feat(vfx): port retail hidden and teleport presentation

Preserve canonical live-object ownership across Hidden transitions and remote teleport placement so effects, collision, streaming, and targeting remain synchronized.

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

@@ -0,0 +1,194 @@
+using System.Numerics;
+using AcDream.App.Physics;
+using AcDream.Core.Physics;
+using Xunit;
+
+namespace AcDream.App.Tests.Physics;
+
+public sealed class RemoteTeleportPlacementTests
+{
+    [Fact]
+    public void Apply_HardSnapsFullFrameAndPhysicsClock()
+    {
+        var body = new PhysicsBody
+        {
+            Orientation = Quaternion.Identity,
+            LastUpdateTime = 2.0,
+        };
+        body.SnapToCell(
+            0x01010001u,
+            new Vector3(3f, 4f, 5f),
+            new Vector3(3f, 4f, 5f));
+        var remote = new AcDream.App.Rendering.GameWindow.RemoteMotion(body);
+        Quaternion orientation = Quaternion.CreateFromAxisAngle(Vector3.UnitZ, 0.75f);
+
+        RemoteTeleportPlacement.Apply(
+            remote,
+            body,
+            new ResolveResult(
+                new Vector3(210f, 220f, 12f),
+                0x02020123u,
+                IsOnGround: false),
+            new Vector3(18f, 28f, 12f),
+            orientation,
+            17.5,
+            previousContact: body.InContact,
+            previousOnWalkable: body.OnWalkable);
+
+        Assert.Equal(new Vector3(210f, 220f, 12f), body.Position);
+        Assert.Equal(0x02020123u, body.CellPosition.ObjCellId);
+        Assert.Equal(new Vector3(18f, 28f, 12f), body.CellPosition.Frame.Origin);
+        Assert.Equal(orientation, body.Orientation);
+        Assert.Equal(17.5, body.LastUpdateTime);
+        Assert.True(body.InWorld);
+    }
+
+    [Fact]
+    public void Apply_InstallsPlacementDerivedContactAndSynchronizesAirborneState()
+    {
+        var velocity = new Vector3(1f, 2f, 3f);
+        var body = new PhysicsBody
+        {
+            Velocity = velocity,
+            TransientState = TransientStateFlags.Active,
+            State = PhysicsStateFlags.Gravity | PhysicsStateFlags.ReportCollisions,
+        };
+        var contactPlane = new Plane(Vector3.UnitZ, 0f);
+        var remote = new AcDream.App.Rendering.GameWindow.RemoteMotion(body)
+        {
+            Airborne = true,
+        };
+
+        RemoteTeleportPlacement.Apply(
+            remote,
+            body,
+            new ResolveResult(
+                new Vector3(200f, 200f, 50f),
+                0x02020001u,
+                IsOnGround: true,
+                InContact: true,
+                OnWalkable: true,
+                ContactPlane: contactPlane,
+                ContactPlaneCellId: 0x02020001u),
+            new Vector3(8f, 8f, 50f),
+            Quaternion.Identity,
+            9.0,
+            previousContact: false,
+            previousOnWalkable: false);
+
+        Assert.Equal(Vector3.Zero, body.Velocity);
+        Assert.True(body.InContact);
+        Assert.True(body.OnWalkable);
+        Assert.True(body.ContactPlaneValid);
+        Assert.Equal(contactPlane, body.ContactPlane);
+        Assert.False(remote.Airborne);
+    }
+
+    [Fact]
+    public void Apply_PendingHydrationUsesPreservedSourceFlagsBeforeCollisionResponse()
+    {
+        var originalVelocity = new Vector3(-3f, 0f, 0f);
+        var body = new PhysicsBody
+        {
+            Velocity = originalVelocity,
+            State = PhysicsStateFlags.Gravity | PhysicsStateFlags.ReportCollisions,
+        };
+        // ParkPending deliberately clears these flags while the destination
+        // landblock is absent. SetPositionInternal must still receive the
+        // grounded source edge captured before parking.
+        body.TransientState &= ~(TransientStateFlags.Contact | TransientStateFlags.OnWalkable);
+        var remote = new AcDream.App.Rendering.GameWindow.RemoteMotion(body)
+        {
+            Airborne = true,
+        };
+
+        RemoteTeleportPlacement.Apply(
+            remote,
+            body,
+            new ResolveResult(
+                new Vector3(200f, 200f, 50f),
+                0x02020001u,
+                IsOnGround: true,
+                CollisionNormalValid: true,
+                CollisionNormal: Vector3.UnitX,
+                InContact: true,
+                OnWalkable: true,
+                ContactPlane: new Plane(Vector3.UnitZ, 0f),
+                ContactPlaneCellId: 0x02020001u),
+            new Vector3(8f, 8f, 50f),
+            Quaternion.Identity,
+            9.0,
+            previousContact: true,
+            previousOnWalkable: true);
+
+        // Staying on walkable ground suppresses reflection. If the parked
+        // false/false flags were used, the -X velocity would reflect to +X.
+        Assert.Equal(originalVelocity, body.Velocity);
+        Assert.True(body.OnWalkable);
+        Assert.False(remote.Airborne);
+    }
+
+    [Fact]
+    public void Apply_PendingGroundToSteepContact_RestoresSourceWalkabilityForFirstAcceleration()
+    {
+        var body = new PhysicsBody
+        {
+            Omega = new Vector3(0f, 0f, 3f),
+            State = PhysicsStateFlags.Gravity | PhysicsStateFlags.ReportCollisions,
+        };
+        // The unloaded-destination parking frame cleared both bits. Retail
+        // restores the captured source OnWalkable bit through the first
+        // calc_acceleration, which clears grounded angular drift, before
+        // set_on_walkable installs the steep destination's false value.
+        body.TransientState &= ~(TransientStateFlags.Contact | TransientStateFlags.OnWalkable);
+        var remote = new AcDream.App.Rendering.GameWindow.RemoteMotion(body);
+
+        RemoteTeleportPlacement.Apply(
+            remote,
+            body,
+            new ResolveResult(
+                new Vector3(200f, 200f, 50f),
+                0x02020001u,
+                IsOnGround: false,
+                InContact: true,
+                OnWalkable: false,
+                ContactPlane: new Plane(Vector3.Normalize(new Vector3(1f, 0f, 0.2f)), 0f),
+                ContactPlaneCellId: 0x02020001u),
+            new Vector3(8f, 8f, 50f),
+            Quaternion.Identity,
+            9.0,
+            previousContact: true,
+            previousOnWalkable: true);
+
+        Assert.Equal(Vector3.Zero, body.Omega);
+        Assert.True(body.InContact);
+        Assert.False(body.OnWalkable);
+        Assert.True(remote.Airborne);
+    }
+
+    [Fact]
+    public void Apply_RejectsMalformedPlacementWithoutMutatingBody()
+    {
+        var original = new Vector3(7f, 8f, 9f);
+        var body = new PhysicsBody { Position = original };
+        var remote = new AcDream.App.Rendering.GameWindow.RemoteMotion(body);
+
+        Assert.Throws<ArgumentOutOfRangeException>(() =>
+            RemoteTeleportPlacement.Apply(
+                remote,
+                body,
+                new ResolveResult(
+                    new Vector3(float.NaN, 0f, 0f),
+                    0,
+                    IsOnGround: false,
+                    Ok: false),
+                Vector3.Zero,
+                Quaternion.Identity,
+                double.NaN,
+                previousContact: false,
+                previousOnWalkable: false));
+
+        Assert.Equal(original, body.Position);
+        Assert.Equal(0u, body.CellPosition.ObjCellId);
+    }
+}