Added a new MBAC documentation.

[KidGbzin]

This is a new documentation that I wrote for the MBAC format, it’s not finished yet.

I’ve been trying to implement an MTRA-to-Blender animation converter for some years, and because of that I found some inconsistencies in the current MBAC-to-OBJ conversion. So I studied the format and the existing converter, refactored a few things here and there, and started writing notes like a book. Here’s the document I’ve written so far. Later I’ll also commit the refactored converter.

But here are some notes: the current converter generates imprecise meshes due to some divisions. The original MascotCapsule engine uses bit-shifting for purely integer math. Because of those float inaccuracies, some meshes may show flickering faces during rendering, and these imprecisions can also affect MTRA actions.

I don’t know if it was intended or not, but the original converter didn’t export normals.