Add support for project texture files (Kenney 3D Models)

Add support for project texture files (for example in some of Kenney 3D Models).

Thanks to https://twitter.com/DavitMasia for the question about this.

https://kenney.nl/assets/mini-dungeon

For example, for Kenney's mini-dungeon, I set the following works (make sure that you use the same directory structure as defined in the original assets directory.