Godot: How to limit player movement to certain tiles only? - game-engine

Question

I'm trying to make a 'Stone Age' clone.
And I'm trying to figure a way to limit my player movement to certain tiles. Meaning that a player can move only on certain tiles.
What I did so far is make two TileMaps one for 'walk-able floor' and one for 'un walk-able floor'. I put them on different collision layers and I have my player only collide with the 'un walk-able floor'. So the player is prevented from entering it:
Here (https://i.imgur.com/sPGCS0V.png): The walkable floor is the brown tiles and the unwalkable are the ones that say 'FLOOR'.
This method is a problem because I have platforms I want to move my player on. (The tiles with the arrows on them) But If all the background is unwalkable, my player will collide with it when he'll be on a platform, so he won't be able to use the platforms to move...
Is there a better way to do this?

Answer 1

I found a solution on this guide and slightly modified it. In a nutshell the solution is to use ray-cast in the direction of the movement and see if there is a collision.
What I did was create a tilemap and call all the tiles that allow player movement 'walkable_[something]'. In the player script where I detect the collision from the ray cast I check the name of the tile the raycast collided with. If the name begins with 'walkable' I allow movement and in all other cases I don't.
onready var ray = $RayCast2D
var speed = 256 # big number because it's multiplied by delta
var tile_size = 64 # size in pixels of tiles on the grid
var last_position = Vector2() # last idle position
var target_position = Vector2() # desired position to move towards
var movedir = Vector2() # move direction
func _process(delta):
# MOVEMENT
if ray.is_colliding():
var collision = ray.get_collider()
if collision is TileMap:
var tile_name = get_tile(collision)
if !(tile_name.begins_with("Walkable")):
position = last_position
target_position = last_position
else:
position += speed * movedir * delta
if position.distance_to(last_position) >= tile_size - speed * delta: # if we've moved further than one space
position = target_position # snap the player to the intended position
else:
position += speed * movedir * delta
if position.distance_to(last_position) >= tile_size - speed * delta: # if we've moved further than one space
position = target_position # snap the player to the intended position
This is the get_tile() function, it gets the string name of the tile the ray cast collided with. Because the raycast collision returns the whole tile map we need to know which specific tile we collided with. So I used the position of the player + the direction of the ray cast vector to figure out the correct tile. First I added half a tile in width and height of a tile size because the player position is considered the top left corner of the player node. For example if the player is a square of size 2x2 and he's positioned on (0,0). It means it's top left corner is on 0,0. Which means that 1,1 is the center of the square.
func get_tile(tile_map):
if tile_map is TileMap:
var v = Vector2(tile_size / 2 , tile_size /2)
var tile_pos = tile_map.world_to_map(position + v + ray.cast_to)
var tile_id = tile_map.get_cellv(tile_pos)
if (tile_id == -1):
return "None"
else:
return tile_map.tile_set.tile_get_name(tile_id)
For the sake of completion here is a pastebin of the full player script.