diff --git a/src/AcDream.App/Rendering/Wb/GlobalMeshBuffer.cs b/src/AcDream.App/Rendering/Wb/GlobalMeshBuffer.cs
index 3441c66a..3e2c78e2 100644
--- a/src/AcDream.App/Rendering/Wb/GlobalMeshBuffer.cs
+++ b/src/AcDream.App/Rendering/Wb/GlobalMeshBuffer.cs
@@ -1,3 +1,4 @@
+using AcDream.Content;
 using Chorizite.Core.Render.Enums;
 using Silk.NET.OpenGL;
 using System;
diff --git a/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs b/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs
index 7d9368ef..c41ab98e 100644
--- a/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs
+++ b/src/AcDream.App/Rendering/Wb/ObjectMeshManager.cs
@@ -26,118 +26,6 @@ using SixLabors.ImageSharp;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace AcDream.App.Rendering.Wb {
-    /// <summary>
-    /// Vertex format for scenery mesh rendering: position, normal, UV.
-    /// </summary>
-    [StructLayout(LayoutKind.Sequential)]
-    public struct VertexPositionNormalTexture {
-        public Vector3 Position;
-        public Vector3 Normal;
-        public Vector2 UV;
-
-        public static int Size => 8 * sizeof(float); // 3+3+2 = 8 floats = 32 bytes
-
-        public VertexPositionNormalTexture(Vector3 position, Vector3 normal, Vector2 uv) {
-            Position = position;
-            Normal = normal;
-            UV = uv;
-        }
-    }
-
-    /// <summary>
-    /// Staged data for a particle emitter to be created on the GL thread.
-    /// </summary>
-    public struct StagedEmitter {
-        public ParticleEmitter Emitter;
-        public uint PartIndex;
-        public Matrix4x4 Offset;
-    }
-
-    /// <summary>
-    /// CPU-side mesh data prepared on a background thread.
-    /// Contains vertex data and per-batch index/texture info, but NO GPU resources.
-    /// </summary>
-    public class ObjectMeshData {
-        public ulong ObjectId { get; set; }
-        public bool IsSetup { get; set; }
-        public VertexPositionNormalTexture[] Vertices { get; set; } = Array.Empty<VertexPositionNormalTexture>();
-        public List<MeshBatchData> Batches { get; set; } = new();
-
-        /// <summary>
-        /// #125 (2026-06-12): GL upload-retry counter. A failed
-        /// <see cref="ObjectMeshManager.UploadMeshData"/> (returns null from its
-        /// catch) used to be dropped permanently — the staged item was consumed,
-        /// no render data was produced, and the prepared data lingered in the CPU
-        /// cache where <c>PrepareMeshDataAsync</c>'s cache-hit short-circuit
-        /// returned it without ever re-staging it for upload (session-sticky
-        /// invisible mesh, one [wb-error] line). The drain loop now re-stages a
-        /// failed upload for the NEXT frame up to <see cref="ObjectMeshManager.
-        /// MaxUploadRetries"/> times. The counter lives on the mesh-data object so
-        /// it resets to 0 naturally whenever the id is re-prepared (fresh object),
-        /// and bounds a deterministic GL failure to a few loud lines instead of a
-        /// silent permanent drop OR an unbounded per-frame retry storm. Retail
-        /// loads content synchronously and has no such failure mode — this
-        /// converges our async pipeline toward that guarantee.
-        /// </summary>
-        public int UploadAttempts;
-
-        /// <summary>For EnvCell: the geometry of the cell itself.</summary>
-        public ObjectMeshData? EnvCellGeometry { get; set; }
-
-        /// <summary>For Setup objects: parts with their local transforms.</summary>
-        public List<(ulong GfxObjId, Matrix4x4 Transform)> SetupParts { get; set; } = new();
-
-        /// <summary>Particle emitters from physics scripts.</summary>
-        public List<StagedEmitter> ParticleEmitters { get; set; } = new();
-
-        /// <summary>Per-format texture atlas data (to be uploaded to GPU on main thread).</summary>
-        public Dictionary<(int Width, int Height, TextureFormat Format), List<TextureBatchData>> TextureBatches { get; set; } = new();
-
-        /// <summary>Local bounding box.</summary>
-        public BoundingBox BoundingBox { get; set; }
-
-        /// <summary>Approximate center point used for depth sorting / transparency ordering.</summary>
-        public Vector3 SortCenter { get; set; }
-
-        /// <summary>DataID of a simpler GfxObj to use at long distance / low quality, or GfxObjDegradeInfo.</summary>
-        public uint DIDDegrade { get; set; }
-
-        /// <summary>Sphere used for mouse selection.</summary>
-        public Sphere? SelectionSphere { get; set; }
-
-        /// <summary>Edge line vertices for Environment wireframe rendering.</summary>
-        public Vector3[] EdgeLines { get; set; } = Array.Empty<Vector3>();
-    }
-
-    /// <summary>
-    /// CPU-side data for a single rendering batch (indices + texture reference).
-    /// </summary>
-    public class MeshBatchData {
-        public ushort[] Indices { get; set; } = Array.Empty<ushort>();
-        public (int Width, int Height, TextureFormat Format) TextureFormat { get; set; }
-        public TextureKey TextureKey { get; set; }
-        public int TextureIndex { get; set; }
-        public byte[] TextureData { get; set; } = Array.Empty<byte>();
-        public PixelFormat? UploadPixelFormat { get; set; }
-        public PixelType? UploadPixelType { get; set; }
-        public DatReaderWriter.Enums.CullMode CullMode { get; set; }
-    }
-
-    /// <summary>
-    /// CPU-side texture info for deduplication during background preparation.
-    /// </summary>
-    public class TextureBatchData {
-        public TextureKey Key { get; set; }
-        public byte[] TextureData { get; set; } = Array.Empty<byte>();
-        public PixelFormat? UploadPixelFormat { get; set; }
-        public PixelType? UploadPixelType { get; set; }
-        public List<ushort> Indices { get; set; } = new();
-        public DatReaderWriter.Enums.CullMode CullMode { get; set; }
-        public bool IsTransparent { get; set; }
-        public bool IsAdditive { get; set; }
-        public bool HasWrappingUVs { get; set; }
-    }
-
     /// <summary>
     /// GPU-side render data created on the main thread.
     /// </summary>
diff --git a/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs b/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs
index 8bbdd6bd..9440ba6c 100644
--- a/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs
+++ b/src/AcDream.App/Rendering/Wb/WbMeshAdapter.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using AcDream.Content;
 using AcDream.Core.Meshing;
 using AcDream.Core.Rendering;
 using DatReaderWriter;
diff --git a/src/AcDream.Content/AcDream.Content.csproj b/src/AcDream.Content/AcDream.Content.csproj
index 768639e7..1abed36e 100644
--- a/src/AcDream.Content/AcDream.Content.csproj
+++ b/src/AcDream.Content/AcDream.Content.csproj
@@ -12,6 +12,14 @@
          exact versions (mirror AcDream.App.csproj — keep in lockstep). -->
     <PackageReference Include="BCnEncoder.Net.ImageSharp" Version="1.1.2" />
     <PackageReference Include="SixLabors.ImageSharp" Version="3.1.12" />
+    <!-- MP1a (Task 3, compiler-demanded): MeshBatchData/TextureBatchData carry
+         Silk.NET.OpenGL.PixelFormat?/PixelType? upload-format hints computed
+         during CPU extraction (which format to hand the eventual GL upload).
+         These are plain enums with no GL context/device/unsafe surface — the
+         plan's own boundary survey says the only GL-DOMAIN reference in the
+         Prepare* region is TextureAtlasManager.TextureKey; this is the same
+         class of dependency (a data-only enum), not a functional GL call. -->
+    <PackageReference Include="Silk.NET.OpenGL" Version="2.23.0" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/AcDream.Content/ObjectMeshData.cs b/src/AcDream.Content/ObjectMeshData.cs
new file mode 100644
index 00000000..8bba1e0c
--- /dev/null
+++ b/src/AcDream.Content/ObjectMeshData.cs
@@ -0,0 +1,125 @@
+using Chorizite.Core.Lib;
+using Chorizite.Core.Render.Enums;
+using DatReaderWriter.DBObjs;
+using DatReaderWriter.Types;
+using System;
+using System.Collections.Generic;
+using System.Numerics;
+using System.Runtime.InteropServices;
+using BoundingBox = Chorizite.Core.Lib.BoundingBox;
+using PixelFormat = Silk.NET.OpenGL.PixelFormat;
+using PixelType = Silk.NET.OpenGL.PixelType;
+
+namespace AcDream.Content;
+
+/// <summary>
+/// Vertex format for scenery mesh rendering: position, normal, UV.
+/// </summary>
+[StructLayout(LayoutKind.Sequential)]
+public struct VertexPositionNormalTexture {
+    public Vector3 Position;
+    public Vector3 Normal;
+    public Vector2 UV;
+
+    public static int Size => 8 * sizeof(float); // 3+3+2 = 8 floats = 32 bytes
+
+    public VertexPositionNormalTexture(Vector3 position, Vector3 normal, Vector2 uv) {
+        Position = position;
+        Normal = normal;
+        UV = uv;
+    }
+}
+
+/// <summary>
+/// Staged data for a particle emitter to be created on the GL thread.
+/// </summary>
+public struct StagedEmitter {
+    public ParticleEmitter Emitter;
+    public uint PartIndex;
+    public Matrix4x4 Offset;
+}
+
+/// <summary>
+/// CPU-side mesh data prepared on a background thread.
+/// Contains vertex data and per-batch index/texture info, but NO GPU resources.
+/// </summary>
+public class ObjectMeshData {
+    public ulong ObjectId { get; set; }
+    public bool IsSetup { get; set; }
+    public VertexPositionNormalTexture[] Vertices { get; set; } = Array.Empty<VertexPositionNormalTexture>();
+    public List<MeshBatchData> Batches { get; set; } = new();
+
+    /// <summary>
+    /// #125 (2026-06-12): GL upload-retry counter. A failed
+    /// <see cref="ObjectMeshManager.UploadMeshData"/> (returns null from its
+    /// catch) used to be dropped permanently — the staged item was consumed,
+    /// no render data was produced, and the prepared data lingered in the CPU
+    /// cache where <c>PrepareMeshDataAsync</c>'s cache-hit short-circuit
+    /// returned it without ever re-staging it for upload (session-sticky
+    /// invisible mesh, one [wb-error] line). The drain loop now re-stages a
+    /// failed upload for the NEXT frame up to <see cref="ObjectMeshManager.
+    /// MaxUploadRetries"/> times. The counter lives on the mesh-data object so
+    /// it resets to 0 naturally whenever the id is re-prepared (fresh object),
+    /// and bounds a deterministic GL failure to a few loud lines instead of a
+    /// silent permanent drop OR an unbounded per-frame retry storm. Retail
+    /// loads content synchronously and has no such failure mode — this
+    /// converges our async pipeline toward that guarantee.
+    /// </summary>
+    public int UploadAttempts;
+
+    /// <summary>For EnvCell: the geometry of the cell itself.</summary>
+    public ObjectMeshData? EnvCellGeometry { get; set; }
+
+    /// <summary>For Setup objects: parts with their local transforms.</summary>
+    public List<(ulong GfxObjId, Matrix4x4 Transform)> SetupParts { get; set; } = new();
+
+    /// <summary>Particle emitters from physics scripts.</summary>
+    public List<StagedEmitter> ParticleEmitters { get; set; } = new();
+
+    /// <summary>Per-format texture atlas data (to be uploaded to GPU on main thread).</summary>
+    public Dictionary<(int Width, int Height, TextureFormat Format), List<TextureBatchData>> TextureBatches { get; set; } = new();
+
+    /// <summary>Local bounding box.</summary>
+    public BoundingBox BoundingBox { get; set; }
+
+    /// <summary>Approximate center point used for depth sorting / transparency ordering.</summary>
+    public Vector3 SortCenter { get; set; }
+
+    /// <summary>DataID of a simpler GfxObj to use at long distance / low quality, or GfxObjDegradeInfo.</summary>
+    public uint DIDDegrade { get; set; }
+
+    /// <summary>Sphere used for mouse selection.</summary>
+    public Sphere? SelectionSphere { get; set; }
+
+    /// <summary>Edge line vertices for Environment wireframe rendering.</summary>
+    public Vector3[] EdgeLines { get; set; } = Array.Empty<Vector3>();
+}
+
+/// <summary>
+/// CPU-side data for a single rendering batch (indices + texture reference).
+/// </summary>
+public class MeshBatchData {
+    public ushort[] Indices { get; set; } = Array.Empty<ushort>();
+    public (int Width, int Height, TextureFormat Format) TextureFormat { get; set; }
+    public TextureKey TextureKey { get; set; }
+    public int TextureIndex { get; set; }
+    public byte[] TextureData { get; set; } = Array.Empty<byte>();
+    public PixelFormat? UploadPixelFormat { get; set; }
+    public PixelType? UploadPixelType { get; set; }
+    public DatReaderWriter.Enums.CullMode CullMode { get; set; }
+}
+
+/// <summary>
+/// CPU-side texture info for deduplication during background preparation.
+/// </summary>
+public class TextureBatchData {
+    public TextureKey Key { get; set; }
+    public byte[] TextureData { get; set; } = Array.Empty<byte>();
+    public PixelFormat? UploadPixelFormat { get; set; }
+    public PixelType? UploadPixelType { get; set; }
+    public List<ushort> Indices { get; set; } = new();
+    public DatReaderWriter.Enums.CullMode CullMode { get; set; }
+    public bool IsTransparent { get; set; }
+    public bool IsAdditive { get; set; }
+    public bool HasWrappingUVs { get; set; }
+}