# OpenSpec Change: enterprise-gaming-r3f-physics-core

- **Change ID**: enterprise-gaming-r3f-physics-core
- **Package**: `@suaveplan/r3f-physics-core`
- **Category**: gaming/physics
- **Target path**: `gaming/physics/r3f-physics-core`
- **Status**: PROPOSED
- **Date**: 2026-04-24

---

## Summary

Deliver `@suaveplan/r3f-physics-core` on the genesis branch from scratch at enterprise quality. The package provides a physics engine abstraction layer for React Three Fiber: a `PhysicsProvider` React context wraps any physics backend (Rapier, Cannon, custom); `useRigidBody()`, `useCollider()`, and `usePhysicsWorld()` hooks provide access to physics primitives in a backend-agnostic way. The `PhysicsBackend` interface matches `@suaveplan/character-physics`'s `PhysicsBackend` + `@suaveplan/vehicle-physics`'s `VehiclePhysicsBackend`. Genesis adds structured errors, OTel step-time histogram, and 100% coverage.

---

## Available workspace deps

`@suaveplan/error`, `@suaveplan/types`, `@suaveplan/events`, react, `@react-three/fiber`, three.

---

## Public API surface

```ts
function PhysicsProvider(props: PhysicsProviderProps): JSX.Element
// backend, gravity, fixedStep, debug

function usePhysicsWorld(): PhysicsWorld
function useRigidBody(options: RigidBodyOptions): RigidBodyHandle
function useCollider(body: RigidBodyHandle, desc: ColliderDesc): ColliderHandle

interface PhysicsWorld {
  step(dt: number): void
  raycast(origin: Vec3, dir: Vec3, maxDist: number): RaycastHit | null
  readonly bodies: ReadonlyMap<string, RigidBodyHandle>
}
```

---

## File layout

```text
gaming/physics/r3f-physics-core/
  package.json / tsconfig.json / vitest.config.ts
  src/
    index.ts / error-codes.ts
    types/common.ts + md
    context/physics-provider.tsx + md + test
    hooks/
      use-physics-world.ts + md + test
      use-rigid-body.ts + md + test
      use-collider.ts + md + test
  tests/integration.test.ts
```