@polygonjs/polygonjs/dist/src/core/geometry/modules/tet/utils/tetInsideMesh.js

node-based WebGL 3D engine https://polygonjs.com

"use strict";
import { Vector3, BackSide } from "three";
import { createRaycaster } from "../../../../RaycastHelper";
export const DIRS = [
  new Vector3(1, 0, 0),
  new Vector3(-1, 0, 0),
  new Vector3(0, 1, 0),
  new Vector3(0, -1, 0),
  new Vector3(0, 0, 1),
  new Vector3(0, 0, -1)
];
const _raycaster = createRaycaster();
export function isPositionInsideMesh(pos, mesh, minDist) {
  let numIn = 0;
  const bvh = mesh.geometry.boundsTree;
  _raycaster.ray.origin.copy(pos);
  for (const dir of DIRS) {
    _raycaster.ray.direction.copy(dir);
    const hit = bvh.raycastFirst(_raycaster.ray, BackSide);
    if (hit) {
      const { normal, distance } = hit;
      if (normal) {
        normal.applyMatrix4(mesh.matrixWorld);
        if (normal.dot(dir) <= 0) {
          numIn++;
        }
        if (minDist > 0 && distance < minDist) {
          return false;
        }
      }
    }
  }
  return numIn > 4;
}