EmilandClaude Sonnet 5
792b626396
native/physics-native/lingua_physics.c wraps Box3D at a specific pinned commit (47d7f7c — Box3D has no 1.0 release yet, and its only tag, v0.1.0, already diverges from this API, confirmed by diffing headers rather than assuming). The wrapper is deliberately narrow: Box3D's own b3WorldDef/ b3BodyDef/b3ShapeDef are large structs with function pointers, and b3BoxHull's own doc comment says it "has data hanging off the end and cannot be directly copied" — none of that crosses the P/Invoke boundary. Every exported Lingua_* function takes and returns only plain int32/float/ bool scalars, and handles are this shim's own array-index handles, not Box3D's id structs. C# binds them with classic DllImport rather than the newer LibraryImport specifically because LibraryImport's generated marshalling needs AllowUnsafeBlocks even for an all-scalar signature like every one of these — DllImport needs none, keeping this plugin inside the kernel's "no unsafe in the v1 hot path" rule with no exception required. engine.physics adds Rigidbody/BoxCollider/SphereCollider components and PhysicsWorld, which diffs Query<Rigidbody>() against its own tracked set every Stage.FixedUpdate (there's no destruction event to hook) to create and destroy native bodies, steps Box3D once per invocation — Engine.Host's accumulator decides how many times that runs per frame, not this plugin — and writes each body's resulting transform back to GameObject.Transform. IPhysicsService exposes ApplyLinearImpulse/Get/SetLinearVelocity for gameplay code. Verified twice: a standalone C smoke test against the native shim alone (a box dropped from y=5 onto a static ground settles at y≈1.0, exactly where the two half-heights sum to), and the full pipeline through Engine. Host — a headless run with a real scene, --dump showing the same box settling at y=0.9999 after physics, scene load, and Stage.FixedUpdate all went through the real kernel. 5 new automated tests in Engine.Physics. Tests cover the same settling behavior for both shapes, a missing-collider warning that fires once and doesn't throw, cleanup after a GameObject is destroyed mid-simulation, and that an applied impulse actually changes velocity — all passed on the first run. Physics-enabled GameObjects must be root-level for now: PhysicsWorld writes Box3D's world-space transform straight into LocalPosition/ LocalRotation, correct only when local and world space are the same thing. A parented rigidbody needs the same parent-WorldMatrix-inverse handling GizmoMath.WorldToLocalPosition already does for the gizmo — real, not-yet-done work, not silently wrong. Full suite: 81 tests. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01N1qPfzq8TDCUMFMV3UwV5N
55 lines
1.6 KiB
C#
55 lines
1.6 KiB
C#
using System.Numerics;
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using Engine.Kernel.Diagnostics;
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using Engine.Kernel.Plugins;
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using Engine.Kernel.Scheduling;
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using Engine.Kernel.World;
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using Engine.Physics.Contracts;
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namespace Engine.Physics;
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/// <summary>
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/// M4's physics plugin: Box3D, over the shim in native/physics-native/ —
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/// see that file's own doc comment for why nothing crosses the P/Invoke
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/// boundary but plain scalars. One system, on Stage.FixedUpdate: sync new/
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/// removed Rigidbodies, step once, write results back to Transform. Each
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/// FixedUpdate invocation is exactly one physics step at ITime.
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/// FixedDeltaTime — Engine.Host's accumulator (Time.ConsumeFixedSteps)
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/// decides how many times that runs this frame, not this plugin.
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/// </summary>
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public sealed class PhysicsPlugin : IPlugin
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{
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private static readonly Vector3 Gravity = new(0f, -9.81f, 0f);
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private PhysicsWorld? _world;
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private ITime? _time;
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public void Configure(IPluginContext ctx)
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{
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_time = ctx.Time;
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_world = new PhysicsWorld(Gravity, ctx.Log);
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ctx.Services.Provide<IPhysicsService>(new PhysicsService(_world));
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ctx.Schedule.Add(Stage.FixedUpdate, Step)
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.Reads<Rigidbody>()
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.Reads<BoxCollider>()
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.Reads<SphereCollider>();
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ctx.Log.Info("physics world ready (Box3D)");
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}
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public void Shutdown(IPluginContext ctx)
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{
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ctx.Schedule.RemoveAllFrom("engine.physics");
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ctx.Services.Revoke<IPhysicsService>();
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_world?.Dispose();
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_world = null;
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_time = null;
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}
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private void Step(IWorld world)
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{
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_world!.Sync(world);
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_world.Step(_time!.FixedDeltaTime);
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}
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}
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