Mesh: Move edges to a generic attribute #106638

Hans Goudey · 2023-04-06T19:49:58+02:00

Hans Goudey commented

2023-04-06 19:49:58 +02:00

Implements #95966, as the final step of #95965.

This commit changes the storage of mesh edge vertex indices from the
MEdge type to a new generic int2 attribute type. This follows the
general design for geometry and the attribute system, where the data
storage type and the usage semantics are separated.

The main benefit of the change is reduced memory usage-- the
requirements of storing mesh edges is reduced by 1/3. For example,
this saves 8MB on a 1 million vertex grid. This also gives performance
benefits to any memory bound mesh processing algorithm that uses edges.

Another smaller benefit is that all of the edge's vertex indices are
contiguous. In a few cases, it's helpful to process all of them as
Span<int> rather than Span<int2>. Similarly, the type is more
likely to match a generic format used by a library, or code that
shouldn't know about specific Blender Mesh types.

Various Notes:

The .edge_verts name is used to reflect a mapping between domains,
similar to .corner_verts, etc. The period means that it the data
shouldn't change arbitrarily by the user or procedural operations.
edge[0] is now used instead of edge.v1
The spreadsheet and RNA API are implemeneted for new attribute type
Signed integers are used instead of unsigned to reduce the mixing
of signed-ness, which can be error prone.
All of the previously used core mesh data types (MVert, MEdge,
MLoop, MPoly are now deprecated. Only generic types are used).
The vec2i DNA type is used in the few C files where necessary.

Implements #95966, as the final step of #95965. This commit changes the storage of mesh edge vertex indices from the `MEdge` type to a new generic `int2` attribute type. This follows the general design for geometry and the attribute system, where the data storage type and the usage semantics are separated. The main benefit of the change is reduced memory usage-- the requirements of storing mesh edges is reduced by 1/3. For example, this saves 8MB on a 1 million vertex grid. This also gives performance benefits to any memory bound mesh processing algorithm that uses edges. Another smaller benefit is that all of the edge's vertex indices are contiguous. In a few cases, it's helpful to process all of them as `Span<int>` rather than `Span<int2>`. Similarly, the type is more likely to match a generic format used by a library, or code that shouldn't know about specific Blender `Mesh` types. Various Notes: - The `.edge_verts` name is used to reflect a mapping between domains, similar to `.corner_verts`, etc. The period means that it the data shouldn't change arbitrarily by the user or procedural operations. - `edge[0]` is now used instead of `edge.v1` - The spreadsheet and RNA API are implemeneted for new attribute type - Signed integers are used instead of unsigned to reduce the mixing of signed-ness, which can be error prone. - All of the previously used core mesh data types (`MVert`, `MEdge`, `MLoop`, `MPoly` are now deprecated. Only generic types are used). - The `vec2i` DNA type is used in the few C files where necessary.

❤️ 2 🎉 2

Hans Goudey added 11 commits 2023-04-06 19:50:17 +02:00

582bee087a Mesh: Replace edge struct with generic attribute

b49d2f8a71 Fix split edges

6c4f822b2b Fix mesh boolean convert

2699800c7b Fix BMesh to Mesh conversion

787be9b4c6 Fix freestyle mistakes

e738bad728 Display int2 attributes in spreadsheet

511ce477cd Merge branch 'main' into refactor-mesh-edges-generic

ade8af4aed Don't write edge verts attribute in old format

c9dd514e10 Add int2 spreadsheet row filter

c70f7b4b3d Merge branch 'main' into refactor-mesh-edges-generic