Refactoring mesh code, it has become clear that local cleanups and
simplifications are limited by the need to keep a C public API for
mesh functions. This change makes code more obvious and makes further
refactoring much easier.
- Add a new `BKE_mesh.hh` header for a C++ only mesh API
- Introduce a new `blender::bke::mesh` namespace, documented here:
https://wiki.blender.org/wiki/Source/Objects/Mesh#Namespaces
- Move some functions to the new namespace, cleaning up their arguments
- Move code to `Array` and `float3` where necessary to use the new API
- Define existing inline mesh data access functions to the new header
- Keep some C API functions where necessary because of RNA
- Move all C++ files to use the new header, which includes the old one
In the future it may make sense to split up `BKE_mesh.hh` more, but for
now keeping the same name as the existing header keeps things simple.
Pull Request: blender/blender#105416
With the goal of clearly differentiating between arrays and single
elements, improving consistency across Blender, and using wording
that's easier to read and say, change variable names for Mesh edges
and polygons/faces.
Common renames are the following, with some extra prefixes, etc.
- `mpoly` -> `polys`
- `mpoly`/`mp`/`p` -> `poly`
- `medge` -> `edges`
- `med`/`ed`/`e` -> `edge`
`MLoop` variables aren't affected because they will be replaced
when they're split up into to arrays in #104424.
The material indices from the caps were only copied if the base mesh had
a material index attribute. Fix that by copying them manually if the cap
has the attribute.
Blender currently has 2 algorithms for merging vertices:
- `BKE_mesh_merge_verts`;
- `blender::geometry::create_merged_mesh`
`BKE_mesh_merge_verts` has a simplified algorithm to work with Array,
Mirror and Screw modifiers. It doesn't support merge results that would
create new faces. However it has shortcuts to be more efficient in
these modifiers.
`blender::geometry::create_merged_mesh` tries to predict all possible
outcomes. So it's a more complex. But it loses in performance to
`BKE_mesh_merge_verts` in some cases.
The performance comparison between these two depends on many factors.
`blender::geometry::create_merged_mesh` works with a context that has
only the affected geometry. Thus a smaller region of the mesh is read
for duplicate checking. Therefore, the smaller the affected geometry,
the more efficient the operation.
By my tests `blender::geometry::create_merged_mesh` beats
`BKE_mesh_merge_verts` when less than 20% of the geometry is affected
in worst case `MESH_MERGE_VERTS_DUMP_IF_EQUAL` or 17% in case of
`MESH_MERGE_VERTS_DUMP_IF_MAPPED` .
For cases where the entire geometry is affected, a 30% loss was noticed,
largely due to the creation of a context that represents the entire mesh.
Co-authored-by: Germano Cavalcante <germano.costa@ig.com.br>
Pull Request #105136
Using spans instead of raw pointers helps to differentiate ararys from
pointers to single elements, gives bounds checking in debug builds, and
conveniently stores the number of elements in the same variable.
Also make variable naming consistent. For example, use `loops` instead
of `mloop`. The plural helps to clarify that the variable is an array.
I didn't change positions because there is a type mismatch between
C and C++ code that is ugly to manage. All remaining code can be
converted to C++, then that change will be simpler.
Pull Request #105138
This code seems to be left over from before edges, polys, and loops were
stored in CustomData. They are already copied by the CustomData copy
calls directly above, which already deal with every other layer.
Use a consistent style for declaring the names of struct members
in their declarations. Note that this convention was already used in
many places but not everywhere.
Remove spaces around the text (matching commented arguments) with
the advantage that the the spell checking utility skips these terms.
Making it possible to extract & validate these comments automatically.
Also use struct names for `bAnimChannelType` & `bConstraintTypeInfo`
which were using brief descriptions.
Currently you can retrieve a mutable array from a const CustomData.
That makes code unsafe since the compiler can't check for correctness
itself. Fix that by introducing a separate function to retrieve mutable
arrays from CustomData. The new functions have the `_for_write`
suffix that make the code's intention clearer.
Because it makes retrieving write access an explicit step, this change
also makes proper copy-on-write possible for attributes.
Notes:
- The previous "duplicate referenced layer" functions are redundant
with retrieving layers with write access
- The custom data functions that give a specific index only have
`for_write` to simplify the API
Differential Revision: https://developer.blender.org/D14140
Currently the `MLoopUV` struct stores UV coordinates and flags related
to editing UV maps in the UV editor. This patch changes the coordinates
to use the generic 2D vector type, and moves the flags into three
separate boolean attributes. This follows the design in T95965, with
the ultimate intention of simplifying code and improving performance.
Importantly, the change allows exporters and renderers to use UVs
"touched" by geometry nodes, which only creates generic attributes.
It also allows geometry nodes to create "proper" UV maps from scratch,
though only with the Store Named Attribute node for now.
The new design considers any 2D vector attribute on the corner domain
to be a UV map. In the future, they might be distinguished from regular
2D vectors with attribute metadata, which may be helpful because they
are often interpolated differently.
Most of the code changes deal with passing around UV BMesh custom data
offsets and tracking the boolean "sublayers". The boolean layers are
use the following prefixes for attribute names: vert selection: `.vs.`,
edge selection: `.es.`, pinning: `.pn.`. Currently these are short to
avoid using up the maximum length of attribute names. To accommodate
for these 4 extra characters, the name length limit is enlarged to 68
bytes, while the maximum user settable name length is still 64 bytes.
Unfortunately Python/RNA API access to the UV flag data becomes slower.
Accessing the boolean layers directly is be better for performance in
general.
Like the other mesh SoA refactors, backward and forward compatibility
aren't affected, and won't be changed until 4.0. We pay for that by
making mesh reading and writing more expensive with conversions.
Resolves T85962
Differential Revision: https://developer.blender.org/D14365
**Changes**
As described in T93602, this patch removes all use of the `MVert`
struct, replacing it with a generic named attribute with the name
`"position"`, consistent with other geometry types.
Variable names have been changed from `verts` to `positions`, to align
with the attribute name and the more generic design (positions are not
vertices, they are just an attribute stored on the point domain).
This change is made possible by previous commits that moved all other
data out of `MVert` to runtime data or other generic attributes. What
remains is mostly a simple type change. Though, the type still shows up
859 times, so the patch is quite large.
One compromise is that now `CD_MASK_BAREMESH` now contains
`CD_PROP_FLOAT3`. With the general move towards generic attributes
over custom data types, we are removing use of these type masks anyway.
**Benefits**
The most obvious benefit is reduced memory usage and the benefits
that brings in memory-bound situations. `float3` is only 3 bytes, in
comparison to `MVert` which was 4. When there are millions of vertices
this starts to matter more.
The other benefits come from using a more generic type. Instead of
writing algorithms specifically for `MVert`, code can just use arrays
of vectors. This will allow eliminating many temporary arrays or
wrappers used to extract positions.
Many possible improvements aren't implemented in this patch, though
I did switch simplify or remove the process of creating temporary
position arrays in a few places.
The design clarity that "positions are just another attribute" brings
allows removing explicit copying of vertices in some procedural
operations-- they are just processed like most other attributes.
**Performance**
This touches so many areas that it's hard to benchmark exhaustively,
but I observed some areas as examples.
* The mesh line node with 4 million count was 1.5x (8ms to 12ms) faster.
* The Spring splash screen went from ~4.3 to ~4.5 fps.
* The subdivision surface modifier/node was slightly faster
RNA access through Python may be slightly slower, since now we need
a name lookup instead of just a custom data type lookup for each index.
**Future Improvements**
* Remove uses of "vert_coords" functions:
* `BKE_mesh_vert_coords_alloc`
* `BKE_mesh_vert_coords_get`
* `BKE_mesh_vert_coords_apply{_with_mat4}`
* Remove more hidden copying of positions
* General simplification now possible in many areas
* Convert more code to C++ to use `float3` instead of `float[3]`
* Currently `reinterpret_cast` is used for those C-API functions
Differential Revision: https://developer.blender.org/D15982
