Datasets:
File size: 4,485 Bytes
12b5ac7 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 | #!/usr/bin/env python3
"""Surgical rename of corrupted Mixamo bone namespaces in binary FBX:
'mixamorig<N>:' -> 'mixamorig:'.
Parses the FBX node tree, edits ONLY string properties, re-serializes with
recomputed offsets. Mesh, materials, textures, geometry are preserved exactly.
Correctness gate: with no edits the output must be BYTE-IDENTICAL to the input
(`--selftest`). Some nodes carry a trailing null record despite having no
children; that is tracked per-node (`nullrec`) so round-trips are exact.
"""
import os, re, struct, sys
RENAME = re.compile(rb'mixamorig[0-9]+:')
ELEM = {'f':4,'d':8,'l':8,'i':4,'b':1}
SCALAR = {"Y":2,"C":1,"I":4,"F":4,"D":8,"L":8}
class Node:
__slots__=("name","props","children","nullrec")
def __init__(s,name): s.name=name; s.props=[]; s.children=[]; s.nullrec=False
def parse(path):
d=open(path,'rb').read()
assert d[:21]==b"Kaydara FBX Binary \x00", "not a binary FBX"
version=struct.unpack("<I",d[23:27])[0]
u64 = version>=7500
NREC = 25 if u64 else 13
def rd_prop(p):
t=chr(d[p]); s=p; p+=1
if t in SCALAR:
p+=SCALAR[t]; return p,(t,d[s+1:p])
if t in ELEM:
length,enc,clen=struct.unpack("<III",d[p:p+12]); hdr=d[p:p+12]; p+=12
body=clen if enc else length*ELEM[t]
data=d[p:p+body]; p+=body
return p,(t,hdr+data)
if t in "SR":
ln=struct.unpack("<I",d[p:p+4])[0]; p+=4
data=d[p:p+ln]; p+=ln
return p,(t,data)
raise ValueError("bad prop type %r @%d"%(t,s))
def is_null(p):
return p+NREC<=len(d) and d[p:p+NREC]==b"\x00"*NREC
def rd_node(p):
if u64: end,nprop,plen=struct.unpack("<QQQ",d[p:p+24]); q=p+24
else: end,nprop,plen=struct.unpack("<III",d[p:p+12]); q=p+12
if end==0 and nprop==0 and plen==0:
return None,p+NREC
nl=d[q]; q+=1; name=d[q:q+nl]; q+=nl
n=Node(name); p=q
for _ in range(nprop):
p,pr=rd_prop(p); n.props.append(pr)
# nested list (children), possibly terminated by a null record
while p < end:
if is_null(p):
n.nullrec=True; p+=NREC; break
c,p2=rd_node(p)
if c is None: n.nullrec=True; p=p2; break
n.children.append(c); p=p2
return n,end
p=27; top=[]; toplevel_null=False
while p < len(d):
if is_null(p):
toplevel_null=True; p+=NREC; break
n,p2=rd_node(p)
if n is None: toplevel_null=True; p=p2; break
top.append(n); p=p2
return {"header":d[:27],"u64":u64,"top":top,"footer":d[p:],
"toplevel_null":toplevel_null,"orig":d,"version":version}
def edit(node,c):
for i,(t,pay) in enumerate(node.props):
if t in "SR" and RENAME.search(pay):
node.props[i]=(t,RENAME.sub(b'mixamorig:',pay)); c[0]+=1
for ch in node.children: edit(ch,c)
def pbytes(t,pay):
if t in "SR": return t.encode()+struct.pack("<I",len(pay))+pay
return t.encode()+pay
def nsize(n,u64):
NREC=25 if u64 else 13
sz=(25 if u64 else 13)+len(n.name)
sz+=sum(len(pbytes(t,p)) for t,p in n.props)
sz+=sum(nsize(c,u64) for c in n.children)
if n.nullrec: sz+=NREC
return sz
def wnode(out,n,u64):
NREC=25 if u64 else 13
props=b"".join(pbytes(t,p) for t,p in n.props)
end=len(out)+nsize(n,u64)
out+= struct.pack("<QQQ",end,len(n.props),len(props)) if u64 else \
struct.pack("<III",end,len(n.props),len(props))
out+=bytes([len(n.name)])+n.name+props
for c in n.children: wnode(out,c,u64)
if n.nullrec: out+=b"\x00"*NREC
def serialize(t):
out=bytearray(t["header"])
for n in t["top"]: wnode(out,n,t["u64"])
if t["toplevel_null"]: out+=b"\x00"*(25 if t["u64"] else 13)
out+=t["footer"]
return bytes(out)
def process(inp,outp,do_edit=True):
t=parse(inp); c=[0]
if do_edit:
for n in t["top"]: edit(n,c)
data=serialize(t)
if outp: open(outp,"wb").write(data)
return c[0],data,t
if __name__=="__main__":
a=sys.argv[1:]
if a and a[0]=="--selftest":
ok=True
for f in a[1:]:
_,out,t=process(f,None,do_edit=False)
same = out==t["orig"]
ok &= same
print(" %-22s identical=%s (%d bytes)"%(os.path.basename(f),same,len(t["orig"])))
sys.exit(0 if ok else 1)
n,data,_=process(a[0],a[1]); print("renamed %d strings -> %s"%(n,a[1]))
|