DepthProbe

The depth of the G-buffer at up to kCapacity pixels, in one draw and one readback (field-presentation §FVL-5, matrix FVW-60).

In the namespace construct::rendering. Declared in src/libs/libconstruct/construct/rendering/DepthProbe.hpp.

Detailed description

A D32F depth texture cannot be read back on OpenGL (§VPP-5, matrix C3), so the probe draws one fragment per pixel into an N x 1 R32F color target: each fragment samples the depth at its pixel's texel. The readback of N texels completes with the frame, so a caller reads the answer one frame late, with no stall.

The anchored labels use it to dim a marker that a surface hides (occludedAnchors()). The worker viewport records it in the producer's frame, the inline one before its final blit.