[Dev Builds] Added the MBF21 improved wall scrollers

[printz]

Eternity now has the linedef types 1024, 1025 and 1026 from MBF21, which scroll linedef textures by sidedef offsets in an improved way compared with what the classic Boom special 255 is capable of. They allow you to tag all the intended lines to scroll and (based on whether you choose 1025 or 1026) add displacement or accelerative effects. Full specifications here.

 

We also have updated the Scroll_Texture_Offsets UDMF special to allow this equivalent functionality.