takes an “image_user” argument, and textures have this inherently. Can I add a custom “image_user” attribute to my material property group? I can’t figure out how to do it.
I tried creating the attribute as a property in my property group, it’s a PointerProperty whose “type” is a custom class inheriting from bpy.types.ImageUser. But then I get register errors when it tries to register the property group.
You can only use what already exists (so if you find other suitable pointer properties and image users, that should be fine), or change blender and compile your customized version.