Currently the compositor reads cryptomatte meta-data from the render
result. When loading a multilayer open exr file the meta-data was ignored.
This patch will also load the cryptomatte meta-data from multilayer open
exr files.
This enabled workflows where the rendering and compositing are done in
separate scenes or for future changes where the cryptomatte node will
use the meta-data for name matching and color picking.
Reviewed By: Sergey Sharybin
Differential Revision: https://developer.blender.org/D10384
This change will try to add meta data when using a multilayered open
exr file output node in the compositor. It adds the current scene meta
data and converts existing cryptomatte keys so it follows the
naming that is configured in the file output node.
This change supports the basic use-case where the compositor is
used to output cryptomatte layers with a different naming scheme to
support external compositors. In this case the Multilayered OpenEXR
files are used and the meta data is read from the render result.
Meta data is found when render layer node is connected with the
file output node without any other nodes in between. Redirects and empty
node groups are allowed.
The patch has been verified to work with external compositors.
See https://devtalk.blender.org/t/making-sense-of-cryptomatte-usage-in-third-party-programs/16576/17
See patch for example files.
Reviewed By: Sergey Sharybin
Differential Revision: https://developer.blender.org/D10016
