Fix package name missmatch in a few module files. IE "ALEMBIC" was
defined in the file but the find_package commands used "Alembic"
Some modules state that they set and use the _LIBRARY variable but the
do in fact not do this. Removed these comments from those files.
The spelling and capitalization of package name passed to find_package()
and find_package_handle_standard_args() needs to match.
Silences CMake warning about mismatch.
Differential Revision: https://developer.blender.org/D8247
Reduce the number of possible locations used to find libraries,
to simplify troubleshooting.
Only keep '*_ROOT_DIR' and the path used by 'install_deps.sh'.
Note that this is turned off by default and must be enabled at build time with the CMake WITH_CYCLES_EMBREE flag.
Embree must be built as a static library with ray masking turned on, the `make deps` scripts have been updated accordingly.
There, Embree is off by default too and must be enabled with the WITH_EMBREE flag.
Using Embree allows for much faster rendering of deformation motion blur while reducing the memory footprint.
TODO: GPU implementation, deduplication of data, leveraging more of Embrees features (e.g. tessellation cache).
Differential Revision: https://developer.blender.org/D3682
