FA-51522 / Raster clipping / Member archive

Ranked alpha clip coverage: geometry combine · case 02

Geometric coverage is unioned with alpha coverage instead of constraining it.

Member previewVariant 2 · 3 implementations · 11 checks per implementation

Case contract

Each command supplies alpha numerator over denominator, a permutation ranking the physical samples, rotation, geometric sample mask, fixed enable mask and optional shader mask. Alpha selects floor(alpha*size) ranks, clamped to [0,size]; alpha-disabled commands select all ranks. Rotate selected physical sample IDs modulo size, then intersect masks. A missing shader mask passes all samples; an explicit empty mask passes none. Return sorted surviving sample IDs.

Why this case matters

Raster clip state can leak coverage across draws even when every individual region is valid.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
explicit sequence 0	`[[0, 1, 2, 3, 4]]`	`[[0, 1]]`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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