(new animation by Extex101)
The original texture is now "nether_portal_alt.png", and used to provide a "nether:portal_alt" node, which is used/demoed by the Surface-portal as the original animation still has a "it's full of stars" charm coming out when used for lighter coloured portals.
Currently proof of concept: Removes wormhole colour from .png texture and specifies it through MT API instead. The post_effect_color may call for registering a separate node per portal colour.
Palette 0 will have to be the traditional portal magenta (instead of 0 being black) for map compatibility with mod when colour was in the texture and not param2.