b }, { x: col.a, y: c.hi.a });
  }));
  for (let i = 0; i < xs.length; i++) {
    const x = xs[i];
    const left = i > 0 ? cols[i - 1].cells.filter(c => c.filled).map(c => [c.lo.b, c.hi.b]) : [];
    const right = i < cols.length ? cols[i].cells.filter(c => c.filled).map(c => [c.lo.a, c.hi.a]) : [];
    const ys = uniq(left.concat(right).flat());
    for (let k = 0; k < ys.length - 1; k++) {
      const ya = ys[k], yb = ys[k + 1], ym = (ya + yb) / 2;
      if (yb - ya <= eps) continue;
      const lf = left.some(([p, q]) => ym > p && ym < q), rf = right.some(([p, q]) => ym > p && ym < q);
      if (lf && !rf) addEdge({ x, y: ya }, { x, y: yb });
      else if (rf && !lf) addEdge({ x, y: yb }, { x, y: ya });
    }
  }

  const loops = [];
  edges.forEach((list, start) => {
    while (list.length) {
      const loop = [start];
      let next = list.pop(), guard = 0;
      while (next !== start && guard++ < 100000) {
        loop.push(next);
        const outs = edges.get(next);
        if (!outs || !outs.length) break;
        next = outs.pop();
      }
      if (next === start) loops.push(loop);
    }
  });
  const polys = loops.map(loop => {
    const pts = loop.map(k => verts[k]);
    return pts.filter((p, k) => {
      const a = pts[(k - 1 + pts.length) % pts.length], b = pts[(k + 1) % pts.length];
      return Math.abs((p.x - a.x) * (b.y - a.y) - (p.y - a.y) * (b.x - a.x)) > 1e-12;
    });
  });

  const signedArea = (pts) => pts.reduce((s, p, k) => {
    const q = pts[(k + 1) % pts.length];
    return s + (p.x * q.y - q.x * p.y);
  }, 0) / 2;
  const inside = (pt, poly) => {
    let c = false;
    for (let a = 0, b = poly.length - 1; a < poly.length; b = a++) {
      if ((poly[a].y > pt.y) !== (poly[b].y > pt.y) &&
          pt.x < (poly[b].x - poly[a].x) * (pt.y - poly[a].y) / (poly[b].y - poly[a].y) + poly[a].x) c = !c;
    }
    return c;
  };
  const outers = polys.filter(p => p.length >= 3 && signedArea(p) > 1e-12).map(p => ({ outer: p, holes: [] }));
  outers.sort((p, q) => signedArea(p.outer) - signedArea(q.outer));
  polys.filter(p => p.length >= 3 && signedArea(p) < -1e-12).forEach(hole => {
    const mid = { x: (hole[0].x + hole[1].x) / 2, y: (hole[0].y + hole[1].y) / 2 };
    const owner = outers.find(o => inside(mid, o.outer)) || outers[0];
    if (owner) owner.holes.push(hole);
  });
  return outers;
}

function rectUnionLoops(rects) {
  const eps = 1e-6;
  const uniq = (arr) => arr.sort((a, b) => a - b).filter((v, i, a) => i === 0 || v - a[i - 1] > eps);
  const xs = uniq(rects.flatMap(r => [r.x0, r.x1]));
  const zs = uniq(rects.flatMap(r => [r.z0, r.z1]));
  const nx = xs.length - 1, nz = zs.length - 1;
  const filled = (i, j) => {
    if (i < 0 || j < 0 || i >= nx || j >= nz) return false;
    const xm = (xs[i] + xs[i + 1]) / 2, zm = (zs[j] + zs[j + 1]) / 2;
    return rects.some(r => xm > r.x0 && xm < r.x1 && zm > r.z0 && zm < r.z1);
  };
  const edges = new Map();
  const add = (a, b) => { const k = a.join(','); if (!edges.has(k)) edges.set(k, []); edges.get(k).push(b); };
  for (let i = 0; i < nx; i++) {
    for (let j = 0; j < nz; j++) {
      if (!filled(i, j)) continue;
      if (!filled(i, j - 1)) add([i, j], [i + 1, j]);
      if (!filled(i + 1, j)) add([i + 1, j], [i + 1, j + 1]);
      if (!filled(i, j + 1)) add([i + 1, j + 1], [i, j + 1]);
      if (!filled(i - 1, j)) add([i, j + 1], [i, j]);
    }
  }
  const loops = [];
  edges.forEach((list, startKey) => {
    while (list.length) {
      const loop = [startKey.split(',').map(Number)];
      let next = list.pop();
      while (next.join(',') !== startKey) {
        loop.push(next);
        next = edges.get(next.join(',')).pop();
      }
      const pts = loop.map(([i, j]) => ({ x: xs[i], z: zs[j] }));
      loops.push(pts.filter((p, k) => {
        const a = pts[(k - 1 + pts.length) % pts.length], b = pts[(k + 1) % pts.length];
        return Math.abs((p.x - a.x) * (b.z - a.z) - (p.z - a.z) * (b.x - a.x)) > eps;
      }));
    }
  });
  const area = (pts) => pts.reduce((s, p, k) => { const q = pts[(k + 1) % pts.length]; return s + p.x * q.z - q.x * p.z; }, 0) / 2;
  return loops.map(pts => ({ pts, area: area(pts) })).sort((a, b) => Math.abs(b.area) - Math.abs(a.area));
}

function rectilinearNormal(a, b) {
  const dx = b.x - a.x, dz = b.z - a.z, len = Math.hypot(dx, dz) || 1;
  return { x: dz / len, z: -dx / len };
}

function offsetRectilinearLoop(pts, d) {
  const n = pts.length;
  return pts.map((p, k) => {
    const prev = pts[(k - 1 + n) % n], next = pts[(k + 1) % n];
    const n1 = rectilinearNormal(prev, p), n2 = rectilinearNormal(p, next);
    const same = Math.abs(n1.x - n2.x) < 1e-9 && Math.abs(n1.z - n2.z) < 1e-9;
    return same ? { x: p.x + n1.x * d, z: p.z + n1.z * d } : { x: p.x + (n1.x + n2.x) * d, z: p.z + (n1.z + n2.z) * d };
  });
}

function groupFacadeRuns(segs, opts) {
  const lineTol = (opts && opts.lineTol) || 1, gapTol = (opts && opts.gapTol) || 5;
  const runs = [];
  segs.slice().sort((a, b) => a.s0 - b.s0).forEach(sg => {
    const run = runs.find(r => r.axis === sg.axis && Math.abs(r.normal.x - sg.normal.x) < 1e-6 && Math.abs(r.normal.z - sg.normal.z) < 1e-6 &&
      Math.abs(r.line - sg.line) < lineTol && sg.s0 <= r.s1 + gapTol);
    if (run) { run.segs.push(sg); run.s1 = Math.max(run.s1, sg.s1); }
    else runs.push(Object.assign({}, sg, { s0: sg.s0, s1: sg.s1, segs: [sg] }));
  });
  return runs;
}