Prevent body_entered if another collision shape is on top

housatic

I have a bunch Area2Ds that might overlap, and a player moving between them. Is there a way to make it so
body_entered and body_exited are only received by the "highest" (lowest in the scene tree) Area2D?

E.g. in this image if I move up, I want Area 3's body_entered to trigger, but not Area 2's and Area 1's. But if I hide Area 3, then I want Area 2's body_entered to trigger.

housatic

To clarify, I'm trying to get collisions to behave like mouse input when a node's mouse_filter is set to "Stop". If I hover on the node it receives mouse_entered, then the input is marked as handled and doesn't get passed to other nodes. But I don't know if there's such a thing as "marking collisions as handled", or if I should manually check which collision shape is lowest in the scene tree (how?) and visible, or is there a another way?

Edit: I'm trying RayCast2D, with "collide_with_areas = true" it's looking promising. Though I don't know what "the closest object" means in a 2D context, right now get_collider() returns an area which is visually further away than another area on top.

housatic

Found a post with the same issue https://forum.godotengine.org/t/get-closest-node-in-tree-order-of-overlapping-nodes/44860/ !

Though intersect_point() is throwing an error when I use PhysicsShapeQueryParameters2D, PhysicsPointQueryParameters2D works fine:

var direct_space = get_world_2d().direct_space_state

var query = PhysicsShapeQueryParameters2D.new()
query.collide_with_areas = true
query.set_shape(collision.shape)
query.collision_mask = collision_layer

# same error:
# var circle_shape = CircleShape2D.new()
# circle_shape.radius = 10
# query.set_shape(circle_shape)

# but this works:
# var query2 = PhysicsPointQueryParameters2D.new()
# query2.collide_with_areas = true
# query2.position = position

var intersections = direct_space.intersect_point(query) # "p_point_query.is_null()" is true. Returning: Array()

EDIT: It needed intersect_shape, not intersect_point...
working code:

var direct_space : PhysicsDirectSpaceState2D
var query = PhysicsShapeQueryParameters2D.new()

func _ready() -> void:
	direct_space = get_world_2d().direct_space_state
	query.collide_with_areas = true
	query.set_shape(collision.shape)
	query.collision_mask = collision_layer

func _process(delta: float) -> void:
	query.transform = Transform2D(0, position)
	var intersections = direct_space.intersect_shape(query)
	if intersections:
		intersections.sort_custom(func(a, b):
			var obj_a = a.collider
			var obj_b = b.collider
			return obj_a.is_greater_than(obj_b)
		)
		var collider_on_top = intersections[0].collider

kuligs2

housatic what error you have?

Please post full script or function

housatic

kuligs2 This is the whole function right now, I'm running it in _process for testing. I wrote the error in the code but here's the full thing:

E 0:00:00:949   player.gd:48 @ _process(): Condition "p_point_query.is_null()" is true. Returning: Array()
  <C++ Source>  servers/physics_server_2d.cpp:361 @ _intersect_point()
  <Stack Trace> player.gd:48 @ _process()
https://github.com/godotengine/godot/blob/f62fdbde15035c5576dad93e586201f4d41ef0cb/servers/physics_server_2d.cpp#L361

Line 48 is the var intersections = direct_space.intersect_point(query). When I make query a PhysicsPointQueryParameters2D instead it works, so the problem might be with the shape? But I've tried assigning it in multiple ways (query.shape_rid = shape, query.set_shape(shape), using an existing shape, creating a new shape - see edited code above) and it didn't help.

If I'm looking at the source code right it's failing because the parameters are null? but the query object I'm passing is clearly not null.

kuligs2

housatic maybe the first query is missing position?

housatic

kuligs2 It wasn't the cause but you're right, I also have to update the position with query.transform = Transform2D(0, position)

housatic

Nevermind, I'm dumb. You need to use intersect_shape when using PhysicsShapeQueryParameters2D and intersect_point when using PhysicsPointQueryParameters2D. I'm so used to C# screaming at me if I try to pass a parameter of the wrong type it didn't even occur to me that could be the issue.