MSC ASTC to CAB

-- Only mostly shitty MSC ASTC exporter.

-- Repackages the texture data into Unity
-- CABs so's AssetStudio can parse it.

-- Processes all files and subfolders it can find.
-- *.png / *.jpg / *.tga will end up with *.cab next to them.

require "lfs"

local function processImg(infile, entry)
    local input = io.open("c281abfcf2c9ab349a5adca88b286ec0", "rb")

    local output = io.open(infile:sub(1, #infile - 3) .. "cab", "wb")

    output:write(input:read(4096))

    if #entry > 12 then entry = entry:sub(1, 12) end
    if #entry < 12 then entry = entry .. string.rep(" ", 12 - #entry) end

    output:write("\12\00\00\00" .. entry)

    input:read(16)
    output:write(input:read(8))

    local input2 = io.open(infile, "rb")

    local size = lfs.attributes(infile).size - 16

    input2:read(4)
    local texType = 44 + input2:read(1):byte()
    input2:read(2)
    local wB = input2:read(2)
    local width = wB:byte(1) + wB:byte(2) * 256
    input2:read(1)
    local hB = input2:read(2)
    local height = hB:byte(1) + hB:byte(2) * 256
    input2:read(4)

    output:write(wB .. "\0\0" .. hB .. "\0\0")

    input:read(8)

    --[[
    0x30 48 ASTC_4x4    ASTC (4x4 pixel block in 128 bits) compressed RGB(A) texture format.
    0x31 49 ASTC_5x5    ASTC (5x5 pixel block in 128 bits) compressed RGB(A) texture format.
    0x32 50 ASTC_6x6    ASTC (6x6 pixel block in 128 bits) compressed RGB(A) texture format.
    ASTC_8x8    ASTC (8x8 pixel block in 128 bits) compressed RGB(A) texture format.
    ASTC_10x10  ASTC (10x10 pixel block in 128 bits) compressed RGB(A) texture format.
    ASTC_12x12  ASTC (12x12 pixel block in 128 bits) compressed RGB(A) texture format.
    ]]--

    output:write(input:read(4) .. string.char(texType))

    input:read(1)

    output:write(input:read(59))

    input:read(size)
    output:write(input2:read(size))

    output:write(input:read(4198508) or "something fucked up here")

    input:close()
    input2:close()
    output:close()
end

local function scanDir(dir)
    for entry in lfs.dir(dir) do if entry ~= "." and entry ~= ".." then
        local attrib = lfs.attributes(dir .. "/" .. entry)
        local ext = entry:sub(-3):lower()

        if not attrib then print("Failed to access attribute data for " .. dir .. "/" .. entry) end

        if attrib.mode == "directory" then
            scanDir(dir .. "/" .. entry)
        elseif ext == "png" or ext == "jpg" or ext == "tga" or ext == "bmp" then
            processImg(dir .. "/" .. entry, entry:sub(1, #entry - 4))
        end
    end end
end

return scanDir(lfs.currentdir())