# Scene Binary Format (SCN1)

This document describes the binary format used for 3D scenes exported from Blender.

## Overview

- **Extension:** `.bin` or `.scene`
- **Endianness:** Little Endian
- **Layout:** Header followed by sequential blocks.

## Header (16 bytes)

| Offset | Type     | Description |
|--------|----------|-------------|
| 0      | char[4]  | Magic bytes "SCN1" |
| 4      | uint32_t | Number of objects |
| 8      | uint32_t | Number of cameras (reserved) |
| 12     | uint32_t | Number of lights (reserved) |

## Object Block

Repeated `num_objects` times.

| Offset | Type     | Description |
|--------|----------|-------------|
| 0      | char[64] | Object Name (UTF-8, null-padded) |
| 64     | uint32_t | Object Type (Enum) |
| 68     | vec3     | Position (x, y, z) - 12 bytes |
| 80     | quat     | Rotation (x, y, z, w) - 16 bytes |
| 96     | vec3     | Scale (x, y, z) - 12 bytes |
| 108    | vec4     | Color (r, g, b, a) - 16 bytes |
| 124    | uint32_t | Mesh Name Length (N) |
| 128    | char[N]  | Mesh Asset Name (if N > 0) |
| 128+N  | float    | Mass |
| 132+N  | float    | Restitution |
| 136+N  | uint32_t | Is Static (0=Dynamic, 1=Static) |

### Object Types

```cpp
enum class ObjectType {
  CUBE = 0,
  SPHERE = 1,
  PLANE = 2,
  TORUS = 3,
  BOX = 4,
  SKYBOX = 5,
  MESH = 6
};
```

## Coordinate System

- **Position**: Blender coordinates (Z-up) should be converted to engine coordinates (Y-up) by the exporter or loader. Currently raw export.
- **Rotation**: Blender quaternions are (w, x, y, z). Exporter writes (x, y, z, w). Engine uses (x, y, z, w).

## Asset Resolution

Mesh assets are referenced by name string (e.g., "MESH_CUBE"). The loader uses `GetAssetIdByName` to resolve this to a runtime `AssetId`.