# sporel-tool-atlas-baker

Builds paired diffuse + height PNG atlases for the Sporel map-lib v0.3.0+ format.

**v0.2.0** adds edge-replicated padding (Rev 4 §13.3), `--schema blob-14` slot
validation (E1), a `collision.json` sidecar (E2 validation + pass-through), and
alpha-analysis that sets a per-tile `tile.opaque` flag. Source tiles may be
PNG, WebP, or JPG (decoded via jimp).

## Usage

```bash
sporel-atlas-baker \
  --in <source-dir> \
  --out <atlas-dir> \
  --atlas-id <stable-id> \
  [--tile-size 64 | auto] \
  [--max-size 4096] \
  [--pad-px <N>] \
  [--schema blob-14] \
  [--lock <existing-lock.json>] \
  [--blocks-sight-pattern <regex>] \
  [--verbose]
```

### Flags

| Flag | Meaning |
| --- | --- |
| `--in <source-dir>` | Directory of source tile images. |
| `--out <atlas-dir>` | Output directory for the baked atlas + sidecars. |
| `--atlas-id <stable-id>` | Stable atlas identifier written into the lock. |
| `--tile-size <N\|auto>` | Tile edge length in pixels, or `auto` to infer it from the source tiles. |
| `--max-size <N>` | Maximum atlas dimension in pixels (default 4096). |
| `--pad-px <N>` | Edge-replicated padding (gutter) applied around each tile, in pixels (Rev 4 §13.3). |
| `--schema <blob-14>` | Slot-validation schema for the source set. `blob-14` is the v0.2 14-slot blob schema (E1); required by lib-core.maps v0.5.1. |
| `--lock <existing-lock.json>` | Reuse an existing lock to keep tile indices stable. |
| `--blocks-sight-pattern <regex>` | Regex matching tile names that block line of sight. |
| `--verbose` | Print detailed per-tile diagnostics. |

See `sporel-meta/docs/superpowers/specs/2026-05-21-map-multi-layer-design.md` §4 for the format spec.

## Development

```bash
npm install
npm test
```