reikhelm/.dev/2026-05-28-procgen-map-core/tasks/11-door-placer.md

Task 11: DoorPlacer Pass

Depends on: Task 6

Context Files

• .dev/2026-05-28-procgen-map-core/spec/design.md — §4.7 (Placer role), §5 (data flow).
• .dev/2026-05-28-procgen-map-core/README.md — inter-pass data contract (DoorPlacer row).
• reikhelm-core/src/pass.rs — Pass, GenContext (Task 6).
• reikhelm-core/src/map.rs, reikhelm-core/src/region.rs — Tile, Region, ConnGraph, Edge (Task 5).
• reikhelm-core/src/grid.rs — neighbor queries (Task 3).
• reikhelm-core/src/passes/mod.rs — append the module declaration here.

Files

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

What to Build

A placer (spec §4.7) that puts doors where a corridor meets a room. Scan for boundary Wall cells that sit between a room interior and a corridor (a Wall whose opposite neighbors are both Floor, one belonging to a Room region and one to a Corridor region) and convert them to Tile::Door. For each graph edge, record a representative door location into edge.at = Some(point) via ConnGraph::edges_mut() (Task 5). Use ctx.regions to distinguish room floor from corridor floor (membership by cells/bounds), and Grid neighbor queries for adjacency. Bounds-safe; idempotent enough that it won't create doors mid-corridor or mid-room.

This is the final pass; it reads ctx.tiles/ctx.regions/ctx.graph and writes Door tiles + populates edge.at. Tests construct a small room+corridor+wall layout directly.

Interface Dependencies

• Consumes: Pass, GenContext, Rng (Task 6); Tile, Region, ConnGraph, Edge (Task 5); Grid neighbor queries (Task 3).
• Produces:
  • struct DoorPlacer { /* unit or small config; Default */ } — default()/new(); impl Pass with name() == "door_placer".
  • Writes to context: Door tiles at room↔corridor boundaries; edge.at = Some(point) for connected edges.

Tests

• Given a hand-built room rect + a corridor reaching its wall (with a single wall cell between room floor and corridor floor), after running: that wall cell becomes Door.
• No Door is placed in the middle of a room or corridor (only at boundaries).
• At least one connected edge has at == Some(_) after running on a connected layout.
• Bounds-safe: never panics on doors near the map edge.
• Determinism: same input → identical door placement.

Success Criteria

• DoorPlacer converts room↔corridor boundary walls to Door and sets edge.at.
• No spurious doors inside rooms/corridors; bounds-safe.
• pub mod door; appended to passes/mod.rs.
• Tests pass: cargo test -p reikhelm-core door

Commit

"feat(core): DoorPlacer pass"