FA-86760 / Procedural level generation constraints / Member archive

Rotated prefab stamping: Rejected stamp leaks partial tiles · case 05

A failed placement leaves half a prefab in the level.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

The prefab (rows of chars, ' ' transparent) is rotated clockwise rot times (rot taken mod 4, negative allowed) and stamped with its top-left at column ox, row oy. If any non-transparent tile would land out of bounds or on a locked 'X' tile, the stamp is rejected and the original grid returned with False; otherwise the new grid with True.

Why this case matters

Procedural generators silently emit unplayable or unfair levels when a single constraint check uses the wrong boundary, axis, neighborhood or update order; the defect is visible in exact generated geometry.

One recorded failure

Sample boundary fixture

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

Boundary fixture	Actual	Expected	Outcome
regression rejection result #1	`[["....D", ".X...", "....X", "X...#", "....."], false]`	`[["....#", ".X...", "....X", "X...#", "....."], false]`	Failed

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

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