OSL_SHADEOP void osl_trunc_vv (void *r, void *x_) {
    const Vec3 &x (VEC(x_));
    VEC(r).setValue (truncf(x[0]), truncf(x[1]), truncf(x[2]));
}
OSL_SHADEOP float osl_trunc_ff (float x) { return truncf(x); }