This commit makes it so OpenSubdiv's topology refiner is kept
in memory and reused for until topology changes. There are the
following modifications which causes topology refiner to become
invalid:
- Change in a mesh topology (for example, vertices, edges, and
faces connectivity).
- Change in UV islands (adding new islands, merging them and
so on),
- Change in UV smoothing options.
- Change in creases.
- Change in Catmull-Clark / Simple subdivisions.
The following limitations are known:
- CPU evaluator is not yet cached.
- UV islands topology is not checked.
The UV limitation is currently a stopper for making this cache
enabled by default.
This fixes following errors:
- The code didn't work correctly for edges reconstructed by
the OpenSubdiv's topology refiner (due to indexing
difference).
- Sharpness of non-manifold and boundary edges was not
working correctly.
C++11 doesn't need the space between '> >' in a nested templated
declaration, so instead of `std::vector<std::pair<a, b> >` we can now
write `std::vector<std::pair<a, b> >`.
It's now possible to export curves and NURBS as mesh data to Alembic.
This allows artists to do any crazy thing on curves and export the
visual result to Alembic for interoperability with other software (or
caching for later use, etc.). It's an often-requested feature.
This works around T60503 and the fixes export part of T51311.
Note that exporting zero-width curves is currently not supported, as
exporting a faceless mesh (e.g. just edges and vertices) is not
supported by the mesh writer at all.
To test, create a curve with thickness (for example extruded), export to
Alembic and check the 'Curves to Mesh' checkbox in the export options.
Reviewers: sergey
Differential Revision: https://developer.blender.org/D4213
I moved most of the `AbcMeshWriter` code to a new class
`AbcGenericMeshWriter`. The latter is an abstract class and does not
make any assumptions about the type of Blender object being written.
This makes it possible to write metaballs, curves, nurbs surfaces, etc.
as mesh to Alembic files.
The `AbcMeshWriter` class now is the concrete implementation of
`AbcGenericMeshWriter` for writing mesh objects.
Reviewers: sergey
Differential Revision: https://developer.blender.org/D4213
If the triangulated mesh was in itself a new mesh that should be freed this
should happen before the function returns (as it only returns a single mesh,
and thus the caller can only free one).
