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