code: function scaling(v, dst) {
    dst = dst || new MatType(16);
  
    dst[ 0] = v[0];
    dst[ 1] = 0;
    dst[ 2] = 0;
    dst[ 3] = 0;
    dst[ 4] = 0;
    dst[ 5] = v[1];
    dst[ 6] = 0;
    dst[ 7] = 0;
    dst[ 8] = 0;
    dst[ 9] = 0;
    dst[10] = v[2];
    dst[11] = 0;
    dst[12] = 0;
    dst[13] = 0;
    dst[14] = 0;
    dst[15] = 1;
  
    return dst;
  }
docs: Creates a 4-by-4 matrix which scales in each dimension by an amount given by
  the corresponding entry in the given vector; assumes the vector has three
  entries.
  @param {module:twgl/v3.Vec3} v A vector of
  three entries specifying the factor by which to scale in each dimension.
  @param {module:twgl/m4.Mat4} [dst] matrix to hold result. If none new one is created..
  @return {module:twgl/m4.Mat4} The scaling matrix.
  @memberOf module:twgl/m4