test(physics): pin issue 270 animation fixes

tests/AcDream.App.Tests/Physics/RemoteSpawnPlacementSettlerTests.cs

@@ -0,0 +1,109 @@
+using System.Numerics;
+using AcDream.App.Physics;
+using AcDream.Core.Physics;
+
+namespace AcDream.App.Tests.Physics;
+
+public sealed class RemoteSpawnPlacementSettlerTests
+{
+    private const uint Landblock = 0xA9B40000u;
+    private const uint Cell = Landblock | 0x0001u;
+    private const float Radius = 0.48f;
+    private const float Height = 1.835f;
+
+    [Fact]
+    public void FloorWithinFirstGravityFrame_CommitsGroundContactOnce()
+    {
+        PhysicsEngine engine = BuildFlatEngine();
+        PhysicsBody body = AirborneBody(new Vector3(12f, 12f, 0.25f));
+        int hitGround = 0;
+        int leaveGround = 0;
+
+        bool settled = RemoteSpawnPlacementSettler.TrySettle(
+            engine,
+            body,
+            body.Position,
+            Cell,
+            Radius,
+            Height,
+            ObjectInfoState.EdgeSlide,
+            movingEntityId: 0x70000001u,
+            () => hitGround++,
+            () => leaveGround++);
+
+        Assert.True(settled);
+        Assert.True(body.InContact);
+        Assert.True(body.OnWalkable);
+        Assert.Equal(1, hitGround);
+        Assert.Equal(0, leaveGround);
+    }
+
+    [Fact]
+    public void MissingCell_CanRetryAfterHydrationWithoutReconstructingBody()
+    {
+        var engine = new PhysicsEngine { DataCache = new PhysicsDataCache() };
+        PhysicsBody body = AirborneBody(new Vector3(12f, 12f, 0.25f));
+        Vector3 originalPosition = body.Position;
+
+        Assert.False(TrySettle(engine, body));
+        Assert.False(body.InContact);
+        Assert.Equal(originalPosition, body.Position);
+
+        AddFlatLandblock(engine);
+
+        Assert.True(TrySettle(engine, body));
+        Assert.True(body.InContact);
+        Assert.True(body.OnWalkable);
+    }
+
+    [Fact]
+    public void FloorOutsideSettleDistance_LeavesGenuinelyAirborneBodyUnchanged()
+    {
+        PhysicsEngine engine = BuildFlatEngine();
+        PhysicsBody body = AirborneBody(new Vector3(12f, 12f, 1.25f));
+        Vector3 originalPosition = body.Position;
+
+        Assert.False(TrySettle(engine, body));
+
+        Assert.False(body.InContact);
+        Assert.False(body.OnWalkable);
+        Assert.Equal(originalPosition, body.Position);
+    }
+
+    private static bool TrySettle(PhysicsEngine engine, PhysicsBody body) =>
+        RemoteSpawnPlacementSettler.TrySettle(
+            engine,
+            body,
+            body.Position,
+            Cell,
+            Radius,
+            Height,
+            ObjectInfoState.EdgeSlide,
+            movingEntityId: 0x70000001u,
+            static () => { },
+            static () => { });
+
+    private static PhysicsBody AirborneBody(Vector3 position) => new()
+    {
+        Position = position,
+        Orientation = Quaternion.Identity,
+        State = PhysicsStateFlags.Gravity | PhysicsStateFlags.ReportCollisions,
+        TransientState = TransientStateFlags.None,
+    };
+
+    private static PhysicsEngine BuildFlatEngine()
+    {
+        var engine = new PhysicsEngine { DataCache = new PhysicsDataCache() };
+        AddFlatLandblock(engine);
+        return engine;
+    }
+
+    private static void AddFlatLandblock(PhysicsEngine engine) =>
+        engine.AddLandblock(
+            Landblock,
+            new TerrainSurface(new byte[81], new float[256]),
+            Array.Empty<CellSurface>(),
+            Array.Empty<PortalPlane>(),
+            worldOffsetX: 0f,
+            worldOffsetY: 0f);
+}