# Manifest schema v1

Manifests are UTF-8 YAML and may use the compact flat form:

```yaml
version: 1
defaults: {dirs: 8, fps: 12, pivot: bottom_center}

demo_actor:
  backend: blender
  rig: rigs/demo.blend
  anims: [idle, walk]

demo_floor:
  backend: procedural
  generator: floor_tile
  params: {color: '#706860', variants: 4}
  dirs: 1
```

An explicit `assets:` mapping is also supported, but it cannot be mixed with
flat asset declarations. Asset IDs and backend names match
`[a-z][a-z0-9_]*`. Unknown fields are errors, while generator-specific options
belong under `params`.

Common fields are `backend`, `dirs`, `fps`, `pivot`, `size`, `palette`,
`palettes`, `tags`, `seed`, and `postprocess_scale`. A pivot is a standard name
(`bottom_center`, `center`, `bottom_left`, `top_left`) or signed `x,y`.
Sizes use `WIDTHxHEIGHT`.

`postprocess_scale` applies a fixed nearest-neighbour scale before tight alpha
cropping and target-size fitting. Set it to `0.25` for a 4x supersampled
Blender render. Unlike adaptive bbox fitting, this preserves the relative world
scale of short and tall assets.

Backend contracts:

| Backend | Required field |
|---|---|
| `procedural` | `generator` |
| `blender` | `rig` |
| `import` | `source` |
| `composite` | non-empty `layers` |

Additional backends register a contract through
`register_backend_contract()` and put backend-specific configuration in
`params`; neither the loader nor the manifest core needs modification.

Validate without producing assets:

```text
sf validate assets/environment.yaml assets/actors.yaml
sf build assets/environment.yaml --tag environment --jobs 4 --dry-run
```

Diagnostics use `absolute-file:line:column` followed by the YAML property path.