Add swept_volume binding, bump libigl to f378129

[alecjacobson]

Summary

• Bumps the pinned libigl to f378129b334f374116242537701ffe379a53d50d.
• Adds a Python binding for igl::swept_volume (src/swept_volume.cpp).
• Bumps the dev version to 2.6.3.dev5.

Note on the API

Upstream's swept_volume signature changed at this commit. It no longer takes a transform(t) callback plus a steps count; it now takes a list of rigid transforms and a SignedDistanceType:

igl::swept_volume(V, F, transforms, sign_type, grid_res, isolevel, SV, SF);

The binding follows the new signature:

SV, SF = igl.swept_volume(V, F, transforms,
                          sign_type=igl.SIGNED_DISTANCE_TYPE_FAST_WINDING_NUMBER,
                          grid_res=50, isolevel=0.0)

• transforms accepts either an (n,4,4) float64 array or a list of 4x4 / 3x4 matrices (a 3x4 is padded with 0,0,0,1).
• Raises RuntimeError on an empty list or a wrongly-shaped transform.
• Returns (SV: float64 #SV by 3, SF: int64 #SF by 3).

Exposing the list-of-transforms API rather than wrapping a Python transform(t) callback also sidesteps the callback-binding problem that left dual_contouring commented out (#194).

Testing

• test_swept_volume added to tests/test_all.py: covers shapes/dtypes, that the result spans the motion, (n,4,4) vs. list-of-3x4 equivalence, isolevel dilation, and both error paths.
• Full suite passes against the bumped libigl: 99 passed.

🤖 Generated with Claude Code