Discussion in 'Sega Dreamcast Development and Research' started by Renard, Oct 3, 2018.
We can almost do our music stage for samba de amigo with your tools
Thanks - but I think I'm halfway there.
I believe I've completely documented the "Amigo"blocks (difficulty levels) EASY, NORM, HARD, SUPR. One could create a level editor for this (with audio sync and player movements) without problems.
Amigo blocks DA_E, DA_N, DA_H and DA_S are the equivalent in hustle mode, and very similar in format, but I'm not sure about the meaning of a few bits (probably related to the speed of the movements). Still, creating / editing hustle mode levels should not be difficult.
I didn't spend much time with HEAD, CAM_ and ACT_ blocks, though. They seem to handle camera position and movements, as well as "actors" and "extras". There's some debug code in the game that could shed a light on this - I've seen mentions of "stand, jump, side_step, fr_bk_step, act_bakuten, act_object" (BTW, "bakuten" is "backflip" in Japanese). To create/edit the background animations, these blocks must be understood.
I noticed that for the same song in both DC & Wii (Bamboleo):
Amigo blocks are almost identical (at least in format)
HEAD blocks are identical
half of the ACT_ blocks are identical, the others have a few bits slightly different
CAM_ blocks are VERY different (at least in content)
So, to complete the reverse engineering of Amigo files, we need to understand a few bits of Amigo blocks and the meaning of HEAD, CAM_ and ACT_ blocks. My current workflow is:
Dump an Amigo file with amigo_explorer.py
Play & record the gameplay
Trim the video so it will start at "frame 0" (which is the 1st frame after fading to black)
Play the video with ffplay and follow along with the dump (timing on both is in the same format)
Notice what happens in the video and correlate with the values in the dump
If anyone wants to help with that, I'd be grateful.
P.S.: I also would love to have native Python libraries to read & write files (such as AFS, PVR, TPL, ...) to automate file conversions and thus translation of the game. I could do it all manually with currently available tools, but that's not fun - and such libraries would help in other projects as well.
If anyone is interested, check out the Kaitai Struct Web IDE, where you can load a .ksy file (defining a file structure), load a file (such as a DC .AMG Amigo file) and see the data being mapped to the structure that you can edit in real time. It would be a great reverse engineering tool just for that, but it also can create code to parse the structure in many different languages as well! So if anyone could contribute with a Kaitai Struct file format as well, it would be awesome!
P.P.S.: I tried using the Null DC debugger, but the debugger seems to be buggy! Does anyone recommend another emulator with a debugger (that works)?
As you can see in the video above, I replaced "Tubthumping" with "Arriba Allez" with v. 0.2 of amg_explorer, and even the animations work correctly!
I described (almost) completely the .AMG format, both in text format and in Kaitai Struct files. Please see https://github.com/AltoRetrato/samba-de-amigo-2k_modding for details.
This means that song conversion is basically done! I didn't test anything besides what's in the video, though, so bug reports, bug fixes and suggestions are welcome.
Edit: First bug report is from me. Only afterwards I noticed the game seems to be a bit out of sync, and hustle mode crashed the emulator. Oh well, back to the drawing board (but only when I get some free time)...
You are working very well
I've finally been able to play around a bit with Kaitai. I'm really impressed, this is a fantastic tool. Combined with the documentation you already wrote, this is absolutely bonkers!
Please show us when you can
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