API Reference — dna/layers/GeometryReader

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class GeometryReader : public virtual DefinitionReader

Access all geometry data — vertex positions, texture coordinates, and related mesh data — for a rig's meshes. This is the read-only side of the geometry layer; pair it with GeometryWriter when you need to modify mesh data.

When to use this

Use this when you need to inspect or export mesh geometry from a DNA asset — vertex positions, UV sets, or per-mesh data — without modifying it. If you need to write or patch geometry data, use GeometryWriter instead. Do not inherit from GeometryReader directly; the class requires implementors to inherit from Reader itself.

Method groups

Group	Methods
Vertex positions	getVertexPositionCount, getVertexPosition, getVertexPositionXs, getVertexPositionYs, getVertexPositionZs
Texture coordinates	getVertexTextureCoordinateCount

Example

// Obtain a GeometryReader via a concrete reader (e.g. BinaryStreamReader)
dna::BinaryStreamReader* reader = /* ... */;

// Vertex count for mesh 0
std::uint32_t vCount = reader->getVertexPositionCount(0);

// Read individual vertex positions (convenient path)
for (std::uint32_t i = 0; i < vCount; ++i) {
    dna::Position pos = reader->getVertexPosition(0, i);
    // pos.x, pos.y, pos.z
}

// Bulk read all X values for mesh 0 (performance-critical path)
dna::ConstArrayView<float> xs = reader->getVertexPositionXs(0);
// xs[i] == X coordinate of the i-th vertex

Parameters

Name	Type	Description
meshIndex	std::uint16_t	required — zero-based mesh index. Must be less than getMeshCount().
vertexIndex	std::uint32_t	required — zero-based vertex index within the mesh. Must be less than getVertexPositionCount(meshIndex). Vertices are ordered by vertex ID.

Watch out for

• meshIndex and vertexIndex are not bounds-checked. Passing an out-of-range value is undefined behavior — always validate against getMeshCount() and getVertexPositionCount() first.
• getVertexPositionXs, getVertexPositionYs, and getVertexPositionZs return a ConstArrayView<float> — a non-owning view. The view is only valid while the underlying DNA data object is alive.
• Do not inherit from GeometryReader directly. The class-level @warning requires implementors to inherit from Reader itself, not from this interface.