SN2SurvivalTweaks

# SN2SurvivalTweaks

**Dial Subnautica 2's survival pressure to taste.** A lightweight UE4SS Lua mod with five independent sliders — oxygen, hunger, thirst, max health, and damage taken — all configurable in-game via SN2ModSettings. No `.pak` overrides, no save-file edits.

Every slider is "**bigger number = easier**", so it's impossible to make the game *harder* by accident — set anything to `1` and that aspect stays vanilla.

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## What it does

| Slider | Default | Range | Effect |

|---|---|---|---|

| **Oxygen Lasts Longer** | 2× | 1–10× | Oxygen drains N× slower underwater (also extends the grace period once your tank hits empty). |

| **Food Lasts Longer** | 2× | 1–10× | Hunger builds N× slower. |

| **Water Lasts Longer** | 2× | 1–10× | Thirst builds N× slower. |

| **Max Health** | 2× | 1–10× | N× bigger health pool. (Heal up to fill the larger bar.) |

| **Damage Taken Reduced** | 2× | 1–10× | Take 1/N damage from all sources — 10× ≈ near-invincible. |

Each has its own enable toggle, plus a debug-logging toggle.

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## ⚠️ Single-player / host only

This mod changes Gameplay Ability System attributes, which are **server-authoritative**. It works perfectly in single-player and for the **host** of a co-op session, but **joining players won't see the effect** on their own stats. No crashes — it just won't apply for non-host clients.

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## Requirements

1. **UE4SS for Subnautica 2** — [Nexus](https://www.nexusmods.com/subnautica2/mods/36) / [GitHub](https://github.com/Subnautica2Modding/Subnautica2-UE4SS)

2. **SN2ModSettings** — [Nexus](https://www.nexusmods.com/subnautica2/mods/20) — provides the in-game slider UI.

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## Installation

1. Make sure UE4SS is installed (the loader `dwmapi.dll` sits next to `Subnautica2-Win64-Shipping.exe`, with the `ue4ss/` folder beside it).

2. Extract this archive so the `SN2SurvivalTweaks/` folder lands in:

  ```

  <game> Subnautica2 Binaries Win64 ue4ss Mods

  ```

3. **Add this line to `ue4ss Mods mods.txt`** (anywhere):

  ```

  SN2SurvivalTweaks : 1

  ```

  This makes the mod load *before* SN2ModSettings so it shows up in the settings UI on first launch. (If you skip this, just restart the game once and it'll appear.)

4. Launch, open **Settings → Mods → Survival Tweaks**, and set your sliders.

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## Configuration

Open **Settings → Mods → Survival Tweaks** in-game and move the sliders — changes apply within ~1–2 seconds, live, no restart needed. Values persist in `ue4ss Mods SN2ModSettings saved SN2SurvivalTweaks.lua`.

---

## How it works (technical)

Subnautica 2's survival system is built on Unreal's Gameplay Ability System (GAS). Targets verified from a UE4SS object/header dump:

| Aspect | Target | Method |

|---|---|---|

| Food / Water | `UWESurvivalAttributeSet.StarvationRateScalar` / `DehydrationRateScalar` | Direct `FGameplayAttributeData` write (`BaseValue` + `CurrentValue` = vanilla / N). |

| Oxygen | `SN2BreathingCalc.SN2BreathingOxygenPerSecond`, `SN2SuffocateCalc.OxygenConsumptionPerSec(+BelowNominalDepth)` | Calc-class CDO floats scaled by 1/N. (`SuffocationRateScalar` is also scaled, but that only governs damage *after* O₂ is empty — normal depletion lives on the calc CDOs.) |

| Max Health | `UWEHealthSetComponent:SetMaxHealth()` | Proper setter UFunction (applies a GameplayEffect internally). |

| Damage Taken | `UWEHealthSetComponent:SetDamageMultiplier(1/N)` | Proper setter UFunction. |

Health is applied **only to the local player pawn's** component (every creature has a health component too — we match by owner so enemies aren't buffed). Each value's vanilla base is snapshotted once, so sliding a multiplier always recomputes from the true baseline and never compounds. A 1 Hz loop re-asserts the direct writes (self-healing against GAS recomputation) and reacts to slider changes.

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## Credits

- **UE4SS** — ported for Subnautica 2 by the [Subnautica2Modding](https://github.com/Subnautica2Modding/Subnautica2-UE4SS) group.

- **SN2ModSettings** by [Just-Chaldea](https://github.com/Just-Chaldea/SN2-ModSettings) — the in-game slider UI.

- ConfigManager pattern adapted from **Capacity & QuickBar Tweaks** by [iTestor](https://www.nexusmods.com/subnautica2/mods/252).

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## License

MIT — see [LICENSE](./LICENSE).

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## Changelog

### 1.0.0

- Initial release: oxygen, food, water, max health, and damage-taken multipliers (1–10× each), with SN2ModSettings sliders and per-aspect toggles.