FA-86668 / Procedural level generation constraints / Member archive

Wall autotile bitmask: Floors look like isolated pillars · case 03

Floor cells receive the isolated-wall sprite.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

For each '#' cell the mask sums N=1, E=2, S=4, W=8 for 4-neighbours that are '#' (row 0 is north). Out-of-bounds neighbours count as walls when same_oob. Non-wall cells get -1. Returns rows of integers.

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
door next to wall #1	`[[0, 0]]`	`[[0, -1]]`	Failed

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