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blp: Simplify dxt1/dxt3/dxt5 decoding

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This commit is contained in:
Jerome Leclanche 2018-02-18 04:55:55 +02:00
parent adaa703576
commit fcba3583c3
1 changed files with 62 additions and 92 deletions
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154
src/PIL/BlpImagePlugin.py
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@ -46,28 +46,29 @@ BLP_ALPHA_ENCODING_DXT3 = 1
BLP_ALPHA_ENCODING_DXT5 = 7 BLP_ALPHA_ENCODING_DXT5 = 7
def unpack_565(i):
return (
((i >> 11) & 0x1f) << 3,
((i >> 5) & 0x3f) << 2,
(i & 0x1f) << 3
)
def decode_dxt1(data, alpha=False): def decode_dxt1(data, alpha=False):
""" """
input: one "row" of data (i.e. will produce 4*width pixels) input: one "row" of data (i.e. will produce 4*width pixels)
""" """
blocks = len(data) // 8 # number of blocks in row blocks = len(data) // 8 # number of blocks in row
final = (bytearray(), bytearray(), bytearray(), bytearray()) ret = (bytearray(), bytearray(), bytearray(), bytearray())
for block in range(blocks): for block in range(blocks):
# Decode next 8-byte block. # Decode next 8-byte block.
idx = block * 8 idx = block * 8
color0, color1, bits = struct.unpack("<HHI", data[idx:idx + 8]) color0, color1, bits = struct.unpack("<HHI", data[idx:idx + 8])
# color 0, packed 5-6-5 r0, g0, b0 = unpack_565(color0)
r0 = ((color0 >> 11) & 0x1f) << 3 r1, g1, b1 = unpack_565(color1)
g0 = ((color0 >> 5) & 0x3f) << 2
b0 = (color0 & 0x1f) << 3
# color 1, packed 5-6-5
r1 = ((color1 >> 11) & 0x1f) << 3
g1 = ((color1 >> 5) & 0x3f) << 2
b1 = (color1 & 0x1f) << 3
# Decode this block into 4x4 pixels # Decode this block into 4x4 pixels
# Accumulate the results onto our 4 row accumulators # Accumulate the results onto our 4 row accumulators
@ -77,39 +78,35 @@ def decode_dxt1(data, alpha=False):
control = bits & 3 control = bits & 3
bits = bits >> 2 bits = bits >> 2
a = 0xFF
if control == 0: if control == 0:
final[j].append(r0) r, g, b = r0, g0, b0
final[j].append(g0)
final[j].append(b0)
elif control == 1: elif control == 1:
final[j].append(r1) r, g, b = r1, g1, b1
final[j].append(g1)
final[j].append(b1)
elif control == 2: elif control == 2:
if color0 > color1: if color0 > color1:
final[j].append((2 * r0 + r1) // 3) r = (2 * r0 + r1) // 3
final[j].append((2 * g0 + g1) // 3) g = (2 * g0 + g1) // 3
final[j].append((2 * b0 + b1) // 3) b = (2 * b0 + b1) // 3
else: else:
final[j].append((r0 + r1) // 2) r = (r0 + r1) // 2
final[j].append((g0 + g1) // 2) g = (g0 + g1) // 2
final[j].append((b0 + b1) // 2) b = (b0 + b1) // 2
elif control == 3: elif control == 3:
if color0 > color1: if color0 > color1:
final[j].append((2 * r1 + r0) // 3) r = (2 * r1 + r0) // 3
final[j].append((2 * g1 + g0) // 3) g = (2 * g1 + g0) // 3
final[j].append((2 * b1 + b0) // 3) b = (2 * b1 + b0) // 3
else: else:
final[j].append(0) r, g, b, a = 0, 0, 0, 0
final[j].append(0)
final[j].append(0)
if alpha:
final[j].append(0)
if alpha: if alpha:
final[j].append(0xFF) ret[j].extend([r, g, b, a])
else:
ret[j].extend([r, g, b])
return final return ret
def decode_dxt3(data): def decode_dxt3(data):
@ -118,7 +115,7 @@ def decode_dxt3(data):
""" """
blocks = len(data) // 16 # number of blocks in row blocks = len(data) // 16 # number of blocks in row
final = (bytearray(), bytearray(), bytearray(), bytearray()) ret = (bytearray(), bytearray(), bytearray(), bytearray())
for block in range(blocks): for block in range(blocks):
idx = block * 16 idx = block * 16
@ -129,15 +126,8 @@ def decode_dxt3(data):
code, = struct.unpack("<I", block[12:]) code, = struct.unpack("<I", block[12:])
# color 0, packed 5-6-5 r0, g0, b0 = unpack_565(color0)
r0 = ((color0 >> 11) & 0x1f) << 3 r1, g1, b1 = unpack_565(color1)
g0 = ((color0 >> 5) & 0x3f) << 2
b0 = (color0 & 0x1f) << 3
# color 1, packed 5-6-5
r1 = ((color1 >> 11) & 0x1f) << 3
g1 = ((color1 >> 5) & 0x3f) << 2
b1 = (color1 & 0x1f) << 3
for j in range(4): for j in range(4):
high = False # Do we want the higher bits? high = False # Do we want the higher bits?
@ -155,27 +145,21 @@ def decode_dxt3(data):
color_code = (code >> 2 * (4 * j + i)) & 0x03 color_code = (code >> 2 * (4 * j + i)) & 0x03
if color_code == 0: if color_code == 0:
final[j].append(r0) r, g, b = r0, g0, b0
final[j].append(g0)
final[j].append(b0)
final[j].append(a)
elif color_code == 1: elif color_code == 1:
final[j].append(r1) r, g, b = r1, g1, b1
final[j].append(g1)
final[j].append(b1)
final[j].append(a)
elif color_code == 2: elif color_code == 2:
final[j].append((2 * r0 + r1) // 3) r = (2 * r0 + r1) // 3
final[j].append((2 * g0 + g1) // 3) g = (2 * g0 + g1) // 3
final[j].append((2 * b0 + b1) // 3) b = (2 * b0 + b1) // 3
final[j].append(a)
elif color_code == 3: elif color_code == 3:
final[j].append((2 * r1 + r0) // 3) r = (2 * r1 + r0) // 3
final[j].append((2 * g1 + g0) // 3) g = (2 * g1 + g0) // 3
final[j].append((2 * b1 + b0) // 3) b = (2 * b1 + b0) // 3
final[j].append(a)
return final ret[j].extend([r, g, b, a])
return ret
def decode_dxt5(data): def decode_dxt5(data):
@ -184,7 +168,7 @@ def decode_dxt5(data):
""" """
blocks = len(data) // 16 # number of blocks in row blocks = len(data) // 16 # number of blocks in row
final = (bytearray(), bytearray(), bytearray(), bytearray()) ret = (bytearray(), bytearray(), bytearray(), bytearray())
for block in range(blocks): for block in range(blocks):
idx = block * 16 idx = block * 16
@ -202,15 +186,8 @@ def decode_dxt5(data):
code, = struct.unpack("<I", block[12:]) code, = struct.unpack("<I", block[12:])
# color 0, packed 5-6-5 r0, g0, b0 = unpack_565(color0)
r0 = ((color0 >> 11) & 0x1f) << 3 r1, g1, b1 = unpack_565(color1)
g0 = ((color0 >> 5) & 0x3f) << 2
b0 = (color0 & 0x1f) << 3
# color 1, packed 5-6-5
r1 = ((color1 >> 11) & 0x1f) << 3
g1 = ((color1 >> 5) & 0x3f) << 2
b1 = (color1 & 0x1f) << 3
for j in range(4): for j in range(4):
for i in range(4): for i in range(4):
@ -230,38 +207,31 @@ def decode_dxt5(data):
a = a1 a = a1
elif a0 > a1: elif a0 > a1:
a = ((8 - alphacode) * a0 + (alphacode - 1) * a1) // 7 a = ((8 - alphacode) * a0 + (alphacode - 1) * a1) // 7
elif alphacode == 6:
a = 0
elif alphacode == 7:
a = 255
else: else:
if alphacode == 6: a = ((6 - alphacode) * a0 + (alphacode - 1) * a1) // 5
a = 0
elif alphacode == 7:
a = 255
else:
a = ((6 - alphacode) * a0 + (alphacode - 1) * a1) // 5
color_code = (code >> 2 * (4 * j + i)) & 0x03 color_code = (code >> 2 * (4 * j + i)) & 0x03
if color_code == 0: if color_code == 0:
final[j].append(r0) r, g, b = r0, g0, b0
final[j].append(g0)
final[j].append(b0)
final[j].append(a)
elif color_code == 1: elif color_code == 1:
final[j].append(r1) r, g, b = r1, g1, b1
final[j].append(g1)
final[j].append(b1)
final[j].append(a)
elif color_code == 2: elif color_code == 2:
final[j].append((2 * r0 + r1) // 3) r = (2 * r0 + r1) // 3
final[j].append((2 * g0 + g1) // 3) g = (2 * g0 + g1) // 3
final[j].append((2 * b0 + b1) // 3) b = (2 * b0 + b1) // 3
final[j].append(a)
elif color_code == 3: elif color_code == 3:
final[j].append((2 * r1 + r0) // 3) r = (2 * r1 + r0) // 3
final[j].append((2 * g1 + g0) // 3) g = (2 * g1 + g0) // 3
final[j].append((2 * b1 + b0) // 3) b = (2 * b1 + b0) // 3
final[j].append(a)
return tuple(final) ret[j].extend([r, g, b, a])
return ret
def getpalette(data): def getpalette(data):