MeshData

Remarks

The CPU side of MeshDraw. That struct holds buffer handles and a range, because it is read once per object in a frame; this holds arrays, because it is read once per build by something deciding what those buffers should contain.

Parallel arrays, and typed ones. A vertex is not a struct here, because the layout is a compile-time decision — which attributes are present, in what order, at what precision, interleaved or not — and doc 08 puts that in ModelCompiler where the whole model is in hand. Separate arrays let a compiler drop an attribute nothing samples without rewriting the ones it keeps.

An attribute the file did not have is an empty array rather than a null or a defaulted one. Empty says "this mesh has no tangents"; an array of zeros says "this mesh has tangents and they are all degenerate", and a compiler cannot tell the second from a bug in the first.

⚠ There is no vertex-colour channel and no second texture coordinate set, and that is a decision rather than an omission. Both were here — read from Assimp, serialized, round-trip tested — and both were dropped by Pack on the way to the only vertex layout the engine draws through, for the whole time they existed. An importer that carries a channel nothing draws is the worst of the three available states: it costs bytes in every mesh chunk, it reads as support in the type's own signature, and it fails silently, because a colour that never arrives looks exactly like a mesh nobody painted.

The objection that kept them undrawn was wrong, and correcting it did not make the change small. Widening SurfaceVertex was recorded as costing sixteen bytes a vertex; UNorm8X4 is four, is documented for exactly this, and translates on all three backends. What the arithmetic does not reach is the shape of the change: the interleaved stream is one of three ways a vertex attribute gets to a shader, and the other two — ModelCompiler.PageAttributes for the cluster pages, and VisibilityResolve's fetch out of them — pack their own records. A colour added to the interleaved stream alone is a mesh that is tinted until it clusters and untinted after, which is worse than not having one. Nor is the free version available: VertexChannel carries no binding index and a VertexSchema has one stride, so VertexSchema.Layout returns a single buffer by construction, and the two renderers that do bind a second stream build their VertexBufferLayout[] by hand rather than through a schema.

So the channels land with the change that needs them, and not before. Doc 31 § B3 already says which one — the per-instance record change, which is the same class of edit to the same three paths — and doc 24 § P5 records the blockout painting that wants it. Re-adding the importer half is ten lines of ModelReader; that is the cheap half, and holding it open for two phases that closed without it bought nothing. The second coordinate set does not come back with them: its headline consumer was a lightmap, and the engine's global illumination is dynamic by decision — no unwrap, no chart packing, no atlas — so a detail map or a trim sheet addressing off the first set is what is actually on offer.

Fields and properties (18)

• public string Name

  What the mesh is called. Its sub-asset name, and part of its address.

• public Vector3[] Positions

  One position per vertex.

• public Vector3[] Normals

  One normal per vertex, or empty.

• public Vector4[] Tangents

  One tangent per vertex, or empty. W is the bitangent's sign.

• public Vector2[] TexCoords

  One texture coordinate per vertex, or empty.

• public int[] Indices

  Three indices per triangle.

• public int[] BoneIndices

  Four joint indices per vertex, or empty if the mesh is not skinned.

• public float[] BoneWeights

  Four weights per vertex, summing to one, or empty.

• public int MaterialIndex

  Which of the model's materials this is drawn with.

• public BoundingBox Bounds

  Everything the mesh occupies, in the model's space.

• public AssetReference Clusters

  This mesh's cluster hierarchy and page records, or null if it has none.

• public AssetReference ClusterPages

  Where this mesh's page blob is, or null if it has no clusters.

• public MorphTargetData[] MorphTargets

  The blend shapes this mesh carries, or empty.

• public bool IsClustered

  Whether it was built with a cluster hierarchy.

• public bool IsMorphed

  Whether it carries blend shapes.

• public int VertexCount

  How many vertices it has.

• public int TriangleCount

  How many triangles it has.

• public bool IsSkinned

  Whether it carries skinning weights.

Used by (86, showing 40)

• AssetMeshSourceVixen.Engine.Renderer
• AssetVirtualGeometrySourceVixen.Engine.Renderer
• BuilderVixen.Rendering
• CompositorImageTestsVixen.Graphics.Golden.Tests
• DeferredMeshSourceVixen.Engine.Renderer.Tests
• DeferredQuadVixen.Rendering.Tests
• EditorGizmoFacingDeviceTestsVixen.Graphics.Golden.Tests
• EntryVixen.Engine.Renderer
• EveryMeshVixen.Rendering.Tests
• GeometryVixen.Rendering.Tests
• GeometryResidencyVixen.Rendering
• IMeshSourceVixen.Rendering
• MeshExtractionSystemVixen.Rendering
• MeshExtractionTestsVixen.Rendering.Tests
• MeshInstanceRendererVixen.Rendering
• MeshInstanceRendererTestsVixen.Rendering.Tests
• MeshPrimitivesVixen.Rendering
• MeshPrimitivesTestsVixen.Rendering.Tests
• MeshRenderableVixen.Rendering
• ModelDataTestsVixen.Rendering.Tests
• MorphRenderFeatureVixen.Rendering
• MorphRenderFeatureTestsVixen.Rendering.Tests
• MorphScatterDeviceTestsVixen.Graphics.Golden.Tests
• MorphedClusterTestsVixen.Rendering.Tests
• OneMeshVixen.Rendering.Tests
• OneMeshVixen.Rendering.Tests
• OneMeshVixen.Graphics.Golden.Tests
• OneMeshVixen.Rendering.Tests
• OneTriangleVixen.Rendering.Tests
• OneTriangleVixen.Rendering.Terrain.Tests
• QuadVixen.Rendering.Tests
• SurfaceGeometryVixen.Rendering
• SurfaceGeometryTestsVixen.Rendering.Tests
• TerrainSceneRendererVixen.Rendering.Terrain
• TextureDemandTestsVixen.Engine.Renderer.Tests
• TypeRegistrationVixen.Rendering
• VfxEmitterVixen.Rendering
• VfxExtractionSystemVixen.Rendering
• VirtualGeometryCasterTestsVixen.Rendering.Tests
• Vixen_Rendering_MeshDataSerializerVixen.Rendering