@jscad/modeling/src/geometries/geom3/fromCompactBinary.js

Constructive Solid Geometry (CSG) Library for JSCAD

const vec3 = require('../../maths/vec3')
const mat4 = require('../../maths/mat4')

const poly3 = require('../poly3')

const create = require('./create')

/**
 * Construct a new 3D geometry from the given compact binary data.
 * @param {TypedArray} data - compact binary data
 * @returns {geom3} a new geometry
 * @alias module:modeling/geometries/geom3.fromCompactBinary
 */
const fromCompactBinary = (data) => {
  if (data[0] !== 1) throw new Error('invalid compact binary data')

  const created = create()

  created.transforms = mat4.clone(data.slice(1, 17))

  const numberOfVertices = data[21]
  let ci = 22
  let vi = data.length - (numberOfVertices * 3)
  while (vi < data.length) {
    const verticesPerPolygon = data[ci]
    ci++

    const vertices = []
    for (let i = 0; i < verticesPerPolygon; i++) {
      vertices.push(vec3.fromValues(data[vi], data[vi + 1], data[vi + 2]))
      vi += 3
    }
    created.polygons.push(poly3.create(vertices))
  }

  // transfer known properties, i.e. color
  if (data[17] >= 0) {
    created.color = [data[17], data[18], data[19], data[20]]
  }
  // TODO: how about custom properties or fields ?
  return created
}

module.exports = fromCompactBinary