fromScalar = (out, scalar) => {
  out[0] = scalar
  out[1] = scalar
  out[2] = scalar
  return out
}
Creates a vector from a single scalar value.
All components of the resulting vector have the given value.

@param {vec3} out - receiving vector
@param {Number} scalar
@returns {vec3} out
@alias module:modeling/maths/vec3.fromScalar