MC Worldgen
===========

Procedural Minecraft Java region exporter. The C exporter is the maintained path:
it builds without Python dependencies and writes `.mca` region files that can be
copied into an existing world's `region/` folder.

Requirements
------------

- GCC or Clang
- `make`
- zlib development headers (`zlib1g-dev` on Debian/Ubuntu)
- pthreads, normally included with libc toolchains

Build
-----

```sh
cd worldgen-c
make
```

Quick smoke test:

```sh
./bin/worldgen --radius 0 --out /tmp/mcworldgen-smoke
```

That should create `/tmp/mcworldgen-smoke/r.0.0.mca`.

Diagnostic feature scan:

```sh
make scan
./bin/worldgen-scan --radius 2 --center-x -3200 --center-z 3200
```

The scanner prints counts for cabin blocks, gravel/path columns, redwood biome
columns, and titan-height tree trunks.

Generate Regions
----------------

Small area around chunk 0,0:

```sh
./bin/worldgen --radius 4 --trails --out output
```

Specific chunk rectangle:

```sh
./bin/worldgen --min-x -8 --max-x 8 --min-z -8 --max-z 8 --trails --out output
```

Useful options:

- `--radius N`: generate chunks from `center - N` through `center + N`.
- `--center-x X --center-z Z`: center chunk for radius mode.
- `--min-x --max-x --min-z --max-z`: explicit chunk bounds.
- `--threads N`: worker thread count.
- `--seed S`: deterministic world seed.
- `--sea-level L`: sea level, default `70`.
- `--snow-line H`: snow threshold, default `sea-level + 38`.
- `--trails`: enable trail and cabin prepass.
- `--wall`: build a brutalist border wall around the generated area.
- `--format mca|bin`: write Minecraft region files or raw debug chunks.
- `--out DIR`: output directory.

Features
--------

- Redwoods are enabled automatically. The biome classifier marks high-rainfall,
  higher-relief areas as redwood forest, then places titan trees, dirt/mulch
  floor cover, tall grass, and occasional fallen logs.
- General forests grow as broad, coherent oak, maple, birch, pine, spruce,
  walnut, and cypress stands with occasional companion species. Seeded
  clearings, sparse field trees, regenerating edges, mature interiors, variable
  tree height, and irregular crown spacing keep the distribution from resolving
  into a uniform grid.
- Cabins are enabled automatically. With `--trails`, cabins only try to spawn on
  chunks crossed by the trail network so their spur paths can connect to roads.
  Without `--trails`, cabins can still spawn, but they are rarer and unconnected.
- Cabin generation includes compact homesteads, longhouses, two-story houses,
  L-shaped cabins, cross-gabled lodges, mixed-height tower lodges, and rambling
  multi-wing cabins. Roof direction, wing height, material palette, windows,
  porches, chimneys, decay, and path width vary by design.
- Seeded woodland-community regions raise the local cabin frequency and give
  their roads permission to bridge narrowly bounded water at exact sea level.
  Eligible crossings must have nearby dry banks on both sides; deep water,
  broad lakes, and open ocean remain impassable. Bridges use raised spruce
  decks, timber supports, and intermittent edge posts rather than gravel fill.
- Trails are optional because they need a prepass over the target area. Use
  `--trails` when you want roads and better-connected cabins.
- Long roads search a broad terrain corridor and prefer valley floors, gentle
  contour-following grades, low ridge crossings, and stable side slopes. Deep
  water remains impassable; shallow water is crossed only when the detour cost
  is greater, keeping fords and causeways short. Short cabin spurs use looser
  engineering constraints so they can still reach the main network.

Minecraft Version
-----------------

The exporter writes Java Edition 1.17.1 chunk data (`DataVersion` 2730). That
version is chosen because the generator includes copper ore. Open the generated
regions in Minecraft Java 1.17.1 or a newer version that can upgrade old worlds.

The exporter writes region files only. To use them in game, create or choose a
Java world, close Minecraft, back up the save, and replace or add files under:

```text
<minecraft save>/region/
```

Python Exporter
---------------

`export_mca.py` is the older prototype exporter. It now shares the same 1.17.1
data version and maps generated coal correctly, but the C exporter is faster and
has the current terrain features.