@jscad/regl-renderer/src/bound-utils/computeBounds.js

Renderer for JSCAD Geometries

const vec3 = require('gl-vec3')

const { flatten } = require('@jscad/array-utils')

const boundingBox = require('./boundingBox')

/*
 * Compute the bounds of the given geometries.
 * See geometry-utils-V2
 * @param  {geometry|Array} geometries - geometry or list of geometries to measure
 * @return {Object} the bounds of the given geometries
 * bounds: {
 *   dia: 40,
 *   center: [0,20,8],
 *   min: [9, -10, 0],
 *   max: [15, 10, 4]
 *   size: [6,20,4]
 * }
 */
const computeBounds = (...geometries) => {
  geometries = flatten(geometries)

  let bbox // min and max
  geometries.forEach((geometry) => {
    let gbbox = boundingBox(geometry.positions)
    gbbox = gbbox.map((bounds) => vec3.transformMat4(bounds, bounds, geometry.transforms))
    if (bbox) {
      vec3.min(bbox[0], bbox[0], gbbox[0])
      vec3.max(bbox[1], bbox[1], gbbox[1])
    } else {
      bbox = gbbox
    }
  })

  const min = vec3.min(vec3.create(), bbox[1], bbox[0])
  const max = vec3.max(vec3.create(), bbox[1], bbox[0])

  const size = vec3.subtract(vec3.create(), max, min)
  let center = vec3.scale(vec3.create(), size, 0.5)
  center = vec3.add(center, min, center)
  // aproximate diamter
  const dia = vec3.distance(center, max)

  const bounds = {
    dia,
    center: [...center],
    min: [...min],
    max: [...max],
    size: [...size]
  }
  return bounds
}

module.exports = computeBounds