fix #451: stabilize portal seam rendering

src/AcDream.App/Rendering/RetailPViewPassExecutor.cs

@@ -134,6 +134,8 @@ internal sealed class RetailPViewPassExecutor :
     private readonly TerrainDrawDiagnosticsController _terrainDiagnostics;
     private readonly RetailPViewParticleClassifications _particleClassifications = new();
     private readonly HashSet<uint> _noSceneParticleEntityIds = [];
+    private readonly Dictionary<uint, int> _singleCellClipRouting = new(1);
+    private readonly Dictionary<uint, int> _noCellClipRouting = new(0);
 
     /// <summary>
     /// Borrowed until the next late landscape pass. The outdoor-root post-world
@@ -207,6 +209,8 @@ internal sealed class RetailPViewPassExecutor :
     {
         List<Exception>? failures = null;
         TryAbort(_frameGlState.RestoreFrameDefaults);
+        TryAbort(() => _envCells.SetClipRouting(null));
+        TryAbort(_entities.ClearClipRouting);
         TryAbort(_particleClassifications.BeginFrame);
         TryAbort(_noSceneParticleEntityIds.Clear);
         if (failures is { Count: > 0 })
@@ -230,6 +234,11 @@ internal sealed class RetailPViewPassExecutor :
         ClipFrameAssembly reuseAssembly) =>
         ClipFrameAssembler.Assemble(_clipFrame, portalFrame, reuseAssembly);
 
+    public void AppendLookInClipFrames(
+        IReadOnlyList<PortalVisibilityFrame> lookInFrames,
+        ClipFrameAssembly assembly) =>
+        ClipFrameAssembler.AppendLookInFrames(_clipFrame, lookInFrames, assembly);
+
     public void PrepareClipFrame(int terrainUploadCount) =>
         _surface.PrepareClipFrame(terrainUploadCount);
 
@@ -246,6 +255,24 @@ internal sealed class RetailPViewPassExecutor :
         _entities.ClearClipRouting();
     }
 
+    public void UseCellPortalViewRouting(uint cellId, ClipViewSlice slice)
+    {
+        _singleCellClipRouting.Clear();
+        _singleCellClipRouting.Add(cellId, slice.Slot);
+        _envCells.SetClipRouting(_singleCellClipRouting);
+        // Retail DrawMesh only viewcone-checks an object's sphere under the
+        // installed PortalList and then draws the mesh whole. Hard clipping the
+        // object here slices a stationary player when the chase camera crosses
+        // into the opposite cathedral cell while the player remains behind.
+        _entities.ClearClipRouting();
+    }
+
+    private void UseOutdoorPortalViewRouting(ClipViewSlice slice) =>
+        _entities.SetClipRouting(
+            _noCellClipRouting,
+            outdoorSlot: slice.Slot,
+            outdoorVisible: true);
+
     public void PrepareCellBatches(
         RetailPViewFrameInput frame,
         HashSet<uint> visibleCellIds) =>
@@ -376,6 +403,7 @@ internal sealed class RetailPViewPassExecutor :
 
         if (scissor)
             _surface.EndScissor();
+        _entities.ClearClipRouting();
         DisableClipDistances();
     }
 
@@ -418,8 +446,7 @@ internal sealed class RetailPViewPassExecutor :
 
         _particleClassifications.ReplaceOutdoor(context.ParticleOwnerIds);
 
-        if (!frame.RootCell.IsOutdoorNode
-            && _particleClassifications.Outdoor.Count > 0
+        if (_particleClassifications.Outdoor.Count > 0
             && _particles is not null
             && _particleRenderer is not null)
         {
@@ -427,7 +454,8 @@ internal sealed class RetailPViewPassExecutor :
                 frame.Camera,
                 frame.CameraWorldPosition,
                 ParticleRenderPass.Scene,
-                _particleClassifications.Outdoor);
+                _particleClassifications.Outdoor,
+                clipSlot: (uint)context.Slice.Slot);
         }
 
         EnableClipDistances();
@@ -456,6 +484,77 @@ internal sealed class RetailPViewPassExecutor :
 
         if (scissor)
             _surface.EndScissor();
+        _entities.ClearClipRouting();
+        DisableClipDistances();
+    }
+
+    public void DrawLandscapeStaticParticles(
+        RetailPViewFrameInput frame,
+        RetailPViewLandscapeStaticParticleContext context)
+    {
+        bool scissor = BeginDoorwayScissor(context.Slice.NdcAabb);
+        _surface.BindTerrainClip();
+        DisableClipDistances();
+
+        _particleClassifications.ReplaceOutdoor(context.ParticleOwnerIds);
+        if (_particleClassifications.Outdoor.Count > 0
+            && _particles is not null
+            && _particleRenderer is not null)
+        {
+            _particleRenderer.DrawForOwners(
+                frame.Camera,
+                frame.CameraWorldPosition,
+                ParticleRenderPass.Scene,
+                _particleClassifications.Outdoor,
+                clipSlot: (uint)context.Slice.Slot);
+        }
+
+        if (scissor)
+            _surface.EndScissor();
+        _entities.ClearClipRouting();
+        DisableClipDistances();
+    }
+
+    public void DrawLandscapeBuildingShellSlice(
+        RetailPViewFrameInput frame,
+        RetailPViewLandscapeBuildingShellSliceContext context)
+    {
+        UseOutdoorPortalViewRouting(context.Slice);
+        bool scissor = BeginDoorwayScissor(context.Slice.NdcAabb);
+        _surface.BindTerrainClip();
+        DisableClipDistances();
+
+        if (context.EntityDraw is RenderFrameEntityDrawRequest request)
+        {
+            RenderFrameView drawView = request.View;
+            _entities.DrawPackedProductionRoute(
+                frame.Camera,
+                in drawView,
+                request.Route,
+                request.RouteIndex,
+                request.CellId,
+                request.TupleLandblockId);
+        }
+        else if (context.BuildingShells.Count > 0)
+        {
+            var buildingEntry = (
+                frame.PlayerLandblockId ?? 0u,
+                Vector3.Zero,
+                Vector3.Zero,
+                context.BuildingShells,
+                (IReadOnlyDictionary<uint, WorldEntity>?)null);
+            _entities.Draw(
+                frame.Camera,
+                new[] { buildingEntry },
+                frame.Frustum,
+                neverCullLandblockId: frame.PlayerLandblockId,
+                visibleCellIds: null,
+                animatedEntityIds: frame.AnimatedEntityIds);
+        }
+
+        if (scissor)
+            _surface.EndScissor();
+        _entities.ClearClipRouting();
         DisableClipDistances();
     }
 
@@ -468,10 +567,13 @@ internal sealed class RetailPViewPassExecutor :
 
     public void DrawLookInPortalPunch(
         RetailPViewFrameInput frame,
-        RetailPViewCellSliceContext context) =>
-        DrawPortalDepthWrite(context, frame, forceFarZ: true);
+        RetailPViewCellSliceContext context,
+        int portalIndex) =>
+        DrawPortalDepthWrite(context, frame, forceFarZ: true, portalIndex);
 
-    public void DrawUnattachedSceneParticles(RetailPViewFrameInput frame)
+    public void DrawUnattachedSceneParticles(
+        RetailPViewFrameInput frame,
+        ClipViewSlice slice)
     {
         if (_particles is null || _particleRenderer is null)
             return;
@@ -482,7 +584,8 @@ internal sealed class RetailPViewPassExecutor :
             frame.CameraWorldPosition,
             ParticleRenderPass.Scene,
             _noSceneParticleEntityIds,
-            includeUnattached: true);
+            includeUnattached: true,
+            clipSlot: (uint)slice.Slot);
     }
 
     public void FlushLandscapeAlpha() => _alpha.Flush();
@@ -509,7 +612,8 @@ internal sealed class RetailPViewPassExecutor :
             frame.Camera,
             frame.CameraWorldPosition,
             ParticleRenderPass.Scene,
-            visible);
+            visible,
+            clipSlot: (uint)context.Slice.Slot);
         DisableClipDistances();
     }
 
@@ -552,7 +656,8 @@ internal sealed class RetailPViewPassExecutor :
     private void DrawPortalDepthWrite(
         RetailPViewCellSliceContext context,
         RetailPViewFrameInput frame,
-        bool forceFarZ)
+        bool forceFarZ,
+        int? onlyPortalIndex = null)
     {
         // Retail D3DPolyRender::DrawPortalPolyInternal @ 0x0059BC90.
         // Main interior roots stamp true depth (seal); outdoor and look-in
@@ -566,6 +671,8 @@ internal sealed class RetailPViewPassExecutor :
         Span<Vector3> world = stackalloc Vector3[32];
         for (int index = 0; index < cell.Portals.Count; index++)
         {
+            if (onlyPortalIndex.HasValue && index != onlyPortalIndex.Value)
+                continue;
             if (cell.Portals[index].OtherCellId != 0xFFFF)
                 continue;
             if (index >= cell.PortalPolygons.Count)