MBF Line 271

[Coraline]

Hi everyone,

Playing recent Boom wads in 3DGE. Support is pretty decent - however, I noticed it does not recognize Linetype 271 (sky transfer).

Can anyone provide info on what that linetype is supposed to do? Not having it function has not hindered my ports ability to play through them, but it seems MBF specific.

Does it do other things or is it just used for one purpose?

Thanks!

[Rayziik]

As far as I know, it just takes the texture you put on the upper sidedef and sticks it into the sky instead of the default sky texture.

[Graf Zahl]

271 and 272 are both sky transfers, 272 mirrors the sky just like the default sky. You'll have to look out for scrolling which is not 1:1. If I read GZDoom's code correctly, scrolling 65536 map units in x direction means one full rotation.

[Coraline]

Okay, I will have to add support via DDFLINE then. So it is just used as a trigger to change the sky textures according to the line tag? If so I can definitely write a DDF linetype that can catch the tag and convert the sky that way.

Graf - you mentioned scrollers - it is also used to scroll the skybox itself?

[Da Werecat]

It should take effect immediately after starting the map, and it should be possible to view multiple skies at once. That's how it always worked, anyway.

Have you implemented generalized actions, by the way?

[Coraline]

Working on it. If you remembered, 3DGE only supported a small set of generalized actions. It seems daunting to figure out what generalized actions do what at the given time per-map..

Multiple skies at once? As in, two skies layered together? Or two skies in different parts of the map (different sectors)? I was playing a newer wad (that colorful alien-something boomset that just came out), but I havent tried running it in PrBoom yet to see what is supposed to change. Wad plays just fine otherwise.

[Da Werecat]

Different skies displayed in different sectors. Even visible simultaneously.

Chu said:

It seems daunting to figure out what generalized actions do what at the given time per-map..

Wouldn't it be easier to look at the source code?

[Gez]

Chu said:

Or two skies in different parts of the map (different sectors)?

That. Several of these sectors can be in sight simultaneously.

And yes, the offset on the linedef should be transferred to the sky, with the result that a scrolling wall effect results in a scrolling sky.

[Coraline]

Da Werecat said:

Wouldn't it be easier to look at the source code?

Sure, but none of it applies to 3DGE regardless. It has to make sectors and lines that use Boom/etc -> DDF. So, in this case it is easier to ask people that actually use it. :)

[Da Werecat]

I highly doubt it's a good idea to reverse-engineer generalized actions by running Boom maps and talking to people. Moreso, I doubt it's feasible to write a script for every action number possible with this system, if that's what you're doing.

[Graf Zahl]

Da Werecat said:

Moreso, I doubt it's feasible to write a script for every action number possible with this system, if that's what you're doing.

Definitely. Even ZDoom implements a special case for this in the linedef translation code. It's just far too many types. Besides, they are using bitmasks which are well documented in boomref.txt.