Translating to/from World coordinates?

[shanesveller]

Good morning, and thanks for the awesome crate! Does bevy_ecs_tilemap have any functionality to translate world coords to tilemap coords? At least for the trivial top-down squares style? I see some chatter in the issues that things like hexagons/isometric pose significant challenges, which I can easily believe.

[MrGVSV]

If your map's origin is (0.0, 0.0) and you're only concerned about basic top-down square tiles, then you should be able to just divide your world coordinates by your tile size (rounded down).

let tile_size = 32.0;
let tile_pos = (coords / tile_size).as_uvec();

For a tile size of 32.0, this should map like:

World	Tile
(0.0, 0.0)	(0, 0)
(32.0, 0.0)	(1, 0)
(63.0, 0.0)	(1, 0)
(65.0, 32.0)	(2, 1)

---

Edit: Sorry math was completely wrong lol, should be fixed now.

[shanesveller]

Appreciate it, will mark as answered when I get a chance to test this. Thanks!

[StarArawn]

when you call as_uvec I believe it just drops the decimal numbers instead of rounding or flooring. In my opinion you should probably floor the coordinates as well, but you might find round or ceil to work better depending on your use case.

[bzm3r]

@shanesveller We have now provided a whole bunch of stuff to handle calculating tile position. See:

bevy_ecs_tilemap/examples/mouse_to_tile.rs

Line 372 in eabd66e

TilePos::from_world_pos(&cursor_in_map_pos, map_size, grid_size, map_type)

And:

bevy_ecs_tilemap/examples/mouse_to_tile.rs

Line 257 in eabd66e

let tile_center = tile_pos.center_in_world(&grid_size, &map_type).extend(1.0);