Thank you for the help on this one, it was indeed a magic number. I got my
script to read the model file correctly and assign each object in the file
with the correct parent based on the exported hierarchy from maya.
Thanks a lot!
-- Ben
On Sunday, 1 March 2015 16:58:50 UTC+1, Ben Hearn wrote:
>
> Hello all,
>
> I am currently in the process of writing a tool for work that requires the
> need to read our in house.model format which is a binary file.
>
> Here's the thing, the guy who wrote the tools that I inherited never
> finished them and never commented them so I have been hacking at the old
> code for a few months now which has been great fun and a brilliant learning
> process. He left an old file that seems like it reads a binary file which
> is exactly what I need.
>
> I am however confused over something involved reading the data in a binary
> file, so here goes.
>
> To get the information from the binary file it would appear that certain
> functions need to be called in a certain order. The only thing is all they
> essentially do is read the file in byte chunks. If I comment any of the
> functions out and run the code the data is all wrong.
>
> So my question is, when you are reading binary files (or any files) every
> time you perform a read function or a struct.unpack does the position in
> the file that you read from change? Or is it something simpler like if you
> have written your binary file in a certain way, you HAVE to read it in
> exactly the same way?
>
> I might be missing some crucial theory so any help would be much
> appreciated :)
>
> Here are the function calls and the loop that contains the reading of info:
>
> def _read_uint32(file):
> data = file.read(4)
> data = struct.unpack('I', data)[0]
> return data
>
> def _read_string(file):
> size = _read_uint32(file)
> data = file.read(size)
> return data
>
> def _read_int32(file):
> data = file.read(4)
> data = struct.unpack('i', data)[0]
> return data
>
> def _read_matrix4(file):
> data = file.read(8 * 16)
> return data
>
>
> And here is the function that I am using to loop through the file and
> gather the data:
>
> def unserialize(file):
>
> materials = []
>
> print "OPENING THIS FILE PATH: ", file
>
> file = QtCore.QFile(file)
>
> file.open(QtCore.QIODevice.ReadOnly)
>
> buf = file.read(4)
>
> total_size = _read_uint32(file)
>
> start_offset = file.pos()
>
> passes = 1
>
> for i in range(passes):
> file.seek(start_offset)
> while( (file.pos() - start_offset) <
> total_size):
> type_id = _read_uint32(file)
> chunk_size = _read_uint32(file)
> if type_id == 0 and i == 0:
> print "ID: ",
> _read_int32(file)
> print "NAME: ",
> _read_string(file)
> print "TRANSFORM ",
> _read_matrix4(file)
> print "PIVOT TRANSFORM ",
> _read_matrix4(file)
> print "PARENT ID ",
> _read_int32(file)
> print
> elif type_id == MATERIAL and i == 0:
> print _read_int32(file)
> print _read_string(file)
> print _read_int32(file)
> else:
> file.seek(file.pos() + chunk_size)
>
>
> Cheers!
>
> Ben
>
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