Make backpacks more consistent

[ampersand55]

Summary

SUMMARY: Balance "Make backpacks more consistent

Purpose of change

Adjust the new backpacks to be consistent with the old backpacks.

Fixes #33292 (to some degree).

Describe the solution

We are given storage capacity. We assume that storage capacity is proportional to volume and material use and weight is proportional to surface area times material thickness.

Assuming a backpack has the shape of a 1x1x2 box, it will have a surface area proportional to ~6.2996 x volume.

We normalize material use from to the regular backpack, which use 1 rag per storage per thickness (20 rags, 10L storage, 2 thickness).

• Relative material cost of materials is calculated using the duffel bag recipe, which uses 40 rags, 32 fur pelts, 24 leather or 6 hides.

• Old backpacks material is left as is.

• Warmth is calculated as coverage x material_thickness / 10.

• Survivor gear warmth is left as is (at 0).

• Coverage of new backpacks is reduced. Assuming the high-volume rucksack covers the entire back it has a coverage of 50%.

• Other values are left as is.

• Removed "steel" as a material for high volume rucksack as it made its armor value far to high.

• Backpacks (all belted torso items used for general storage) moved to backpacks.json.

Describe alternatives you've considered

Backpacks probably need more rebalancing. Some things to consider for a future PR:

• Allow new backpacks to be made out of rags, and change default material to cotton.
• Take a look at weight and volume for the backpacks.
• Make survivor versions of new backpacks.

Additional context

https://docs.google.com/spreadsheets/d/1i72c0SF2o6ZMDmcTU2I4NBQKpshlr4Ps0y7cGH7Saco/edit?usp=sharing
https://en.wikipedia.org/wiki/Surface-area-to-volume_ratio

[anothersimulacrum]

Moving items and making changes to the in the same PR is confusing, because it obfuscates what changes you make. Doing so in the same commit makes it incredibly impractical to tell what changes you made.

[ampersand55]

Moving items and making changes to the in the same PR is confusing, because it obfuscates what changes you make. Doing so in the same commit makes it incredibly impractical to tell what changes you made.

That's true, sorry. I thought of it, but too late.

The changes in backpack.json are to material, material_thickness, coverage and warmth for the new backpacks and warmth for the old backpacks.

I've detailed all changes I made in the spreadsheet.

Should I make a new PR?

[anothersimulacrum]

No, the spreadsheet is fine, just please don't do it in the future.

[ampersand55]

No, the spreadsheet is fine, just please don't do it in the future.

Will do. I mean not do that in the future.

[ampersand55]

I could rather quickly make a json parser and change volume to be in liters and milliliters in all json files. Is that something we would want?

[anothersimulacrum]

Yes, just waiting on someone to do it. We have adjust_values.py that could be adjusted a bit to do that, or so I've heard.

[ampersand55]

Ok, it wasn't quite as trivial as I thought as music instruments use the key "volume" to denote sound volume and items that use proportional volume gets messed up.

I'll have to look into it some more and properly parse the files instead of just a regexp replace.

---

EDIT:

This works, I think. Or at least loads without errors. Basically a regexp replace with some hacks to handle music instruments and proportional volume.

• https://github.com/ampersand55/CddaTools/blob/master/cddaUpdateJsonVolume.js
• https://github.com/ampersand55/Cataclysm-DDA/tree/change_volume_to_metric

[anothersimulacrum]

Please add the script to ./tools/ when you have it working!

[ampersand55]

Please add the script to ./tools/ when you have it working!

Well. It's working but it's ugly and not robust.

[JacobKessler]

I like backpack consistency. Some thoughts:

• Should the volume be based on the volume with the packmule trait? It seems like having the manufacturer claimed volume match up with a maximally-efficient survivor seems better than some survivors be able to get 40% more volume out of nowhere.
• Given the new realistic volumes, 1L/encumbrance seems excessive. A hiking pack is not as encumbering as a poorly-fitting entry suit or wrapping yourself in a blanket. In fact, it seems like the more-advanced packs might want to give better storage/encumbrance ratios at the expense of weight due to the hip and back supports, like the vanilla MOLLE pack. Duffel bags seems like the 'huge storage, very encumbering' class of storage containers.

[ampersand55]

I think rebalancing storage / encumbrance is beyond the scope of this PR, but I agree backpacks need to be looked at further.

[ampersand55]

I did a hard reset and made the balance changes in a separate commit as I should have done from the start.