FA-86534 / Procedural level generation constraints / Member archive

BSP dungeon partition: Square regions always split vertically · case 04

BSP layouts are biased to vertical slices.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Recursively split the rectangle while depth remains. An axis can be split when that side is >= 2*min_size; if neither can, it is a leaf. Split vertically when w > h, or when w == h at even remaining depth; if the chosen axis cannot be split use the other. The first child gets floor(side/2). Returns leaves [x, y, w, h] in left/top-first order.

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 orientation choice #1	`[[3, 1, 3, 2], [3, 3, 3, 2], [6, 1, 3, 2], [6, 3, 3, 2], [9, 1, 3, 2], [9, 3, 3, 2], [12, 1, 2, 4], [14, 1, 2, 4], [16, 1, 3, 2], [16, 3, 3, 2], [19, 1, 3, 2], [19, 3, 3, 2], [22, 1, 3, 2], [22, 3, 3, 2], [25, 1, 2, 4], [27, 1, 2, 4]]`	`[[3, 1, 3, 2], [3, 3, 3, 2], [6, 1, 3, 2], [6, 3, 3, 2], [9, 1, 3, 2], [9, 3, 3, 2], [12, 1, 4, 2], [12, 3, 4, 2], [16, 1, 3, 2], [16, 3, 3, 2], [19, 1, 3, 2], [19, 3, 3, 2], [22, 1, 3, 2], [22, 3, 3, 2], [25, 1, 4, 2], [25, 3, 4, 2]]`	Failed

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

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