Noisy change, but safe, and better do it sooner than later if we are to
rework copying code. Also, previous commit shows this *is* useful to
catch some mistakes.
It's now less confusing (for example, using nr_of_samples directly,
instead of using 1 / 1 / nr_of_samples). Might also have fixed a bug.
Also added unittests.
Houdini writes vertex data in a different format than Blender does; Houdini
uses "face-varying scope", which means that the vertex colours are indexed
by an ever-increasing number over all vertices of all faces instead of the
vertex index.
I've also merged the read_custom_data_mcols() and read_mcols() functions,
because the latter was only called from the former, and the changes in this
commit would add yet more function parameters to pass.
By mistake, the code relied on ALEMBIC_ROOT_DIR being defined by the user
running the tests. Now CMake macros are used to correctly find the Alembic
root directory.
It is disabled by default, so should not affect existing configurations.
Main benefits of this goes as:
- Linux distros can use that to avoid libraries duplication and link
blender package against gflags package from the system.
- It it easier to test whether Blender works with updated version of
Gflags prior to re-bundling the library.
Example, imagine an object Cube in collections 1 and 2 where both
collections are nested to A. Now we set a "color" property as follow:
```
Scene -> GREEN
--
A -> RED
↳ 1 -> BLUE
↳ 2 -> -
```
In this case the object will be RED, because of A↳ 2.
Now if we have:
```
Scene -> GREEN
--
A -> RED
↳ 1 -> -
↳ 2 -> PINK
1 -> -
--
The object will be PINK because of A↳ 2.
Note that the (top level) collection 1 doesn't influence the object color
because there are no overrides on it. The scene render settings (GREEN
in this case) are only used as fallback if an override is not set at
all.
The ABC_export and ABC_import functions both take a as_background_job
parameter, and return a boolean.
When as_background_job=true, returns false immediately after scheduling
a background job. This was the old behaviour of this function, which makes
it very hard for scripts to do something with the data after the import
or export completes.
When as_background_job=false, performs the export synchronously, and
returns true when the export was ok, and false if there were any errors.
This allows further processing.
The Scene.alembic_export() function is deprecated, and will be removed from
Blender 2.8 in favour of calling the bpy.ops.wm.alembic_export() operator.
As such, it has been hard-coded to the old background job behaviour.
The export is still slower than needed, as the particle systems themselves
aren't disabled during the export. It's only the writing to the Alembic
file that's skipped.
Curve resolution isn't natively supported by Alembic, hence it is stored
in a user property "blender:resolution". I've looked at a Maya curves
example file, but that also didn't contain any information about curve
resolution.
Differential Revision: https://developer.blender.org/D2634
Reviewers: kevindietrich
