(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define(["exports", "three"], factory);
  } else if (typeof exports !== "undefined") {
    factory(exports, require("three"));
  } else {
    var mod = {
      exports: {}
    };
    factory(mod.exports, global.three);
    global.ParametricGeometry = mod.exports;
  }
})(typeof globalThis !== "undefined" ? globalThis : typeof self !== "undefined" ? self : this, function (_exports, _three) {
  "use strict";

  Object.defineProperty(_exports, "__esModule", {
    value: true
  });
  _exports.ParametricGeometry = void 0;

  function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

  function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }

  function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

  function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } Object.defineProperty(subClass, "prototype", { value: Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }), writable: false }); if (superClass) _setPrototypeOf(subClass, superClass); }

  function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }

  function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = _getPrototypeOf(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }

  function _possibleConstructorReturn(self, call) { if (call && (typeof call === "object" || typeof call === "function")) { return call; } else if (call !== void 0) { throw new TypeError("Derived constructors may only return object or undefined"); } return _assertThisInitialized(self); }

  function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }

  function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Boolean.prototype.valueOf.call(Reflect.construct(Boolean, [], function () {})); return true; } catch (e) { return false; } }

  function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) { return o.__proto__ || Object.getPrototypeOf(o); }; return _getPrototypeOf(o); }

  var ParametricGeometry = /*#__PURE__*/function (_BufferGeometry) {
    _inherits(ParametricGeometry, _BufferGeometry);

    var _super = _createSuper(ParametricGeometry);

    function ParametricGeometry() {
      var _this;

      var func = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : function (u, v, target) {
        return target.set(u, v, Math.cos(u) * Math.sin(v));
      };
      var slices = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 8;
      var stacks = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : 8;

      _classCallCheck(this, ParametricGeometry);

      _this = _super.call(this);
      _this.type = 'ParametricGeometry';
      _this.parameters = {
        func: func,
        slices: slices,
        stacks: stacks
      }; // buffers

      var indices = [];
      var vertices = [];
      var normals = [];
      var uvs = [];
      var EPS = 0.00001;
      var normal = new _three.Vector3();
      var p0 = new _three.Vector3(),
          p1 = new _three.Vector3();
      var pu = new _three.Vector3(),
          pv = new _three.Vector3();

      if (func.length < 3) {
        console.error('THREE.ParametricGeometry: Function must now modify a Vector3 as third parameter.');
      } // generate vertices, normals and uvs


      var sliceCount = slices + 1;

      for (var i = 0; i <= stacks; i++) {
        var v = i / stacks;

        for (var j = 0; j <= slices; j++) {
          var u = j / slices; // vertex

          func(u, v, p0);
          vertices.push(p0.x, p0.y, p0.z); // normal
          // approximate tangent vectors via finite differences

          if (u - EPS >= 0) {
            func(u - EPS, v, p1);
            pu.subVectors(p0, p1);
          } else {
            func(u + EPS, v, p1);
            pu.subVectors(p1, p0);
          }

          if (v - EPS >= 0) {
            func(u, v - EPS, p1);
            pv.subVectors(p0, p1);
          } else {
            func(u, v + EPS, p1);
            pv.subVectors(p1, p0);
          } // cross product of tangent vectors returns surface normal


          normal.crossVectors(pu, pv).normalize();
          normals.push(normal.x, normal.y, normal.z); // uv

          uvs.push(u, v);
        }
      } // generate indices


      for (var _i = 0; _i < stacks; _i++) {
        for (var _j = 0; _j < slices; _j++) {
          var a = _i * sliceCount + _j;
          var b = _i * sliceCount + _j + 1;
          var c = (_i + 1) * sliceCount + _j + 1;
          var d = (_i + 1) * sliceCount + _j; // faces one and two

          indices.push(a, b, d);
          indices.push(b, c, d);
        }
      } // build geometry


      _this.setIndex(indices);

      _this.setAttribute('position', new _three.Float32BufferAttribute(vertices, 3));

      _this.setAttribute('normal', new _three.Float32BufferAttribute(normals, 3));

      _this.setAttribute('uv', new _three.Float32BufferAttribute(uvs, 2));

      return _this;
    }

    return _createClass(ParametricGeometry);
  }(_three.BufferGeometry);

  _exports.ParametricGeometry = ParametricGeometry;
});