Limb Project outline and MVP

[Venera3]

Is your feature request related to a problem? Please describe.

Limb Stuff has been chugging along for the last few cycles, if a good bit slower than desired. This cycle got it to the level where limbs could be added and not break loudly, while the base infrastructure for them still being far too patchy for primetime.

This issue aims to lay down the steps necessary for Actual Limb Stuff to work and allow others to tackle parts of them should I get indisposed again, and to aggregate outstanding issues on the current limb system.

Solution you would like.

Stage 1:

• [x] Move mainline limby content (Gastropod Foot, prosthetics/amputation traits) into a WIP Limb Stuff mod, default off - #70721
• [ ] Move all in-code score references to character modifiers
  • [ ] Cache character modifiers instead of calculating them on demand
• [ ] Limbify currently unlimbed core game systems, like
  • [ ] Driving (no limb integration currently)
  • [ ] Vehicle crafting (only lifting score is integrated)
  • [ ] Reading (tangential vision/night vision integration, no manipulation impact)
  • [ ] Crafting (currently flat manipulation modifier even for less-than-precise recipes)
  • [ ] Movement (climbing, move speed and crawl are integrated, opening doors, dragging aren't)
  • [ ] Rework wielding checks
  • [ ] Ranged combat (flat vision/manipulation modifiers currently, no ranged attacks hitting custom limbs)
  • [ ] Rework melee attack vectors to deal with custom limbs - resurrect #67883 or redo it
  • [ ] #51294 (needs reproduction / auditing, including it as an archive of past issues)
  • [ ] YOUR LIMBY ISSUE HERE
• [ ] Savegame.cpp resets anatomy and saves your limbs as base limbs
• [x] Debug menu -> Set HP menu uses hardcoded ids - #71123
• [ ] #72044
• [ ] UI Stuff (scary)
  • [ ] #70859
  • [ ] #70860
  • [ ] Body status display
  • [ ] Health window - total limb score readout (optional?)
  • [ ] Health toolbar (including customizing toolbar visibility)
• [ ] Armors on custom limbs
  • [x] Bodypart coverage doesn't respect new limbs unless the limb is explicitly defined in the item definition - #71896
    • [x] #71474
    • [ ] #72092
  • [ ] Covered ugliness seems to have broken in the migration to outfits (worn.covers doesn't take custom limb coverage into account)
  • [ ] Migrate armor conflicts to per-BP instead of per-trait (to allow for e.g. stumps not conflicting)
• [ ] Improve prosthetics support
  • [ ] Handle stumps on a limb level
  • [ ] Audit prosthetic scores and drops
  • [ ] Handle prosthetics damage
  • [ ] #70730
• [ ] Move mutation limbs over to the new system
  • [x] Bird Wings
  • [x] Insect Compound Eyes #71387

Stage 2:

• [ ] When enough of the above are in place flip the WIP mod into default on to gather more bug reports / feedback
• [ ] Stamp out any issues that come up
• [ ] Handle/add bodygraphs for custom anatomy
• [ ] Continue work on less-than-essential limbification for extra credit e.g.
  • [ ] Limb/Stance interactions
  • [ ] Add a dedicated mutation EoC framework for larger limb changes
  • [ ] Add more limby traits

Stage 3:

• [ ] Migrate the mod contents into mainline

Describe alternatives you have considered.

Revert limby stuff until Everything Just Works - not cool, and keeping people working in this space helps set up the system. Keep the current content in mainline and try to fix them - too high chance of constant character breakage without informed consent as both the systems shift and more limby content makes it into mainline. Go back to just being Creepy Crawlies and Medicine Guy - tempting.

Additional context

The above limbification TODO list is open to expansion, I've probably forgotten some major systems.

[fairyarmadillo]

Currently, losing one arm cancels any arm-related mutations, as does losing one leg. This doesn't always make a ton of sense, as you'd presumably still have one limb affected by whatever weirdness you had going on. I'm not totally sure what ought to happen instead.

It's apparently intended for some drastic mutations (like arm tentacles) to regrow your arms when they are acquired. This won't work in cases like the one in #70479 where feathered arms is a prereq for bird wings. The simplest solution I can think of is to add a SUPPRESSES json entry that lets you keep the mutation in your character sheet but prevents you from getting the effects. That still wouldn't work for stuff like paws, where you'd go from being a bear with two paws to a bear with one human arm, and it's especially tricky for cases where the mutation doesn't come with a limb json.

[Venera3]

The hand-defined stubbing is set up very restrictively, and will need serious thought put into it - it's one of the areas we'll need a generic way to handle before the cancel lists balloon to the stars. We'll see how it all shakes out but I don't think it's scaleable in any way currently.

[GuardianDll]

It mostly depends on how we will handle mutations in the future - if we be able to jsonify it completely using EoC, i can clearly see that we can setup generified EoC that handle limb grow

[Venera3]

I have a limb growth EoC chain I'll be able to add to the mod shortly - a big plus of the mod route is get stuff out early, before getting lost in the minor details.

That said stump handling and such is both enticing (since then you can have detrimental limbs you need to surgically remove/trim) and not straightforward in the least.