[Other] Does hidden item take up a flag space?

[mzn1]

Hi, everyone.

I have a question that is not answered by anyone (at least it seemed so to me). After a lot of googling, I decided to take it here to get help. Here it goes:

We all know that we can use Advance Map to add hidden item to the game. It's simple and the beauty of it is its one-off effect -- works like a flag: once you pick up a hidden item, it would be gone forever.

I just don't understand. How would the game tell if I had already picked up this hidden item every time it loads my .save file? I am pretty sure a flag mechanism is used in hidden item and the flag no. is in my .save file.

If my guess turn out to be corret, then here comes the problem: (if) the hidden item did take up a flag number, I must know what number it is, otherwise I would mess it up with other scripts that involve the use of flags.

Would anyone please tell me how the hidden item mechanism works and how do I find out what flag number it used? Thank you for your time.

BTW, what is "hidden id"?

 

[Squeetz]

I am pretty sure a flag mechanism is used in hidden item
BTW, what is "hidden id"?

You almost answered your own question!
The hidden ID is the "flag" for the hidden item (0-FF).

 

[mzn1]

You almost answered your own question!
The hidden ID is the "flag" for the hidden item (0-FF).

Oh really? So what you are saying is that "hidden ID" is the flag no. for the hidden item, and that flag system is different from the one we talked about when writing scripts?

If that is the case, then obviously the original game (clean rom) have used some hidden IDs already, as there were certain hidden items in the game. And from the attached image we can further tell that I used the wrong hidden ID for the item I created. Because hidden ID "00" must be a flag number already used by some item in the original game!

So what hidden IDs have been used by the original game and what range/section should I used for newly added hidden items of my hack?

Thank you ! Squeetz

 

[Deokishisu]

I doubt that a full list of used hidden IDs have been compiled. You'll have to comb through the game yourself and figure out which ones are used where.

 

[mzn1]

I doubt that a full list of used hidden IDs have been compiled. You'll have to comb through the game yourself and figure out which ones are used where.

OMG that is almost impossible! Do you have any walkthrough that shows all the hidden items in the game??????

 

[Deokishisu]

It's actually not impossible. You open up a clean ROM in Advance Map and open every map one-by-one, jotting down all the hidden items, their location, and their hidden IDs. It's time consuming, but not impossible.

 

[DizzyEgg]

Hi, everyone.

I have a question that is not answered by anyone (at least it seemed so to me). After a lot of googling, I decided to take it here to get help. Here it goes:

We all know that we can use Advance Map to add hidden item to the game. It's simple and the beauty of it is its one-off effect -- works like a flag: once you pick up a hidden item, it would be gone forever.

I just don't understand. How would the game tell if I had already picked up this hidden item every time it loads my .save file? I am pretty sure a flag mechanism is used in hidden item and the flag no. is in my .save file.

If my guess turn out to be corret, then here comes the problem: (if) the hidden item did take up a flag number, I must know what number it is, otherwise I would mess it up with other scripts that involve the use of flags.

Would anyone please tell me how the hidden item mechanism works and how do I find out what flag number it used? Thank you for your time.

BTW, what is "hidden id"?

Hidden ID is a flag that the hidden item uses. In Emerald the flag is 0x1F4 + hiddenID. In Fire Red it's the same but the flag number differs. If you pick up an item, the flag gets set. So that's how the game knows you've picked it.