/**
* @author zz85 / https://github.com/zz85
* Parametric Surfaces Geometry
* based on the brilliant article by @prideout http://prideout.net/blog/?p=44
*
* new THREE.ParametricGeometry( parametricFunction, uSegments, ySegements );
*
*/
export class ParametricGeometry {
   // THREE.ParametricGeometry = function(func, slices, stacks) {
   //    THREE.Geometry.call(this);
   //    this.type = 'ParametricGeometry';
   //    this.parameters = {
   //       func: func,
   //       slices: slices,
   //       stacks: stacks
   //    };
   //    var verts = this.vertices;
   //    var faces = this.faces;
   //    var uvs = this.faceVertexUvs[0];
   //    var i, j, p;
   //    var u, v;
   //    var sliceCount = slices + 1;
   //    for (i = 0; i <= stacks; i++) {
   //       v = i / stacks;
   //       for (j = 0; j <= slices; j++) {
   //          u = j / slices;
   //          p = func(u, v);
   //          verts.push(p);
   //       }
   //    }
   //    var a, b, c, d;
   //    var uva, uvb, uvc, uvd;
   //    for (i = 0; i < stacks; i++) {
   //       for (j = 0; j < slices; j++) {
   //          a = i * sliceCount + j;
   //          b = i * sliceCount + j + 1;
   //          c = (i + 1) * sliceCount + j + 1;
   //          d = (i + 1) * sliceCount + j;
   //          uva = new THREE.Vector2(j / slices, i / stacks);
   //          uvb = new THREE.Vector2((j + 1) / slices, i / stacks);
   //          uvc = new THREE.Vector2((j + 1) / slices, (i + 1) / stacks);
   //          uvd = new THREE.Vector2(j / slices, (i + 1) / stacks);
   //          faces.push(new THREE.Face3(a, b, d));
   //          uvs.push([uva, uvb, uvd]);
   //          faces.push(new THREE.Face3(b, c, d));
   //          uvs.push([uvb.clone(), uvc, uvd.clone()]);
   //       }
   //    }
   //    // console.log(this);
   //    // magic bullet
   //    // var diff = this.mergeVertices();
   //    // console.log('removed ', diff, ' vertices by merging');
   //    this.computeFaceNormals();
   //    this.computeVertexNormals();
   // };
   // THREE.ParametricGeometry.prototype = Object.create(THREE.Geometry.prototype);
   // THREE.ParametricGeometry.prototype.constructor = THREE.ParametricGeometry;
}