refactor(runtime): extract the live object frame

src/AcDream.App/Rendering/LiveAnimationPresentationContext.cs

@@ -0,0 +1,46 @@
+using AcDream.App.Input;
+using AcDream.App.Physics;
+using AcDream.App.World;
+using AcDream.Core.Physics;
+
+namespace AcDream.App.Rendering;
+
+/// <summary>
+/// Resolves the current motion owner without retaining the application window.
+/// </summary>
+internal sealed class LiveAnimationPresentationContext
+    : ILiveAnimationPresentationContext
+{
+    private readonly LiveEntityRuntime _runtime;
+    private readonly ILocalPlayerIdentitySource _localPlayer;
+    private readonly ILocalPlayerControllerSource _playerController;
+
+    public LiveAnimationPresentationContext(
+        LiveEntityRuntime runtime,
+        ILocalPlayerIdentitySource localPlayer,
+        ILocalPlayerControllerSource playerController)
+    {
+        _runtime = runtime ?? throw new ArgumentNullException(nameof(runtime));
+        _localPlayer = localPlayer ?? throw new ArgumentNullException(nameof(localPlayer));
+        _playerController = playerController
+            ?? throw new ArgumentNullException(nameof(playerController));
+    }
+
+    public uint LocalPlayerGuid => _localPlayer.ServerGuid;
+
+    public MotionInterpreter? ResolveMotionInterpreter(LiveEntityRecord record)
+    {
+        ArgumentNullException.ThrowIfNull(record);
+        if (!_runtime.TryGetRecord(record.ServerGuid, out LiveEntityRecord current)
+            || !ReferenceEquals(current, record))
+        {
+            return null;
+        }
+
+        if (record.ServerGuid == _localPlayer.ServerGuid)
+            return _playerController.Controller?.Motion;
+        return record.RemoteMotionRuntime is RemoteMotion remote
+            ? remote.Motion
+            : null;
+    }
+}