[Other] Questions about file size and custom roms

[Myxtro]

I'm still new to the world of ROM hacking and I'm enjoying it so far. However, I have a few questions which I hope you guys can answer.

To start off: I've read something about increasing the maximum file size. Why is this necessary? Is this common practice or is it something you rarely do? I had an error when I tried making a custom map for a building which got an error. Is this due to lack of space?

How are those large custom rom hacks made? Do they keep all of the original maps and rework them, or do they start from scratch? And how do you accomplish that without breaking everything? I can find a lot of information on how to edit existing games to your liking, but barely anything about creating a new game from scratch. (With from scratch I mean making the whole map and story, instead of just making a reskinned pokemon emerald for example.)

 

[BrandoSheriff]

I've been away from rom hacking and just recently got back into it, but I think I still might be able to answer your questions. I'll try to do so to the best off my ability.

Concerning file size: I actually asked this question myself a while back! It's only really necessary to expand the rom's file size if you absolutely need more space with which to do things with. The base rom actually contains a lot of free space. Open the rom in a hex editor and see; all the large lines of FF's are free space you can use to your liking. From what I've seen, it's rarely done due to those reasons, and only romhacks with a ton of features like all new music and all 800+ Pokemon are done on expanded roms since custom music and new Pokemon data for like 500-ish new Pokemon takes up a lot of space.

The error you experienced: I might need more details. Did you happen to repoint/overwrite space not considered free space?

Most rom hacks with many custom maps actually reuse the maps from the base rom and edit those into new ones rather than start fresh by adding new ones, as, unless you plan to use those maps elsewhere, it's more efficient to use what's already there. In AdvanceMap you are able to change the existing maps' data to your liking, whether it's size, collision, scripts, or number of NPCs. All you have to do is repoint that new data to free space when it asks; the program's built-in free space finder helps a bunch with this. All of this essentially allows you to create a new game from scratch by building off of the assets that are already there.

I hope I was able to answer your questions well enough! Let me know if you're still confused by anything.

 

[Myxtro]

I've been away from rom hacking and just recently got back into it, but I think I still might be able to answer your questions. I'll try to do so to the best off my ability.

Concerning file size: I actually asked this question myself a while back! It's only really necessary to expand the rom's file size if you absolutely need more space with which to do things with. The base rom actually contains a lot of free space. Open the rom in a hex editor and see; all the large lines of FF's are free space you can use to your liking. From what I've seen, it's rarely done due to those reasons, and only romhacks with a ton of features like all new music and all 800+ Pokemon are done on expanded roms since custom music and new Pokemon data for like 500-ish new Pokemon takes up a lot of space.

The error you experienced: I might need more details. Did you happen to repoint/overwrite space not considered free space?

Most rom hacks with many custom maps actually reuse the maps from the base rom and edit those into new ones rather than start fresh by adding new ones, as, unless you plan to use those maps elsewhere, it's more efficient to use what's already there. In AdvanceMap you are able to change the existing maps' data to your liking, whether it's size, collision, scripts, or number of NPCs. All you have to do is repoint that new data to free space when it asks; the program's built-in free space finder helps a bunch with this. All of this essentially allows you to create a new game from scratch by building off of the assets that are already there.

I hope I was able to answer your questions well enough! Let me know if you're still confused by anything.

Thanks for your reply! About the memory, this is the part I understand the least about. How are maps stored in the memory and how do I allocate new space for it? I know how to do that for scripts but I haven't seen that option in AdvanceMap.

 

[BrandoSheriff]

Thanks for your reply! About the memory, this is the part I understand the least about. How are maps stored in the memory and how do I allocate new space for it? I know how to do that for scripts but I haven't seen that option in AdvanceMap.

Maps are stored essentially the same way as the game's scripts are. I don't remember off the top of my head where in the rom they are located, but from my experiences, it's usually irrelevant to know when you're just editing the maps.

When editing maps, space actually is allocated by you, if said map needs its data repointed. Say you're changing something like increasing the number of NPCs and stuff. You'd edit the amount in the bottom right corner, then hit "change events",

Spoiler:

and a little box should pop up in AdvanceMap asking for that particular portion of the map's data to be repointed.

Spoiler:

Here, you'll input an arbitrary offset in the first box under where it says "specify searched area from", and it will spit out one or many choices at or from that offset where free space is available to stick the new data. You'll click one of these, preferably the first one, then hit "repoint", and you're good to go!

Spoiler:

I hope this helps somewhat. A pretty safe offset to start from is 800000, so I recommend using that as your arbitrary offset.

 

[Myxtro]

Thanks for all the help!