C Specification

When submitting depth images along with projection layers, add the XrCompositionLayerDepthInfoKHR to the next chain for all XrCompositionLayerProjectionView structures in the given layer.

The XrCompositionLayerDepthInfoKHR structure is defined as:

// Provided by XR_KHR_composition_layer_depth
typedef struct XrCompositionLayerDepthInfoKHR {
    XrStructureType        type;
    const void*            next;
    XrSwapchainSubImage    subImage;
    float                  minDepth;
    float                  maxDepth;
    float                  nearZ;
    float                  farZ;
} XrCompositionLayerDepthInfoKHR;

Members

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.

  • subImage identifies the depth image XrSwapchainSubImage to be associated with the color swapchain. The swapchain must have been created with a XrSwapchainCreateInfo::faceCount of 1.

  • minDepth and maxDepth are the window space depths that correspond to the near and far frustum planes, respectively. minDepth must be less than maxDepth. minDepth and maxDepth must be in the range [0, 1].

  • nearZ and farZ are the positive distances in meters to the near and far frustum planes, respectively. nearZ and farZ must not be equal. nearZ and farZ must be in the range (0, +infinity].

Description

Note

The window space depth values minDepth and maxDepth are akin to the parameters of glDepthRange that specify the mapping from normalized device coordinates into window space.
Note

A reversed mapping of depth, such that points closer to the view have a window space depth that is greater than points further away can be achieved by making nearZ > farZ.

XrCompositionLayerDepthInfoKHR contains the information needed to associate depth with the color information in a projection layer. When submitting depth images along with projection layers, add the XrCompositionLayerDepthInfoKHR to the next chain for all XrCompositionLayerProjectionView structures in the given layer.

The homogeneous transform from view space z to window space depth is given by the following matrix, where a = minDepth, b = maxDepth, n = nearZ, and f = farZ.

windowFromView
Figure 1. Homogeneous transform from view space to window space depth

Homogeneous values are constructed from real values by appending a w component with value 1.0.

General homogeneous values are projected back to real space by dividing by the w component.

Valid Usage (Implicit)

See Also

XR_KHR_composition_layer_depth, XrCompositionLayerBaseHeader, XrCompositionLayerProjection, XrCompositionLayerProjectionView, XrFrameEndInfo, XrStructureType, XrSwapchainSubImage, xrEndFrame

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 2014-2024, The Khronos Group Inc.

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