ΔP

[AutumnalModding]

About the PR

Ports Delta-P from space-wizards/space-station-14#39238

Why / Balance

Atmospherics can have a little suffering, as a treat.

On a more serious note, plasma/tritium fires and TEG/reactor meltdowns are nowhere near as scary as they should be, and are almost always localized to Engineering. This is.. pretty mediocre, and doesn't really invoke the sense of "oh fuck oh no" that such meltdowns or fires are supposed to invoke. Tritfires already aren't scary because you can just place 1 directional fan.

Technical details

From space-wizards/space-station-14#39238:

This is put up primarily for code review on the processing side - the constants are not tuned yet and other misc stuff like CVARs and AtmosTime modifications are not implemented yet (though easy to do, I just wanted to write this).

Entities that want to take pressure damage need to have a DeltaPressureComponent that defines the damage and at what pressure, as well as the scaling type.

A new processing mode has been added, DeltaPressure.

Atmospherics will process entities that need to be calculated via a queue.
Entities will automatically add and remove themselves from the hashset that stores these entities on the GridAtmosComponent for processing.

When an entity is dequeued for processing:

• The entity's tile indices position is retrieved
• This is used to get the TileAtmospheres around the entity
• The pressures of these TileAtmospheres are split into anti-directional pairs and loaded into a span to do SIMD calculations using helper methods in NumericsHelpers
• The delta-pressure is then computed from this and damage is done from the entity based on that

A good chunk of the slowdown is from the retrieval of elements from the dictionary, as well as retrieval of the actual pressure from the tile (as we have to call a GasMixture get method). I might take a crack at implementing a proper cache however my last attempt at this yielded no measurable performance improvement, though I might try again.

How to test

Place a tritium and O2 miner in an enclosed, windowed area.
Invoke your inner pyromaniac arsonist. Watch the windows shatter.

Media

Breaking changes

Changelog

🆑 Illumos

• add: Ported ΔP from Wizden.

[Magniras]

Haha, yes!

[R3v3l4t1on]

Maps will need reviewing to see if the chamber won't instantly explode. However. I like

[Mauserati]

This will damage/destroy a lot of ships on load as well.

That should be taken into consideration before implementing this.

[AutumnalModding]

This will damage/destroy a lot of ships on load as well.

Not unless they save with hellish burns, which they shouldn't be doing.

[AutumnalModding]

Directional fan changes marked as "revisit later" pending planned rework by @NotLivyathan

[TeliaRS643]

This will damage/destroy a lot of ships on load as well.

Not unless they save with hellish burns, which they shouldn't be doing.

Ships save with on-tile atmos. Burns are not stopped, atmos pressures persist. And more importantly, things that are designed to hold its pressure until flow is reactivated (pumps need to be manually turned on every ship load) will also suffer.

[Ray3424]

Fires can ash a room full of people and kill somebody a room over in a very short amount of time if they aren't managed quickly as-is. It's one of the things that I had to deal with as Station AI, with a timely panic siphon being primarily what prevented more damage. Personally, I'm just not in favor of anything that makes the safe engines vastly less safe, or that makes atmospherics more brutal in general. Particularly in a way that will play nastily with ship saves from a standstill. It is OK for people to have things figured out and more time to tinker than do damage control; it's not necessary to increase complexity/difficulty whenever everybody becomes too used to a slice of gameplay.

[Magniras]

Oh, I do notice. There's not a deltaP value attached to plastitanium windows, does that mean pressure won't break those windows?

[AutumnalModding]

Oh, I do notice. There's not a deltaP value attached to plastitanium windows, does that mean pressure won't break those windows?

Likely omitted given that plastiwindows are supposed to be uncraftable. However, it's not unwarranted - I may look into giving them absurdly high DP values or keep them unbreakable.