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Created March 30, 2012 05:18
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IRIDAS .look to .csp LUT
"""From the seemingly undocumented IRIDAS .look format to .csp
import re
import os
import sys
import struct
import binascii
import xml.etree.ElementTree as ET
class LookParsingError(Exception):
def warn(msg):
sys.stderr.write("%s\n" % msg)
def chunks(l, n):
""" Yield successive n-sized chunks from l.
for i in xrange(0, len(l), n):
yield l[i:i+n]
class LookParser(object):
"""Slightly hacky parser for IRIDAS's .look LUT
def __init__(self, source):
"""source is string containing .look file contents
tree = ET.fromstring(source)
self.lut3d = self.parse_lut3d(tree)
def parse_lut3d(self, tree):
"""Parses the LUT section of the .look, which contains a
edge-size and binary 3D LUT.
Data is packed series of (float, float, float), and probably
something else (there is a suspicious 12 bytes left over..)
# Data to return
lut3d = {}
# Get 3D LUT edge size from
# <LUT>
# <size>"8"</size>
lut = tree.find("LUT")
cube_edge_size = int(lut.find("size").text.replace("\"", ""))
lut3d['edgelen'] = cube_edge_size
# Clean up LUT data - remove whitespace, quotes etc
lutdata = lut.find("data").text
lutdata = re.sub("[^A-Z0-9]+", "", lutdata)
# Parse 3D LUT data
data_binary = binascii.unhexlify(lutdata)
# Little endian, 3 floats
format = "<fff"
samples = list(struct.unpack(format, chunk) for chunk in chunks(data_binary, struct.calcsize(format)))
if len(samples) != cube_edge_size ** 3:
raise LookParsingError("Cube size was not correct, was %s, expected %s (%s**3)" % (
lut3d['samples'] = samples
return lut3d
def csp_header_with_noop_prelut():
lines = []
for x in range(3):
lines.append("0.0 1.0")
lines.append("0.0 1.0")
return lines
def main(in_fname = None):
if in_fname is None:
in_fname = sys.argv[1]
f = open(in_fname)
contents =
p = LookParser(contents)
outcsp = csp_header_with_noop_prelut()
outcsp.append("%s %s %s" % ((p.lut3d['edgelen'],)*3))
for s in p.lut3d['samples']:
outcsp.append("%.05f %.05f %.05f" % s)
out_fname = os.path.splitext(in_fname)[0] + ".csp"
df = open(out_fname, "w")
if __name__ == "__main__":
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