This fixes the glitching hairs described in T56408, T63534, and possibly
also T63534.
The fix consists of returning the original mesh (i.e. as visible in edit
mode) when constructing the ORCO mesh. This allows a static set of
coordinates to be used when computing the child hair positions.
The original mesh is only returned when it has the same topology (at
least same number of vertices, loops, and polys. It's up the author of
the Alembic file to ensure stable geometry when it's desired to be
compatible with Blender's hair system.
Reviewers: mont29, brecht
Differential Revision: https://developer.blender.org/D5492
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This is often invalid, outdated or misleading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.
C++11 doesn't need the space between '> >' in a nested templated
declaration, so instead of `std::vector<std::pair<a, b> >` we can now
write `std::vector<std::pair<a, b> >`.
The depsgraph was always created within a fixed evaluation context. Passing
both risks the depsgraph and evaluation context not matching, and it
complicates the Python API where we'd have to expose both which is not so
easy to understand.
This also removes the global evaluation context in main, which assumed there
to be a single active scene and view layer.
Differential Revision: https://developer.blender.org/D3152
Note that some little parts of code have been dissabled because eval_ctx
was not available there. This should be resolved once DerivedMesh is
replaced.
No longer passing time as float and constructing ISampleSelectors all
over the place. Instead, just construct an ISampleSelector once and
pass it along.
Previously, a GHash was used to store a flattened mapping of parent
information based on the Alembic hierarchy, and then that hash was used to
set parent pointers on Blender objects. This resulted in errors and
some duplicate objects. The new approach stores parent pointers while
traversing the Alembic hierarchy, which means that there is much more
information about the actual context of the Alembic object itself,
producing a more stable import.
Also renamed AbcObjectReader::readObjectMatrix to
setupObjectTransform, as it does more than just reading the object
matrix; it also sets up an object constraint if the Alembic Xform is
animated.
Most of them are harmless implicit conversions (e.g. Alembic deals with
doubles for storing time information when Blender uses both ints and
floats/doubles) or class/struct mismatch on forward declarations.
Crash is due by mismatching loops and faces counts between the Alembic
data and the Blender derivedmesh which does not appear so
straightforward to fix (the crash happens deep in the derivedmesh code).
So for now, try to detect if the topology has changed and if so, both
only read vertices (vertex colors and UVs won't be read, as tied to face
loops) and add a warning message in the modifier's UI to let the user
know.
constraints.
This avoids traversing the archive everytime object data is needed and
gives an overall consistent ~2x speedup here with files containing
between 136 and 500 Alembic objects. Also this somewhat nicely de-
duplicates code between data creation (upon import) and data streaming
(modifiers and constraints).
The only worying part is what happens when a CacheFile is deleted and/or
has its path changed. For now, we traverse the whole scene and for each
object using the CacheFile we free the pointer and NULL-ify it (see
BKE_cachefile_clean), but at some point this should be re-considered and
make use of the dependency graph.
All in all, this patch adds an Alembic importer, an Alembic exporter,
and a new CacheFile data block which, for now, wraps around an Alembic
archive. This data block is made available through a new modifier ("Mesh
Sequence Cache") as well as a new constraint ("Transform Cache") to
somewhat properly support respectively geometric and transformation data
streaming from alembic caches.
A more in-depth documentation is to be found on the wiki, as well as a
guide to compile alembic: https://wiki.blender.org/index.php/
User:Kevindietrich/AlembicBasicIo.
Many thanks to everyone involved in this little project, and huge shout
out to "cgstrive" for the thorough testings with Maya, 3ds Max, Houdini
and Realflow as well as @fjuhec, @jensverwiebe and @jasperge for the
custom builds and compile fixes.
Reviewers: sergey, campbellbarton, mont29
Reviewed By: sergey, campbellbarton, mont29
Differential Revision: https://developer.blender.org/D2060
