Comparing Tile Types doesn't seem to work accurately. What am I doing wrong?

UnknownUser

So I'm working on a small 2d project, in which I procedurally generate a 2d tilemap of caves using cellular automata. It's my first time ever doing this, but I'm proud of the results:

Every time the scene is loaded, the cave system is procedurally generated again. However, an empty cave isn't really fun to explore. My plan was to detect the top edges of the black tiles, and have a percent chance to spawn coins or something.

What I tried to do was detect if a tile was black and had a white tile above it, and return true. Then I would instance something on or above that tile. It boils down to two functions: `func SpawnLoot():

var temp = loot1.instance()

for i in range(Mwidth):
	for j in range(1, Mheight):
		if (i < Mwidth and j < Mheight):
			if (isUpClear(Vector2(i,j))):
				add_child(temp.duplicate())
				temp.set_position(map_to_world(Vector2(i,j)) + cell_size/2)

func isUpClear(var pos): var bottom = get_cellv(Vector2(pos.x,pos.y)) var top = get_cellv(Vector2(pos.x,pos.y-1))

if (bottom == 1 and top == 0):
	return true
return false

` What I expect for the moment is just instancing my green loot block on every black tile with a white tile above it. However, the output is this:

I can't figure out any rhyme or reason as to why it results like this. It's different every time I load the scene, but doesn't seem to result in a way that's related to how the tiles have generated.

Am I misunderstanding something fundamental here? Halp plz :(

vinpogo

actually i dont see any issues with your code... Maybe this solution works?

for cell_position in {yourTileMapInstance}.get_used_cells():
	var current_tile = get_cellv(cell_position)
	var tile_above = get_cellv(Vector2(cell_position.x, cell_position.y -1))
	if current_tile == {BLACK_TILE_INDEX} and tile_above == {WHITE_TILE_INDEX}:
		spawn_coin()

the only difference is that if your tilemap is offsetted, then this code should also work, because you acces the used_cells directly

UnknownUser

I'm afraid this didn't work, @vinpogo :( Using your code, the output results as:

(Ignore the fact that the tiles are now blue- I just swapped out the sprites)

Megalomaniak

Well, compared to the previous result it's clearly a significant improvement.

vinpogo

Hm... Are your sure your run this algorithm after your map is fully generated? Maybe you set the wrong position on your loot instance?

You can try to first spawn a loot instance on every black tile. If that works, try to shift them all 1 tile up. If that works try only doing it when the tile above is white. And if that works, add your probability. Might be easier this way to find out what exactly goes wrong.

UnknownUser

Alright, I figured it out! It's a convoluted work-around / hackjob... but it works!

1) I set my dark blue tiles to be flipped along the x axis, which is a simple boolean input in the set_cell() function. Since I'm working with solid-colour tiles, there's no visual difference.

2) I independently create a list of booleans, going through each tile and checking if they are flipped along the x axis. I pass into the function the width and height of the cave system I've generated.

func create_2d_array_of_flippedTiles(width, height):
	var a = []
	
	for y in range(height):
		a.append([])
		a[y].resize(width)
	
		for x in range(width):
			a[y][x] = is_cell_x_flipped(x,y)
	
	return a

<br> 3) I pass this list of booleans into my function for spawning loot. If the tile at (x,y) returns true, meaning that it is flipped along the x, and the tile of above it returns false, then I spawn loot at (x, y-1). Remember, if it's flipped, that means it's a solid wall (dark blue) and if it isn't, it's part of the background (light blue)

func spawnLootCentre(var l):
	var temp = loot1.instance()
	
	for x in range(width):
		for y in range(1, height):
			if (l[y][x] == true and l[y-1][x] == false):
				add_child(temp.duplicate())
				temp.set_position(map_to_world(Vector2(x, y - 1))+ cell_size/2)

<br> This is the output: <br> Thank you @vinpogo for your suggestions. I don't know why your solutions (or my original code) didn't work. I tried multiple ways of delaying the generation of the loot in case it had something to do with loot spawning in before the map had finished generating. Using timers and coroutines to add delays didn't work. Spawning loot on top of one type of tile id would be as random and chaotic as the other methods. It just seems like get_cell() simply wasn't returning the tile id's correctly.

vinpogo

glad you got it working!

i experienced a similar issue where tile indices didnt update correctly, now i remember that you said that. Actually i just needed to call update_dirty_quadrants to force godot to update those references/indices.

Anyways, if it works it works!

EDIT: fix typos