API Reference — dna/layers/DefinitionReader

---

class DNAAPI DefinitionReader : public DescriptorReader

Read the rig's static data: GUI and raw control names, joint names, per-LOD joint indices and the joint hierarchy.

Read-only interface to the rig's static definition data — controls, joints, blend shape channels, animated maps, meshes, and neutral joint transforms.

When to use this

Use this when you need to query the structural definition of a DNA rig without modifying it. Reach for DefinitionWriter when you need to write or replace any of these same attributes.

Method groups

Group	Methods
GUI Controls	getGUIControlCount, getGUIControlName
Raw Controls	getRawControlCount, getRawControlName
Joints	getJointCount, getJointName, getJointIndexListCount, getJointIndicesForLOD, getJointParentIndex
Blend Shape Channels	getBlendShapeChannelCount, getBlendShapeChannelName, getBlendShapeChannelIndexListCount, getBlendShapeChannelIndicesForLOD
Animated Maps	getAnimatedMapCount, getAnimatedMapName, getAnimatedMapIndexListCount, getAnimatedMapIndicesForLOD
Meshes	getMeshCount, getMeshName, getMeshIndexListCount, getMeshIndicesForLOD
Mesh-Blend Shape Mappings	getMeshBlendShapeChannelMappingCount, getMeshBlendShapeChannelMapping, getMeshBlendShapeChannelMappingIndicesForLOD
Neutral Joint Transforms	getNeutralJointTranslation, getNeutralJointTranslationXs, getNeutralJointTranslationYs, getNeutralJointTranslationZs, getNeutralJointRotation, getNeutralJointRotationXs, getNeutralJointRotationYs, getNeutralJointRotationZs

Example

// Iterate GUI control names
std::uint16_t guiCount = def->getGUIControlCount();
for (std::uint16_t i = 0; i < guiCount; ++i) {
    StringView name = def->getGUIControlName(i);  // valid until next DNA call
}

// Collect LOD-0 joint names using the joint index list
ConstArrayView<std::uint16_t> lod0Joints = def->getJointIndicesForLOD(0);
for (std::uint16_t idx : lod0Joints) {
    StringView jointName = def->getJointName(idx);
    std::uint16_t parentIdx = def->getJointParentIndex(idx);  // same as idx for root
}

// Resolve mesh-blend shape mappings at LOD 1
ConstArrayView<std::uint16_t> mappingIndices =
    def->getMeshBlendShapeChannelMappingIndicesForLOD(1);
for (std::uint16_t mi : mappingIndices) {
    MeshBlendShapeChannelMapping m = def->getMeshBlendShapeChannelMapping(mi);
    // m.meshIndex, m.blendShapeChannelIndex
}

Parameters

Name	Type	Description
index	std::uint16_t	required. Position in the zero-indexed name array. Must be less than the matching count.
lod	std::uint16_t	required. Level of detail. Must be less than getLODCount.

Returns

StringView over a name, or ConstArrayView<std::uint16_t> over joint indices.

Watch out for

• The joint hierarchy can be rebuilt from the parent-index array. For names [A..I] and hierarchy [0, 0, 0, 1, 1, 4, 2, 6, 2], A is the root, B and C are its children, and so on.
• Do not inherit from DefinitionReader directly — inherit from Reader instead. Inheriting from DefinitionReader bypasses required Reader infrastructure and produces an incomplete implementation.
• Every index-based accessor (getGUIControlName, getJointName, getBlendShapeChannelName, etc.) requires the index to be strictly less than its corresponding count return value. Passing an out-of-range index is undefined behavior; always guard with the count accessor first.
• The *IndexListCount methods (getJointIndexListCount, getBlendShapeChannelIndexListCount, getMeshIndexListCount, getAnimatedMapIndexListCount) are meaningful only in the context of DefinitionWriter. Do not use them to iterate LOD-filtered data — use the corresponding *IndicesForLOD methods instead.
• getJointParentIndex returns UINT16_MAX for out-of-bounds requests, and returns the same index as the input for the root joint (index 0). Check for both sentinel values when traversing the joint hierarchy.
• Blend shape channel LOD indices from getBlendShapeChannelIndicesForLOD are not interchangeable with LOD values from BehaviorReader::getBlendShapeChannelLODs.
• The bulk scalar accessors (getNeutralJointTranslationXs, getNeutralJointRotationYs, etc.) are advanced, performance-critical APIs. For general use, prefer getNeutralJointTranslation and getNeutralJointRotation.

MeshBlendShapeChannelMapping

Mapping that associates a blend shape channel with its mesh.

Why this exists

Blend shape channels in the DNA layer are stored as a flat list with no intrinsic grouping by mesh. This struct provides the explicit pairing needed to reconstruct which channels belong to which mesh, enabling O(1) lookup of mesh ownership per channel. It is the element type returned by getMeshBlendShapeChannelMapping and indexed through getMeshBlendShapeChannelMappingIndicesForLOD when iterating LOD-filtered mappings.

A blend shape channel is identified by an index, and that index alone does not say which mesh it belongs to. This struct pairs the two indices so the association is explicit.

Fields

Name	Type	Description
meshIndex	std::uint16_t	required. Index of the mesh.
blendShapeChannelIndex	std::uint16_t	required. Index of the blend shape channel belonging to that mesh.

Relationships

• DefinitionReader — declared in the same header as the Reader layer for rig static data
• DefinitionReader — produces values of this type via getMeshBlendShapeChannelMapping and getMeshBlendShapeChannelMappingIndicesForLOD