ReferenceImageLayer

Draws the reference images of a Construct: one textured quad each, double-sided, depth-tested without depth write, blended back to front (construct-reference-images §CRID-5).

Declared in src/libs/libconstruct/construct/layers/ReferenceImageLayer.hpp.

Detailed description

It sits after ExportBoundsLayer and before the gizmos, the last scene layer before the overlays, so every opaque layer has written the main pass depth. The side of a quad is decided in the fragment shader from geometry, never from gl_FrontFacing: the winding and the clip-space Y convention differ per backend (windows-field-defects §WFD-RL-72). A reference with no pixels (a missing file, a decode in flight) draws the tinted placeholder of §CRID-6c.

Every QRhi resource is created and uploaded in prepareResources(), outside the pass (§WFD-C1); renderPre() only records draws.