Switch BNTX research

[aboood40091]

Found another unknown format in Splatoon 2, 0x3106, which seems to be ASTC-based. I sent it to you to check out at your own leisure.

It's ASTC 6x6 with SRGB color space. (ASTC 6x6 SRGB for short)

Thanks for the files. I managed to fix some stuff and discover what some of the unknowns means with them. Extraction of non power of 2 textures is still hit or miss unfortunately, I still didn't totally figured out how the swizzle works, but its better at least. Tomorrow I plan to work to fix the remaining swizzling issues.

About the unknown formats you sent me, I took a look on the last one, and it's using ASTC compression. Heres one of them decoded (tc_MiiSuit_39^w):


This compressed format is still not supported on my tool (and i'm not on the mood to write a ASTC decompressor :I but I will end up doing it sooner or later anyway).

It's always flipped for me:


Lastly, I want to report that your swizzle algorithm works with XTX files, the Switch's equivalent of the Wii U's GTX, as well! Good job!