83 lines
3.2 KiB
Python
83 lines
3.2 KiB
Python
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"""Scan GLBs: list finger joints and which animations have live (non-frozen) finger rotation tracks."""
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import json, struct, sys, math
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from pathlib import Path
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FINGER_TOKENS = ("thumb", "index", "middle", "ring", "pinky", "finger")
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def read_glb(path):
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data = Path(path).read_bytes()
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magic, ver, length = struct.unpack_from("<III", data, 0)
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assert magic == 0x46546C67, "not glb"
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off = 12
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gltf = None
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bin_chunk = None
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while off < length:
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clen, ctype = struct.unpack_from("<II", data, off)
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off += 8
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chunk = data[off:off+clen]
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if ctype == 0x4E4F534A:
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gltf = json.loads(chunk.decode("utf-8"))
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elif ctype == 0x004E4942:
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bin_chunk = chunk
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off += clen
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return gltf, bin_chunk
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def accessor_data(gltf, binc, idx):
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acc = gltf["accessors"][idx]
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bv = gltf["bufferViews"][acc["bufferView"]]
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comp = {5126: ("f", 4)}[acc["componentType"]]
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n = {"SCALAR":1, "VEC3":3, "VEC4":4}[acc["type"]]
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off = bv.get("byteOffset", 0) + acc.get("byteOffset", 0)
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count = acc["count"]
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vals = struct.unpack_from("<%d%s" % (count*n, comp[0]), binc, off)
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return [vals[i*n:(i+1)*n] for i in range(count)]
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def scan(path, verbose_joints=False):
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gltf, binc = read_glb(path)
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nodes = gltf.get("nodes", [])
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names = [nd.get("name", f"node{i}") for i, nd in enumerate(nodes)]
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# joints from skins
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joint_set = set()
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for skin in gltf.get("skins", []):
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joint_set.update(skin.get("joints", []))
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fingers = sorted(n for i in joint_set for n in [names[i]] if any(t in n.lower() for t in FINGER_TOKENS))
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print(f"\n== {Path(path).name} ==")
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print(f"joints: {len(joint_set)}, finger joints: {len(fingers)}")
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if verbose_joints:
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for n in sorted(names[i] for i in joint_set):
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print(" ", n)
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elif fingers:
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print(" finger joints:", ", ".join(fingers))
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for anim in gltf.get("animations", []):
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aname = anim.get("name", "?")
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live, frozen = [], []
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for ch in anim.get("channels", []):
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tgt = ch["target"]
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if tgt.get("path") != "rotation":
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continue
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nname = names[tgt["node"]]
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if not any(t in nname.lower() for t in FINGER_TOKENS):
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continue
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samp = anim["samplers"][ch["sampler"]]
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quats = accessor_data(gltf, binc, samp["output"])
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# measure max angular deviation from first frame
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q0 = quats[0]
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maxdot = 1.0
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for q in quats[1:]:
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d = abs(sum(a*b for a, b in zip(q0, q)))
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maxdot = min(maxdot, min(d, 1.0))
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ang = 2*math.degrees(math.acos(maxdot))
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(live if ang > 2.0 else frozen).append((nname, ang))
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total = len(live) + len(frozen)
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if total:
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print(f" anim '{aname}': {total} finger rot tracks, {len(live)} live (>2deg), {len(frozen)} frozen")
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if live:
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top = sorted(live, key=lambda x: -x[1])[:4]
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print(" top movers:", ", ".join(f"{n} {a:.0f}deg" for n, a in top))
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else:
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print(f" anim '{aname}': NO finger tracks")
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if __name__ == "__main__":
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for p in sys.argv[1:]:
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scan(p, verbose_joints="--joints" in sys.argv)
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