reikhelm/.dev/2026-05-28-procgen-map-core/tasks/10-corridor-carver.md

Task 10: CorridorCarver Pass

Depends on: Task 6

Context Files

• .dev/2026-05-28-procgen-map-core/spec/design.md — §4.7 (Connector role), §5 (data flow).
• .dev/2026-05-28-procgen-map-core/README.md — inter-pass data contract (CorridorCarver row).
• reikhelm-core/src/pass.rs — Pass, GenContext (Task 6).
• reikhelm-core/src/region.rs, reikhelm-core/src/map.rs — ConnGraph, Region, RegionKind::Corridor, Tile::Floor.
• reikhelm-core/src/geometry.rs — Line, Point (Task 2).
• reikhelm-core/src/passes/mod.rs — append the module declaration here.

Files

• Create: reikhelm-core/src/passes/corridor.rs — CorridorCarver.
• Modify: reikhelm-core/src/passes/mod.rs — append pub mod corridor; and re-export CorridorCarver.

What to Build

A connector (spec §4.7) that physically carves the connections chosen by MstConnect. For each edge in ctx.graph, carve an L-shaped corridor (one horizontal run + one vertical run, joined at an elbow; randomize which leg comes first) of Tile::Floor between the two rooms' centers. Append a Region { kind: Corridor, .. } describing each carved corridor's cells. All grid writes go through bounds-safe accessors (never panic). Carving over an existing Floor cell is fine (corridors may pass through or merge).

This pass does not set door tiles or edge.at — that's DoorPlacer. It reads ctx.graph + Room region centers and writes ctx.tiles + Corridor regions. Tests construct the precondition (rooms + a graph) directly.

Interface Dependencies

• Consumes: Pass, GenContext, Rng (Task 6); ConnGraph, Region, Tile (Task 5); Line, Point (Task 2).
• Produces:
  • struct CorridorCarver { /* unit or small config; Default */ } — default()/new(); impl Pass with name() == "corridor_carver".
  • Writes to context: Floor corridors in ctx.tiles; one Corridor region per edge.

Tests

• Given two rooms (carved Floor rects) and one graph edge between them, after running: a contiguous Floor path connects the two room interiors (verify by flood-fill: both room centers are in the same connected floor component).
• An L-corridor's cells are all in-bounds; carving never panics even if a center is near the map edge.
• One Corridor region is added per edge.
• Determinism: same seed/sub-stream → identical carved corridors.

Success Criteria

• CorridorCarver carves L-shaped Floor corridors for every graph edge and adds Corridor regions; rooms become floor-connected.
• Bounds-safe; sets no doors and does not touch edge.at.
• pub mod corridor; appended to passes/mod.rs.
• Tests pass: cargo test -p reikhelm-core corridor

Commit

"feat(core): CorridorCarver pass"