API Reference — dna/layers/GeometryReader

class DNAAPI GeometryReader : public virtual DefinitionReader

Read vertex data (positions and texture coordinates) of the meshes in a rig, without modifying it.

When to use this

Use it to read mesh geometry from a loaded DNA. Use getVertexPosition for convenient per-vertex access. Use the getVertexPositionXs, Ys and Zs accessors for performance-critical bulk access. If you need to write or patch geometry data, use GeometryWriter instead.

Method groups

Group Methods
VertexPosition getVertexPositionCount, getVertexPosition, getVertexPositionXs, getVertexPositionYs, getVertexPositionZs
VertexTextureCoordinate 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. Position in the zero-indexed array of meshes. Must be less than getMeshCount.
vertexIndex std::uint32_t required. Position in the zero-indexed array of vertex positions. Must be less than getVertexPositionCount.

Returns

Position, ConstArrayView<float> or std::uint32_t, depending on the method. These are a vertex position, a view over all X, Y or Z values of a mesh, and an element count.

Constraints

  • meshIndex must be less than the value returned by getMeshCount.
  • vertexIndex must be less than the value returned by getVertexPositionCount.
  • Vertices are sorted by vertex ID.

Watch out for

  • Implementors should inherit from Reader itself, not this class.
  • The destructor is protected, so you cannot delete an instance through a GeometryReader pointer.
  • 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.