What is a "self-referencing" sector?

[Ravick]

Hi there.

So, I'm trying to use this trick, but I got stuck: What is this "self-referencing sector" thing?

I've downloaded the examples, and it seems to be some kind of weird sector that does not really appear in-game, just like it is not connected with the area it is in. How do I do that?


Thanks for any help, and... sorry if it is a too-"cacking"-simple question. I just could not figure out what it means.

[Kappes Buur]

Self-referencing sectors are essentially hacks used in vanilla DOOM.

Jens Hykkelbjerg was the first to give examples of how to apply them
https://www.doomworld.com/idgames/docs/editing/spcial12

See also
https://doomwiki.org/wiki/Making_a_self ... ing_sector
In the example, change the heights of the self-referencing sectors to really see how this works.

Or for something more complex
https://www.doomworld.com/tutorials/fx8.php

[Rachael]

Self referencing sectors are sectors whose both front and back linedefs reference said sector. What happens is the blockmap registers the presence of these sectors, and it causes the player to be able to traverse the sector's heights (aka the "crystal sector" trick in UAC_Dead, also used to create submergeable water, like the Sewers map (25? iirc) in Plutonia).

They mainly work by fooling the renderer into thinking that the sector properties on both sides of the line are exactly the same, which removes the sector's subsectors from the visplane array, and causes the renderer not to show them. But they are also still rendered to the level's blockmap, which causes any mobile object including the player to register their presence and travel atop the sector's height rather than its surrounding space.

[Kappes Buur]

Self referencing sectors are sectors .....

Nice technical explanation.
Should be in the WIKI.

[Ravick]

Thanks for the explaing, pals.

Alter the sidedefs of the sub-sector so that both sides reference the sub-sector. This is now a self-referencing sector.

How do I do this part?

[Kappes Buur]

How do I do this part?

After you created the sector which is to be the self-referencing sector, select and highlight that sector. Then go into Linedefs Mode to highlight the linedefs making up that sector and rightclick on one of the highlighted linedefs.

In the menu window which pops up, set the Sector Index of the back sidedef to be the same as that of the front sidedef.

In Doom in Hexen format this is easy to see since both front and back sidedefs are in the same menu

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In UDMF the front and back sidedefs have separate menus

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so check what the sector index of the front sidedef is and set the sector index of the back sidedef to the same number.

[Ravick]

Thank you a lot!