refactor(lambda-rs-platform): split rapier2d implementation across multiple

[vmarcella]

Summary

Refactor the internal lambda-rs-platform 2D Rapier backend from a single
large source file into a rapier2d module. This keeps the
existing backend behavior and public exports unchanged while making the code
easier to navigate and maintain.

Related Issues

N/A

Changes

• Replace crates/lambda-rs-platform/src/physics/rapier2d.rs with a
  folder-backed module at crates/lambda-rs-platform/src/physics/rapier2d/.
• Keep the existing physics::rapier2d module path and PhysicsBackend2D
  exports stable through rapier2d/mod.rs.
• Split the backend implementation by responsibility:
  • rigid_bodies.rs
  • colliders.rs
  • queries.rs
  • simulation.rs
  • helpers.rs
  • tests.rs
• Move the existing unit tests into tests.rs without changing their
  assertions or backend semantics.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• Feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation (updates to docs, specs, tutorials, or comments)
• Refactor (code change that neither fixes a bug nor adds a feature)
• Performance (change that improves performance)
• Test (adding or updating tests)
• Build/CI (changes to build process or CI configuration)

Affected Crates

• lambda-rs
• lambda-rs-platform
• lambda-rs-args
• lambda-rs-logging
• Other:

Checklist

• Code follows the repository style guidelines (cargo +nightly fmt --all)
• Code passes clippy (cargo clippy --workspace --all-targets -- -D warnings)
• Tests pass (cargo test --workspace)
• New code includes appropriate documentation
• Public API changes are documented
• Breaking changes are noted in this PR description

Testing

Commands run:

cargo +nightly fmt --all
cargo test -p lambda-rs-platform rapier2d -- --nocapture
cargo test -p lambda-rs-platform --features physics-2d --lib physics::rapier2d -- --nocapture

Manual verification steps (if applicable):

Screenshots/Recordings

N/A

Platform Testing

• macOS
• Windows
• Linux

Additional Notes

[github-actions]

✅ Coverage Report

📊 View Full HTML Report (download artifact)

Overall Coverage

Metric	Value
Total Line Coverage	72.95%
Lines Covered	13964 / 19143

Changed Files in This PR

File	Coverage	Lines
crates/lambda-rs-platform/src/physics/rapier2d.rs	N/A	(no coverage data)
crates/lambda-rs-platform/src/physics/rapier2d/colliders.rs	97.17%	240/247
crates/lambda-rs-platform/src/physics/rapier2d/helpers.rs	89.61%	207/231
crates/lambda-rs-platform/src/physics/rapier2d/mod.rs	0.00%	0/24
crates/lambda-rs-platform/src/physics/rapier2d/queries.rs	90.70%	78/86
crates/lambda-rs-platform/src/physics/rapier2d/rigid_bodies.rs	96.73%	266/275
crates/lambda-rs-platform/src/physics/rapier2d/simulation.rs	93.40%	99/106
crates/lambda-rs-platform/src/physics/rapier2d/tests.rs	N/A	(no coverage data)

PR Files Coverage: 91.84% (890/969 lines)

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Generated by cargo-llvm-cov · Latest main coverage

_{Last updated: 2026-04-03 20:50:34 UTC · Commit: 3e1358e}

[Copilot]

Pull request overview

Refactors the lambda-rs-platform Rapier-backed 2D physics backend by splitting the former single rapier2d.rs implementation into a folder-backed physics::rapier2d module, keeping the module path and public exports stable while improving navigability and maintainability.

Changes:

• Replaced crates/lambda-rs-platform/src/physics/rapier2d.rs with crates/lambda-rs-platform/src/physics/rapier2d/ and a mod.rs entrypoint.
• Split backend implementation across focused submodules (rigid_bodies, colliders, queries, simulation, helpers).
• Moved existing unit tests into rapier2d/tests.rs without changing assertions/semantics.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/lambda-rs-platform/src/physics/rapier2d/mod.rs	New module entrypoint preserving public types/exports and wiring submodules.
crates/lambda-rs-platform/src/physics/rapier2d/rigid_bodies.rs	Rigid body creation/state/force APIs extracted into a dedicated module.
crates/lambda-rs-platform/src/physics/rapier2d/colliders.rs	Collider creation/attachment and debug slot validation extracted.
crates/lambda-rs-platform/src/physics/rapier2d/queries.rs	Point/AABB/raycast query helpers extracted.
crates/lambda-rs-platform/src/physics/rapier2d/simulation.rs	Stepping and collision event aggregation extracted.
crates/lambda-rs-platform/src/physics/rapier2d/helpers.rs	Shared helper functions extracted (validation, friction encoding, contact selection, etc.).
crates/lambda-rs-platform/src/physics/rapier2d/tests.rs	Unit tests moved from the old monolithic file into a module test file.
crates/lambda-rs-platform/src/physics/rapier2d.rs	Removed monolithic backend source file (superseded by folder-backed module).

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