@jscad/csg/src/FuzzyFactory3d.js

const {EPS} = require('./constants')
const Polygon = require('./math/Polygon3')
const FuzzyFactory = require('./FuzzyFactory')

// ////////////////////////////////////
const FuzzyCSGFactory = function () {
  this.vertexfactory = new FuzzyFactory(3, EPS)
  this.planefactory = new FuzzyFactory(4, EPS)
  this.polygonsharedfactory = {}
}

FuzzyCSGFactory.prototype = {
  getPolygonShared: function (sourceshared) {
    let hash = sourceshared.getHash()
    if (hash in this.polygonsharedfactory) {
      return this.polygonsharedfactory[hash]
    } else {
      this.polygonsharedfactory[hash] = sourceshared
      return sourceshared
    }
  },

  getVertex: function (sourcevertex) {
    let elements = [sourcevertex.pos._x, sourcevertex.pos._y, sourcevertex.pos._z]
    let result = this.vertexfactory.lookupOrCreate(elements, function (els) {
      return sourcevertex
    })
    return result
  },

  getPlane: function (sourceplane) {
    let elements = [sourceplane.normal._x, sourceplane.normal._y, sourceplane.normal._z, sourceplane.w]
    let result = this.planefactory.lookupOrCreate(elements, function (els) {
      return sourceplane
    })
    return result
  },

  getPolygon: function (sourcepolygon) {
    let newplane = this.getPlane(sourcepolygon.plane)
    let newshared = this.getPolygonShared(sourcepolygon.shared)
    let _this = this
    let newvertices = sourcepolygon.vertices.map(function (vertex) {
      return _this.getVertex(vertex)
    })
        // two vertices that were originally very close may now have become
        // truly identical (referring to the same Vertex object).
        // Remove duplicate vertices:
    let newverticesDedup = []
    if (newvertices.length > 0) {
      let prevvertextag = newvertices[newvertices.length - 1].getTag()
      newvertices.forEach(function (vertex) {
        let vertextag = vertex.getTag()
        if (vertextag !== prevvertextag) {
          newverticesDedup.push(vertex)
        }
        prevvertextag = vertextag
      })
    }
        // If it's degenerate, remove all vertices:
    if (newverticesDedup.length < 3) {
      newverticesDedup = []
    }
    return new Polygon(newverticesDedup, newshared, newplane)
  }
}

module.exports = FuzzyCSGFactory