In ACNH, skeletal animations and matching texture swap animations (that is, facial expressions) are stored as two separate resources with the same name.
I was thinking for Project Special K I might have an object, of any type ("empty"?) with custom properties in Blender for the eyes and mouth texture swaps, so those could be animated and stored together with skeletal animations.
Unfortunately, it seems Blender's FBX export doesn't seem to support this — making an otherwise empty scene with a single object in it that has two custom int properties for the facial expressions and keyframing one of them over nine frames, then exporting it and opening it in Autodesk FBX Explorer shows only one frame's worth of custom properties.
Which is something, but not at all what I wanted.
So either I have an empty named "FaceAnim" (purely for identification purposes) and use its X/Y positions as the eyes/mouth frame indices, which since it doesn't involve custom properties at all should by all accounts work¹, or someone here gives me a better idea.
¹: though this might also involve a pair of custom properties that drive the X/Y position maybe? I dunno, I'm a kitty.
