triangle-object-positions-without-allow-data-access-flag
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/triangle-object-positions-without-allow-data-access-flag.md contains the canonical detection logic + GPU reasoning.
TL;DR
TriangleObjectPositions() requires the underlying acceleration structure to have been built with D3D12_RAYTRACING_GEOMETRY_FLAG_USE_ORIENTED_BOUNDING_BOX (D3D12) or VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_DATA_ACCESS_BIT_KHR (Vulkan). Without the flag, the call is undefined behaviour: drivers may return garbage positions, segfault, or silently fall back to an older BVH layout.
What the rule fires on
Every call site of TriangleObjectPositions() (SM 6.10 ray-tracing intrinsic). Project-side state (the BLAS-build flag) is invisible from shader source, so the rule fires on every call site as a reminder.
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 triangle-object-positions-without-allow-data-access-flag.md -> Examples.
See also
- Rule page -- canonical reference + change log.
- dxr overview -- broader context.
- ADR 0018 -- v1.0 readiness plan.
This is a v1.0-ship stub. Full analysis pending; track issue link TBD.