class_name Walls
extends StaticBody2D
## Screen edges. The bottom edge is its own body in the "bottom" group, so the game can tell
## when a ball or power-up falls out.


func _ready() -> void:
	collision_layer = Params.LAYER_WALLS
	collision_mask = 0
	var size := get_viewport_rect().size
	_add_boundary(self, Vector2.RIGHT, 0.0)
	_add_boundary(self, Vector2.LEFT, -size.x)
	_add_boundary(self, Vector2.DOWN, 0.0)

	var bottom := StaticBody2D.new()
	bottom.collision_layer = Params.LAYER_WALLS
	bottom.collision_mask = 0
	bottom.add_to_group("bottom")
	add_child(bottom)
	_add_boundary(bottom, Vector2.UP, -size.y)


## Adds a half-plane; [param normal] points into the open (playable) side.
func _add_boundary(body: StaticBody2D, normal: Vector2, distance: float) -> void:
	var shape := WorldBoundaryShape2D.new()
	shape.normal = normal
	shape.distance = distance
	var collision := CollisionShape2D.new()
	collision.shape = shape
	body.add_child(collision)