diff --git a/src/AcDream.App/Rendering/GameWindow.cs b/src/AcDream.App/Rendering/GameWindow.cs
index fee413b..61f4084 100644
--- a/src/AcDream.App/Rendering/GameWindow.cs
+++ b/src/AcDream.App/Rendering/GameWindow.cs
@@ -6076,6 +6076,12 @@ public sealed class GameWindow : IDisposable
 
         _gl!.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
 
+        // Phase N.4: drain WB pipeline queues (staged mesh data +
+        // GL thread queue). Must happen before any draw work so that
+        // resources uploaded this frame are available immediately.
+        // No-op when ACDREAM_USE_WB_FOUNDATION is off (_wbMeshAdapter is null).
+        _wbMeshAdapter?.Tick();
+
         // Phase D.2a — begin ImGui frame. Paired with the Render() call
         // after the scene draws (below). ImGuiController.Update()
         // consumes buffered Silk.NET input events and calls ImGui.NewFrame.
diff --git a/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs b/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs
index ec5f407..b8a3a23 100644
--- a/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs
+++ b/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs
@@ -94,6 +94,38 @@ public sealed class WbMeshAdapter : IDisposable, IWbMeshAdapter
         _meshManager.DecrementRefCount(id);
     }
 
+    /// <summary>
+    /// Per-frame drain of the WB pipeline's main-thread work queues. MUST be
+    /// called once per frame from the render thread. Without this, the staged
+    /// mesh data queue grows unbounded (memory leak) and queued GL actions
+    /// never execute.
+    ///
+    /// <para>
+    /// Order matters: <c>ProcessGLQueue</c> runs first to apply any pending GL
+    /// state changes (e.g., texture uploads queued by background workers
+    /// during mesh prep). Then we drain staged mesh data, calling
+    /// <c>UploadMeshData</c> on each item to materialize the actual GL VAO /
+    /// VBO / IBO resources. After Tick, <c>GetRenderData</c> for any id
+    /// previously passed to <c>IncrementRefCount</c> may return non-null.
+    /// </para>
+    ///
+    /// <para>
+    /// No-op when the adapter is uninitialized (e.g., flag is off and the
+    /// adapter was constructed via <c>CreateUninitialized</c>).
+    /// </para>
+    /// </summary>
+    public void Tick()
+    {
+        if (_isUninitialized) return;
+        if (_disposed) return;
+
+        _graphicsDevice!.ProcessGLQueue();
+        while (_meshManager!.StagedMeshData.TryDequeue(out var meshData))
+        {
+            _meshManager.UploadMeshData(meshData);
+        }
+    }
+
     /// <inheritdoc/>
     public void Dispose()
     {
diff --git a/tests/AcDream.Core.Tests/Rendering/Wb/WbMeshAdapterTests.cs b/tests/AcDream.Core.Tests/Rendering/Wb/WbMeshAdapterTests.cs
index 1aaa33d..5758026 100644
--- a/tests/AcDream.Core.Tests/Rendering/Wb/WbMeshAdapterTests.cs
+++ b/tests/AcDream.Core.Tests/Rendering/Wb/WbMeshAdapterTests.cs
@@ -46,4 +46,20 @@ public sealed class WbMeshAdapterTests
         var adapter = WbMeshAdapter.CreateUninitialized();
         Assert.Null(adapter.GetRenderData(0x01000001ul));
     }
+
+    [Fact]
+    public void Tick_OnUninitializedAdapter_DoesNotThrow()
+    {
+        var adapter = WbMeshAdapter.CreateUninitialized();
+        adapter.Tick();  // no-op, no throw
+        adapter.Tick();  // idempotent
+    }
+
+    [Fact]
+    public void Tick_AfterDispose_DoesNotThrow()
+    {
+        var adapter = WbMeshAdapter.CreateUninitialized();
+        adapter.Dispose();
+        adapter.Tick();  // no-op, no throw
+    }
 }