This refactors how volume grids are stored with the following new goals in mind:
* Get a **stand-alone volume grid** data structure that can be used by geometry nodes.
Previously, the `VolumeGrid` data structure was tightly coupled with the `Volume` data block.
* Support **implicit sharing of grids and trees**. Previously, it was possible to share data
when multiple `Volume` data blocks loaded grids from the same `.vdb` files but this was
not flexible enough.
* Get a safe API for **lazy-loading and unloading** of grids without requiring explicit calls
to some "load" function all the time.
* Get a safe API for **caching grids from files** that is not coupled to the `Volume` data block.
* Get a **tiered API** for different levels of `openvdb` involvement:
* No `OpenVDB`: Since `WITH_OPENVDB` is optional, it's helpful to have parts of the API that
still work in this case. This makes it possible to write high level code for volumes that does
not require `#ifdef WITH_OPENVDB` checks everywhere. This is in `BKE_volume_grid_fwd.hh`.
* Shallow `OpenVDB`: Code using this API requires `WITH_OPENVDB` checks. However, care
is taken to not include the expensive parts of `OpenVDB` and to use forward declarations as
much as possible. This is in `BKE_volume_grid.hh` and uses `openvdb_fwd.hh`.
* "Full" `OpenVDB`: This API requires more heavy `OpenVDB` includes. Fortunately, it turned
out to be not necessary for the common API. So this is only used for task specific APIs.
At the core of the new API is the `VolumeGridData` type. It's a wrapper around an
`openvdb::Grid` and adds some features on top like implicit sharing, lazy-loading and unloading.
Then there are `GVolumeGrid` and `VolumeGrid` which are containers for a volume grid.
Semantically, each `VolumeGrid` has its own independent grid, but this is cheap due to implicit
sharing. At highest level we currently have the `Volume` data-block which contains a list of
`VolumeGrid`.
```mermaid
flowchart LR
Volume --> VolumeGrid --> VolumeGridData --> openvdb::Grid
```
The loading of `.vdb` files is abstracted away behind the volume file cache API. This API makes
it easy to load and reuse entire files and individual grids from disk. It also supports caching
simplify levels for grids on disk.
An important new concept are the "tree access tokens". Whenever some code wants to work
with an openvdb tree, it has to retrieve an access token from the corresponding `VolumeGridData`.
This access token has to be kept alive for as long as the code works with the grid data. The same
token is valid for read and write access. The purpose of these access tokens is to make it possible
to detect when some code is currently working with the openvdb tree. This allows freeing it if it's
possible to reload it later on (e.g. from disk). It's possible to free a tree that is referenced by
multiple owners, but only no one is actively working with. In some sense, this is similar to the
existing `ImageUser` concept.
The most important new files to read are `BKE_volume_grid.hh` and `BKE_volume_grid_file_cache.hh`.
Most other changes are updates to existing code to use the new API.
Pull Request: https://projects.blender.org/blender/blender/pulls/116315
Listing the "Blender Foundation" as copyright holder implied the Blender
Foundation holds copyright to files which may include work from many
developers.
While keeping copyright on headers makes sense for isolated libraries,
Blender's own code may be refactored or moved between files in a way
that makes the per file copyright holders less meaningful.
Copyright references to the "Blender Foundation" have been replaced with
"Blender Authors", with the exception of `./extern/` since these this
contains libraries which are more isolated, any changed to license
headers there can be handled on a case-by-case basis.
Some directories in `./intern/` have also been excluded:
- `./intern/cycles/` it's own `AUTHORS` file is planned.
- `./intern/opensubdiv/`.
An "AUTHORS" file has been added, using the chromium projects authors
file as a template.
Design task: #110784
Ref !110783.
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.
Use a shorter/simpler license convention, stops the header taking so
much space.
Follow the SPDX license specification: https://spdx.org/licenses
- C/C++/objc/objc++
- Python
- Shell Scripts
- CMake, GNUmakefile
While most of the source tree has been included
- `./extern/` was left out.
- `./intern/cycles` & `./intern/atomic` are also excluded because they
use different header conventions.
doc/license/SPDX-license-identifiers.txt has been added to list SPDX all
used identifiers.
See P2788 for the script that automated these edits.
Reviewed By: brecht, mont29, sergey
Ref D14069
This commit uses OpenVDB more directly for the voxel remesher, without
the extra indirection of copying to a Blender API. This makes the code
simpler, shorter, and easier to understand (though I didn't observe any
performance improvement).
This also removes the rest of the unused and undocumented OpenVDB C API,
which was written when Blender's code didn't really use C++, and doesn't
serve a purpose anymore. Those features will be implemented as nodes in
the future anyway (see D12100).
Differential Revision: https://developer.blender.org/D12097
This is a more correct fix to the issue Brecht was fixing in D6600.
While the fix in that patch worked fine for linking it broke ASAN
runtime under some circumstances.
For example, `make full debug developer` would compile, but trying
to start blender will cause assert failure in ASAN (related on check
that ASAN is not running already).
Top-level idea: leave it to CMake to keep track of dependency graph.
The root of the issue comes to the fact that target like "blender" is
configured to use a lot of static libraries coming from Blender sources
and to use external static libraries. There is nothing which ensures
order between blender's and external libraries. Only order of blender
libraries is guaranteed.
It was possible that due to a cycle or other circumstances some of
blender libraries would have been passed to linker after libraries
it uses, causing linker errors.
For example, this order will likely fail:
libbf_blenfont.a libfreetype6.a libbf_blenfont.a
This change makes it so blender libraries are explicitly provided
their dependencies to an external libraries, which allows CMake to
ensure they are always linked against them.
General rule here: if bf_foo depends on an external library it is
to be provided to LIBS for bf_foo.
For example, if bf_blenkernel depends on opensubdiv then LIBS in
blenkernel's CMakeLists.txt is to include OPENSUBDIB_LIBRARIES.
The change is made based on searching for used include folders
such as OPENSUBDIV_INCLUDE_DIRS and adding corresponding libraries
to LIBS ion that CMakeLists.txt. Transitive dependencies are not
simplified by this approach, but I am not aware of any downside of
this: CMake should be smart enough to simplify them on its side.
And even if not, this shouldn't affect linking time.
Benefit of not relying on transitive dependencies is that build
system is more robust towards future changes. For example, if
bf_intern_opensubiv is no longer depends on OPENSUBDIV_LIBRARIES
and all such code is moved to bf_blenkernel this will not break
linking.
The not-so-trivial part is change to blender_add_lib (and its
version in Cycles). The complexity is caused by libraries being
provided as a single list argument which doesn't allow to use
different release and debug libraries on Windows. The idea is:
- Have every library prefixed as "optimized" or "debug" if
separation is needed (non-prefixed libraries will be considered
"generic").
- Loop through libraries passed to function and do simple parsing
which will look for "optimized" and "debug" words and specify
following library to corresponding category.
This isn't something particularly great. Alternative would be to
use target_link_libraries() directly, which sounds like more code
but which is more explicit and allows to have more flexibility
and control comparing to wrapper approach.
Tested the following configurations on Linux, macOS and Windows:
- make full debug developer
- make full release developer
- make lite debug developer
- make lite release developer
NOTE: Linux libraries needs to be compiled with D6641 applied,
otherwise, depending on configuration, it's possible to run into
duplicated zlib symbols error.
Differential Revision: https://developer.blender.org/D6642
This aligns with the VFX reference platform 2020 along with the decision
to stick to Python 3.7, see T68774.
Blosc was downgraded to 1.5 as recommended by the OpenVDB documentation.
IlmBase and OpenEXR are now built together with CMake rather separately
using autoconf.
Differential Revision: https://developer.blender.org/D6593
This code is needed to implement the Voxel Remesher as well as other features like a better remesh modifier with filters and CSG operations.
Done by Martin Felke and Pablo Dobarro
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D5364
No functional change, this adds LIB definition and args to cmake files.
Without this it's difficult to migrate away from 'BLENDER_SORTED_LIBS'
since there are many platforms/configurations that could break when
changing linking order.
Manually add and enable WITHOUT_SORTED_LIBS to try building
without sorted libs (currently fails since all variables are empty).
This check will eventually be removed.
See T46725.
BF-admins agree to remove header information that isn't useful,
to reduce noise.
- BEGIN/END license blocks
Developers should add non license comments as separate comment blocks.
No need for separator text.
- Contributors
This is often invalid, outdated or misleading
especially when splitting files.
It's more useful to git-blame to find out who has developed the code.
See P901 for script to perform these edits.
Better fix for T54457. It seems Debian compiles OpenVDB without ABI 3
compatibility, while Arch does enable it as is the default in the OpeVDB
CMake build system.
So now there's an option that the distribution can set depending on how
they compile their OpenVDB package.
This is used to determine which voxels are to be considered empty space.
Previously it was hardcoded for converting dense grids to OpenVDB grids
to reduce disk space usage.
This value is also useful for rendering engines to know, i.e. to
optimize ray marching.
Some other software cannot handle grid names with spaces in them. We still check for names with spaces so as to not break old
files.
This fixes T53802.
One crucial thing here: OpenVDB shoudl be compiled WITHOUT
OPENVDB_ENABLE_3_ABI_COMPATIBLE flag. This is how OpenVDB's Makefile is
configured and it's not really possible to detect this for a compiled library.
If we ever want to support that option, we need to add extra CMake argument and
use old version 3 API everywhere.
Issue was that before writing to disk grids are clipped against the
density field's tree to optimize for memory/disk space, which in the
case of simulations with no density field results in all grids having
empty trees.
For now avoid clipping against empty grids, but perhaps in the future it
can be interresting to have some UI parameters to let the user choose
the grid used for clipping.
simulations.
This commits implements OpenVDB as an extra cache format in the Point
Cache system for smoke simulations. Compilation with the library is
turned off by default for now, and shall be enabled when the library is
present.
A documentation of its doings is available here: http://
wiki.blender.org/index.php/User:Kevindietrich/OpenVDBSmokeExport.
A guide to compile OpenVDB can be found here (Linux): http://
wiki.blender.org/index.php?title=Dev:Doc/Building_Blender/Linux/
Dependencies_From_Source#OpenVDB
Reviewers: sergey, lukastoenne, brecht, campbellbarton
Reviewed By: brecht, campbellbarton
Subscribers: galenb, Blendify, robocyte, Lapineige, bliblubli,
jtheninja, lukasstockner97, dingto, brecht
Differential Revision: https://developer.blender.org/D1721
Jacques Lucke
Campbell Barton
Ray Molenkamp
Sergey Sharybin
Hans Goudey
Campbell Barton
Dalai Felinto
Brecht Van Lommel
Brecht Van Lommel
Sergey Sharybin
Brecht Van Lommel
Pablo Dobarro
Kévin Dietrich