# Isla Apocalypse — v2

The rewrite (**D-049**). A post-apocalyptic survival voxel game: one island, generated once offline,
loaded by everyone.

**Status: Phase 0 — foundation.** This repo is a *skeleton*. It builds, it resolves its own runtime
directory, and it carries the two data contracts and the tooling rails. **It generates nothing.**

---

## ⚠ Two repos. Never one.

| Repo | Role |
|---|---|
| **`~/celerNexus/islaApocalypse-v2/`** *(this)* | The rewrite. **Every line of new code is written here.** |
| **`~/celerNexus/islaApocalypse/`** | ⛔ **READ-ONLY.** The pre-rewrite prototype, archived at `ab78883`, tag `pre-rewrite-reference`. **Ported FROM; never written to.** |
| **`~/celerNexus/islaApocalypse-vault-v0.1/`** | The design vault — **the source of truth for WHAT and WHY.** The vault leads. |

**The old codebase is a spent quarry** (D-050): mined, never tracked, never synced, never canon'd.
Writing rewrite code into it would corrupt the very thing being ported from.

## ⚠ Runtime data isolation — do not weaken

This project pins its `user://` directory **away from the old prototype's**, which holds the
preserved reference seeds, blueprints and batches:

```
user:// → ~/.local/share/islaApocalypse-v2/          ← this project
          ~/.local/share/godot/app_userdata/islaApocalypse/   ← ⛔ the OLD prototype. Never touch.
```

Pinned two ways in `project.godot` (distinct project name **and** `use_custom_user_dir`). After any
change to that block, re-run the probe:

```bash
Godot_v4.7.2-stable_mono_linux.x86_64 --headless \
  --path ~/celerNexus/islaApocalypse-v2 res://Tools/Scenes/UserDirProbe.tscn
```

## Layout

```
Core/     math + data only, ENGINE-FREE   — depends on nothing above it
Server/   authoritative logic             — may use Core          (empty: Phase 0)
Client/   rendering                       — may use Core          (empty: Phase 0)
Tools/    the offline generator           — ⚠ may NOT use Client  (Phase 1 fills it)
```

Each layer has a `README.md` stating its role and its boundary. Read the one for the layer you are
about to write in — they carry the reasons, not just the rules.

## The contracts this phase establishes

- **★★ The column model** (D-053) — the world as a 2D grid of columns, each a stack of
  `(material, thickness)` runs. **Air is the top run; there is no air-vs-solid height branch.**
  → `Core/Scripts/Column.cs`
- **The material schemas** (D-054) — terrain and building, two schemas bridged by a transformation
  seam that is **deliberately empty.** Identity is a registry key, never an ordinal. Mesh style is
  per-origin, never a material property. → `Core/Scripts/MaterialRegistry.cs`
- **The scaling discipline** — nothing uses a raw pixel number.
  → `Core/Scripts/GenerationScale.cs`
- **Tooling safety** — every path env-overridable, deletion refused by code.
  → `Core/Scripts/ToolingPaths.cs`, `Core/Scripts/FileSafety.cs`

## Build

```bash
dotnet build
Godot_v4.7.2-stable_mono_linux.x86_64 --headless --import --path .
```

**Godot 4.7.2** (mono) · **.NET 8** (`net8.0`) · `Godot.NET.Sdk/4.7.2`

> The reference repo is Godot 4.7.1. This repo deliberately targets **4.7.2** — clean rewrite,
> current tooling. 4.7.1 is the *port source*, not a constraint on new code.

## What this phase is NOT

No generation, no mesher, no stratigraphy, no biomes, no water, no algorithms of any kind. The
pipeline is **2D-maps-first** (D-056): stages 1–5 are flat maps, gotten completely right before a
single 3D vertex exists. Building the mesher before the data is right is the specific trap this
rewrite exists to undo.