@Number6You can use
source: ../folder
or
source: ../folder/file
Yes, these are still relative paths..
a Single dot means this Folder
and the Double Dot means the Parent Folder or the One Above.
As suggested by
@TheEmuIf Scene creators all agreed to use a Shared folder for assets
Such as Data/Scenes/shared
Then from within the scene
members could use
../shared/filename
where filename is the name of a shared asset
or, if the assets were to be more organized
a set of sub folders could be agreed upon
shared/backgrounds
shared/shaders
shared/frags
shared/masks
so in the Scene code
members would reference a shared asset by using
../shared/backgrounds/FileName
../shared/shaders/FileName
../shared/frags/FileName
../shared/masks/FileName