code: function scale(out, a, b) {
    out[0] = a[0] * b;
    out[1] = a[1] * b;
    out[2] = a[2] * b;
    return out;
  }
docs: Scales a vec3 by a scalar number
  
  @param {vec3} out the receiving vector
  @param {vec3} a the vector to scale
  @param {Number} b amount to scale the vector by
  @returns {vec3} out