site/node_modules/robust-predicates/esm/incircle.js

import {epsilon, splitter, resulterrbound, estimate, vec, sum, sum_three, scale} from './util.js';

const iccerrboundA = (10 + 96 * epsilon) * epsilon;
const iccerrboundB = (4 + 48 * epsilon) * epsilon;
const iccerrboundC = (44 + 576 * epsilon) * epsilon * epsilon;

const bc = vec(4);
const ca = vec(4);
const ab = vec(4);
const aa = vec(4);
const bb = vec(4);
const cc = vec(4);
const u = vec(4);
const v = vec(4);
const axtbc = vec(8);
const aytbc = vec(8);
const bxtca = vec(8);
const bytca = vec(8);
const cxtab = vec(8);
const cytab = vec(8);
const abt = vec(8);
const bct = vec(8);
const cat = vec(8);
const abtt = vec(4);
const bctt = vec(4);
const catt = vec(4);

const _8 = vec(8);
const _16 = vec(16);
const _16b = vec(16);
const _16c = vec(16);
const _32 = vec(32);
const _32b = vec(32);
const _48 = vec(48);
const _64 = vec(64);

let fin = vec(1152);
let fin2 = vec(1152);

function finadd(finlen, a, alen) {
    finlen = sum(finlen, fin, a, alen, fin2);
    const tmp = fin; fin = fin2; fin2 = tmp;
    return finlen;
}

function incircleadapt(ax, ay, bx, by, cx, cy, dx, dy, permanent) {
    let finlen;
    let adxtail, bdxtail, cdxtail, adytail, bdytail, cdytail;
    let axtbclen, aytbclen, bxtcalen, bytcalen, cxtablen, cytablen;
    let abtlen, bctlen, catlen;
    let abttlen, bcttlen, cattlen;
    let n1, n0;

    let bvirt, c, ahi, alo, bhi, blo, _i, _j, _0, s1, s0, t1, t0, u3;

    const adx = ax - dx;
    const bdx = bx - dx;
    const cdx = cx - dx;
    const ady = ay - dy;
    const bdy = by - dy;
    const cdy = cy - dy;

    s1 = bdx * cdy;
    c = splitter * bdx;
    ahi = c - (c - bdx);
    alo = bdx - ahi;
    c = splitter * cdy;
    bhi = c - (c - cdy);
    blo = cdy - bhi;
    s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
    t1 = cdx * bdy;
    c = splitter * cdx;
    ahi = c - (c - cdx);
    alo = cdx - ahi;
    c = splitter * bdy;
    bhi = c - (c - bdy);
    blo = bdy - bhi;
    t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
    _i = s0 - t0;
    bvirt = s0 - _i;
    bc[0] = s0 - (_i + bvirt) + (bvirt - t0);
    _j = s1 + _i;
    bvirt = _j - s1;
    _0 = s1 - (_j - bvirt) + (_i - bvirt);
    _i = _0 - t1;
    bvirt = _0 - _i;
    bc[1] = _0 - (_i + bvirt) + (bvirt - t1);
    u3 = _j + _i;
    bvirt = u3 - _j;
    bc[2] = _j - (u3 - bvirt) + (_i - bvirt);
    bc[3] = u3;
    s1 = cdx * ady;
    c = splitter * cdx;
    ahi = c - (c - cdx);
    alo = cdx - ahi;
    c = splitter * ady;
    bhi = c - (c - ady);
    blo = ady - bhi;
    s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
    t1 = adx * cdy;
    c = splitter * adx;
    ahi = c - (c - adx);
    alo = adx - ahi;
    c = splitter * cdy;
    bhi = c - (c - cdy);
    blo = cdy - bhi;
    t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
    _i = s0 - t0;
    bvirt = s0 - _i;
    ca[0] = s0 - (_i + bvirt) + (bvirt - t0);
    _j = s1 + _i;
    bvirt = _j - s1;
    _0 = s1 - (_j - bvirt) + (_i - bvirt);
    _i = _0 - t1;
    bvirt = _0 - _i;
    ca[1] = _0 - (_i + bvirt) + (bvirt - t1);
    u3 = _j + _i;
    bvirt = u3 - _j;
    ca[2] = _j - (u3 - bvirt) + (_i - bvirt);
    ca[3] = u3;
    s1 = adx * bdy;
    c = splitter * adx;
    ahi = c - (c - adx);
    alo = adx - ahi;
    c = splitter * bdy;
    bhi = c - (c - bdy);
    blo = bdy - bhi;
    s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
    t1 = bdx * ady;
    c = splitter * bdx;
    ahi = c - (c - bdx);
    alo = bdx - ahi;
    c = splitter * ady;
    bhi = c - (c - ady);
    blo = ady - bhi;
    t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
    _i = s0 - t0;
    bvirt = s0 - _i;
    ab[0] = s0 - (_i + bvirt) + (bvirt - t0);
    _j = s1 + _i;
    bvirt = _j - s1;
    _0 = s1 - (_j - bvirt) + (_i - bvirt);
    _i = _0 - t1;
    bvirt = _0 - _i;
    ab[1] = _0 - (_i + bvirt) + (bvirt - t1);
    u3 = _j + _i;
    bvirt = u3 - _j;
    ab[2] = _j - (u3 - bvirt) + (_i - bvirt);
    ab[3] = u3;

    finlen = sum(
        sum(
            sum(
                scale(scale(4, bc, adx, _8), _8, adx, _16), _16,
                scale(scale(4, bc, ady, _8), _8, ady, _16b), _16b, _32), _32,
            sum(
                scale(scale(4, ca, bdx, _8), _8, bdx, _16), _16,
                scale(scale(4, ca, bdy, _8), _8, bdy, _16b), _16b, _32b), _32b, _64), _64,
        sum(
            scale(scale(4, ab, cdx, _8), _8, cdx, _16), _16,
            scale(scale(4, ab, cdy, _8), _8, cdy, _16b), _16b, _32), _32, fin);

    let det = estimate(finlen, fin);
    let errbound = iccerrboundB * permanent;
    if (det >= errbound || -det >= errbound) {
        return det;
    }

    bvirt = ax - adx;
    adxtail = ax - (adx + bvirt) + (bvirt - dx);
    bvirt = ay - ady;
    adytail = ay - (ady + bvirt) + (bvirt - dy);
    bvirt = bx - bdx;
    bdxtail = bx - (bdx + bvirt) + (bvirt - dx);
    bvirt = by - bdy;
    bdytail = by - (bdy + bvirt) + (bvirt - dy);
    bvirt = cx - cdx;
    cdxtail = cx - (cdx + bvirt) + (bvirt - dx);
    bvirt = cy - cdy;
    cdytail = cy - (cdy + bvirt) + (bvirt - dy);
    if (adxtail === 0 && bdxtail === 0 && cdxtail === 0 && adytail === 0 && bdytail === 0 && cdytail === 0) {
        return det;
    }

    errbound = iccerrboundC * permanent + resulterrbound * Math.abs(det);
    det += ((adx * adx + ady * ady) * ((bdx * cdytail + cdy * bdxtail) - (bdy * cdxtail + cdx * bdytail)) +
        2 * (adx * adxtail + ady * adytail) * (bdx * cdy - bdy * cdx)) +
        ((bdx * bdx + bdy * bdy) * ((cdx * adytail + ady * cdxtail) - (cdy * adxtail + adx * cdytail)) +
        2 * (bdx * bdxtail + bdy * bdytail) * (cdx * ady - cdy * adx)) +
        ((cdx * cdx + cdy * cdy) * ((adx * bdytail + bdy * adxtail) - (ady * bdxtail + bdx * adytail)) +
        2 * (cdx * cdxtail + cdy * cdytail) * (adx * bdy - ady * bdx));

    if (det >= errbound || -det >= errbound) {
        return det;
    }

    if (bdxtail !== 0 || bdytail !== 0 || cdxtail !== 0 || cdytail !== 0) {
        s1 = adx * adx;
        c = splitter * adx;
        ahi = c - (c - adx);
        alo = adx - ahi;
        s0 = alo * alo - (s1 - ahi * ahi - (ahi + ahi) * alo);
        t1 = ady * ady;
        c = splitter * ady;
        ahi = c - (c - ady);
        alo = ady - ahi;
        t0 = alo * alo - (t1 - ahi * ahi - (ahi + ahi) * alo);
        _i = s0 + t0;
        bvirt = _i - s0;
        aa[0] = s0 - (_i - bvirt) + (t0 - bvirt);
        _j = s1 + _i;
        bvirt = _j - s1;
        _0 = s1 - (_j - bvirt) + (_i - bvirt);
        _i = _0 + t1;
        bvirt = _i - _0;
        aa[1] = _0 - (_i - bvirt) + (t1 - bvirt);
        u3 = _j + _i;
        bvirt = u3 - _j;
        aa[2] = _j - (u3 - bvirt) + (_i - bvirt);
        aa[3] = u3;
    }
    if (cdxtail !== 0 || cdytail !== 0 || adxtail !== 0 || adytail !== 0) {
        s1 = bdx * bdx;
        c = splitter * bdx;
        ahi = c - (c - bdx);
        alo = bdx - ahi;
        s0 = alo * alo - (s1 - ahi * ahi - (ahi + ahi) * alo);
        t1 = bdy * bdy;
        c = splitter * bdy;
        ahi = c - (c - bdy);
        alo = bdy - ahi;
        t0 = alo * alo - (t1 - ahi * ahi - (ahi + ahi) * alo);
        _i = s0 + t0;
        bvirt = _i - s0;
        bb[0] = s0 - (_i - bvirt) + (t0 - bvirt);
        _j = s1 + _i;
        bvirt = _j - s1;
        _0 = s1 - (_j - bvirt) + (_i - bvirt);
        _i = _0 + t1;
        bvirt = _i - _0;
        bb[1] = _0 - (_i - bvirt) + (t1 - bvirt);
        u3 = _j + _i;
        bvirt = u3 - _j;
        bb[2] = _j - (u3 - bvirt) + (_i - bvirt);
        bb[3] = u3;
    }
    if (adxtail !== 0 || adytail !== 0 || bdxtail !== 0 || bdytail !== 0) {
        s1 = cdx * cdx;
        c = splitter * cdx;
        ahi = c - (c - cdx);
        alo = cdx - ahi;
        s0 = alo * alo - (s1 - ahi * ahi - (ahi + ahi) * alo);
        t1 = cdy * cdy;
        c = splitter * cdy;
        ahi = c - (c - cdy);
        alo = cdy - ahi;
        t0 = alo * alo - (t1 - ahi * ahi - (ahi + ahi) * alo);
        _i = s0 + t0;
        bvirt = _i - s0;
        cc[0] = s0 - (_i - bvirt) + (t0 - bvirt);
        _j = s1 + _i;
        bvirt = _j - s1;
        _0 = s1 - (_j - bvirt) + (_i - bvirt);
        _i = _0 + t1;
        bvirt = _i - _0;
        cc[1] = _0 - (_i - bvirt) + (t1 - bvirt);
        u3 = _j + _i;
        bvirt = u3 - _j;
        cc[2] = _j - (u3 - bvirt) + (_i - bvirt);
        cc[3] = u3;
    }

    if (adxtail !== 0) {
        axtbclen = scale(4, bc, adxtail, axtbc);
        finlen = finadd(finlen, sum_three(
            scale(axtbclen, axtbc, 2 * adx, _16), _16,
            scale(scale(4, cc, adxtail, _8), _8, bdy, _16b), _16b,
            scale(scale(4, bb, adxtail, _8), _8, -cdy, _16c), _16c, _32, _48), _48);
    }
    if (adytail !== 0) {
        aytbclen = scale(4, bc, adytail, aytbc);
        finlen = finadd(finlen, sum_three(
            scale(aytbclen, aytbc, 2 * ady, _16), _16,
            scale(scale(4, bb, adytail, _8), _8, cdx, _16b), _16b,
            scale(scale(4, cc, adytail, _8), _8, -bdx, _16c), _16c, _32, _48), _48);
    }
    if (bdxtail !== 0) {
        bxtcalen = scale(4, ca, bdxtail, bxtca);
        finlen = finadd(finlen, sum_three(
            scale(bxtcalen, bxtca, 2 * bdx, _16), _16,
            scale(scale(4, aa, bdxtail, _8), _8, cdy, _16b), _16b,
            scale(scale(4, cc, bdxtail, _8), _8, -ady, _16c), _16c, _32, _48), _48);
    }
    if (bdytail !== 0) {
        bytcalen = scale(4, ca, bdytail, bytca);
        finlen = finadd(finlen, sum_three(
            scale(bytcalen, bytca, 2 * bdy, _16), _16,
            scale(scale(4, cc, bdytail, _8), _8, adx, _16b), _16b,
            scale(scale(4, aa, bdytail, _8), _8, -cdx, _16c), _16c, _32, _48), _48);
    }
    if (cdxtail !== 0) {
        cxtablen = scale(4, ab, cdxtail, cxtab);
        finlen = finadd(finlen, sum_three(
            scale(cxtablen, cxtab, 2 * cdx, _16), _16,
            scale(scale(4, bb, cdxtail, _8), _8, ady, _16b), _16b,
            scale(scale(4, aa, cdxtail, _8), _8, -bdy, _16c), _16c, _32, _48), _48);
    }
    if (cdytail !== 0) {
        cytablen = scale(4, ab, cdytail, cytab);
        finlen = finadd(finlen, sum_three(
            scale(cytablen, cytab, 2 * cdy, _16), _16,
            scale(scale(4, aa, cdytail, _8), _8, bdx, _16b), _16b,
            scale(scale(4, bb, cdytail, _8), _8, -adx, _16c), _16c, _32, _48), _48);
    }

    if (adxtail !== 0 || adytail !== 0) {
        if (bdxtail !== 0 || bdytail !== 0 || cdxtail !== 0 || cdytail !== 0) {
            s1 = bdxtail * cdy;
            c = splitter * bdxtail;
            ahi = c - (c - bdxtail);
            alo = bdxtail - ahi;
            c = splitter * cdy;
            bhi = c - (c - cdy);
            blo = cdy - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = bdx * cdytail;
            c = splitter * bdx;
            ahi = c - (c - bdx);
            alo = bdx - ahi;
            c = splitter * cdytail;
            bhi = c - (c - cdytail);
            blo = cdytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 + t0;
            bvirt = _i - s0;
            u[0] = s0 - (_i - bvirt) + (t0 - bvirt);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 + t1;
            bvirt = _i - _0;
            u[1] = _0 - (_i - bvirt) + (t1 - bvirt);
            u3 = _j + _i;
            bvirt = u3 - _j;
            u[2] = _j - (u3 - bvirt) + (_i - bvirt);
            u[3] = u3;
            s1 = cdxtail * -bdy;
            c = splitter * cdxtail;
            ahi = c - (c - cdxtail);
            alo = cdxtail - ahi;
            c = splitter * -bdy;
            bhi = c - (c - -bdy);
            blo = -bdy - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = cdx * -bdytail;
            c = splitter * cdx;
            ahi = c - (c - cdx);
            alo = cdx - ahi;
            c = splitter * -bdytail;
            bhi = c - (c - -bdytail);
            blo = -bdytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 + t0;
            bvirt = _i - s0;
            v[0] = s0 - (_i - bvirt) + (t0 - bvirt);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 + t1;
            bvirt = _i - _0;
            v[1] = _0 - (_i - bvirt) + (t1 - bvirt);
            u3 = _j + _i;
            bvirt = u3 - _j;
            v[2] = _j - (u3 - bvirt) + (_i - bvirt);
            v[3] = u3;
            bctlen = sum(4, u, 4, v, bct);
            s1 = bdxtail * cdytail;
            c = splitter * bdxtail;
            ahi = c - (c - bdxtail);
            alo = bdxtail - ahi;
            c = splitter * cdytail;
            bhi = c - (c - cdytail);
            blo = cdytail - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = cdxtail * bdytail;
            c = splitter * cdxtail;
            ahi = c - (c - cdxtail);
            alo = cdxtail - ahi;
            c = splitter * bdytail;
            bhi = c - (c - bdytail);
            blo = bdytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 - t0;
            bvirt = s0 - _i;
            bctt[0] = s0 - (_i + bvirt) + (bvirt - t0);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 - t1;
            bvirt = _0 - _i;
            bctt[1] = _0 - (_i + bvirt) + (bvirt - t1);
            u3 = _j + _i;
            bvirt = u3 - _j;
            bctt[2] = _j - (u3 - bvirt) + (_i - bvirt);
            bctt[3] = u3;
            bcttlen = 4;
        } else {
            bct[0] = 0;
            bctlen = 1;
            bctt[0] = 0;
            bcttlen = 1;
        }
        if (adxtail !== 0) {
            const len = scale(bctlen, bct, adxtail, _16c);
            finlen = finadd(finlen, sum(
                scale(axtbclen, axtbc, adxtail, _16), _16,
                scale(len, _16c, 2 * adx, _32), _32, _48), _48);

            const len2 = scale(bcttlen, bctt, adxtail, _8);
            finlen = finadd(finlen, sum_three(
                scale(len2, _8, 2 * adx, _16), _16,
                scale(len2, _8, adxtail, _16b), _16b,
                scale(len, _16c, adxtail, _32), _32, _32b, _64), _64);

            if (bdytail !== 0) {
                finlen = finadd(finlen, scale(scale(4, cc, adxtail, _8), _8, bdytail, _16), _16);
            }
            if (cdytail !== 0) {
                finlen = finadd(finlen, scale(scale(4, bb, -adxtail, _8), _8, cdytail, _16), _16);
            }
        }
        if (adytail !== 0) {
            const len = scale(bctlen, bct, adytail, _16c);
            finlen = finadd(finlen, sum(
                scale(aytbclen, aytbc, adytail, _16), _16,
                scale(len, _16c, 2 * ady, _32), _32, _48), _48);

            const len2 = scale(bcttlen, bctt, adytail, _8);
            finlen = finadd(finlen, sum_three(
                scale(len2, _8, 2 * ady, _16), _16,
                scale(len2, _8, adytail, _16b), _16b,
                scale(len, _16c, adytail, _32), _32, _32b, _64), _64);
        }
    }
    if (bdxtail !== 0 || bdytail !== 0) {
        if (cdxtail !== 0 || cdytail !== 0 || adxtail !== 0 || adytail !== 0) {
            s1 = cdxtail * ady;
            c = splitter * cdxtail;
            ahi = c - (c - cdxtail);
            alo = cdxtail - ahi;
            c = splitter * ady;
            bhi = c - (c - ady);
            blo = ady - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = cdx * adytail;
            c = splitter * cdx;
            ahi = c - (c - cdx);
            alo = cdx - ahi;
            c = splitter * adytail;
            bhi = c - (c - adytail);
            blo = adytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 + t0;
            bvirt = _i - s0;
            u[0] = s0 - (_i - bvirt) + (t0 - bvirt);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 + t1;
            bvirt = _i - _0;
            u[1] = _0 - (_i - bvirt) + (t1 - bvirt);
            u3 = _j + _i;
            bvirt = u3 - _j;
            u[2] = _j - (u3 - bvirt) + (_i - bvirt);
            u[3] = u3;
            n1 = -cdy;
            n0 = -cdytail;
            s1 = adxtail * n1;
            c = splitter * adxtail;
            ahi = c - (c - adxtail);
            alo = adxtail - ahi;
            c = splitter * n1;
            bhi = c - (c - n1);
            blo = n1 - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = adx * n0;
            c = splitter * adx;
            ahi = c - (c - adx);
            alo = adx - ahi;
            c = splitter * n0;
            bhi = c - (c - n0);
            blo = n0 - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 + t0;
            bvirt = _i - s0;
            v[0] = s0 - (_i - bvirt) + (t0 - bvirt);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 + t1;
            bvirt = _i - _0;
            v[1] = _0 - (_i - bvirt) + (t1 - bvirt);
            u3 = _j + _i;
            bvirt = u3 - _j;
            v[2] = _j - (u3 - bvirt) + (_i - bvirt);
            v[3] = u3;
            catlen = sum(4, u, 4, v, cat);
            s1 = cdxtail * adytail;
            c = splitter * cdxtail;
            ahi = c - (c - cdxtail);
            alo = cdxtail - ahi;
            c = splitter * adytail;
            bhi = c - (c - adytail);
            blo = adytail - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = adxtail * cdytail;
            c = splitter * adxtail;
            ahi = c - (c - adxtail);
            alo = adxtail - ahi;
            c = splitter * cdytail;
            bhi = c - (c - cdytail);
            blo = cdytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 - t0;
            bvirt = s0 - _i;
            catt[0] = s0 - (_i + bvirt) + (bvirt - t0);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 - t1;
            bvirt = _0 - _i;
            catt[1] = _0 - (_i + bvirt) + (bvirt - t1);
            u3 = _j + _i;
            bvirt = u3 - _j;
            catt[2] = _j - (u3 - bvirt) + (_i - bvirt);
            catt[3] = u3;
            cattlen = 4;
        } else {
            cat[0] = 0;
            catlen = 1;
            catt[0] = 0;
            cattlen = 1;
        }
        if (bdxtail !== 0) {
            const len = scale(catlen, cat, bdxtail, _16c);
            finlen = finadd(finlen, sum(
                scale(bxtcalen, bxtca, bdxtail, _16), _16,
                scale(len, _16c, 2 * bdx, _32), _32, _48), _48);

            const len2 = scale(cattlen, catt, bdxtail, _8);
            finlen = finadd(finlen, sum_three(
                scale(len2, _8, 2 * bdx, _16), _16,
                scale(len2, _8, bdxtail, _16b), _16b,
                scale(len, _16c, bdxtail, _32), _32, _32b, _64), _64);

            if (cdytail !== 0) {
                finlen = finadd(finlen, scale(scale(4, aa, bdxtail, _8), _8, cdytail, _16), _16);
            }
            if (adytail !== 0) {
                finlen = finadd(finlen, scale(scale(4, cc, -bdxtail, _8), _8, adytail, _16), _16);
            }
        }
        if (bdytail !== 0) {
            const len = scale(catlen, cat, bdytail, _16c);
            finlen = finadd(finlen, sum(
                scale(bytcalen, bytca, bdytail, _16), _16,
                scale(len, _16c, 2 * bdy, _32), _32, _48), _48);

            const len2 = scale(cattlen, catt, bdytail, _8);
            finlen = finadd(finlen, sum_three(
                scale(len2, _8, 2 * bdy, _16), _16,
                scale(len2, _8, bdytail, _16b), _16b,
                scale(len, _16c, bdytail, _32), _32,  _32b, _64), _64);
        }
    }
    if (cdxtail !== 0 || cdytail !== 0) {
        if (adxtail !== 0 || adytail !== 0 || bdxtail !== 0 || bdytail !== 0) {
            s1 = adxtail * bdy;
            c = splitter * adxtail;
            ahi = c - (c - adxtail);
            alo = adxtail - ahi;
            c = splitter * bdy;
            bhi = c - (c - bdy);
            blo = bdy - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = adx * bdytail;
            c = splitter * adx;
            ahi = c - (c - adx);
            alo = adx - ahi;
            c = splitter * bdytail;
            bhi = c - (c - bdytail);
            blo = bdytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 + t0;
            bvirt = _i - s0;
            u[0] = s0 - (_i - bvirt) + (t0 - bvirt);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 + t1;
            bvirt = _i - _0;
            u[1] = _0 - (_i - bvirt) + (t1 - bvirt);
            u3 = _j + _i;
            bvirt = u3 - _j;
            u[2] = _j - (u3 - bvirt) + (_i - bvirt);
            u[3] = u3;
            n1 = -ady;
            n0 = -adytail;
            s1 = bdxtail * n1;
            c = splitter * bdxtail;
            ahi = c - (c - bdxtail);
            alo = bdxtail - ahi;
            c = splitter * n1;
            bhi = c - (c - n1);
            blo = n1 - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = bdx * n0;
            c = splitter * bdx;
            ahi = c - (c - bdx);
            alo = bdx - ahi;
            c = splitter * n0;
            bhi = c - (c - n0);
            blo = n0 - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 + t0;
            bvirt = _i - s0;
            v[0] = s0 - (_i - bvirt) + (t0 - bvirt);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 + t1;
            bvirt = _i - _0;
            v[1] = _0 - (_i - bvirt) + (t1 - bvirt);
            u3 = _j + _i;
            bvirt = u3 - _j;
            v[2] = _j - (u3 - bvirt) + (_i - bvirt);
            v[3] = u3;
            abtlen = sum(4, u, 4, v, abt);
            s1 = adxtail * bdytail;
            c = splitter * adxtail;
            ahi = c - (c - adxtail);
            alo = adxtail - ahi;
            c = splitter * bdytail;
            bhi = c - (c - bdytail);
            blo = bdytail - bhi;
            s0 = alo * blo - (s1 - ahi * bhi - alo * bhi - ahi * blo);
            t1 = bdxtail * adytail;
            c = splitter * bdxtail;
            ahi = c - (c - bdxtail);
            alo = bdxtail - ahi;
            c = splitter * adytail;
            bhi = c - (c - adytail);
            blo = adytail - bhi;
            t0 = alo * blo - (t1 - ahi * bhi - alo * bhi - ahi * blo);
            _i = s0 - t0;
            bvirt = s0 - _i;
            abtt[0] = s0 - (_i + bvirt) + (bvirt - t0);
            _j = s1 + _i;
            bvirt = _j - s1;
            _0 = s1 - (_j - bvirt) + (_i - bvirt);
            _i = _0 - t1;
            bvirt = _0 - _i;
            abtt[1] = _0 - (_i + bvirt) + (bvirt - t1);
            u3 = _j + _i;
            bvirt = u3 - _j;
            abtt[2] = _j - (u3 - bvirt) + (_i - bvirt);
            abtt[3] = u3;
            abttlen = 4;
        } else {
            abt[0] = 0;
            abtlen = 1;
            abtt[0] = 0;
            abttlen = 1;
        }
        if (cdxtail !== 0) {
            const len = scale(abtlen, abt, cdxtail, _16c);
            finlen = finadd(finlen, sum(
                scale(cxtablen, cxtab, cdxtail, _16), _16,
                scale(len, _16c, 2 * cdx, _32), _32, _48), _48);

            const len2 = scale(abttlen, abtt, cdxtail, _8);
            finlen = finadd(finlen, sum_three(
                scale(len2, _8, 2 * cdx, _16), _16,
                scale(len2, _8, cdxtail, _16b), _16b,
                scale(len, _16c, cdxtail, _32), _32, _32b, _64), _64);

            if (adytail !== 0) {
                finlen = finadd(finlen, scale(scale(4, bb, cdxtail, _8), _8, adytail, _16), _16);
            }
            if (bdytail !== 0) {
                finlen = finadd(finlen, scale(scale(4, aa, -cdxtail, _8), _8, bdytail, _16), _16);
            }
        }
        if (cdytail !== 0) {
            const len = scale(abtlen, abt, cdytail, _16c);
            finlen = finadd(finlen, sum(
                scale(cytablen, cytab, cdytail, _16), _16,
                scale(len, _16c, 2 * cdy, _32), _32, _48), _48);

            const len2 = scale(abttlen, abtt, cdytail, _8);
            finlen = finadd(finlen, sum_three(
                scale(len2, _8, 2 * cdy, _16), _16,
                scale(len2, _8, cdytail, _16b), _16b,
                scale(len, _16c, cdytail, _32), _32, _32b, _64), _64);
        }
    }

    return fin[finlen - 1];
}

export function incircle(ax, ay, bx, by, cx, cy, dx, dy) {
    const adx = ax - dx;
    const bdx = bx - dx;
    const cdx = cx - dx;
    const ady = ay - dy;
    const bdy = by - dy;
    const cdy = cy - dy;

    const bdxcdy = bdx * cdy;
    const cdxbdy = cdx * bdy;
    const alift = adx * adx + ady * ady;

    const cdxady = cdx * ady;
    const adxcdy = adx * cdy;
    const blift = bdx * bdx + bdy * bdy;

    const adxbdy = adx * bdy;
    const bdxady = bdx * ady;
    const clift = cdx * cdx + cdy * cdy;

    const det =
        alift * (bdxcdy - cdxbdy) +
        blift * (cdxady - adxcdy) +
        clift * (adxbdy - bdxady);

    const permanent =
        (Math.abs(bdxcdy) + Math.abs(cdxbdy)) * alift +
        (Math.abs(cdxady) + Math.abs(adxcdy)) * blift +
        (Math.abs(adxbdy) + Math.abs(bdxady)) * clift;

    const errbound = iccerrboundA * permanent;

    if (det > errbound || -det > errbound) {
        return det;
    }
    return incircleadapt(ax, ay, bx, by, cx, cy, dx, dy, permanent);
}

export function incirclefast(ax, ay, bx, by, cx, cy, dx, dy) {
    const adx = ax - dx;
    const ady = ay - dy;
    const bdx = bx - dx;
    const bdy = by - dy;
    const cdx = cx - dx;
    const cdy = cy - dy;

    const abdet = adx * bdy - bdx * ady;
    const bcdet = bdx * cdy - cdx * bdy;
    const cadet = cdx * ady - adx * cdy;
    const alift = adx * adx + ady * ady;
    const blift = bdx * bdx + bdy * bdy;
    const clift = cdx * cdx + cdy * cdy;

    return alift * bcdet + blift * cadet + clift * abdet;
}