vrs-without-perprimitive-or-screenspace-source
Status: stub. The full-length analysis is queued for a v1.0.x patch release per ADR 0018, section 5, criterion #6. The companion rule page at docs/rules/vrs-without-perprimitive-or-screenspace-source.md contains the canonical detection logic + GPU reasoning.
TL;DR
PS-emitted VRS rates without an upstream source are silently ignored on most IHVs (Turing+, RDNA 2+, Battlemage). The shading-rate signal needs a combiner pair: per-pixel + per-primitive (or per-pixel + screen-space). A PS that emits a rate without a peer signal is dead code from the rasterizer's perspective.
What the rule fires on
A pixel-shader entry point that emits SV_ShadingRate but the source contains no upstream VRS source ([earlydepthstencil], per-primitive coarse-rate hint, or screen-space VRS image).
See the What it detects section of the rule page for the full pattern definition.
Why it matters
The full GPU-mechanism analysis lives in the Why it matters on a GPU section of the companion rule page.
Examples
The bad / good code snippets are kept canonical on the rule page; see vrs-without-perprimitive-or-screenspace-source.md -> Examples.
See also
- Rule page -- canonical reference + change log.
- vrs overview -- broader context.
- ADR 0018 -- v1.0 readiness plan.
This is a v1.0-ship stub. Full analysis pending; track issue link TBD.