# Settled Reach — Sprite Render Pipeline

Offline Godot 4 renderer for the 3D-to-2D sprite pipeline. Produces entity and structural sprites at three resolutions from a fixed camera angle, with outlines applied at working resolution.

## Camera Specification (D-019)

- **Angle**: -72.5° from horizontal (= 17.5° from vertical, the midpoint of the 15-20° from vertical range)
- **Projection**: Orthographic (`size = 1.4`)
- **Position**: `(0, 3, 1)` — above and slightly in front of the model origin
- **Godot Transform3D**: `Transform3D(1, 0, 0, 0, 0.30071, 0.95372, 0, -0.95372, 0.30071, 0, 3, 1)`

This is "the angle" per D-019 amendment (2026-02-12). All entity, object, and wall sprites for v0.1 are rendered at this angle. The Godot gameplay camera is purely orthographic — this tilt is an art convention expressed through the 3D render.

## Lighting Rig

Three-point studio rig. All lights have `shadow_enabled = false` — sprites are shape templates, no baked shadows or directional lighting. The Godot runtime PointLight2D pipeline provides all scene lighting at runtime (D-043).

| Light | Energy | Direction | Purpose |
|-------|--------|-----------|---------|
| KeyLight | 1.0 | Matches camera angle (-72.5° from horizontal) | Main illumination; ensures front face is lit as the camera sees it |
| FillLight | 0.4 | 45° from right side (-45° pitch, +90° yaw) | Fills shadow opposite the key; no deep-black patches on right face |
| RimLight | 0.3 | 45° from behind (-45° pitch, +180° yaw) | Back-edge accent; defines silhouette boundary for outline processing |

**Rationale**: Even 3-light coverage ensures no black patches on a convex mesh, keeping surface colors flat and readable for the outline processing step.

## Resolution Chain (D-043, D-044)

```
1024×1024  — source PNG, full fidelity for outline processing
    ↓ bilinear resize
256×256    — working PNG, outline applied at 4-8px, color #333340
    ↓ bilinear resize
64×64      — runtime PNG, deployed to client/assets/sprites/
```

Outline implementation: alpha-mask dilation + flat color fill. Outline width in `render_export.gd`: `outline_width_px = 4` (at 256px = 1px effective at 64px).

## Entity Footprint Spec (D-044, D-066)

- Entity sprites occupy a **24×32px footprint** within the 64×64 visual tile
- Entities render across a **2×2 sim tile sprite footprint** (D-066)
- Visual tile = 64×64px at runtime; sim tile = 32×32px (0.5m)
- **NPC model scale**: `CapsuleMesh(radius=0.25, height=0.62)` at camera size 1.4 produces ~24×32px apparent size in the 64px output tile

## Usage

### Command Line

```bash
# From the repository root
godot --path renderer/ --headless --quit-after 1200 res://render_scene.tscn -- <model_name>
```

The `/sprite-gen` skill wraps this command and handles output placement.

### Adding a New Model

1. Create `renderer/models/<model_name>.tscn` — root node is a `MeshInstance3D` (or `Node3D` with children)
2. Center the mesh at the origin
3. Use a flat `StandardMaterial3D` (no baked shadows — just albedo color + roughness)
4. Run: `godot --path renderer/ --headless --quit-after 1200 res://render_scene.tscn -- <model_name>`
5. Output: 12 PNGs in `renderer/output/` (4 directions × 3 resolutions)
6. Runtime sprites: copy 64px variants to `client/assets/sprites/`

### Material Guidelines

- **Entity sprites**: neutral flat material (albedo Color(0.5, 0.5, 0.5)). D-033 relationship color tinting applied at runtime by the client's entity renderer. Outline color (#333340 per D-043) is compatible with all D-033 tint colors — the dark blue-grey outline remains visible against teal, green, amber, and red entity tints.
- **Structural sprites**: use zone-appropriate texture (`textures/wall_institutional_era1.png`, etc.)
- No specularity: `metallic = 0.0`, `roughness = 0.9`
- No emission, no normal maps — shape is the signal

## Models

| Model | File | Type | Notes |
|-------|------|------|-------|
| `wall_structural` | `models/wall_structural.tscn` | Structure | 1.0×0.8×0.2 box, institutional era-1 texture |
| `wall_bar_green` | `models/wall_bar_green.tscn` | Structure | 1.0×0.8×0.2 box, green panel texture (model only — no sprites rendered yet) |
| `npc_generic` | `models/npc_generic.tscn` | Entity | Capsule silhouette, neutral grey, 24×32px footprint. Rotationally symmetric — north/south and east/west pairs are near-identical by design (asymmetric silhouettes come from named NPC models with identifying features per D-044). |

## Output Naming Convention

```
<model_name>_<direction>_<resolution>.png

wall_structural_north_64.png
npc_generic_south_256.png
```

Directions: `north`, `east`, `south`, `west` (model rotated 0°, 90°, 180°, 270° around Y axis).

## Runtime Sprite Path

64px sprites are deployed to: `client/assets/sprites/`

Naming convention at the client side matches the pipeline output: `<model_name>_<direction>_64.png`. The 1024 and 256 variants stay in `renderer/output/` as pipeline intermediates (gitignored).

## Design Constraints

- **No baked lighting**: sprites are shape templates. Lighting is applied at runtime by Godot's PointLight2D per D-046.
- **No baked shadows**: shadow direction would conflict with runtime point lights at arbitrary positions.
- **No baked mood**: flat materials, three-point neutral rig. Zone atmosphere comes from runtime CanvasModulate.
- **Outline applied at 256px, not 64px**: ensures outline is crisp after bilinear downscale.
- **Transparent background**: `SubViewport.transparent_bg = true` — sprites are PNG with alpha, composited at runtime.

## Cross-References

- D-019: Camera angle spec and amendment
- D-043: Art direction — "functional warmth," resolution chain, outline color
- D-044: Visual hierarchy, entity footprint spec
- D-049: Z-level rendering stack (sprites land on layers 2-3)
- D-066: Dual-scale grid, 2×2 sim tile entity footprint