vertices: array[ m * n ]

m*n-m ...                     m*n-1


       --------------------------
       | (j+1)*m+i  (j+1)*m+i+1 |
       |    j *m+i     j *m+i+1 |                    0 <= j < n
       -------------------------- 


2m  ....                       3m-1 [...2m]
 m  m+1 m+2 ....               2m-1 [... m]
 0  1   2   3   4  ....         m-1 [... 0]

    0 <= i < m

d--c
| /|
|/ |
a--b


If we are replicating the same vertex value on left and right columns:

face: array [ 2 * (m-1) * (n-1) ]

    faces = [];
    for (var j = 0 ; j < n-1 ; j++)
    for (var i = 0 ; i < m-1 ; i++) {
       var a =    j  * m + i;
       var b =    j  * m + i + 1;
       var c = (j+1) * m + i + 1;
       var d = (j+1) * m + i;
       faces.push( [ a, b, c ] );
       faces.push( [ c, d, a ] );
    }

If we are NOT replicating the same vertex value on left and right columns:
          
face: array [ 2 * m * (n-1) ]

    faces = [];
    for (var j = 0 ; j < n-1 ; j++)
    for (var i = 0 ; i < m   ; i++) {
       var a =    j  * m + i;
       var b =    j  * m + (i + 1) % m;
       var c = (j+1) * m + (i + 1) % m;
       var d = (j+1) * m + i;
       faces.push( [ a, b, c ] );
       faces.push( [ c, d, a ] );
    }

Wrap both ways (eg: Torus):

face: array [ 2 * m * n ]

    faces = [];
    for (var j = 0 ; j < n ; j++)
    for (var i = 0 ; i < m ; i++) {
       var a =        j  * m + i;
       var b =        j  * m + (i + 1) % m;
       var c = ((j+1)%n) * m + (i + 1) % m;
       var d = ((j+1)%n) * m + i;
       faces.push( [ a, b, c ] );
       faces.push( [ c, d, a ] );
    }

Vertex = {
   point : [x,y,z],
   normal: [x,y,z],
   uv    : [u,v],
};