* \param values initial parameter value, up to 4 GLfloats, or NULL
* \param state state indexes, or NULL
* \return index of new parameter in the list, or -1 if error (out of mem)
* \param values initial parameter value, up to 4 GLfloats, or NULL
* \param state state indexes, or NULL
* \return index of new parameter in the list, or -1 if error (out of mem)