[Wii] Coraline | dxt Converter / Unpacker / Packer / Extractor | Magic: 30 81 80 00 / \x30\x81\x80\x00 / 30818000 / 308180

dxt_to_png.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
[Wii] Coraline
  .dxt <-> PNG

Requirements:
  pip install -U pillow

Usage:
# ./*.dxt -> ./*.dxt.png
  script.py
# filename.dxt -> filename.dxt.png
  script.py filename.dxt
# filename.dxt.png + filename.dxt (header) -> filename.dxt
  script.py filename.dxt.png

Useful Tool:
  Color quantizer - http://x128.ho.ua/color-quantizer.html
"""
__version__ = "1.1"
__author__  = "infval"


import sys
from pathlib import Path
from struct import unpack
from collections import OrderedDict

from PIL import Image

HEADER_SIZE = 0x80

class Texture:
    """
    [Wii] Color Index 8-bits (C8) + Palette RGBA8
    """

    def __init__(self, path, offset, w, h, pal_offset):
        self.path = path
        self.offset = offset
        self.w = w
        self.h = h
        self.pal_offset = pal_offset

    def to_png(self, png_path):
        im = Image.new("RGBA", (self.w, self.h))
        pixels = im.load()

        with open(self.path, "rb") as f:
            f.seek(self.offset)
            b = f.read(self.w * self.h)

            f.seek(self.pal_offset)
            b_pal = f.read(256 * 4)

            pal = []
            for i in range(256):
                index = i * 2
                pal.append((b_pal[index+1],        # R
                            b_pal[index+0],        # G
                            b_pal[index+1+0x200],  # B
                            b_pal[index+0+0x200])) # A

            tw = 8
            th = 4
            bytes_in_tile = tw * th
            bytes_in_row = self.w * th

            x = 0
            y = 0
            for i in range(self.w * self.h):
                index = i // bytes_in_row * bytes_in_row
                index += x // tw * bytes_in_tile
                index += (y % th) * tw + x % tw

                c = b[index]
                pixels[x, y] = pal[c]
                x += 1
                if x == self.w:
                    x = 0
                    y += 1

        im.save(png_path, "PNG")
        print("Unpacked: {} -> {}".format(self.path, png_path))

    def from_png(self, bin_path, base_path=None):
        im = Image.open(self.path).convert("RGBA")
        pixels = im.load()
        self.w, self.h = im.size

        if not base_path:
            # Raw
            self.offset = 0
            self.pal_offset = self.w * self.h
            b = bytearray(self.w * self.h + 256 * 4)
        else:
            with open(base_path, "rb") as f:
                b = bytearray(f.read())

        pal = OrderedDict()
        pal_i = 0

        b_img = bytearray(self.w * self.h)

        tw = 8
        th = 4
        bytes_in_tile = tw * th
        bytes_in_row = self.w * th

        i = 0
        for y in range(self.h):
            for x in range(self.w):
                c = pixels[x, y]
                if c not in pal:
                    if len(pal) >= 256:
                        print("Too many colors! Max: 256.", self.path)
                        sys.exit(1)
                    else:
                        pal[c] = pal_i
                        pal_i += 1

                index = i // bytes_in_row * bytes_in_row
                index += x // tw * bytes_in_tile
                index += (y % th) * tw + x % tw

                b_img[index] = pal[c]
                i += 1

        b[self.offset: self.offset + self.w * self.h] = b_img

        pal = list(pal.keys())
        pal += [(0, 0, 0, 0)] * (256 - len(pal)) # Unused colors

        for i in range(256):
            index1 = self.pal_offset + i * 2
            index2 = self.pal_offset + i * 2 + 0x200
            cR, cG, cB, cA = pal[i]
            b[index2+0] = cA
            b[index2+1] = cB
            b[index1+0] = cG
            b[index1+1] = cR

        with open(bin_path, "wb") as f:
            f.write(b)
        print("Packed: {} -> {}".format(self.path, bin_path))

def dxt_to_png(path):
    with open(path, "rb") as f:
        f.seek(0x0A)
        w, h = unpack("<BB", f.read(2))
        w = 1 << w
        h = 1 << h
    png_path = path.with_name(path.name + ".png")
    Texture(path, HEADER_SIZE, w, h, HEADER_SIZE + w * h).to_png(png_path)

def png_to_dxt(path):
    bin_path = path.with_suffix('')
    with open(bin_path, "rb") as f:
        f.seek(0x0A)
        w, h = unpack("<BB", f.read(2))
        w = 1 << w
        h = 1 << h
    Texture(path, HEADER_SIZE, None, None, HEADER_SIZE + w * h).from_png(bin_path, bin_path)

if __name__ == '__main__':
    if len(sys.argv) == 1:
        path = Path(".")
        for p in path.glob("*.dxt"):
            dxt_to_png(p)
    else:
        p = Path(sys.argv[1])
        if p.suffix == ".png":
            png_to_dxt(p)
        else:
            dxt_to_png(p)