Trying to make my own build mechanic

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1

Godot Version

4.4.stable

Question

I am trying to code my own build mechanic, with a preview building function and so far, I was able to figure out how to implement the preview version of the building. The building follows the mouse in an opaque form. However, I’m trying to implement the “build” mechanic by using the set_cell function when the “click” input is done. However, I don’t see the building get built. I feel like I’m close, but I have no idea why this is not happening the way it’s intended. Nodes are organized as follows:

image
image257×201 7.67 KB

extends TileMapLayer

var source_id: int
var building_vector: Vector2i
var mouse_position: Vector2i
var old_mouse_position: Vector2i

func _ready():
	#Ensures no building is shown on the mouse pointer on startup
	source_id = -1
	#Makes the preview version of the tile the default setting
	modulate.a = 0.5

func get_snapped_position(global_pos: Vector2) -> Vector2i:
	var local_pos = to_local(global_pos)
	var tile_pos = local_to_map(local_pos)
	return tile_pos

func _input(event: InputEvent) -> void:
	#Creates preview version of building sprite, hovers on mouse position
	if event is InputEventMouseMotion:
		#Gets the new coordinates of mouse pointer when mouse moves
		mouse_position = get_snapped_position(get_global_mouse_position())
		#Erases tile in old position, so the building preview 'follows' the mouse
		if old_mouse_position != mouse_position:
			erase_cell(old_mouse_position)
		#Places the building tile onto the grid and stores the new tile coordinates
		set_cell(mouse_position, source_id, building_vector)
		old_mouse_position = mouse_position

	if Input.is_action_just_pressed("click"):
		print(mouse_position)
		set_cell(mouse_position, source_id, building_vector)
			
func _on_solar_plant_pressed():
	source_id = 0
	building_vector = Vector2i(0, 6)

func _on_wind_turbine_pressed():
	source_id = 0
	building_vector = Vector2i(0, 0)
2

Does the mouse position print? You may need to use event.is_action_pressed("click") instead of the Input singleton.

Can you explain what you expect to happen vs what really happens?

3

The mouse position does print, so that function is being triggered. What I was hoping would happen is a building would be placed on a tile permanently when you left click on the mouse button. However, that never happens when you left click.

I tried your event.is_action_just_pressed() but I get this error:
image

4

This is what happens. building preview does follow the mouse as intended but when I left click, the building tile doesn’t get placed permanently on the scene.

5

is_action_just_pressed doesn’t exist on event, and the just isn’t needed as the event only exists for the frame of the input anyways.

Thanks for the video, much clearer. Your code does nothing to stop the ghost and _input deletes any previously moused over tile. Maybe you need a seperate ghost tile map layer and a “real” tile map layer

6

Thanks, that worked:

	if Input.is_action_pressed("click"):
		buildings.set_cell(mouse_position, source_id, building_vector)