Wall portals

[Graf Zahl]

I just committed the line portal transitioning. It's only tested for static (Eternity-style) portals but it looks ok - even camera interpolation is working, but that was one nasty bit of code...
I'll do the arbitrary line portals tomorrow. The code is there but not complete and not tested yet.

[Gez]

And, just on cue, Eternity portals are no longer static.

[Graf Zahl]

Yeah, that was also one of my long-term plans to make polyobject portals that are supposed to simulate moving geometry a bit more interactive. But that's still some time off. First the basics need to work.

But it's really cool finally being able to run through Vaporware without being blocked by nonexistent portal transitions (and equally important, no visual hiccups when transitioning through a portal.)

[Major Cooke]

And, just on cue, Eternity portals are no longer static.

Heh, the heat is real!

[printz]

Question: does ZDoom use the Build engine to render the portals? I thought it would be fitting, considering Build is quite a big portal user.

[Major Cooke]

Graf has been implementing his own genuine entirely hand-built one from the looks of it.

[Gez]

Graf doesn't touch the software renderer, or only reluctantly. It's ZZYZX who made ZDoom's line portal code. The Build approach cannot really be used in Doom since in Build, portals are basically how the renderer works (this video explains it well); everything that is an "opening" in Doom is a portal in Build.

[Graf Zahl]

And looking at the occasional glitches in the demo map clearly shows that it's all using BSP traversal - if it uses Build's algorithm there wouldn't be phantom walls occasionally showing in the portals. Even in GZDoom I haven't addressed that problem yet.

[Graf Zahl]

Ok, most of the movement stuff is working. What still needs to be done for the first phase is proper position checking when stepping into a non-static portal with a floor height difference.

And I finally decided to make one-sided walls outside of polyobjects non-crossable - so you got to have enough free space behind it. I'm not willing to compromise on overall stability of the movement code which is sensitive enough to glitching already. For polyobjects I made an exception because otherwise their use would be too restricted (and since they are always inside a sector, their lines are not really one-sided in the sense that the player can step outside the map.)

[Major Cooke]

Huh. Line_SetPortal was missing from action specials. Fixed that. Or does that not belong there?

[Graf Zahl]

It wasn't the only one that's missing.

[printz]

Huh. Line_SetPortal was missing from action specials. Fixed that. Or does that not belong there?

Good. Does it mean I can port Line_SetPortal special into Eternity? I mean it will not change? So I can load Hexen-format maps compatible both with ZDoom and with Eternity, that also have portals.

[Major Cooke]

UDMF and Hexen are not recommended for eternity portals.

@Graf: I forgot there were still two pages with line_setportal. One of them needs deleting. I've updated the specials to use the one you've edited.

http://zdoom.org/wiki/Line_setportal
http://zdoom.org/wiki/Line_SetPortal

[Graf Zahl]

Use the one with proper capitalization.

[Graf Zahl]

Good. Does it mean I can port Line_SetPortal special into Eternity? I mean it will not change? So I can load Hexen-format maps compatible both with ZDoom and with Eternity, that also have portals.

Unless some blocking issue comes around the current set of features should not change. There may be additions later (like a flag bit.)
And if you want to port this, don't forget about Sector_SetPortal (which has some extensions which are only documented in the source right now.