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: https://projects.blender.org/blender/blender/pulls/105416
Consistent with naming from 1af62cb3bf. Keep the "coord"
naming in the "vert_coords_alloc" set of functions since they should be
removed (see #103789).
Remove the use of a separate contiguous positions array now that
they are stored that way in the first place. This allows removing the
complexity of tracking whether it is allocated and deformed in the
mesh modifier stack.
Instead of deferring the creation of the final mesh until after the
positions have been copied and deformed, create the final mesh
first and then deform its positions.
Since vertex and face normals are calculated lazily, we can rely on
individual modifiers to calculate them as necessary and simplify
the modifier stack. This was hard to change before because of the
separate array of deformed positions.
Differential Revision: https://developer.blender.org/D16971
The goal is to give technical artists the ability to optimize modifier usage
and/or geometry node groups for performance. In the long term, it
would be useful if Blender could provide its own UI to display profiling
information to users. However, right now, there are too many open
design questions making it infeasible to tackle this in the short term.
This commit uses a simpler approach: Instead of adding new ui for
profiling data, it exposes the execution-time of modifiers in the Python
API. This allows technical artists to access the information and to build
their own UI to display the relevant information. In the long term this
will hopefully also help us to integrate a native ui for this in Blender
by observing how users use this information.
Note: The execution time of a modifier highly depends on what other
things the CPU is doing at the same time. For example, in many more
complex files, many objects and therefore modifiers are evaluated at
the same time by multiple threads which makes the measurement
much less reliable. For best results, make sure that only one object
is evaluated at a time (e.g. by changing it in isolation) and that no
other process on the system keeps the CPU busy.
As shown below, the execution time has to be accessed on the
evaluated object, not the original object.
```lang=python
import bpy
depsgraph = bpy.context.view_layer.depsgraph
ob = bpy.context.active_object
ob_eval = ob.evaluated_get(depsgraph)
modifier_eval = ob_eval.modifiers[0]
print(modifier_eval.execution_time, "s")
```
Differential Revision: https://developer.blender.org/D17185
**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
These functions are almost identical, the main difference being
BLI_join_dirfile didn't trim existing slashes when joining paths
however this isn't an important difference that warrants a separate
function.
This commit replaces the `Mesh_Runtime` struct embedded in `Mesh`
with `blender::bke::MeshRuntime`. This has quite a few benefits:
- It's possible to use C++ types like `std::mutex`, `Array`,
`BitVector`, etc. more easily
- Meshes saved in files are slightly smaller
- Copying and writing meshes is a bit more obvious without
clearing of runtime data, etc.
The first is by far the most important. It will allows us to avoid a
bunch of manual memory management boilerplate that is error-prone and
annoying. It should also simplify future CoW improvements for runtime
data.
This patch doesn't change anything besides changing `mesh.runtime.data`
to `mesh.runtime->data`. The cleanups above will happen separately.
Differential Revision: https://developer.blender.org/D16180
This is the conventional way of dealing with unused arguments in C++,
since it works on all compilers.
Regex find and replace: `UNUSED\((\w+)\)` -> `/*$1*/`
