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""" | |
A Pillow loader for .ftc and .ftu files (FTEX) | |
Jerome Leclanche <[email protected]> | |
The contents of this file are hereby released in the public domain (CC0) | |
Full text of the CC0 license: | |
https://creativecommons.org/publicdomain/zero/1.0/ | |
Independence War 2: Edge Of Chaos - Texture File Format - 16 October 2001 | |
The textures used for 3D objects in Independence War 2: Edge Of Chaos are in a | |
packed custom format called FTEX. This file format uses file extensions FTC | |
and FTU. | |
* FTC files are compressed textures (using standard texture compression). | |
* FTU files are not compressed. | |
Texture File Format | |
The FTC and FTU texture files both use the same format. This | |
has the following structure: | |
{header} | |
{format_directory} | |
{data} | |
Where: | |
{header} = { | |
u32:magic, | |
u32:version, | |
u32:width, | |
u32:height, | |
u32:mipmap_count, | |
u32:format_count | |
} | |
* The "magic" number is "FTEX". | |
* "width" and "height" are the dimensions of the texture. | |
* "mipmap_count" is the number of mipmaps in the texture. | |
* "format_count" is the number of texture formats (different versions of the | |
same texture) in this file. | |
{format_directory} = format_count * { u32:format, u32:where } | |
The format value is 0 for DXT1 compressed textures and 1 for 24-bit RGB | |
uncompressed textures. | |
The texture data for a format starts at the position "where" in the file. | |
Each set of texture data in the file has the following structure: | |
{data} = format_count * { u32:mipmap_size, mipmap_size * { u8 } } | |
* "mipmap_size" is the number of bytes in that mip level. For compressed | |
textures this is the size of the texture data compressed with DXT1. For 24 bit | |
uncompressed textures, this is 3 * width * height. Following this are the image | |
bytes for that mipmap level. | |
Note: All data is stored in little-Endian (Intel) byte order. | |
""" | |
from __future__ import annotations | |
import struct | |
from enum import IntEnum | |
from io import BytesIO | |
from . import Image, ImageFile | |
MAGIC = b"FTEX" | |
class Format(IntEnum): | |
DXT1 = 0 | |
UNCOMPRESSED = 1 | |
class FtexImageFile(ImageFile.ImageFile): | |
format = "FTEX" | |
format_description = "Texture File Format (IW2:EOC)" | |
def _open(self): | |
if not _accept(self.fp.read(4)): | |
msg = "not an FTEX file" | |
raise SyntaxError(msg) | |
struct.unpack("<i", self.fp.read(4)) # version | |
self._size = struct.unpack("<2i", self.fp.read(8)) | |
mipmap_count, format_count = struct.unpack("<2i", self.fp.read(8)) | |
self._mode = "RGB" | |
# Only support single-format files. | |
# I don't know of any multi-format file. | |
assert format_count == 1 | |
format, where = struct.unpack("<2i", self.fp.read(8)) | |
self.fp.seek(where) | |
(mipmap_size,) = struct.unpack("<i", self.fp.read(4)) | |
data = self.fp.read(mipmap_size) | |
if format == Format.DXT1: | |
self._mode = "RGBA" | |
self.tile = [("bcn", (0, 0) + self.size, 0, 1)] | |
elif format == Format.UNCOMPRESSED: | |
self.tile = [("raw", (0, 0) + self.size, 0, ("RGB", 0, 1))] | |
else: | |
msg = f"Invalid texture compression format: {repr(format)}" | |
raise ValueError(msg) | |
self.fp.close() | |
self.fp = BytesIO(data) | |
def load_seek(self, pos): | |
pass | |
def _accept(prefix): | |
return prefix[:4] == MAGIC | |
Image.register_open(FtexImageFile.format, FtexImageFile, _accept) | |
Image.register_extensions(FtexImageFile.format, [".ftc", ".ftu"]) | |