fix(selection): port SmartBox click lighting pulse

Port the retail high/low material-lighting cadence for successful world clicks, keep it instance-scoped in the modern renderer, and restore authored lighting after 0.8 seconds. Correct the selection oracle and pin timing plus per-frame buffer lifecycle with tests.

Co-authored-by: Codex <codex@openai.com>

src/AcDream.App/Rendering/GameWindow.cs

@@ -12379,6 +12379,8 @@ public sealed class GameWindow : IDisposable
         if (payload is AcDream.App.UI.ItemDragPayload itemPayload)
         {
             uint target = PickWorldGuidAt(x, y, includeSelf: true) ?? 0u;
+            if (target != 0u)
+                _retailSelectionScene?.BeginLightingPulse(target);
             _itemInteractionController?.PlaceIn3D(itemPayload, target);
         }
     }
@@ -13129,6 +13131,11 @@ public sealed class GameWindow : IDisposable
 
         if (picked is uint guid)
         {
+            // Retail UIElement_SmartBoxWrapper::RecvNotice_SmartBoxObjectFound
+            // @ 0x004E5AD0 pulses every successfully found click before it
+            // branches into select/use/targeted-use behavior.
+            _retailSelectionScene?.BeginLightingPulse(guid);
+
             if (_itemInteractionController?.OfferPrimaryClick(guid)
                 is not null and not AcDream.App.UI.ItemPrimaryClickResult.NotActive)
                 return;

src/AcDream.App/Rendering/Selection/IRetailSelectionLightingSource.cs

@@ -0,0 +1,17 @@
+namespace AcDream.App.Rendering.Selection;
+
+/// <summary>
+/// Supplies the transient material lighting override which retail applies to
+/// a world object after SmartBox resolves a click.
+/// </summary>
+internal interface IRetailSelectionLightingSource
+{
+    /// <summary>Advances the retail SmartBox flip cadence once for this frame.</summary>
+    void TickLighting();
+
+    /// <summary>
+    /// Returns the current CMaterial luminosity/diffuse replacement for an
+    /// object, or false when its authored material values must be restored.
+    /// </summary>
+    bool TryGetLighting(uint serverGuid, out RetailSelectionLighting lighting);
+}

src/AcDream.App/Rendering/Selection/RetailSelectionLightingPulse.cs

@@ -0,0 +1,101 @@
+using System.Diagnostics;
+
+namespace AcDream.App.Rendering.Selection;
+
+/// <summary>
+/// Replacement values passed by retail to CPhysicsObj::SetLighting.
+/// CMaterial receives luminosity first and diffuse second.
+/// </summary>
+internal readonly record struct RetailSelectionLighting(float Luminosity, float Diffuse)
+{
+    public static readonly RetailSelectionLighting Normal = new(0f, 1f);
+    public static readonly RetailSelectionLighting Low = new(0f, 0.35f);
+    public static readonly RetailSelectionLighting High = new(0.99f, 1f);
+}
+
+/// <summary>
+/// Retail SmartBox click-confirmation lighting pulse.
+///
+/// UIElement_SmartBoxWrapper::RecvNotice_SmartBoxObjectFound @ 0x004E5AD0
+/// applies HIGH immediately. Global_Loop @ 0x004E5620 then advances
+/// LOW/HIGH/LOW/RESTORE at 0.2-second intervals. A new click restores the old
+/// target implicitly and starts the sequence again on the new target.
+/// </summary>
+internal sealed class RetailSelectionLightingPulse
+{
+    internal const double FlipIntervalSeconds = 0.2;
+
+    private readonly Func<double> _now;
+    private uint _serverGuid;
+    private int _flipCount;
+    private double _nextFlip;
+    private RetailSelectionLighting _lighting;
+
+    public RetailSelectionLightingPulse(Func<double>? now = null)
+        => _now = now ?? MonotonicSeconds;
+
+    public void Start(uint serverGuid)
+    {
+        if (serverGuid == 0u)
+        {
+            Clear();
+            return;
+        }
+
+        _serverGuid = serverGuid;
+        _flipCount = 1;
+        _lighting = RetailSelectionLighting.High;
+        _nextFlip = _now() + FlipIntervalSeconds;
+    }
+
+    /// <summary>
+    /// Advances at most one flip per frame, matching retail Global_Loop. The
+    /// next deadline is based on the current frame time, so a long frame does
+    /// not replay multiple material mutations in one draw.
+    /// </summary>
+    public void Tick()
+    {
+        if (_flipCount == 0)
+            return;
+
+        double now = _now();
+        if (now < _nextFlip)
+            return;
+
+        int nextCount = _flipCount + 1;
+        if (nextCount >= 5)
+        {
+            Clear();
+            return;
+        }
+
+        _flipCount = nextCount;
+        _lighting = (nextCount & 1) != 0
+            ? RetailSelectionLighting.High
+            : RetailSelectionLighting.Low;
+        _nextFlip = now + FlipIntervalSeconds;
+    }
+
+    public bool TryGet(uint serverGuid, out RetailSelectionLighting lighting)
+    {
+        if (_flipCount != 0 && serverGuid != 0u && serverGuid == _serverGuid)
+        {
+            lighting = _lighting;
+            return true;
+        }
+
+        lighting = default;
+        return false;
+    }
+
+    public void Clear()
+    {
+        _serverGuid = 0u;
+        _flipCount = 0;
+        _nextFlip = 0d;
+        _lighting = default;
+    }
+
+    private static double MonotonicSeconds()
+        => Stopwatch.GetTimestamp() / (double)Stopwatch.Frequency;
+}

src/AcDream.App/Rendering/Selection/RetailSelectionScene.cs

@@ -9,9 +9,10 @@ namespace AcDream.App.Rendering.Selection;
 /// The renderer builds one frame while input queries the previously completed
 /// frame, avoiding partial visibility state during multi-slice portal drawing.
 /// </summary>
-internal sealed class RetailSelectionScene : IRetailSelectionRenderSink
+internal sealed class RetailSelectionScene : IRetailSelectionRenderSink, IRetailSelectionLightingSource
 {
     private readonly RetailSelectionGeometryCache _geometry;
+    private readonly RetailSelectionLightingPulse _lightingPulse;
     private List<RetailSelectionPart> _building = new();
     private List<RetailSelectionPart> _published = new();
     private readonly HashSet<PartKey> _buildingKeys = new();
@@ -21,8 +22,26 @@ internal sealed class RetailSelectionScene : IRetailSelectionRenderSink
 
     private readonly record struct PartKey(uint LocalEntityId, int PartIndex, uint GfxObjId);
 
-    public RetailSelectionScene(RetailSelectionGeometryCache geometry)
-        => _geometry = geometry ?? throw new ArgumentNullException(nameof(geometry));
+    public RetailSelectionScene(
+        RetailSelectionGeometryCache geometry,
+        RetailSelectionLightingPulse? lightingPulse = null)
+    {
+        _geometry = geometry ?? throw new ArgumentNullException(nameof(geometry));
+        _lightingPulse = lightingPulse ?? new RetailSelectionLightingPulse();
+    }
+
+    /// <summary>
+    /// Starts retail's SmartBox click pulse independently of persistent target
+    /// selection. Examine, use, and targeted-use clicks receive the same pulse.
+    /// </summary>
+    public void BeginLightingPulse(uint serverGuid)
+        => _lightingPulse.Start(serverGuid);
+
+    public void TickLighting()
+        => _lightingPulse.Tick();
+
+    public bool TryGetLighting(uint serverGuid, out RetailSelectionLighting lighting)
+        => _lightingPulse.TryGet(serverGuid, out lighting);
 
     public void BeginFrame()
     {

src/AcDream.App/Rendering/Shaders/mesh_modern.frag

@@ -8,6 +8,7 @@ in vec3 vLit;            // A7: per-vertex Gouraud lighting (ambient + capped li
 in flat uvec2 vTextureHandle;
 in flat uint  vTextureLayer;
 in flat float vOpacityMultiplier;   // #188
+in flat vec2  vSelectionLighting;   // x=luminosity, y=diffuse
 
 // uRenderPass values (Phase N.5 Decision 2 — two-pass alpha-test):
 //   0 = opaque pass     — discard fragments with alpha < 0.95
@@ -84,8 +85,10 @@ void main() {
         if (color.a < 0.05) discard;
     }
 
-    // Per-vertex Gouraud lighting from the vertex shader (ambient + capped lights).
-    vec3 lit = vLit;
+    // Per-vertex Gouraud lighting from the vertex shader (ambient + capped
+    // lights), passed through retail CMaterial's two click-pulse replacements:
+    // emissive/luminosity + diffuse * scene lighting. Normal is (0,1).
+    vec3 lit = vec3(vSelectionLighting.x) + vSelectionLighting.y * vLit;
 
     // #176 stripe-hunt mode 3: show the raw per-vertex light field (texture
     // ignored). Stripes visible HERE = a vertex-lighting artifact; absent =

src/AcDream.App/Rendering/Shaders/mesh_modern.vert

@@ -7,10 +7,6 @@ layout(location = 2) in vec2 aTexCoord;
 
 struct InstanceData {
     mat4 transform;
-    // Reserved for Phase B.4 follow-up (selection-blink retail-faithful
-    // highlight): vec4 highlightColor; — extend stride here, increase the
-    // _instanceSsbo upload size in WbDrawDispatcher, add a flat varying out,
-    // and consume in mesh_modern.frag.
 };
 
 struct BatchData {
@@ -115,6 +111,15 @@ layout(std430, binding = 7) readonly buffer InstanceAlphaBuf {
     float instanceAlpha[];
 };
 
+// Retail SmartBox click confirmation. One vec2 per OBJECT instance, parallel
+// to binding=0: x = CMaterial luminosity, y = CMaterial diffuse. Normal
+// rendering is (0,1); SmartBox alternates LOW=(0,.35) and HIGH=(.99,1).
+// EnvCellRenderer uses uLightingMode=1 and deliberately never reads this
+// object-only binding.
+layout(std430, binding = 8) readonly buffer InstanceSelectionLightingBuf {
+    vec2 instanceSelectionLighting[];
+};
+
 // Core profile: redeclare gl_PerVertex so writing gl_ClipDistance[] is legal
 // alongside gl_Position. The array is sized 8 to match the CellClip plane budget
 // and the GL guarantee (GL_MAX_CLIP_DISTANCES >= 8). The host enables
@@ -277,11 +282,15 @@ out vec3 vLit;            // A7: per-vertex Gouraud lighting (ambient + capped l
 out flat uvec2 vTextureHandle;
 out flat uint  vTextureLayer;
 out flat float vOpacityMultiplier;   // #188
+out flat vec2  vSelectionLighting;
 
 void main() {
     int instanceIndex = gl_BaseInstanceARB + gl_InstanceID;
     mat4 model = Instances[instanceIndex].transform;
     vOpacityMultiplier = instanceAlpha[instanceIndex];   // #188
+    vSelectionLighting = (uLightingMode == 0)
+        ? instanceSelectionLighting[instanceIndex]
+        : vec2(0.0, 1.0);
 
     vec4 worldPos = model * vec4(aPosition, 1.0);
     gl_Position = uViewProjection * worldPos;

src/AcDream.App/Rendering/Wb/WbDrawDispatcher.cs

@@ -87,6 +87,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
     private readonly WbMeshAdapter _meshAdapter;
     private readonly EntitySpawnAdapter _entitySpawnAdapter;
     private readonly IRetailSelectionRenderSink? _selectionSink;
+    private readonly IRetailSelectionLightingSource? _selectionLighting;
 
     private readonly BindlessSupport _bindless;
 
@@ -165,6 +166,10 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
     // a clone of _indoorData / _instIndoorSsbo, one binding higher.
     private uint _instAlphaSsbo;
     private float[] _alphaData = new float[256];
+    // Retail SmartBox click confirmation: per-instance CMaterial luminosity /
+    // diffuse replacement (binding=8), parallel to the transform buffer.
+    private uint _instSelectionLightingSsbo;
+    private Vector2[] _selectionLightingData = new Vector2[256];
     // This frame's point-light snapshot, handed in by GameWindow before Draw via
     // SetSceneLights. Null/empty ⇒ only ambient + sun render (all instance sets -1).
     private IReadOnlyList<LightSource>? _pointSnapshot;
@@ -178,6 +183,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
     // (ParentCellId is an EnvCell). Appended to InstanceGroup.IndoorFlags in
     // AppendCurrentLightSet; uploaded as binding=6 instanceIndoor[].
     private bool _currentEntityIndoor;
+    private Vector2 _currentEntitySelectionLighting = new(0f, 1f);
 
     // Phase U.3: the SHARED per-cell clip-region SSBO (binding=2), owned by the
     // GameWindow-level ClipFrame and handed to us via SetClipRegionSsbo. When 0
@@ -375,6 +381,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         _cache = classificationCache;
         _translucencyFades = translucencyFades;
         _selectionSink = selectionSink;
+        _selectionLighting = selectionSink as IRetailSelectionLightingSource;
 
         _bindless = bindless ?? throw new ArgumentNullException(nameof(bindless));
         _instanceSsbo   = _gl.GenBuffer();
@@ -385,6 +392,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         _instLightSetSsbo = _gl.GenBuffer();        // Fix B binding=5
         _instIndoorSsbo = _gl.GenBuffer();          // #142 binding=6
         _instAlphaSsbo  = _gl.GenBuffer();          // #188 binding=7
+        _instSelectionLightingSsbo = _gl.GenBuffer(); // SmartBox binding=8
     }
 
     /// <summary>
@@ -927,6 +935,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         EntitySet set = EntitySet.All)
     {
         _shader.Use();
+        _selectionLighting?.TickLighting();
         _indoorProbeFrameCounter++;
         var vp = camera.View * camera.Projection;
         _shader.SetMatrix4("uViewProjection", vp);
@@ -1131,6 +1140,10 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
                 // is constant across the entity's parts/tuples), by the entity's
                 // bounding sphere — camera-INDEPENDENT (minimize_object_lighting).
                 ComputeEntityLightSet(entity);
+                _currentEntitySelectionLighting =
+                    _selectionLighting?.TryGetLighting(entity.ServerGuid, out var lighting) == true
+                        ? new Vector2(lighting.Luminosity, lighting.Diffuse)
+                        : new Vector2(0f, 1f);
 
                 // #119 decisive probe: one-shot dump (+ change re-emission) for
                 // ACDREAM_DUMP_ENTITY-targeted entities. Before the culled-continue
@@ -1508,6 +1521,9 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         if (_alphaData.Length < totalInstances)
             _alphaData = new float[totalInstances + 256];
 
+        if (_selectionLightingData.Length < totalInstances)
+            _selectionLightingData = new Vector2[totalInstances + 256];
+
         _opaqueDraws.Clear();
         _translucentDraws.Clear();
 
@@ -1546,6 +1562,8 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
                 // #188: Opacities[] is parallel to Matrices[]; write at the same
                 // cursor so binding=7 instanceAlpha[] tracks binding=0 instances.
                 _alphaData[cursor] = grp.Opacities[i];
+                // SmartBox CMaterial replacement, parallel to Matrices.
+                _selectionLightingData[cursor] = grp.SelectionLighting[i];
                 cursor++;
             }
 
@@ -1643,6 +1661,12 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         fixed (float* ap = _alphaData)
             UploadSsbo(_instAlphaSsbo, 7, ap, totalInstances * sizeof(float));
 
+        // SmartBox click lighting: x=luminosity, y=diffuse. mesh_modern.vert
+        // reads this only for the object path (uLightingMode=0), so EnvCell's
+        // independent mode-1 renderer does not consume this binding.
+        fixed (Vector2* hp = _selectionLightingData)
+            UploadSsbo(_instSelectionLightingSsbo, 8, hp, totalInstances * sizeof(float) * 2);
+
         // Fix B: global point-light buffer (binding=4) + per-instance light-set
         // buffer (binding=5). The global buffer is this frame's PointSnapshot; the
         // per-instance buffer holds 8 int indices into it per instance, laid out
@@ -2189,6 +2213,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         // state for entities whose animation hooks fired — so a cached
         // instance can never be mid-fade. Always unmodified opacity.
         grp.Opacities.Add(1.0f);
+        grp.SelectionLighting.Add(_currentEntitySelectionLighting);
     }
 
     /// <summary>
@@ -2370,6 +2395,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
             grp.Slots.Add(_currentEntitySlot); // Phase U.4 — parallel to Matrices
             AppendCurrentLightSet(grp);        // Fix B — 8 ints per instance, parallel to Matrices
             grp.Opacities.Add(opacityMultiplier); // #188 — parallel to Matrices
+            grp.SelectionLighting.Add(_currentEntitySelectionLighting);
             collector?.Add(new CachedBatch(key, texHandle, restPose));
         }
     }
@@ -2453,6 +2479,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         if (_instLightSetSsbo != 0) _gl.DeleteBuffer(_instLightSetSsbo);       // Fix B binding=5
         if (_instIndoorSsbo != 0) _gl.DeleteBuffer(_instIndoorSsbo);           // #142 binding=6
         if (_instAlphaSsbo != 0) _gl.DeleteBuffer(_instAlphaSsbo);             // #188 binding=7
+        if (_instSelectionLightingSsbo != 0) _gl.DeleteBuffer(_instSelectionLightingSsbo); // SmartBox binding=8
         if (_gpuQueriesInitialized)
         {
             for (int i = 0; i < GpuQueryRingDepth; i++)
@@ -2660,6 +2687,10 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
         // the same cursor, so the binding=7 instanceAlpha[] tracks binding=0.
         public readonly List<float> Opacities = new();
 
+        // Retail SmartBox click lighting, parallel to Matrices. Each vec2 is
+        // (luminosity, diffuse) and is uploaded to binding=8.
+        public readonly List<Vector2> SelectionLighting = new();
+
         /// <summary>
         /// Resets every per-instance parallel list for a new frame. These lists are
         /// appended in lockstep (one entry per drawn instance) during group build, so
@@ -2677,6 +2708,7 @@ public sealed unsafe class WbDrawDispatcher : IDisposable
             LightSets.Clear();
             IndoorFlags.Clear();
             Opacities.Clear();
+            SelectionLighting.Clear();
         }
     }
 }