Implemented as Godot plugin.

[sitton76]

Hello, I recently started work on using this as the base for a Godot plugin, the thought process I had was to help enable people to release GBA homebrew games as PC releases(with the rom included in the files for a release) ATM the repo is still privated and I still need to get the audio working for it.

As for why I want to do this for a game engine, it is to allow people to easily add stuff unrelated that is not directly related to the game. or controller friendly UIs to activate emulator features. One example of what I want to enable would be the Castlevania Advance Collection as that contains other content aside from just the games.

I have a few questions I wanted to ask, one relates to this project, and one about the suggested bios reimplementation linked in the readme.

First question, is this something you folks would like to be upstreamed here? ATM I am using this project as a submodule and using some of its structs in the GDExtention bindings. But I noticed that this repo has a few platforms implemented as well so I figured it would not hurt to ask if you would prefer it that way, or if it would be better for it to exist as a separate repo. If this sounds like something you would want upstreamed ill be happy to show it off once its ready for a PR, but otherwise im content with it being on its own branch.

The other question, and frankly maybe this might be the wrong place to ask because you folks don't work on it, but what is the legally of using the reimplemented bios? The bios is needed to run the emulator which would mean people who use these Godot bindings would also need to redistribute it, I would be lying if I said this did not cause me a bit of concern from a legality POV. I just don't want to put people in legal issues over this sort of thing is all, I noticed in some parts of the code it would auto download the bios so I assumed that this is something you folks have had to consider before as well. I have looked into a bit which has caused me some doubts which is what prompted me to ask here, if it turns out to be in some sort of grey area I may need to drop this project.

Or, if it is possible to run homebrew specifically without the BIOS, that would also be ideal, however I don't know enough about what the bios provides outside of the boot splash or maybe hardware support for stuff like Link cables and such. Might try to see if I can make things work without it just to see if it is possible.

Regardless I been having a blast getting this working with Godot, so thanks in advance for maintaining this emulator.

EDIT:
Just after posting this I found a project also aiming to add a GB/GBC/GBA emulator to Godot, although seemed they dropped support for the GBA portion due to the BIOS issues.

[michelhe]

Hi — first of all, thank you for being interested in my project :)

Regarding the Godot plugin, it sounds awesome! That said, I don’t think it’s a good idea to accept it upstream. The simple reason is that I really don’t have the time to maintain this project, and even small fixes or corrections would be blocked on me having to review and test them.

As for the open-source BIOS legality… I honestly don’t know. If the repository is still up, it’s either because nobody cares enough to take it down, or because it can’t be proven that the authors didn’t rely on existing BIOS machine code as “inspiration.” The documented BIOS functions in the AGB SDKs are fairly simple, so anyone could theoretically create a ROM that implements them. But other services, like booting the actual hardware, aren’t as well documented, which means reverse engineering must have been involved to some extent.

Either way, it’s probably a gray area — and I’m not convinced that even printing the download URL in fn ask_download_bios() is a good idea..

[sitton76]

Thanks for the reply. The main motivating factor for me working on this was due to my own interest in making homebrew games and I figured it would be cool if I could publish them in such a way where people could easily play them.

That said legal gray area of the bios is def something I want to avoid, even more so since I intended to make this usable by others, thanks for your awesome work on this project however. I will def be keeping a eye on it. Hope you have a wonderful day.