The converter is an abstraction that takes a base mesh to be subdivided
and provides its topology information to the OpenSubdiv library. It does
this with one level of indirection: first extracting the base mesh
topology with a virtual function call per element to local arrays,
then giving the information in those arrays to OpenSubdiv.
That level of indirection also handles cache invalidation for the
intermediate data structures which optimize repeated subdivisions of a
changing base mesh with constant topology. However, these days the mesh
data is stored with simpler to compare data arrays, and we also have
implicit sharing which provides another way to detect unchanged
shared data.
As a very first step to a design where we use OpenSubdiv more directly
and don't store duplicate topology arrays for the base mesh, this PR
provides the converter with the mesh's face offsets array directly
rather than using function calls. For multires reshape the temporary
format is changed to match.
Next steps will do the same thing for face vertices ("corner verts" in
Blender lingo), edges, and creases. Then we can remove the "converter"
indirection completely, then we can work on a better cache invalidation
strategy using implicit sharing. That's a ways off though. On its own,
this PR should just reduce function call overhead a bit.
Reference #130917.
Pull Request: https://projects.blender.org/blender/blender/pulls/130241
Remove the indirection previously used for the topology refiner
to separate C and C++ code. Instead retrieve the base level in
calling code and call opensubdiv API functions directly. This
avoids copying arrays of mesh indices and should reduce
function call overhead since index retrieval can now be inlined.
It also lets us remove a lot of boilerplate shim code.
The downside is increased need for WITH_OPENSUBDIV defines
in various parts of blenkernel, but I think that is required to avoid
the previous indirection and have the kernel deal with OpenSubdiv
more directly.
Pull Request: https://projects.blender.org/blender/blender/pulls/120825
Replace the C-class pattern function pointers with actual class methods.
Other than the obvious benefit of not requiring the "this" pointer to be
explicitly passed into every function call, this will make it much simpler
to remove the entire C-API class and replace it with its "impl" next.
For that next step we need to expose code to the implementation
of the topology refiner, so instead of defining stubs locally in the
opensubdiv intern class, we spread some WITH_OPENSUBDIV checks
in the blenkernel. As far as I know this is the only way to remove the
intermediate C-API and call opensubdiv functions directly from there.
Avoid unnecessary indirect includes for the module, which would slow
down compilation. Avoid "using std" which is generally not considered
good practice since it's helpful to see what namespace things are from.
This is just a general cleanup of the area. I was trying to understand
it better to reduce redundant mesh topology storage but finding that
some intermediate cleanups would be helpful to ease the change.
Pull Request: https://projects.blender.org/blender/blender/pulls/120743
Along with the 4.1 libraries upgrade, we are bumping the clang-format
version from 8-12 to 17. This affects quite a few files.
If not already the case, you may consider pointing your IDE to the
clang-format binary bundled with the Blender precompiled libraries.
All the relevant code is C++ now, so we don't need to complicate things
with the trip through C anymore. We will still need some wrappers, since
opensubdiv is an optional dependency though. The goal is to make it
simpler to remove the unnecessary/costly abstraction levels between
Blender mesh data and the opensubdiv code.
The goal is to solve confusion of the "All rights reserved" for licensing
code under an open-source license.
The phrase "All rights reserved" comes from a historical convention that
required this phrase for the copyright protection to apply. This convention
is no longer relevant.
However, even though the phrase has no meaning in establishing the copyright
it has not lost meaning in terms of licensing.
This change makes it so code under the Blender Foundation copyright does
not use "all rights reserved". This is also how the GPL license itself
states how to apply it to the source code:
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>
This program is free software ...
This change does not change copyright notice in cases when the copyright
is dual (BF and an author), or just an author of the code. It also does
mot change copyright which is inherited from NaN Holding BV as it needs
some further investigation about what is the proper way to handle it.
For example
```
OIIOOutputDriver::~OIIOOutputDriver()
{
}
```
becomes
```
OIIOOutputDriver::~OIIOOutputDriver() {}
```
Saves quite some vertical space, which is especially handy for
constructors.
Pull Request: https://projects.blender.org/blender/blender/pulls/105594
Using the `MEM_*` API from C++ code was a bit annoying:
* When converting C to C++ code, one often has to add a type cast on
returned `void *`. That leads to having the same type name three times
in the same line. This patch reduces the amount to two and removes the
`sizeof(...)` from the line.
* The existing alternative of using `OBJECT_GUARDED_NEW` looks a out
of place compared to other allocation methods. Sometimes
`MEM_CXX_CLASS_ALLOC_FUNCS` can be used when structs are defined
in C++ code. It doesn't look great but it's definitely better. The downside
is that it makes the name of the allocation less useful. That's because
the same name is used for all allocations of a type, independend of
where it is allocated.
This patch introduces three new functions: `MEM_new`, `MEM_cnew` and
`MEM_delete`. These cover the majority of use cases (array allocation is
not covered).
The `OBJECT_GUARDED_*` macros are removed because they are not
needed anymore.
Differential Revision: https://developer.blender.org/D13502
Corrects incorrect usage of contraction for 'it is', when possessive 'its' was required.
Differential Revision: https://developer.blender.org/D9250
Reviewed by Campbell Barton
This change makes it so vertices of edge are only stored when edge
has non-zero crease. This allows to lower memory footprint of 1.5M
faces from 78 MiB to 54 MiB in the case all creases are zero.
Meshes with crease are more hard to predict due to array-based
storage, so it all depends on index of edge with crease. Worst case
(all edges are creased) still stays at 78 MiB.
Makes it possible to set adjacent vertices after edge sharpness.
Initially it seemed like useful sanity check, but with time it
became rather a burden.
Avoid per-face pointer and allocation: store everything as continuous
arrays.
Memory footprint for 1.5M faces:
- Theoretical worst case (all vertices and edges have crease) memory
goes down from 114 MiB to 96 MiB (15% improvement).
This case is not currently achievable since Blender does not expose
vertex crease yet.
- Current real life worst case (all edges have crease) memory goes
down from 108 MiB to 90 MiB (17% improvement).
- Best case (no creases at all) memory goes down from 96 MiB to 78 MiB
(19% improvement).
While this looks trivial it already allowed to catch issues in one
of previous attempt to optimize memory usage. It will totally be
useful for an upcoming refactor of face topology storage.
Allows to perform comparison by doing linear comparison of indices.
Before cyclic match was used to deal with possibly changed winding from
OpenSubdiv side.
Speeds up comparison (and hence improves FPS), makes code more reliable
nut uses more memory.
This change makes it so topology refiner comparison will check vertices
of all existing/provided edges.
The initial claim that due to manifold nature of mesh there is no need
in "deep" edges check was wrong: some areas might only provide edges
with non-zero creases. So if crease of one edge goes changes from 1.0
to 0.0 and crease of other edge goes from 0.0 to 1.0 the old comparison
code would not have caught it.
Similar to previous change in vertex sharpness, explicitly store value
provided by the converter.
Allows to avoid rather fragile check for boundary edges.
Also allows to avoid need in constructing edge map. This lowers memory
footprint of the comparison process and avoids memory allocations
during the comparison (which is an extra benefit from the performance
point of view).
This change starts the transition of topology refiner comparison
to compare actual values given by the converter, which will not be
affected by the refinement or face winding synchronization steps.
Currently is only implemented for vertex sharpness, but will be
extended further as followup development.
Fixes T71908: Subdiv: Incorrect topology comparison, leading to poor performance
The idea is to use this explicit storage for topology comparison rather
than using base level. While this will have memory overhead it allows
to simplify comparison of such things as:
- Vertex sharpness (where base level from topology refiner will have it
refined, meaning it will be different from what application requested
for non-manifold and corner vertices).
- It will allow to simplify face-vertices comparison, where currently
O(N^2) algorithm is used due to possible difference in face winding.
- It will also allow to avoid comparison-time allocation of edge map.
Currently no functional changes, just preparing for development which
will happen next.
Previously it was enabled for debug builds, now it is to be enabled
explicitly.
The reason for this is to reduce overhead when debugging other areas
which might involve subdivision surface. When conversion is to be
debugged set this manually in the code.
Consolidate it inside of the topology refiner implementation class,
which would allow to store extra data acquired during construction
of the OpenSubdiv's object.
Only use OBJECT_GUARDED_{NEW. DELETE} for structures which are part of
public C-API (and hence can not have new/delete operators overloaded).
Could try being brave and override new/delete from under C++ ifdef.
