dbl_to_plain_fx
dbl_to_plain_fx(mtx[0]),
dbl_to_plain_fx(mtx[1]),
dbl_to_plain_fx(mtx[2]),
dbl_to_plain_fx(mtx[3]),
dbl_to_plain_fx(mtx[4]),
dbl_to_plain_fx(mtx[5]));