The general idea is to keep the 'old', C-style MEM_callocN signature, and slowly
replace most of its usages with the new, C++-style type-safer template version.
* `MEM_cnew<T>` allocation version is renamed to `MEM_callocN<T>`.
* `MEM_cnew_array<T>` allocation version is renamed to `MEM_calloc_arrayN<T>`.
* `MEM_cnew<T>` duplicate version is renamed to `MEM_dupallocN<T>`.
Similar templates type-safe version of `MEM_mallocN` will be added soon
as well.
Following discussions in !134452.
NOTE: For now static type checking in `MEM_callocN` and related are slightly
different for Windows MSVC. This compiler seems to consider structs using the
`DNA_DEFINE_CXX_METHODS` macro as non-trivial (likely because their default
copy constructors are deleted). So using checks on trivially
constructible/destructible instead on this compiler/system.
Pull Request: https://projects.blender.org/blender/blender/pulls/134771
Before, it was only possible to apply modifiers through a multires modifier if
they were deform-only. The Geometry Nodes modifier is of course not deform-only.
However, often one can build a node setup, that only deforms and does nothing
else.
To make it possible to apply the Geometry Nodes modifier in such cases the
following things had to be done:
* Update `BKE_modifier_deform_verts` to work with modifiers that implement
`modify_geometry_set` instead of `deform_verts`.
* Add error handling for the case when `modify_geometry_set` does more than just
deformation.
* Allow the Geometry Nodes modifier to be applied through a multi-res modifier.
Two new utility types (`ArrayState` and `MeshTopologyState`) have been
introduced to allow for efficient and accurate checking whether the topology has
been modified. In common cases, they can detect that the topology has not been
changed in constant time, but they fall back to linear time checking if it's not
immediately obvious that the topology has not been changed.
This works with the example files from #98559 and #97603.
Pull Request: https://projects.blender.org/blender/blender/pulls/131904
