• Plane.js

  • ¶

    Plane geometry generator.

  • ¶

    Parent class : Geometry

  • ¶

    Example use

     var g = new Plane(1, 1, 10, 10, 'x', 'y');
 var mesh = new Mesh(g, new Materials.SolidColor());

    var geom = require('pex-geom');
var Vec2 = geom.Vec2;
var Vec3 = geom.Vec3;
var Geometry = geom.Geometry;
  • ¶

    Plane ( sx, sy, nx, ny, u, v)

    su - size u / width { Number = 1 }
    sv - size v / height { Number = 1 }
    nu - number of subdivisions on u axis { Number/Int = 1 }
    nv - number of subdivisions on v axis { Number/Int = 1 }
    u - first axis { String = “x” } v - second axis { String = “y” }

    function Plane(su, sv, nu, nv, u, v) {
  su = su || 1;
  sv = sv || su || 1;
  nu = nu || 1;
  nv = nv || nu || 1;
  u = u || 'x';
  v = v || 'y';

  Geometry.call(this, { vertices: true, normals: true, texCoords: true, faces: true, edges: true });

  var w = ['x', 'y', 'z'];
  w.splice(w.indexOf(u), 1);
  w.splice(w.indexOf(v), 1);
  w = w[0];

  var vertices = this.vertices;
  var texCoords = this.texCoords;
  var normals = this.normals;
  var faces = this.faces;
  var edges = this.edges;
  • ¶

    How faces are constructed:

    0-----1 . . 2       n  <----  n+1
|   / .     .       |         A
| /   .     .       V         |
3 . . 4 . . 5      n+nu --> n+nu+1
.     .     .
.     .     .
6 . . 7 . . 8

      var vertShift = vertices.length;
  for(var j=0; j<=nv; ++j) {
    for(var i=0; i<=nu; ++i) {
      var vert = new Vec3();
      vert[u] = (-su/2 + i*su/nu);
      vert[v] = ( sv/2 - j*sv/nv);
      vert[w] = 0;
      vertices.push(vert);

      var texCoord = new Vec2(i/nu, 1.0 - j/nv);
      texCoords.push(texCoord);

      var normal = new Vec3();
      normal[u] = 0;
      normal[v] = 0;
      normal[w] = 1;
      normals.push(normal);
    }
  }
  for(var j=0; j<nv; ++j) {
    for(var i=0; i<nu; ++i) {
      var n = vertShift + j * (nu + 1) + i;
      var face = [n, n + nu  + 1, n + nu + 2, n + 1];

      edges.push([n, n + 1]);
      edges.push([n, n + nu + 1]);

      if (j == nv - 1) {
        edges.push([n + nu + 1, n + nu + 2]);
      }
      if (i == nu - 1) {
        edges.push([n + 1, n + nu + 2]);
      }
      faces.push(face);
    }
  }
}

Plane.prototype = Object.create(Geometry.prototype);

module.exports = Plane;