Rumors are that the casino won't be a smoking place in the future. Part of it is right now though.
There will be two decks where you can smoke on one side in an area (I believe one is on the pool deck). The hint is the ashtrays in the area. Also they are marked and there will be something letting you know about them.
I can't speak for the ship you want to go on but like the other OP said casinos are in the process of going non-smoking. There is usually a place on deck that has smoking.