93 lines
2.7 KiB
Python
93 lines
2.7 KiB
Python
from dataclasses import dataclass
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import sys
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import struct
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from PIL import Image
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codebook_size = 256 * 2 * 4
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@dataclass
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class PVRT:
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texture_data_size: int
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texture_type: int
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width: int
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height: int
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codebook: list[int]
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indices: list[int]
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def parse_pvrt_header(buf):
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header = buf[0:16]
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codebook = buf[16:codebook_size + 16]
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indices = buf[codebook_size + 16:]
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assert len(header) == 16
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assert len(codebook) == codebook_size
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assert header[0:4] == b"PVRT"
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unpacked = struct.unpack('<LLHH', header[4:])
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texture_data_size, texture_type, width, height = unpacked
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print(texture_data_size)
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print(hex(texture_type))
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print(width)
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print(height)
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assert len(indices) + len(codebook) == texture_data_size - 8
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#assert len(indices) == width * height / 4, (len(indices), width * height / 4)
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return PVRT(
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texture_data_size,
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texture_type,
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width,
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height,
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codebook,
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indices,
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)
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def rgb24(color):
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r = (color >> 11) & 31
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g = (color >> 5) & 63
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b = (color >> 0) & 31
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return r << 3, g << 2, b << 3
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def get_colors(buf, codebook_ix):
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codeword = buf[codebook_ix * 2 * 4:][:2 * 4]
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assert len(codeword) == 2 * 4
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colors = struct.unpack('<HHHH', codeword)
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return list(map(rgb24, colors))
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def from_xy(x, y):
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twiddle_ix = 0
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i = 0
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while i <= (20 / 2):
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twiddle_ix |= ((y >> i) & 1) << (i * 2 + 0)
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twiddle_ix |= ((x >> i) & 1) << (i * 2 + 1)
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i += 1
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return twiddle_ix
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def decode_vq_indices(codebook, indices, width, height):
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canvas = [0] * width * height
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for ty in range(height // 2):
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for tx in range(width // 2):
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codebook_ix = indices[from_xy(tx, ty)]
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codeword = get_colors(codebook, codebook_ix)
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ai = ((ty * 2) + 0) * width + ((tx * 2) + 0)
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bi = ((ty * 2) + 1) * width + ((tx * 2) + 0)
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ci = ((ty * 2) + 0) * width + ((tx * 2) + 1)
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di = ((ty * 2) + 1) * width + ((tx * 2) + 1)
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#print(width, height, ai, ty, tx)
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canvas[ai] = codeword[0]
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canvas[bi] = codeword[1]
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canvas[ci] = codeword[2]
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canvas[di] = codeword[3]
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return canvas
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in_filename = sys.argv[1]
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out_filename = sys.argv[2]
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with open(in_filename, 'rb') as f:
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buf = f.read()
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pvrt = parse_pvrt_header(buf)
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canvas = decode_vq_indices(pvrt.codebook, pvrt.indices, pvrt.width, pvrt.height)
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#canvas = decode_vq_indices(buf[:256 * 4 * 2], buf[256*4*2:], 256, 256)
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print(pvrt.texture_data_size, pvrt.texture_type, pvrt.width, pvrt.height)
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palimage = Image.new('RGB', (pvrt.width, pvrt.height))
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#palimage = Image.new('RGB', (256, 256))
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palimage.putdata(canvas)
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palimage.save(out_filename)
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