feat(rendering): compare scene-built PView candidates

Build a same-frame candidate product from incremental render-scene indices and compare its exact PView routes against the accepted current path without changing the production draw source.

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

@@ -9,6 +9,22 @@ internal enum RenderFrameBlendClass : byte
     Alpha,
 }
 
+internal enum RenderFrameCandidateRoute : byte
+{
+    LandscapeOutdoorStatic,
+    LandscapeOutsideDynamic,
+    LookInObject,
+    CellStatic,
+    DynamicLast,
+}
+
+internal readonly record struct RenderFrameCandidateRange(
+    RenderFrameCandidateRoute Route,
+    int RouteIndex,
+    uint CellId,
+    int Offset,
+    int Count);
+
 internal readonly record struct RenderFrameCellRange(
     uint CellId,
     int PViewOrder,
@@ -60,7 +76,8 @@ internal readonly record struct RenderFrameDiagnosticCounts(
     int OpaqueClassificationCount,
     int AlphaClassificationCount,
     int LightSetCount,
-    int SelectionPartCount);
+    int SelectionPartCount,
+    int RouteCandidateCount);
 
 /// <summary>
 /// A validated borrowed view over one reusable frame arena. Copies are safe:
@@ -125,6 +142,12 @@ internal readonly struct RenderFrameView
     public ReadOnlySpan<RenderFrameSelectionPart> SelectionParts =>
         Arena.SelectionParts;
 
+    public ReadOnlySpan<RenderProjectionRecord> RouteCandidates =>
+        Arena.RouteCandidates;
+
+    public ReadOnlySpan<RenderFrameCandidateRange> RouteRanges =>
+        Arena.RouteRanges;
+
     public PortalVisibilityFrame? PortalFrame => Arena.PortalFrame;
 
     public ClipFrameAssembly? ClipAssembly => Arena.ClipAssembly;
@@ -172,6 +195,8 @@ internal sealed class RenderFrameArena
     private RenderFrameClassificationRecord[] _classifications = [];
     private RenderFrameObjectLightSet[] _lightSets = [];
     private RenderFrameSelectionPart[] _selectionParts = [];
+    private RenderProjectionRecord[] _routeCandidates = [];
+    private RenderFrameCandidateRange[] _routeRanges = [];
     private int _outdoorCount;
     private int _cellStaticCount;
     private int _cellRangeCount;
@@ -180,6 +205,8 @@ internal sealed class RenderFrameArena
     private int _classificationCount;
     private int _lightSetCount;
     private int _selectionPartCount;
+    private int _routeCandidateCount;
+    private int _routeRangeCount;
     private int _opaqueClassificationCount;
     private int _alphaClassificationCount;
     private ulong _epoch;
@@ -206,7 +233,8 @@ internal sealed class RenderFrameArena
             _opaqueClassificationCount,
             _alphaClassificationCount,
             _lightSetCount,
-            _selectionPartCount);
+            _selectionPartCount,
+            _routeCandidateCount);
 
     internal ReadOnlySpan<RenderProjectionRecord> OutdoorStaticCandidates =>
         _outdoor.AsSpan(0, _outdoorCount);
@@ -232,6 +260,12 @@ internal sealed class RenderFrameArena
     internal ReadOnlySpan<RenderFrameSelectionPart> SelectionParts =>
         _selectionParts.AsSpan(0, _selectionPartCount);
 
+    internal ReadOnlySpan<RenderProjectionRecord> RouteCandidates =>
+        _routeCandidates.AsSpan(0, _routeCandidateCount);
+
+    internal ReadOnlySpan<RenderFrameCandidateRange> RouteRanges =>
+        _routeRanges.AsSpan(0, _routeRangeCount);
+
     internal ulong BeginWrite(
         RenderSceneGeneration generation,
         ulong frameSequence)
@@ -253,6 +287,8 @@ internal sealed class RenderFrameArena
         _classificationCount = 0;
         _lightSetCount = 0;
         _selectionPartCount = 0;
+        _routeCandidateCount = 0;
+        _routeRangeCount = 0;
         _opaqueClassificationCount = 0;
         _alphaClassificationCount = 0;
         PortalFrame = null;
@@ -393,6 +429,34 @@ internal sealed class RenderFrameArena
         _selectionParts[_selectionPartCount++] = part;
     }
 
+    internal void AddRouteRange(
+        ulong epoch,
+        RenderFrameCandidateRoute route,
+        int routeIndex,
+        uint cellId,
+        ReadOnlySpan<RenderProjectionRecord> records)
+    {
+        EnsureBuilding(epoch);
+        if (routeIndex < 0)
+            throw new ArgumentOutOfRangeException(nameof(routeIndex));
+        if (records.Length == 0)
+            return;
+
+        int offset = _routeCandidateCount;
+        EnsureCapacity(
+            ref _routeCandidates,
+            checked(offset + records.Length));
+        records.CopyTo(_routeCandidates.AsSpan(offset));
+        _routeCandidateCount += records.Length;
+        EnsureCapacity(ref _routeRanges, _routeRangeCount + 1);
+        _routeRanges[_routeRangeCount++] = new RenderFrameCandidateRange(
+            route,
+            routeIndex,
+            cellId,
+            offset,
+            records.Length);
+    }
+
     internal void Publish(ulong epoch)
     {
         EnsureBuilding(epoch);
@@ -549,6 +613,18 @@ internal readonly struct RenderFrameWriter
     public void AddSelectionPart(in RenderFrameSelectionPart part) =>
         Arena.AddSelectionPart(_epoch, in part);
 
+    public void AddRouteRange(
+        RenderFrameCandidateRoute route,
+        int routeIndex,
+        uint cellId,
+        ReadOnlySpan<RenderProjectionRecord> records) =>
+        Arena.AddRouteRange(
+            _epoch,
+            route,
+            routeIndex,
+            cellId,
+            records);
+
     public void Publish() =>
         Owner.Publish(_arenaIndex, _epoch);