C Specification

The XrLipExpressionDataBD structure is defined as:

// Provided by XR_BD_facial_simulation
typedef struct XrLipExpressionDataBD {
    XrStructureType    type;
    void*              next;
    uint32_t           lipsyncExpressionWeightCount;
    float*             lipsyncExpressionWeights;
} XrLipExpressionDataBD;
Member Descriptions

  • type is the XrStructureType of this structure.

  • next is NULL or a pointer to the next structure in a structure chain. No such structures are defined in core OpenXR or this extension.

  • lipsyncExpressionWeightCount is a uint32_t describing the count of elements in lipsyncExpressionWeights array.

  • lipsyncExpressionWeights is a array of float that will be filled with weights of lip expression blend shapes.

Members

The XrLipExpressionDataBD structure contains the lip expression blend weights. See XrFacialSimulationModeBD for details and for how this interacts with facial expression tracking.

Description

If an application creates XrFaceTrackerBD by calling xrCreateFaceTrackerBD using the mode XR_FACIAL_SIMULATION_MODE_COMBINED_AUDIO_WITH_LIP_BD or the mode XR_FACIAL_SIMULATION_MODE_ONLY_AUDIO_WITH_LIP_BD, meaning the application wants to get the lip expression in XrLipExpressionBD, the application must chain an XrLipExpressionDataBD to XrFacialSimulationDataBD::next when calling xrGetFacialSimulationDataBD. If no structure containing lip data is passed, the structure on this chain will be ignored.

The runtime must return lipsyncExpressionWeights representing the weights of the blend shapes of the current lip expression.

The runtime must update the lipsyncExpressionWeights array ordered so that it is indexed using the corresponding lip expression enum XrLipExpressionBD.

An application must preallocate the output lipsyncExpressionWeights array that can contain at least lipsyncExpressionWeightCount of float. lipsyncExpressionWeightCount must be XR_LIP_EXPRESSION_COUNT_BD.

Valid Usage (Implicit)

See Also

XR_BD_facial_simulation, XrStructureType

Document Notes

For more information, see the OpenXR Specification

This page is extracted from the OpenXR Specification. Fixes and changes should be made to the Specification, not directly.

Copyright

Copyright 2014-2025 The Khronos Group Inc.

This work is licensed under a Creative Commons Attribution 4.0 International License.