Linux linking - #10
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I thought maybe a PR would override the github action restriction on only running on main, but given it doesn't there's another very similar branch modified to do actions on all branches that shows success: https://github.com/lucasw/jolt-rust/actions/runs/17313804077 |
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the link order fix (joltc before Jolt) and lib64 search path are now in main. the hello-world build.rs additions weren't needed since joltc-sys handles linking for downstream crates. closing in favor of the direct fix. |
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Fork of SecondHalfGames/jolt-rust@40c3aac with JoltPhysics v5.3.0 submodule for xtreme-game-engine v0.22 (E13 engine-plugin-physics). This is the Step 1 build-spike deliverable: prove the floor of the deterministic Jolt stack on WSL2 Linux Clang 18, then carry the engine-side patches the engine workspace consumes via path-dep. Two day-one patches (documented in vendor.diff.md): (1) cross-platform-deterministic cargo feature on joltc-sys plumbs through to JoltPhysics's CMake CROSS_PLATFORM_DETERMINISTIC=ON (via CMake subdirectory-scope inheritance: JoltC/CMakeLists.txt:83 add_subdirectory + Build/CMakeLists.txt:547). Mirrors the flag into bindgen with -DJPH_CROSS_PLATFORM_DETERMINISTIC=1 so header parsing matches compiled lib layout. Verified via CMakeCache.txt CROSS_PLATFORM_DETERMINISTIC:BOOL=ON. (2) build.rs check_no_fast_math() panics if CFLAGS / CXXFLAGS / RUSTFLAGS / CARGO_ENCODED_RUSTFLAGS contain -ffast-math or -march=native. Both enable FMA contraction and silently break cross-platform determinism. Other layers don't catch this. Notes on patches NOT applied: - Linux undefined-references fix (joltc-sys issues SecondHalfGames#5/SecondHalfGames#9/SecondHalfGames#10): the baseline build succeeded cleanly on WSL2 Linux Clang 18 with no patches. The issues apparently landed upstream between when the engine v0.22 synthesis ran and this spike. - JoltPhysics version bump to 5.3.0: not needed -- the joltc-sys 0.3.1 submodule already resolves to JoltPhysics v5.3.0 (the joltc-sys 0.3.1 "+Jolt-5.0.0" semver build-metadata is just stale). Two new crates added: - crates/joltc-sys/examples/hello_jolt.rs: the deterministic 10-box drop smoke. Drops 10 dynamic boxes onto a static floor, runs 64 ticks at dt=1/64 substeps=1 on JPC_JobSystemSingleThreaded, then runs the same simulation a SECOND time and asserts bit-identical positions. Run: `cargo run -p joltc-sys --release --example hello_jolt --features cross-platform-deterministic`. Output: "determinism OK -- run A and run B are bit-identical across all 10 bodies". This is the floor of v0.22's determinism contract, proven on WSL2 Linux. Cross-platform validation (Win-MSVC / macOS-ARM64) defers to the 4090 relay per engine Rule 16. - crates/engine-jolt/ skeleton: Bevy-agnostic safe wrapper, empty for now (the actual surface -- World, drive_step, ShapeDef, ContactSink, WorldSnapshot -- lands in v0.22 Step 2). Feature graph wired: default = []; native = [dep:joltc-sys]; cross_deterministic = [native, joltc-sys/cross-platform-deterministic]; double_precision / object_layer_u32 / asserts pass through. Exists at Step 1 so engine-plugin-physics' path-dep can resolve during Step 3's plugin-skeleton work. Lints clippy::needless_update + new_without_default match rolt's tolerances. Verifications: cargo check -p engine-jolt 2.86s clean (stub mode, no C++); cargo build -p engine-jolt --release --features cross_deterministic 17s clean; cargo test -p engine-jolt --features cross_deterministic feature_flags_consistent passes; cargo run -p joltc-sys --release --example hello_jolt --features cross-platform-deterministic determinism OK across two runs. vendor.diff.md documents both patches with re-apply checklists for quarterly subtree pulls. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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I've got linux building with a build.rs per hello world, and also cargo test needs linking to happen right where I've moved it to (not sure why).
Fixes #9 and #5