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
73 lines
2.7 KiB
C#
73 lines
2.7 KiB
C#
using System.Runtime.InteropServices;
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namespace Engine.Physics;
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/// <summary>
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/// The entire P/Invoke surface, matching native/physics-native/
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/// lingua_physics.c's exports one-to-one. Every parameter is a plain
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/// int/float/bool — no struct crosses this boundary, on purpose, see that
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/// file's own doc comment for why.
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///
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/// Classic DllImport, not the newer source-generated LibraryImport:
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/// LibraryImport's generated marshalling code needs AllowUnsafeBlocks even
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/// for an all-blittable signature like every one of these, and there's no
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/// reason to open that door — DllImport marshals plain int/float/bool/out
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/// float scalars with no unsafe code at all, which is what actually keeps
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/// this plugin inside the kernel's "no unsafe in the v1 hot path" rule
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/// (Directory.Build.props) instead of needing a narrow exception to it.
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/// </summary>
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internal static class Native
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{
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private const string Lib = "lingua_physics";
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[DllImport(Lib)]
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public static extern int Lingua_CreateWorld(float gravityX, float gravityY, float gravityZ);
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[DllImport(Lib)]
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public static extern void Lingua_DestroyWorld(int worldHandle);
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[DllImport(Lib)]
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public static extern void Lingua_WorldStep(int worldHandle, float timeStep, int subStepCount);
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[DllImport(Lib)]
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public static extern int Lingua_CreateBoxBody(
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int worldHandle,
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float px, float py, float pz,
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float qx, float qy, float qz, float qw,
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float halfWidth, float halfHeight, float halfDepth,
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int bodyType, float density, float friction, float restitution);
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[DllImport(Lib)]
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public static extern int Lingua_CreateSphereBody(
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int worldHandle,
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float px, float py, float pz,
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float qx, float qy, float qz, float qw,
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float radius,
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int bodyType, float density, float friction, float restitution);
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[DllImport(Lib)]
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public static extern void Lingua_DestroyBody(int bodyHandle);
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[DllImport(Lib)]
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public static extern void Lingua_GetBodyTransform(
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int bodyHandle,
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out float px, out float py, out float pz,
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out float qx, out float qy, out float qz, out float qw);
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[DllImport(Lib)]
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public static extern void Lingua_SetBodyTransform(
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int bodyHandle,
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float px, float py, float pz,
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float qx, float qy, float qz, float qw);
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[DllImport(Lib)]
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public static extern void Lingua_ApplyLinearImpulse(
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int bodyHandle, float ix, float iy, float iz, [MarshalAs(UnmanagedType.U1)] bool wake);
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[DllImport(Lib)]
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public static extern void Lingua_GetLinearVelocity(int bodyHandle, out float vx, out float vy, out float vz);
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[DllImport(Lib)]
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public static extern void Lingua_SetLinearVelocity(int bodyHandle, float vx, float vy, float vz);
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}
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