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Foone🏳️‍⚧️

and 16 bytes is exactly the same size as the WiiTextureHeader structure used by the engine!

28 comments
Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

so they have two copies of the resource in the file, but one of them has different FLAGS, which presumably indicates "hey this is the metadata", which has stuff like the texture format and image size. both of them.
it's 32x32 and 32x32. I don't know why there are two.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

I'm gonna have to modify the extractor I'm working on to do two searches and find the CFLAGS=64 version, get the metadata, then extract the other one separately.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

the datafile has 1938 matches for "CFLAGS 64", so... does this game have 1938 separate textures? maybe!

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

fun fact: just about every other game and file format in the world solves this complex problem by JUST PUTTING A FUCKING HEADER IN THE FILE WHAT ARE YOU DOING

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

what do you think this is, classic macos with resource forks?

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

1984 called they want their filesystem design back, Pipeworks!

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

okay having written an extractor for that format, I move onto the next format: GX_TF_RGBA8.
Hey, that seems simple! 8 bits per channel, RBGA, 32bit per pixel. Easy, right?

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

OH GOD NOPE.
So, it's encoded as 4x4 pixel chunks, right? But it's planar... interleaved planar.

So a 4x4 RGB8 chunk looks like this:

ARARARAR ARARARAR
ARARARAR ARARARAR
GBGBGBGB GBGBGBGB
GBGBGBGB GBGBGBGB

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

my favorite part is that nintendo literally calls this RGBA when it's not in RGBA order.
It's in ARGB order. Or, you know, ARARARARA... order.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

re-parsed.
Yeah it turns out my code worked perfectly on the first try!
I just, wasn't, uh... running it.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

well I'm not sure what that is but it didn't parse properly

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

OH GOD THEY CHANGED THE BLOCK SIZE FOR GREYSCALE IMAGES
they're 8x4, not 4x4

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

NINTENDO IS JAPANESE FOR "I HATE THE VERY IDEA FOR MAKING ANY FUCKING SENSE"

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

it's only slightly better when properly parsed, to be honest

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

oh wow. I parsed IA8 correctly on the first try!

(it is, of course, in AI byte-order)

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

the final format I need to implement is GX_TF_CMPR, which is a variant of DXT1 texture compression, in 8x8 blocks.

JUST KIDDING! it's implemented as four 4x4 sub-blocks.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

so for each subblock, there's 64 bits.
The first half is two 16-bit values, c0 and c1. Their numeric value is important, as they're compared, and mean different things which one is bigger.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

so the two numbers are compared, and either way, c0 and c1 are RGB 5:6:5 colors.
Then, depending on which is bigger, c2 and c3 get calculated.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

if c0 is bigger than c1, then:
c2 is set to 2/3rds of c0 + 1/3rd of c1
and
c3 is set to 1/3rd of c0 and 2/3rds of c1.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

but if c1 is bigger than c0, then:
c2 is set to 1/2 c0 and 1/2 c1, and c3 is set to transparent black.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

so now you have 4 colors, c0 through c3.

The final 32 bits of the subblock is an index into this palette, with two bits per pixel.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

so yeah. dxt1 works by having you define two colors, they get an extra bit of metadata by making the order of the colors important, then generate 2 more colors based on those colors + metadata.
Then it's a simple 4-bit paletted image, like we're running a CGA 3D Renderer over here.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

ugh it turns out it's hard to decode 0-width fonts, thanks to divisions.

Foone🏳️‍⚧️ replied to Foone🏳️‍⚧️

I'm now mass-converting all the textures.
I don't think this one is working right. Just a guess.

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