RFC-0008: Physics IR

Status: Draft | Version: 0.1.0

1. Principle

Physics IR describes computation over physical state; it does not define storage ownership.

2. Pipeline

BroadPhase -> NarrowPhase -> ConstraintBuild -> Solve -> Integrate -> Commit

3. Inputs

Transform, mass, inertia, velocity, acceleration, collider, material, constraints, environment.

4. Outputs

Updated transform, velocity, acceleration, contact state, constraint state, events.

5. Solver abstraction

WIR/Physics IR must not require a particular solver. Backend may select impulse, iterative, projected, constraint, particle or specialized methods.

6. Determinism

Stable entity ordering, stable contact ordering, deterministic reductions and explicit floating-point policy are required for strict deterministic mode.

7. Broad phase

BVH, grid, sweep-and-prune, spatial hash are interchangeable implementations under the same semantic contract.

8. GPU

Physics kernels may lower to GPU EIR when parallelism and memory traffic justify dispatch.

9. Acceptance

Physics must access authoritative World storage through PhysicsView and commit through the world transaction model.