@polygonjs/polygonjs
Version:
node-based WebGL 3D engine https://polygonjs.com
61 lines (60 loc) • 1.92 kB
JavaScript
"use strict";
import { Vector3 } from "three";
export function tetCenter(tetGeometry, tetId, target) {
const points = tetGeometry.points;
const tet = tetGeometry.tetrahedrons.get(tetId);
if (!tet) {
return;
}
const id0 = tet.pointIds[0];
const id1 = tet.pointIds[1];
const id2 = tet.pointIds[2];
const id3 = tet.pointIds[3];
const pt0 = points.get(id0);
const pt1 = points.get(id1);
const pt2 = points.get(id2);
const pt3 = points.get(id3);
if (!(pt0 && pt1 && pt2 && pt3)) {
return;
}
target.copy(pt0.position).add(pt1.position).add(pt2.position).add(pt3.position).multiplyScalar(0.25);
}
const b = new Vector3();
const c = new Vector3();
const d = new Vector3();
const b2 = new Vector3();
const c2 = new Vector3();
const d2 = new Vector3();
export function getCircumCenter(p0, p1, p2, p3, target) {
b.copy(p1).sub(p0);
c.copy(p2).sub(p0);
d.copy(p3).sub(p0);
const det = 2 * (b.x * (c.y * d.z - c.z * d.y) - b.y * (c.x * d.z - c.z * d.x) + b.z * (c.x * d.y - c.y * d.x));
if (det == 0) {
return target.copy(p0);
} else {
const dotb = b.dot(b);
const dotc = c.dot(c);
const dotd = d.dot(d);
const cd = c2.copy(c).cross(d);
const db = d2.copy(d).cross(b);
const bc = b2.copy(b).cross(c);
cd.multiplyScalar(dotb).add(db.multiplyScalar(dotc)).add(bc.multiplyScalar(dotd));
cd.divideScalar(det);
return target.copy(p0).add(cd);
}
}
export function tetCircumCenter(tetGeometry, tetId, target) {
const tet = tetGeometry.tetrahedrons.get(tetId);
if (!tet) {
return;
}
const pt0 = tetGeometry.points.get(tet.pointIds[0]);
const pt1 = tetGeometry.points.get(tet.pointIds[1]);
const pt2 = tetGeometry.points.get(tet.pointIds[2]);
const pt3 = tetGeometry.points.get(tet.pointIds[3]);
if (!(pt0 && pt1 && pt2 && pt3)) {
return;
}
getCircumCenter(pt0.position, pt1.position, pt2.position, pt3.position, target);
}