[codex] Fix oversample repack and transfer regressions

Documentation~/EXPERIMENTS.md

@@ -330,6 +330,24 @@
 - Per-shell pre-pack snap — xatlas пересчитает per-chart scale от изменённой parametricArea и отменит snap (см. предыдущий эксперимент).
 - `rotateChartsToAxis = true` для repack existing UVs — мутирует extents.
 
-**Известные регрессии после a218a2b (требуют отдельной сессии):**
-- Пакинг при `internalOversample = 4` сильно дольше: brute-force pack cost ~ O(N × W × H), при 1024² и bruteForce=true может быть 16× медленнее vs 256². Возможно нужен soft fallback на heuristic pack для `internalRes ≥ N`.
-- Transfer стал кривее на некоторых тестовых моделях — вероятно из-за роста atlas size (1389×1360 вместо 256×256), что влияет на ε-параметры в `GroupedShellTransfer` (overlap detection thresholds в pixel space). Нужно прогнать transfer-чекер по test suite и поправить ε или нормализовать early.
+## Эксперимент 2026-05-13 — Oversample heuristic pack + atlas-scaled UV2 tolerances
+
+**Контекст:** после `a218a2b` default `internalOversample = 4` сохранил density spread, но поднял внутренний xatlas pack с 256² до 1024². Старый preflight отключал brute force только по `shellCount × internalRes² > 500M`; Carousel-кейс 149 × 1024² ≈ 156M оставался ниже budget, хотя wall-time стал ощутимо хуже. В transfer path часть UV2 tolerances оставалась в normalized-space константах (`0.005`, `0.01`), что при resolved atlas 1389×1360 превращало ~1.3px старого допуска в ~6.8px.
+
+**Изменение 1 (repack):**
+- `XatlasRepack.ResolvePackBruteForce()` теперь отключает native `bruteForce` при `internalOversample > 1`, даже если stored UI preference включён.
+- Старый safety budget остаётся для `internalOversample = 1`; heuristic safety budget по-прежнему запрещает огромные packs.
+- UI делает `Brute force pack` недоступным при oversample выше 1× и явно показывает effective packer = heuristic.
+
+**Изменение 2 (transfer):**
+- `RepackResult.atlasWidth/atlasHeight` сохраняются в `MeshEntry.repackedAtlasWidth/repackedAtlasHeight`.
+- `GroupedShellTransfer.Transfer()` принимает resolved source atlas size и переводит UV2 pixel margins через `pixels / min(atlasW, atlasH)`.
+- Legacy fallback остаётся прежним (`0.005`, `0.01`) для source meshes с existing UV2 или неизвестным atlas size.
+- Full pipeline теперь явно пропускает transfer/auto-tune, если нет включённых target LOD meshes, вместо трёх source-only repack попыток с `coverage=0%`.
+
+**Проверка:**
+- EditMode red/green: `PackPreflight_DisablesBruteForce_WhenInternalOversampleIsAboveOne`.
+- EditMode red/green: `BruteForceOption_IsUnavailable_WhenInternalOversampleIsAboveOne`.
+- EditMode red/green: `TransferTargetDetection_IgnoresSourceOnlySelection`.
+- EditMode red/green: `Uv2PixelMargin_ScalesFromResolvedAtlasSize`.
+- Full model benchmark (Carousel/Playground/WateringCan) в этом checkout не прогнан: тестовые FBX/`BenchmarkReports/` отсутствуют в репозитории. Нужен ручной Unity прогон на suite для финального сравнения `repackMs`, `density spread`, `overlapShellPairs`, `invertedCount`, `texelDensityBadCount`.

Editor/FbxMetricsExporter.cs

@@ -63,7 +63,7 @@ public static void ExportForSceneLodGroup()
                     if (r == null) continue;
                     var mf = r.GetComponent<MeshFilter>();
                     if (mf == null || mf.sharedMesh == null) continue;
-                    var row = AnalyzeMesh(lod.name, lodIdx, r.name, mf.sharedMesh);
+                    var row = AnalyzeMesh(lod.name, lod.name, lodIdx, r.name, mf.sharedMesh);
                     rows.Add(row);
                     UvPngWriter.Render(Path.Combine(outDir, "png",
                         $"{Sanitize(lod.name)}_LOD{lodIdx}_{Sanitize(r.name)}_uv0.png"),

Editor/Framework/MeshEntry.cs

@@ -45,6 +45,12 @@ public class MeshEntry
         /// Destroyed on pipeline reset or window close.
         /// </summary>
         public Mesh repackedMesh;
+        /// <summary>
+        /// Resolved xatlas dimensions used to produce <see cref="repackedMesh"/>.
+        /// Zero when UV2 came from an existing asset rather than this repack run.
+        /// </summary>
+        public uint repackedAtlasWidth;
+        public uint repackedAtlasHeight;
 
         /// <summary>
         /// UV2-transferred mesh for target LODs. Null until the Transfer step runs.

Editor/Framework/UvToolHub.cs

@@ -176,6 +176,8 @@ void RestoreWorkingMeshes()
                     e.meshFilter.sharedMesh = e.fbxMesh;
                 if (e.transferredMesh != null) { DestroyImmediate(e.transferredMesh); e.transferredMesh = null; }
                 if (e.repackedMesh != null) { DestroyImmediate(e.repackedMesh); e.repackedMesh = null; }
+                e.repackedAtlasWidth = 0;
+                e.repackedAtlasHeight = 0;
                 if (e.originalMesh != null && e.originalMesh != e.fbxMesh) { DestroyImmediate(e.originalMesh); e.originalMesh = null; }
             }
         }

Editor/GroupedShellTransfer.cs

@@ -760,11 +760,29 @@ static void RescoreMergedShells(
         //            fewer inverted/zero-area triangles.
         // ═══════════════════════════════════════════════════════════
 
+        static float ComputeUv2PixelMargin(int atlasWidth, int atlasHeight, float pixels, float fallback)
+        {
+            int w = Mathf.Max(0, atlasWidth);
+            int h = Mathf.Max(0, atlasHeight);
+            int dim = (w > 0 && h > 0) ? Mathf.Min(w, h) : Mathf.Max(w, h);
+            return dim > 0 ? pixels / dim : fallback;
+        }
+
         public static TransferResult Transfer(Mesh targetMesh, Mesh sourceMesh,
             List<OverlapSourceHint> previousLodHints = null,
-            List<CrossLodMatchHint> previousLodMatchHints = null)
+            List<CrossLodMatchHint> previousLodMatchHints = null,
+            int sourceAtlasWidth = 0,
+            int sourceAtlasHeight = 0)
         {
             var result = new TransferResult();
+            float uv2OobMargin = ComputeUv2PixelMargin(sourceAtlasWidth, sourceAtlasHeight, 1.25f, 0.005f);
+            float uv2BoundsTolerance = ComputeUv2PixelMargin(sourceAtlasWidth, sourceAtlasHeight, 2.5f, 0.01f);
+            if (sourceAtlasWidth > 0 || sourceAtlasHeight > 0)
+            {
+                UvtLog.Verbose(UvtLog.Category.Match,
+                    $"[GroupedTransfer] UV2 tolerances from atlas {sourceAtlasWidth}x{sourceAtlasHeight}: " +
+                    $"oobMargin={uv2OobMargin:F6}, boundsTol={uv2BoundsTolerance:F6}");
+            }
 
             // Source data
             var srcVerts = sourceMesh.vertices;
@@ -2028,7 +2046,7 @@ public static TransferResult Transfer(Mesh targetMesh, Mesh sourceMesh,
                             srcTransforms[si],
                             srcIsRibbon[si], srcRibbonAxis[si], srcRibbonAxis2[si], srcRibbonCentroid[si],
                             srcUv2Min, srcUv2Max, groupMembers,
-                            kRayMaxDist);
+                            kRayMaxDist, uv2BoundsTolerance);
 
                         var best = SelectBestCandidate(allCandidates, tShell.faceIndices, tgtTris, tUv0);
                         if (best.HasValue)
@@ -2753,7 +2771,7 @@ public static TransferResult Transfer(Mesh targetMesh, Mesh sourceMesh,
                             srcIsRibbon[chosenSrc], srcRibbonAxis[chosenSrc],
                             srcRibbonAxis2[chosenSrc], srcRibbonCentroid[chosenSrc],
                             srcUv2Min, srcUv2Max, null,
-                            kRayMaxDist);
+                            kRayMaxDist, uv2BoundsTolerance);
 
                         var bestOverlap = SelectBestCandidate(
                             overlapCandidates, tShell.faceIndices, tgtTris, tUv0);
@@ -2848,7 +2866,7 @@ public static TransferResult Transfer(Mesh targetMesh, Mesh sourceMesh,
                     // the outliers using the matched source's constrained UV0 lookup.
                     if (bestMergedUv2 != null && bestMergedUv2.Count > 1 && chosenSrc >= 0)
                     {
-                        const float kUv2Margin = 0.005f;
+                        float kUv2Margin = uv2OobMargin;
                         Vector2 sMin = srcUv2Min[chosenSrc];
                         Vector2 sMax = srcUv2Max[chosenSrc];
 
@@ -3084,7 +3102,7 @@ public static TransferResult Transfer(Mesh targetMesh, Mesh sourceMesh,
                         // Penalize xform if it extrapolates beyond source shell's UV2 bounds.
                         // Extrapolation is the primary cause of cross-source UV2 overlaps,
                         // since interp stays within source UV2 convex hull by construction.
-                        const float kOobMargin = 0.005f;
+                        float kOobMargin = uv2OobMargin;
                         Vector2 srcBMin2 = srcUv2Min[chosenSrc];
                         Vector2 srcBMax2 = srcUv2Max[chosenSrc];
                         Vector2 xfBMin = new Vector2(float.MaxValue, float.MaxValue);
@@ -3494,7 +3512,8 @@ public static TransferResult Transfer(Mesh targetMesh, Mesh sourceMesh,
             {
                 var uv = result.uv2[i];
                 uvMin = Vector2.Min(uvMin, uv); uvMax = Vector2.Max(uvMax, uv);
-                if (uv.x < -0.01f || uv.x > 1.01f || uv.y < -0.01f || uv.y > 1.01f) oob++;
+                if (uv.x < -uv2BoundsTolerance || uv.x > 1f + uv2BoundsTolerance ||
+                    uv.y < -uv2BoundsTolerance || uv.y > 1f + uv2BoundsTolerance) oob++;
             }
             if (oob > 0)
                 UvtLog.Warn($"[GroupedTransfer] '{targetMesh.name}': {oob} verts outside 0-1! " +
@@ -4099,7 +4118,7 @@ static List<OverlapCandidate> GenerateOverlapCandidates(
             // Cross-source UV2 guard data
             Vector2[] srcUv2Min, Vector2[] srcUv2Max, List<int> overlapGroupMembers,
             // Thresholds
-            float kRayMaxDist)
+            float kRayMaxDist, float uv2BoundsTolerance)
         {
             var candidates = new List<OverlapCandidate>();
             int[] tgtTris = null; // not needed — issues counted by caller
@@ -4280,7 +4299,8 @@ static List<OverlapCandidate> GenerateOverlapCandidates(
                     foreach (var kv in uv2Map)
                     {
                         Vector2 uv = kv.Value;
-                        if (uv.x < -0.01f || uv.x > 1.01f || uv.y < -0.01f || uv.y > 1.01f)
+                        if (uv.x < -uv2BoundsTolerance || uv.x > 1f + uv2BoundsTolerance ||
+                            uv.y < -uv2BoundsTolerance || uv.y > 1f + uv2BoundsTolerance)
                         {
                             partXfRejected = true;
                             break;
@@ -4368,8 +4388,8 @@ static List<OverlapCandidate> GenerateOverlapCandidates(
                     }
 
                     // Reject if result goes outside 0-1 range (catches wild extrapolation)
-                    if (xfMin.x < -0.01f || xfMax.x > 1.01f ||
-                        xfMin.y < -0.01f || xfMax.y > 1.01f)
+                    if (xfMin.x < -uv2BoundsTolerance || xfMax.x > 1f + uv2BoundsTolerance ||
+                        xfMin.y < -uv2BoundsTolerance || xfMax.y > 1f + uv2BoundsTolerance)
                         rejected = true;
 
                     // Reject if result extends too far beyond source's UV2 AABB

Editor/Tools/LightmapTransferTool.cs

@@ -23,6 +23,26 @@ public class LightmapTransferTool : IUvTool
         public int    ToolOrder => 0;
         public Action RequestRepaint { set => requestRepaint = value; }
 
+        static bool IsBruteForcePackAvailable(int internalOversample)
+        {
+            int oversample = internalOversample > 0 ? internalOversample : 1;
+            return oversample <= 1;
+        }
+
+        static bool HasIncludedTransferTargets(IEnumerable<MeshEntry> entries, int sourceLodIndex)
+        {
+            if (entries == null) return false;
+            foreach (var e in entries)
+            {
+                if (e == null) continue;
+                if (!e.include) continue;
+                if (e.lodIndex == sourceLodIndex) continue;
+                if (e.originalMesh == null) continue;
+                return true;
+            }
+            return false;
+        }
+
         // ── Internal tab ──
         enum Tab { Setup, Repack, Transfer }
         Tab tab = Tab.Setup;
@@ -583,18 +603,24 @@ void DrawRepack()
                             + "Oversampling makes ceil rounding fractional. UV2 still "
                             + "normalized to [0,1]; Unity bakes at its own resolution.\n\n"
                             + "Default 4× brings density spread from ~14× down to ~2×.\n"
-                            + "8-16× brings spread to ~1.1× but DISABLES brute force pack "
+                            + "2× and above disable brute force pack "
                             + "automatically (search space becomes minutes-per-atlas).\n"
                             + "1× = off, original xatlas behaviour."),
                         osIdx, osLabels);
                     ctx.InternalOversample = osValues[Mathf.Clamp(newOsIdx, 0, osValues.Length - 1)];
                 }
                 EditorGUILayout.Space(4);
                 EditorGUILayout.LabelField("xatlas options", EditorStyles.miniBoldLabel);
-                ctx.XatlasBruteForce = EditorGUILayout.ToggleLeft(
-                    new GUIContent("Brute force pack",
-                        "Run xatlas's exhaustive packer (slower, tighter atlas). Off by default."),
-                    ctx.XatlasBruteForce);
+                bool bruteForceAvailable = IsBruteForcePackAvailable(ctx.InternalOversample);
+                using (new EditorGUI.DisabledScope(!bruteForceAvailable))
+                {
+                    ctx.XatlasBruteForce = EditorGUILayout.ToggleLeft(
+                        new GUIContent("Brute force pack (1× only)",
+                            "Run xatlas's exhaustive packer (slower, tighter atlas). Only active when Internal pack oversample is 1×; 2× and above use the heuristic packer automatically."),
+                        ctx.XatlasBruteForce);
+                }
+                if (!bruteForceAvailable)
+                    EditorGUILayout.LabelField("Effective packer", "Heuristic (oversample > 1)", EditorStyles.miniLabel);
                 ctx.XatlasRotateCharts = EditorGUILayout.ToggleLeft(
                     new GUIContent("Rotate charts",
                         "xatlas may rotate charts to fit better (recommended)."),
@@ -1238,6 +1264,10 @@ bool ExecFullPipelineCore()
                     savedMeshes[e] = UnityEngine.Object.Instantiate(e.originalMesh);
 
             float[] separationConfigs = { 0.10f, 0.05f, 0.20f };
+            bool hasTransferTargets = HasIncludedTransferTargets(ctx.MeshEntries, ctx.SourceLodIndex);
+            if (!hasTransferTargets)
+                UvtLog.Warn("[Pipeline] No included target LOD meshes; running source repack only and skipping transfer/auto-tune.");
+
             int bestRejected = int.MaxValue;
             float bestCoverage = 0f;
             int bestConfigIdx = 0;
@@ -1271,6 +1301,8 @@ bool ExecFullPipelineCore()
                             kv.Key.originalMesh.name = kv.Value.name;
                             kv.Key.wasSymmetrySplit = false;
                             kv.Key.repackedMesh = null;
+                            kv.Key.repackedAtlasWidth = 0;
+                            kv.Key.repackedAtlasHeight = 0;
                             kv.Key.transferredMesh = null;
                             kv.Key.shellTransferResult = null;
                         }
@@ -1293,7 +1325,11 @@ bool ExecFullPipelineCore()
                     else ExecRepack(src);
 
                     // 5. Transfer
-                    if (ctx.HasRepack) ExecTransferAll();
+                    if (ctx.HasRepack && hasTransferTargets) ExecTransferAll();
+                    else if (ctx.HasRepack) ctx.HasTransfer = false;
+
+                    if (!hasTransferTargets)
+                        break;
 
                     // Evaluate quality
                     int totalRejected = 0;
@@ -1469,9 +1505,13 @@ void ExecRepackCore(List<MeshEntry> entries)
                 {
                     UvtLog.Error("[Repack] " + validEntries[i].renderer.name + ": " + results[i].error);
                     UnityEngine.Object.DestroyImmediate(meshCopies[i]);
+                    validEntries[i].repackedAtlasWidth = 0;
+                    validEntries[i].repackedAtlasHeight = 0;
                     continue;
                 }
                 validEntries[i].repackedMesh = meshCopies[i];
+                validEntries[i].repackedAtlasWidth = results[i].atlasWidth;
+                validEntries[i].repackedAtlasHeight = results[i].atlasHeight;
             }
 
             ctx.HasRepack = true;
@@ -1500,6 +1540,14 @@ void ExecTransferAll()
             BenchmarkRecorder.Current?.StageBegin("transfer");
             try
             {
+                if (!HasIncludedTransferTargets(ctx.MeshEntries, ctx.SourceLodIndex))
+                {
+                    ctx.HasTransfer = false;
+                    UvtLog.Warn("[Transfer] No included target LOD meshes; transfer skipped.");
+                    requestRepaint?.Invoke();
+                    return;
+                }
+
                 accumulatedOverlapHints.Clear();
                 accumulatedMatchHints.Clear();
                 for (int li = 0; li < ctx.LodCount; li++)
@@ -1558,7 +1606,9 @@ void ExecTransferLod(int tLod)
 
                 var tr = GroupedShellTransfer.Transfer(tgtMesh, srcMesh,
                     accumulatedOverlapHints.Count > 0 ? accumulatedOverlapHints : null,
-                    accumulatedMatchHints.Count > 0 ? accumulatedMatchHints : null);
+                    accumulatedMatchHints.Count > 0 ? accumulatedMatchHints : null,
+                    srcEntry.repackedAtlasWidth > 0 ? (int)srcEntry.repackedAtlasWidth : 0,
+                    srcEntry.repackedAtlasHeight > 0 ? (int)srcEntry.repackedAtlasHeight : 0);
                 if (tr.uv2 == null) { UvtLog.Warn($"[Transfer] Failed for '{tgt.renderer.name}'"); continue; }
 
                 // Accumulate overlap hints for subsequent LODs
@@ -3620,6 +3670,8 @@ void ResetWorkingCopies()
                     e.meshFilter.sharedMesh = e.fbxMesh;
                 if (e.transferredMesh != null) { UnityEngine.Object.DestroyImmediate(e.transferredMesh); e.transferredMesh = null; }
                 if (e.repackedMesh != null) { UnityEngine.Object.DestroyImmediate(e.repackedMesh); e.repackedMesh = null; }
+                e.repackedAtlasWidth = 0;
+                e.repackedAtlasHeight = 0;
                 if (e.originalMesh != null && e.originalMesh != e.fbxMesh) UnityEngine.Object.DestroyImmediate(e.originalMesh);
                 if (e.fbxMesh != null) e.originalMesh = e.fbxMesh;
                 e.shellTransferResult = null;