While adding test coverage for in-memory and packed texture scenarios, I
found that UDIMs were not being handled correctly in both cases. For
in-memory scenarios the per-tile generated/dirty status was not taken
into account. For packed scenarios the wrong filename substitutions were
being used.
This fixes both of these cases and adds test coverage for these
scenarios now. Both relative and absolute path options are validated.
Note: Both in-memory and packed images behave incorrectly when using the
'KEEP' and 'PRESERVE' texture export modes, so those remain untested
currently. A design on exactly what should happen in these modes is TBD.
Pull Request: https://projects.blender.org/blender/blender/pulls/130391
704d34fe0f