AABB aligned quads would defeat the "witness" accelerator when
using the xatlas packing strategy.
This change reorders the search to allow use of the "witness" technique.
Standardize naming, use spans and references for input parameters,
and improve documentation. Now the functions expect the lookups to
succeed as well, they will fail and assert otherwise.
The functions are also simple enough that it likely makes sense to keep
them all inlined
Add `index_range()` and `is_empty()` functions, rename `ranges_num()`
to `size()` (clarifying the final extra integer as an implementation
detail). Also remove the `size(index)` function which gave almost the
same assembly as `[index].size()` (https://godbolt.org/z/PYzqYs3Kr).
Implements #102359.
Split the `MLoop` struct into two separate integer arrays called
`corner_verts` and `corner_edges`, referring to the vertex each corner
is attached to and the next edge around the face at each corner. These
arrays can be sliced to give access to the edges or vertices in a face.
Then they are often referred to as "poly_verts" or "poly_edges".
The main benefits are halving the necessary memory bandwidth when only
one array is used and simplifications from using regular integer indices
instead of a special-purpose struct.
The commit also starts a renaming from "loop" to "corner" in mesh code.
Like the other mesh struct of array refactors, forward compatibility is
kept by writing files with the older format. This will be done until 4.0
to ease the transition process.
Looking at a small portion of the patch should give a good impression
for the rest of the changes. I tried to make the changes as small as
possible so it's easy to tell the correctness from the diff. Though I
found Blender developers have been very inventive over the last decade
when finding different ways to loop over the corners in a face.
For performance, nearly every piece of code that deals with `Mesh` is
slightly impacted. Any algorithm that is memory bottle-necked should
see an improvement. For example, here is a comparison of interpolating
a vertex float attribute to face corners (Ryzen 3700x):
**Before** (Average: 3.7 ms, Min: 3.4 ms)
```
threading::parallel_for(loops.index_range(), 4096, [&](IndexRange range) {
for (const int64_t i : range) {
dst[i] = src[loops[i].v];
}
});
```
**After** (Average: 2.9 ms, Min: 2.6 ms)
```
array_utils::gather(src, corner_verts, dst);
```
That's an improvement of 28% to the average timings, and it's also a
simplification, since an index-based routine can be used instead.
For more examples using the new arrays, see the design task.
Pull Request: blender/blender#104424
Geometry Nodes: SDF Volume nodes milestone 1
Adds initial support for SDF volume creation and manipulation.
`SDF volume` is Blender's name of an OpenVDB grid of type Level Set.
See the discussion about naming in #91668.
The new nodes are:
- Mesh to SDF Volume: Converts a mesh to an SDF Volume
- Points to SDF Volume: Converts points to an SDF Volume
- Mean Filter SDF Volume: Applies a Mean Filter to an SDF
- Offset SDF Volume: Applies an offset to an SDF
- SDF Volume Sphere: Creates an SDF Volume in the shape of a sphere
For now an experimental option `New Volume Nodes` needs to be
enabled in Blender preferences for the nodes to be visible.
See the current work plan for Volume Nodes in #103248.
Pull Request: blender/blender#105090
This simplifies the usage of the API and is preparation for #104478.
The `CustomData_add_layer` and `CustomData_add_layer_named` now have corresponding
`*_with_data` functions that should be used when creating the layer from existing data.
Pull Request: blender/blender#105708
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
Rename `struct ::UVPackIsland_Params` to
`class blender::geometry::UVPackIsland_Params`
Brings us closer to an "algorithm" style API.
No functional changes.
This is a fix for the previous commit d7c023eb25.
Before, every time the lambda was called, a copy of the BitVector was
made. This was very inefficient.
Now this has been fixed by passing the BitVector by reference (&) in
the lambda function.
In very specific cases, during intersection testing, `intersect` can
add polygons already checked as duplicates in the buffer that
corresponds to the rest of polygons that can form groups of duplicates.
As the buffer cannot have repeated indices, re-adding, even
temporarily, these duplicates can cause a buffer overflow.
While this may have some impact on performance, it's difficult to
predict these cases and thus add a buffer pad.
So the solution is to check if they are already duplicated.
For mesh primitives, the bounds can be calculated trivially in advance
with negligible cost. In case they are needed later on, setting them
eagerly can save the calculation later on. For large meshes, this can
save tens of milliseconds before drawing.
Pull Request: blender/blender#105266
The correction bbc6bb3468 was still wrong because there it was
disregarded that `vert_ctx_len` does not necessarily indicate merges in
the same polygon.
Therefore, it is not safe to rely on `vert_ctx_len` to count possible
new polygons.
NOTE: It might be worth preempting part of the
`weld_poly_split_recursive` logic to identify what the new polygons are
in advance. But this can be left for a future refactor.
Currently the shade smooth status for mesh faces is stored as part of
`MPoly::flag`. As described in #95967, this moves that information
to a separate boolean attribute. It also flips its status, so the
attribute is now called `sharp_face`, which mirrors the existing
`sharp_edge` attribute. The attribute doesn't need to be allocated
when all faces are smooth. Forward compatibility is kept until
4.0 like the other mesh refactors.
This will reduce memory bandwidth requirements for some operations,
since the array of booleans uses 12 times less memory than `MPoly`.
It also allows faces to be stored more efficiently in the future, since
the flag is now unused. It's also possible to use generic functions to
process the values. For example, finding whether there is a sharp face
is just `sharp_faces.contains(true)`.
The `shade_smooth` attribute is no longer accessible with geometry nodes.
Since there were dedicated accessor nodes for that data, that shouldn't
be a problem. That's difficult to version automatically since the named
attribute nodes could be used in arbitrary combinations.
**Implementation notes:**
- The attribute and array variables in the code use the `sharp_faces`
term, to be consistent with the user-facing "sharp faces" wording,
and to avoid requiring many renames when #101689 is implemented.
- Cycles now accesses smooth face status with the generic attribute,
to avoid overhead.
- Changing the zero-value from "smooth" to "flat" takes some care to
make sure defaults are the same.
- Versioning for the edge mode extrude node is particularly complex.
New nodes are added by versioning to propagate the attribute in its
old inverted state.
- A lot of access is still done through the `CustomData` API rather
than the attribute API because of a few functions. That can be
cleaned up easily in the future.
- In the future we would benefit from a way to store attributes as a
single value for when all faces are sharp.
Pull Request: blender/blender#104422
This was caused by an incorrect assumption in the solver:
It tries to solve both collision and length constraints simultaneously,
using the projected movement of a point as a slide direction along the surface.
This only works if the distance of the previous curve point to the surface
is less than the allowed segment length. Otherwise the segment will
exceed the allowed length even with zero slide and NaN values are computed.
The case of larger surface distance can occur if the previous segment
solve was already stretching the current segment and then the point
moves further away. In this case we can simply clamp the segment length
without violating the contact constraint.
Pull Request #105499
This was caused by an incorrect assumption in the solver:
It tries to solve both collision and length constraints simultaneously,
using the projected movement of a point as a slide direction along the surface.
This only works if the distance of the previous curve point to the surface
is less than the allowed segment length. Otherwise the segment will
exceed the allowed length even with zero slide and NaN values are computed.
The case of larger surface distance can occur if the previous segment
solve was already stretching the current segment and then the point
moves further away. In this case we can simply clamp the segment length
without violating the contact constraint.
Fixes#105467
Pull Request #105499
The current API makes more sense as part of a class, but for now, keep
consistency with the other geometry module headers and move the code
to the proper namespace, removing the `GEO_` prefix which is only meant
for C code.
Pull Request #105357
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.
As part of #95966, move the `ME_SEAM` flag on mesh edges
to a generic boolean attribute, called `.uv_seam`. This is the
last bit of extra information stored in mesh edges. After this
is committed we can switch to a different type for them and
have a 1/3 improvement in memory consumption.
It is also now possible to see that a mesh has no UV seams in
constant time, and like other similar refactors, interacting with
only the UV seams can be done with less memory.
The attribute name starts with a `.` to signify that the attribute,
like face sets, isn't meant to be used in arbitrary procedural
situations (with geometry nodes for example). That gives us more
freedom to change things in the future.
Pull Request #104728
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
