FA-86739 / Procedural level generation constraints / Member archive

Rotated prefab stamping: Negative rotations are ignored · case 04

Counter-clockwise requests leave prefabs unrotated.

Member previewVariant 4 · 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
counter-clockwise turn #1	`[["#..", "..."], true]`	`[["...", "#.."], true]`	Failed

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

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