Architecture

Crate Structure

resin/
├── crates/
│   ├── resin/           # umbrella, re-exports all domain crates
│   ├── rhizome-resin-core/      # shared types, traits, math utilities
│   ├── rhizome-resin-mesh/      # 3D mesh generation and manipulation
│   ├── rhizome-resin-audio/     # audio synthesis and processing
│   ├── rhizome-resin-texture/   # procedural texture generation
│   ├── rhizome-resin-vector/    # 2D vector graphics
│   └── rhizome-resin-rig/       # rigging and animation
└── docs/                # VitePress documentation

Core Concepts

Graphs

Operations are composed as directed acyclic graphs (DAGs):

Noise -> Threshold -> Displace
              ↓
           Sphere -> Output

Evaluation is lazy - the graph is a description, computed on demand.

Attributes

Data attached to geometric elements:

• Per-vertex: position, normal, UV, color
• Per-edge: crease, seam
• Per-face: material ID, smooth group

Attributes flow through operations, transformed as appropriate.

Parameters

All operations expose parameters:

• Scalar values
• Expressions (computed at evaluation time)
• Animated values (function of time)
• Data-driven (from external sources)

Why glam?

We use glam for math types (Vec2, Vec3, Quat, Mat4, etc.) because:

• Bevy compatible: bevy uses glam internally, so types work directly without conversion
• Pure Rust: no C dependencies, easy cross-compilation
• SIMD optimized: good performance on supported platforms
• Minimal: does one thing well, few dependencies

Alternatives considered:

• nalgebra: more features but heavier, different API than bevy
• ultraviolet: similar to glam but less ecosystem adoption
• cgmath: older, less maintained

Bevy Integration

Types implement standard conversion traits:

// resin mesh -> bevy mesh
let bevy_mesh: bevy::render::mesh::Mesh = resin_mesh.into();

// glam types used directly (shared with bevy)
let pos: glam::Vec3 = vertex.position;

No bevy dependency in core - conversions live in optional feature flags or adapter crates.