Godot: global position of point is in a different scene - godot

Question

I am creating a map with points, and if you click a point you go to it. The points are all connected by lines. The points are also randomly placed around the map, so I have to program in the functionality to draw lines from themselves to all nearby points. I have created a separate scene for these points, and am instancing them in the main scene. I can draw the lines, but instead of being drawn between the points, they are being drawn from it's parent point's location to the location of the point in its own scene. In other words, wherever I move the point in it's scene, the instanced points in the main scene will draw their lines to that location. Here is my code:
extends Node2D
var point_a = self.get_global_position()
var point_b = 0
var draw_line = false
func _ready():
pass
func _process(_delta):
var overlapping_areas = $Area2D.get_overlapping_areas()
for area in overlapping_areas:
if area.is_in_group("Location"):
point_b = area.get_global_position()
draw_line = true
update()
func _draw():
if draw_line:
draw_line(to_local(point_a), to_local(point_b), Color(1, 1, 1, 1), 2)
draw_line = false

Answer 1

Your problem is that point_a = Vector2(0,0) and to_local(Vector2(0,0)) is ending up being offset somewhere in the negatives. There was also a problem with initializing var point_a = self.get_global_position() because get_global_position will fail when the script loads because the Node has not been added to the SceneTree yet.
It's not necessary to calculate point_a at all, since draw_line's origin is the position of the object. It will always be Vector2(0,0), or Vector2.ZERO. Then, point_b starts as null because there is no valid end point until some areas overlap.
extends Node2D
var point_a = Vector2.ZERO
var point_b = null
func _physics_process(_delta):
var overlapping_areas = $Area2D.get_overlapping_areas()
for area in overlapping_areas:
if area.is_in_group("Location"):
point_b = area.get_global_position()
update()
func _draw():
if point_b != null:
draw_line(point_a, to_local(point_b), Color(1, 1, 1, 1), 2)
However, this logic may not give the desired result unless the paths are linear.
From your description, believe this is what you wanted:
extends Node2D
var point_a = Vector2.ZERO
var point_b_array = []
func _physics_process(_delta):
var overlapping_areas = $Area2D.get_overlapping_areas()
if overlapping_areas.size() > 0:
point_b_array.clear()
for area in overlapping_areas:
if area.is_in_group("Location"):
point_b_array.push_back(area.get_global_position())
update()
func _draw():
for end_point in point_b_array:
draw_line(point_a, to_local(end_point), Color(1, 1, 1, 1), 2)
Instead of using a single variable for point_b I used an array. When we find an overlapping area, it gets added into the array by push_back(), and in draw() we iterate over all of the points and draw lines to them. This also neatly solves the issue of drawing zero lines or what to do when draw is called before the scene is fully loaded.