Add TileMapLayer.get_cell_custom_data()

[timothyqiu]

When using custom data layer, it's a nuisance to write this boilerplate code for each layer:

func is_wall(coord: Vector2i) -> bool:
    var data := map.get_cell_custom_data(coord)
    if not data:
        return true
    return data.get_custom_data("is_wall")

func get_nav_weight(coord: Vector2i) -> int:
    var data := map.get_cell_custom_data(coord)
    if not data:
        return -1
    return data.get_custom_data("nav_weight")

Despite code duplication, the code above is not that robust. get_custom_data() could return null on error, and it's not always distinguishable from actual values of the custom data layer.

I suggest making this established practice a dedicated method on TileMapLayer.

# Returns either `default` or value defined in the custom data layer.
func get_cell_custom_data(coord: Vector2i, layer_name: String, default: Variant) -> Variant:
    ERR_FAIL_COND_V(tile_set.is_null(), default)
    var layer_id = tile_set.get_custom_data_layer_by_name(layer_name)
    ERR_FAIL_COND_V(layer_id < 0, default)

    var data := get_cell_custom_data(coord)
    if not data:
        return default
    return data.get_custom_data_by_id(layer_id)

Original version

func get_cell_custom_data(coord: Vector2i, layer_name: String, default: Variant) -> Variant:
    var data := get_cell_custom_data(coord)
    if not data:
        return default
    return data.get_custom_data(layer_name)

[AThousandShips]

Did you mean to write:

func is_wall(coord: Vector2i) -> bool:
    var data := map.get_cell_tile_data(coord)
    if not data:
        return false
    return data.get_custom_data("is_wall")

And

func get_cell_custom_data(coord: Vector2i, layer_name: String, default: Variant) -> Variant:
    var data := get_cell_tile_data(coord)
    if not data:
        return default
    return data.get_custom_data(layer_name)

[timothyqiu]

Only get_cell_custom_data(), as said in title.

[AThousandShips]

You mention writing boilerplate but that method doesn't exist?

[timothyqiu]

Maybe there's something wrong with my English 😄

I mean, for example, my tile map have three custom data layers: is_wall, is_destination, and nav_weight.

I have to write three functions in order to access data, and these functions are very similar:

func is_wall(coord: Vector2i) -> bool:
    var data := map.get_cell_tile_data(coord)
    if not data:
        return false
    return data.get_custom_data("is_wall")

func is_destination(coord: Vector2i) -> bool:
    var data := map.get_cell_tile_data(coord)
    if not data:
        return false
    return data.get_custom_data("is_destination")

func get_nav_weight(coord: Vector2i) -> float:
    var data := map.get_cell_tile_data(coord)
    if not data:
        return INF
    return data.get_custom_data("nav_weight")

These helper methods are needed because "data" might be missing on some cells. It's even recommended in the documentation of get_cell_tile_data().

Providing get_cell_custom_data() elimates the need of making such helper methods.

[AThousandShips]

So what would map.get_cell_custom_data(coord) return? A special type?

[timothyqiu]

It returns Variant, the same as TileData.get_custom_data().

The actual type depends on the data type of that custom data layer.