refactor(rendering): isolate dispatcher candidate values

src/AcDream.App/Rendering/Scene/RenderInstanceCandidate.cs

@@ -0,0 +1,83 @@
+using System.Numerics;
+using AcDream.Core.World;
+
+namespace AcDream.App.Rendering.Scene;
+
+/// <summary>
+/// The complete acdream-owned value boundary consumed by the object
+/// dispatcher. It contains presentation facts only; the dispatcher must not
+/// call back into <see cref="WorldEntity"/> or any gameplay owner after this
+/// value has been produced.
+/// </summary>
+internal readonly record struct RenderInstanceCandidate(
+    RenderProjectionId ProjectionId,
+    uint LocalEntityId,
+    uint ServerGuid,
+    uint SourceId,
+    uint ParentCellId,
+    Matrix4x4 RootWorld,
+    Vector3 Position,
+    Quaternion Rotation,
+    float Scale,
+    RenderWorldBounds Bounds,
+    PaletteOverride? PaletteOverride,
+    bool IsBuildingShell,
+    bool Animated,
+    int MeshPartCount,
+    uint TupleLandblockId)
+{
+    internal uint Id => LocalEntityId;
+
+    internal uint? ParentCell =>
+        ParentCellId == 0 ? null : ParentCellId;
+
+    internal uint CacheLandblockId =>
+        ParentCellId != 0
+            ? (ParentCellId & 0xFFFF0000u) | 0xFFFFu
+            : TupleLandblockId;
+
+    internal static RenderInstanceCandidate FromWorldEntity(
+        WorldEntity entity,
+        bool animated,
+        int meshPartCount,
+        uint tupleLandblockId)
+    {
+        ArgumentNullException.ThrowIfNull(entity);
+        if (meshPartCount < 0)
+            throw new ArgumentOutOfRangeException(nameof(meshPartCount));
+        if (entity.AabbDirty)
+            entity.RefreshAabb();
+
+        return new RenderInstanceCandidate(
+            ProjectionId: default,
+            LocalEntityId: entity.Id,
+            ServerGuid: entity.ServerGuid,
+            SourceId: entity.SourceGfxObjOrSetupId,
+            ParentCellId: entity.ParentCellId ?? 0u,
+            RootWorld:
+                Matrix4x4.CreateFromQuaternion(entity.Rotation)
+                * Matrix4x4.CreateTranslation(entity.Position),
+            Position: entity.Position,
+            Rotation: entity.Rotation,
+            Scale: entity.Scale,
+            Bounds: new RenderWorldBounds(
+                entity.AabbMin,
+                entity.AabbMax),
+            PaletteOverride: entity.PaletteOverride,
+            IsBuildingShell: entity.IsBuildingShell,
+            Animated: animated,
+            MeshPartCount: meshPartCount,
+            TupleLandblockId: tupleLandblockId);
+    }
+}
+
+/// <summary>
+/// One ordered mesh reference belonging to a dispatcher candidate. Candidate
+/// values repeat across the entity's tuples only in the transitional current
+/// source; the scene frame product supplies the same facts from retained arena
+/// storage.
+/// </summary>
+internal readonly record struct RenderInstanceTuple(
+    RenderInstanceCandidate Candidate,
+    int MeshRefIndex,
+    MeshRef MeshRef);