Making Line2D trail disappear ONLY once the projectile has collided

Help
1

Godot Version

Godot 4.7.1

Question

How would I go about making a trail that disappears from the back only once the projectile has collided with the ceiling. I have added my attempt at doing this below.

extends CharacterBody2D

var hasCollided = false

func _ready():
	$Line2D.global_position = global_position

func _physics_process(_delta: float) -> void:
	if not hasCollided:
		$Line2D.add_point(position, 0)
	move_and_slide()

func _on_projectile_physics_handler_colliding_with_ceiling() -> void:
	while $Line2D.points.size() > 0:
		$Line2D.remove_point(0)
		print($Line2D.points)

The Line2D points get removed all at once, instead of back to front.

2

your while loop executes all at once, it doesn’t wait for any given amount of time, not even a frame.

3

oh lol idk how I didn’t think of that

i fixed the issue by making the signal assign a variable hasCollided to true, then in the physics_process function while true, removing the first point in the Line2D array

so now the points only get deleted every delta seconds

func _physics_process(_delta: float) -> void:
	if not hasCollided:
		$Line2D.add_point(position)
	else:
		$Line2D.remove_point(0)

	move_and_slide()

func _on_projectile_physics_handler_colliding_with_ceiling() -> void:
	hasCollided = true
4

To clarify running this in _physics_process happens about 60 times per second, depending on your project’s physics settings and framerate. If you ran it in _process it would be once per frame. Neither is strictly per-second so if you want a consistent effect it may be best to use a short timer node to add and remove points.