function negate$2(out, a) {
    out[0] = -a[0];
    out[1] = -a[1];
    out[2] = -a[2];
    return out;
  }
Negates the components of a vec3

@param {vec3} out the receiving vector
@param {ReadonlyVec3} a vector to negate
@returns {vec3} out