Camera background images were not shown under transparent objects.
This patch performs an alpha under for background images for cycles.
In order to see the difference the Film transparency needs to be turned on.
Note that workbench and EEVEE still needs to be adapted as they don't
write store alpha value in the viewport.
Side note. This implementation is already an improvement of the current behavior, what users are requesting. (Show background images underneath cycles viewport rendering.) It is clear that this patch still needs to be extended to workbench and eevee. For now that should be marked as a known limitation.
Reviewed By: fclem
Differential Revision: https://developer.blender.org/D5437
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This is often invalid, outdated or misleading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.
