File size: 3,625 Bytes
a84fca7 | 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 | #!/usr/bin/env python3
"""Integrity check for binary FBX.
Beyond "does it parse": walks the whole node tree and verifies the walk lands in
the footer region, which catches truncated or padded files that a shallow parse
would accept. Also reports skeleton and geometry presence so empty shells show up.
"""
import os, struct, sys
SCALAR = {"Y": 2, "C": 1, "I": 4, "F": 4, "D": 8, "L": 8}
ELEM = {"f": 4, "d": 8, "l": 8, "i": 4, "b": 1}
def check(path):
size = os.path.getsize(path)
r = {"size": size, "ok": False, "reason": "", "version": None,
"joints": 0, "meshes": 0, "verts": 0, "curves": 0, "end_gap": None}
if size == 0:
r["reason"] = "zero bytes"; return r
d = open(path, "rb").read()
if d[:21] != b"Kaydara FBX Binary \x00":
r["reason"] = "bad magic (not a binary FBX)"; return r
r["version"] = struct.unpack("<I", d[23:27])[0]
u64 = r["version"] >= 7500
NREC = 25 if u64 else 13
joints = set(); meshes = 0; verts = 0; curves = 0
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], None)
if t in ELEM:
n, enc, clen = struct.unpack("<III", d[p:p+12]); p += 12
p += clen if enc else n * ELEM[t]
return p, (t, None, n)
if t in "SR":
ln = struct.unpack("<I", d[p:p+4])[0]; p += 4
v = d[p:p+ln]; p += ln
return p, (t, v, None)
raise ValueError("bad property type %r at %d" % (t, s))
def rd_node(p, depth=0):
nonlocal meshes, verts, curves
if depth > 64: raise ValueError("node nesting too deep")
if p + (24 if u64 else 12) > len(d): raise ValueError("header past EOF")
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 p + NREC
if end > len(d): raise ValueError("node end offset past EOF")
nl = d[q]; q += 1; name = d[q:q+nl]; q += nl
p = q; props = []
for _ in range(nprop):
p, pr = rd_prop(p); props.append(pr)
if name == b"Model" and len(props) >= 3 and props[2][1] in (b"LimbNode", b"Root"):
joints.add(props[1][1])
elif name == b"Geometry": meshes += 1
elif name == b"Vertices" and props and props[0][2]: verts += props[0][2] // 3
elif name == b"AnimationCurve": curves += 1
while p < end:
if d[p:p+NREC] == b"\x00" * NREC: p += NREC; break
p = rd_node(p, depth + 1)
return end
try:
p = 27
while p < len(d) - 160:
if d[p:p+NREC] == b"\x00" * NREC: p += NREC; break
p = rd_node(p)
except Exception as e:
r["reason"] = "parse: %s" % str(e)[:70]; return r
r.update(joints=len(joints), meshes=meshes, verts=verts, curves=curves,
end_gap=len(d) - p)
if r["end_gap"] < 0:
r["reason"] = "walk ran past EOF"; return r
if r["end_gap"] > 4096:
r["reason"] = "%d trailing bytes unparsed (truncated or padded)" % r["end_gap"]; return r
if not joints and not meshes:
r["reason"] = "no skeleton and no geometry"; return r
r["ok"] = True
return r
if __name__ == "__main__":
for f in sys.argv[1:]:
r = check(f)
print("%-38s %-4s v%-5s joints=%-4d mesh=%-3d verts=%-8d curves=%-6d %s" % (
os.path.basename(f), "OK" if r["ok"] else "BAD", r["version"],
r["joints"], r["meshes"], r["verts"], r["curves"], r["reason"]))
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