The XR_VARJO_composition_layer_depth_test extension.

This extension enables depth-based layer composition inside the compositor.

Core OpenXR specifies that layer compositing must happen in the layer submission order (as described in Compositing). However, an application may want to composite the final image against the other layers based on depth information for proper occlusion. Layers can now provide depth information that will be used to calculate occlusion between those layers, as well as with the environment depth estimator (XR_VARJO_environment_depth_estimation) when enabled.

This extension defines a new type, XrCompositionLayerDepthTestVARJO, which can be chained to XrCompositionLayerProjection in order to activate this functionality. An application must also specify a range where depth testing will happen, potentially covering only a subset of the full depth range.