Godot Tilemap Agent Skill

Godot TileMap (4.3+ TileMapLayer)

Author tile-based levels with TileMapLayer + TileSet, add per-tile collision and

custom data, autotile with terrains, and manipulate cells at runtime. Targets

Godot 4.3+, where TileMapLayer replaces the now-deprecated TileMap node.

When to use

• Use when designing 2D levels from a tile grid, configuring a TileSet (collision,

navigation, custom data, terrains), or reading/writing tiles from code.

• Use when migrating a TileMap node (single node, many layers) to multiple

TileMapLayer nodes (one layer each).

When *not* to use: moving the player across the tiles → godot-2d-movement; general

physics bodies/raycasts → godot-physics; procedural map *generation* algorithms →

procedural-gen; level *design* practice → level-design.

Core workflow

• Add a TileMapLayer node (one per visual/logical layer: background, walls,

foreground). Each holds exactly one layer of tiles.

• Create or assign a TileSet on the layer's tile_set property. Add an atlas

source (a texture sliced into tiles) in the TileSet editor. Save the TileSet as an

external .tres so multiple layers/levels reuse it.

• Add tile data in the TileSet editor: physics layers (collision polygons),

navigation layers, occlusion, and custom data layers (typed per-tile values like

damage or is_ladder).

• Paint in the TileMap bottom panel (Paint/Line/Rectangle/Bucket). For self-

connecting tiles, define a terrain set and paint with Connect/Path mode.

• Enable per-layer collision/navigation via the layer's collision_enabled /

navigation_enabled properties.

• Read/write from code with local_to_map, set_cell, get_cell_source_id, and

get_cell_tile_data(...).get_custom_data(...).

Patterns

1. Convert mouse position to a cell and read its custom data

extends TileMapLayer

func _unhandled_input(event: InputEvent) -> void:
    if event is InputEventMouseButton and event.pressed:
        # local_to_map expects local coords; convert from global first.
        var cell := local_to_map(to_local(event.position))
        var data := get_cell_tile_data(cell)   # TileData or null
        if data:
            var dmg: int = data.get_custom_data("damage")  # custom data layer
            print("Cell %s deals %d damage" % [cell, dmg])

2. Place and erase tiles at runtime

# set_cell(coords, source_id, atlas_coords, alternative_tile = 0)
func place_wall(cell: Vector2i) -> void:
    set_cell(cell, 0, Vector2i(2, 1))   # source 0, atlas tile at column 2, row 1

func dig(cell: Vector2i) -> void:
    erase_cell(cell)                    # same as set_cell(cell, -1)

func clear_level() -> void:
    clear()                             # remove every tile on this layer

3. Autotiling a region with a terrain set

# Paint a filled area with terrain `terrain` of terrain set `terrain_set`;
# Godot picks the correct edge/corner tiles to connect them.
func fill_with_grass(cells: Array[Vector2i]) -> void:
    var terrain_set := 0
    var grass_terrain := 0
    set_cells_terrain_connect(cells, terrain_set, grass_terrain, true)

4. Iterate placed tiles (e.g. find all spawn tiles)

func find_spawns() -> Array[Vector2i]:
    var spawns: Array[Vector2i] = []
    for cell in get_used_cells():
        var data := get_cell_tile_data(cell)
        if data and data.get_custom_data("is_spawn"):
            spawns.append(cell)
    return spawns

Pitfalls

• TileMap node is deprecated in 4.3. Use TileMapLayer nodes (one layer per node);

group them under a parent Node2D. Old TileMap calls that took a layer argument

(set_cell(layer, ...)) do not apply to TileMapLayer.

• local_to_map needs local coordinates. Mouse/global positions must be converted

with to_local(...) first, or cells will be offset.

• get_cell_tile_data returns null for empty cells or non-atlas sources — always

null-check before get_custom_data.

• Custom data is typed. A layer declared as int returns int; reading it as the

wrong type or referencing a non-existent layer name errors. Define the layer in the

TileSet first.

• Terrains need every combination defined. set_cells_terrain_connect produces odd

results if the TileSet's terrain bitmask peering is incomplete.

• Runtime edits are batched to end-of-frame. If you must read updated internals

immediately after set_cell, call update_internals() (expensive — avoid in loops).

• Collision not working? Check the layer's collision_enabled, that the tile has a

physics layer with a polygon, and that the TileSet's physics layer mask matches your

bodies.

References

• For TileSet setup (atlas sources, physics/navigation/custom-data layers, terrain

bitmasks), scene tiles, Y-sorting, and runtime tile-data overrides

(_use_tile_data_runtime_update), read references/tileset-and-terrains.md.

Related skills

• godot-2d-movement — characters that walk on these tiles.
• godot-physics — collision layers/masks the tile collisions participate in.
• procedural-gen — generating tilemaps from noise/RNG.
• level-design / roguelike — design practice and grid-based genres.