mirror of
https://github.com/python-pillow/Pillow.git
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433 lines
15 KiB
Python
433 lines
15 KiB
Python
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"""
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Blizzard Mipmap Format (.blp)
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Jerome Leclanche <jerome@leclan.ch>
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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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BLP1 files, used mostly in Warcraft III, are not fully supported.
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All types of BLP2 files used in World of Warcraft are supported.
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The BLP file structure consists of a header, up to 16 mipmaps of the
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texture
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Texture sizes must be powers of two, though the two dimensions do
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not have to be equal; 512x256 is valid, but 512x200 is not.
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The first mipmap (mipmap #0) is the full size image; each subsequent
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mipmap halves both dimensions. The final mipmap should be 1x1.
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BLP files come in many different flavours:
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* JPEG-compressed (type == 0) - only supported for BLP1.
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* RAW images (type == 1, encoding == 1). Each mipmap is stored as an
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array of 8-bit values, one per pixel, left to right, top to bottom.
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Each value is an index to the palette.
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* DXT-compressed (type == 1, encoding == 2):
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- DXT1 compression is used if alpha_encoding == 0.
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- An additional alpha bit is used if alpha_depth == 1.
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- DXT3 compression is used if alpha_encoding == 1.
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- DXT5 compression is used if alpha_encoding == 7.
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"""
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import struct
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from io import BytesIO
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from . import Image, ImageFile
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BLP_FORMAT_JPEG = 0
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BLP_ENCODING_UNCOMPRESSED = 1
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BLP_ENCODING_DXT = 2
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BLP_ENCODING_UNCOMPRESSED_RAW_BGRA = 3
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BLP_ALPHA_ENCODING_DXT1 = 0
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BLP_ALPHA_ENCODING_DXT3 = 1
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BLP_ALPHA_ENCODING_DXT5 = 7
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def decode_dxt1(data, alpha=False):
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"""
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input: one "row" of data (i.e. will produce 4*width pixels)
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"""
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blocks = len(data) // 8 # number of blocks in row
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final = (bytearray(), bytearray(), bytearray(), bytearray())
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for block in range(blocks):
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# Decode next 8-byte block.
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idx = block * 8
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color0, color1, bits = struct.unpack("<HHI", data[idx:idx + 8])
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# color 0, packed 5-6-5
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r0 = ((color0 >> 11) & 0x1f) << 3
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g0 = ((color0 >> 5) & 0x3f) << 2
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b0 = (color0 & 0x1f) << 3
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# color 1, packed 5-6-5
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r1 = ((color1 >> 11) & 0x1f) << 3
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g1 = ((color1 >> 5) & 0x3f) << 2
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b1 = (color1 & 0x1f) << 3
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# Decode this block into 4x4 pixels
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# Accumulate the results onto our 4 row accumulators
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for j in range(4):
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for i in range(4):
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# get next control op and generate a pixel
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control = bits & 3
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bits = bits >> 2
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if control == 0:
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final[j].append(r0)
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final[j].append(g0)
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final[j].append(b0)
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elif control == 1:
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final[j].append(r1)
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final[j].append(g1)
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final[j].append(b1)
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elif control == 2:
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if color0 > color1:
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final[j].append((2 * r0 + r1) // 3)
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final[j].append((2 * g0 + g1) // 3)
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final[j].append((2 * b0 + b1) // 3)
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else:
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final[j].append((r0 + r1) // 2)
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final[j].append((g0 + g1) // 2)
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final[j].append((b0 + b1) // 2)
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elif control == 3:
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if color0 > color1:
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final[j].append((2 * r1 + r0) // 3)
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final[j].append((2 * g1 + g0) // 3)
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final[j].append((2 * b1 + b0) // 3)
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else:
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final[j].append(0)
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final[j].append(0)
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final[j].append(0)
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if alpha:
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final[j].append(0)
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if alpha:
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final[j].append(0xFF)
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return final
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def decode_dxt3(data):
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"""
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input: one "row" of data (i.e. will produce 4*width pixels)
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"""
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blocks = len(data) // 16 # number of blocks in row
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final = (bytearray(), bytearray(), bytearray(), bytearray())
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for block in range(blocks):
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idx = block * 16
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block = data[idx:idx + 16]
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# Decode next 16-byte block.
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bits = struct.unpack("<8B", block[:8])
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color0, color1 = struct.unpack("<HH", block[8:12])
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code, = struct.unpack("<I", block[12:])
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# color 0, packed 5-6-5
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r0 = ((color0 >> 11) & 0x1f) << 3
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g0 = ((color0 >> 5) & 0x3f) << 2
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b0 = (color0 & 0x1f) << 3
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# color 1, packed 5-6-5
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r1 = ((color1 >> 11) & 0x1f) << 3
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g1 = ((color1 >> 5) & 0x3f) << 2
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b1 = (color1 & 0x1f) << 3
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for j in range(4):
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high = False # Do we want the higher bits?
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for i in range(4):
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alphacode_index = (4 * j + i) // 2
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a = bits[alphacode_index]
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if high:
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high = False
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a >>= 4
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else:
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high = True
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a &= 0xf
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a *= 17 # We get a value between 0 and 15
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color_code = (code >> 2 * (4 * j + i)) & 0x03
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if color_code == 0:
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final[j].append(r0)
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final[j].append(g0)
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final[j].append(b0)
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final[j].append(a)
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elif color_code == 1:
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final[j].append(r1)
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final[j].append(g1)
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final[j].append(b1)
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final[j].append(a)
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elif color_code == 2:
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final[j].append((2 * r0 + r1) // 3)
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final[j].append((2 * g0 + g1) // 3)
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final[j].append((2 * b0 + b1) // 3)
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final[j].append(a)
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elif color_code == 3:
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final[j].append((2 * r1 + r0) // 3)
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final[j].append((2 * g1 + g0) // 3)
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final[j].append((2 * b1 + b0) // 3)
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final[j].append(a)
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return final
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def decode_dxt5(data):
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"""
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input: one "row" of data (i.e. will produce 4 * width pixels)
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"""
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blocks = len(data) // 16 # number of blocks in row
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final = (bytearray(), bytearray(), bytearray(), bytearray())
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for block in range(blocks):
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idx = block * 16
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block = data[idx:idx + 16]
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# Decode next 16-byte block.
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a0, a1 = struct.unpack("<BB", block[:2])
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bits = struct.unpack("<6B", block[2:8])
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alphacode1 = (
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bits[2] | (bits[3] << 8) | (bits[4] << 16) | (bits[5] << 24)
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)
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alphacode2 = bits[0] | (bits[1] << 8)
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color0, color1 = struct.unpack("<HH", block[8:12])
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code, = struct.unpack("<I", block[12:])
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# color 0, packed 5-6-5
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r0 = ((color0 >> 11) & 0x1f) << 3
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g0 = ((color0 >> 5) & 0x3f) << 2
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b0 = (color0 & 0x1f) << 3
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# color 1, packed 5-6-5
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r1 = ((color1 >> 11) & 0x1f) << 3
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g1 = ((color1 >> 5) & 0x3f) << 2
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b1 = (color1 & 0x1f) << 3
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for j in range(4):
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for i in range(4):
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# get next control op and generate a pixel
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alphacode_index = 3 * (4 * j + i)
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if alphacode_index <= 12:
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alphacode = (alphacode2 >> alphacode_index) & 0x07
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elif alphacode_index == 15:
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alphacode = (alphacode2 >> 15) | ((alphacode1 << 1) & 0x06)
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else: # alphacode_index >= 18 and alphacode_index <= 45
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alphacode = (alphacode1 >> (alphacode_index - 16)) & 0x07
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if alphacode == 0:
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a = a0
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elif alphacode == 1:
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a = a1
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elif a0 > a1:
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a = ((8 - alphacode) * a0 + (alphacode - 1) * a1) // 7
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else:
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if alphacode == 6:
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a = 0
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elif alphacode == 7:
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a = 255
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else:
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a = ((6 - alphacode) * a0 + (alphacode - 1) * a1) // 5
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color_code = (code >> 2 * (4 * j + i)) & 0x03
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if color_code == 0:
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final[j].append(r0)
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final[j].append(g0)
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final[j].append(b0)
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final[j].append(a)
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elif color_code == 1:
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final[j].append(r1)
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final[j].append(g1)
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final[j].append(b1)
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final[j].append(a)
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elif color_code == 2:
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final[j].append((2 * r0 + r1) // 3)
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final[j].append((2 * g0 + g1) // 3)
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final[j].append((2 * b0 + b1) // 3)
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final[j].append(a)
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elif color_code == 3:
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final[j].append((2 * r1 + r0) // 3)
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final[j].append((2 * g1 + g0) // 3)
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final[j].append((2 * b1 + b0) // 3)
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final[j].append(a)
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return tuple(final)
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def getpalette(data):
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"""
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Helper to transform a BytesIO object into a palette
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"""
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palette = []
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string = BytesIO(data)
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while True:
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try:
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palette.append(struct.unpack("<4B", string.read(4)))
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except struct.error:
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break
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return palette
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class BLPFormatError(NotImplementedError):
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pass
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class BlpImageFile(ImageFile.ImageFile):
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"""
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Blizzard Mipmap Format
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"""
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format = "BLP"
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format_description = "Blizzard Mipmap Format"
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def _decode_blp1(self):
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header = BytesIO(self.fp.read(28 + 16 * 4 + 16 * 4))
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magic, compression = struct.unpack("<4si", header.read(8))
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encoding, alpha_depth, alpha_encoding, has_mips = struct.unpack(
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"<4b", header.read(4)
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)
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self.size = struct.unpack("<II", header.read(8))
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encoding, subtype = struct.unpack("<ii", header.read(8))
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offsets = struct.unpack("<16I", header.read(16 * 4))
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lengths = struct.unpack("<16I", header.read(16 * 4))
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if compression == BLP_FORMAT_JPEG:
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from PIL.JpegImagePlugin import JpegImageFile
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jpeg_header_size, = struct.unpack("<I", self.fp.read(4))
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jpeg_header = self.fp.read(jpeg_header_size)
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self.fp.read(offsets[0] - self.fp.tell()) # What IS this?
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data = self.fp.read(lengths[0])
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data = jpeg_header + data
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data = BytesIO(data)
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image = JpegImageFile(data)
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image.show()
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self.tile = image.tile # :/
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self.fp = image.fp
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self.mode = image.mode
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elif compression == 1:
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if encoding == 5:
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data = []
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palette_data = self.fp.read(256 * 4)
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palette = getpalette(palette_data)
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_data = BytesIO(self.fp.read(lengths[0]))
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self.mode = "RGB"
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self.tile = []
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while True:
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try:
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offset, = struct.unpack("<B", _data.read(1))
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except struct.error:
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break
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b, g, r, a = palette[offset]
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data.append(struct.pack("<BBB", r, g, b))
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data = b"".join(data)
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self.im = Image.core.new(self.mode, self.size)
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self.frombytes(data)
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else:
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raise BLPFormatError(
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"Unknown or unsupported BLP encoding %r" % (encoding)
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)
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else:
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raise BLPFormatError(
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"Unknown or unsupported BLP compression %r" % (encoding)
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)
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def _decode_blp2(self):
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header = BytesIO(self.fp.read(20 + 16 * 4 + 16 * 4))
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magic, compression = struct.unpack("<4si", header.read(8))
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encoding, alpha_depth, alpha_encoding, has_mips = struct.unpack(
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"<4b", header.read(4)
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)
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self.size = struct.unpack("<II", header.read(8))
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offsets = struct.unpack("<16I", header.read(16 * 4))
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lengths = struct.unpack("<16I", header.read(16 * 4))
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palette_data = self.fp.read(256 * 4)
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self.mode = "RGB"
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self.tile = []
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|
if compression == 1:
|
||
|
|
# Uncompressed or DirectX compression
|
||
|
|
data = []
|
||
|
|
self.fp.seek(offsets[0])
|
||
|
|
|
||
|
|
if encoding == BLP_ENCODING_UNCOMPRESSED:
|
||
|
|
palette = getpalette(palette_data)
|
||
|
|
_data = BytesIO(self.fp.read(lengths[0]))
|
||
|
|
while True:
|
||
|
|
try:
|
||
|
|
offset, = struct.unpack("<B", _data.read(1))
|
||
|
|
except struct.error:
|
||
|
|
break
|
||
|
|
b, g, r, a = palette[offset]
|
||
|
|
data.append(struct.pack("<BBB", r, g, b))
|
||
|
|
|
||
|
|
elif encoding == BLP_ENCODING_DXT:
|
||
|
|
if alpha_encoding == BLP_ALPHA_ENCODING_DXT1:
|
||
|
|
linesize = (self.size[0] + 3) // 4 * 8
|
||
|
|
for yb in range((self.size[1] + 3) // 4):
|
||
|
|
line_data = self.fp.read(linesize)
|
||
|
|
if alpha_depth:
|
||
|
|
self.mode = "RGBA"
|
||
|
|
decoded = decode_dxt1(line_data, alpha=True)
|
||
|
|
else:
|
||
|
|
decoded = decode_dxt1(line_data)
|
||
|
|
for d in decoded:
|
||
|
|
data.append(d)
|
||
|
|
|
||
|
|
elif alpha_encoding == BLP_ALPHA_ENCODING_DXT3:
|
||
|
|
linesize = (self.size[0] + 3) // 4 * 16
|
||
|
|
self.mode = "RGBA"
|
||
|
|
for yb in range((self.size[1] + 3) // 4):
|
||
|
|
decoded = decode_dxt3(self.fp.read(linesize))
|
||
|
|
for d in decoded:
|
||
|
|
data.append(d)
|
||
|
|
|
||
|
|
elif alpha_encoding == BLP_ALPHA_ENCODING_DXT5:
|
||
|
|
linesize = (self.size[0] + 3) // 4 * 16
|
||
|
|
self.mode = "RGBA"
|
||
|
|
for yb in range((self.size[1] + 3) // 4):
|
||
|
|
decoded = decode_dxt5(self.fp.read(linesize))
|
||
|
|
for d in decoded:
|
||
|
|
data.append(d)
|
||
|
|
else:
|
||
|
|
raise BLPFormatError(
|
||
|
|
"Unsupported alpha encoding %r" % (alpha_encoding)
|
||
|
|
)
|
||
|
|
|
||
|
|
self.im = Image.core.new(self.mode, self.size)
|
||
|
|
|
||
|
|
data = b"".join(data)
|
||
|
|
self.frombytes(data)
|
||
|
|
|
||
|
|
def _open(self):
|
||
|
|
magic = self.fp.read(4)
|
||
|
|
self.fp.seek(0)
|
||
|
|
if magic == b"BLP1":
|
||
|
|
return self._decode_blp1()
|
||
|
|
|
||
|
|
if magic == b"BLP2":
|
||
|
|
return self._decode_blp2()
|
||
|
|
|
||
|
|
raise ValueError("not a BLP file (magic: %r)" % (magic))
|
||
|
|
|
||
|
|
|
||
|
|
def _validate(prefix):
|
||
|
|
return prefix[:4] in (b"BLP1", b"BLP2")
|
||
|
|
|
||
|
|
|
||
|
|
Image.register_open(BlpImageFile.format, BlpImageFile, _validate)
|
||
|
|
Image.register_extension(BlpImageFile.format, ".blp")
|