cross = (out, a, b) => {
  out[0] = 0
  out[1] = 0
  out[2] = a[0] * b[1] - a[1] * b[0]
  return out
}
Computes the cross product (3D) of two vectors.

@param {vec3} out - receiving vector (3D)
@param {vec2} a - first operand
@param {vec2} b - second operand
@returns {vec3} out
@alias module:modeling/maths/vec2.cross