Grid finally working and understood

Scenes/Map/map_new.gd

@@ -0,0 +1,45 @@
+extends Node2D
+
+@onready var GroundLayer: TileMapLayer = $Ground
+@onready var ObstacleLayer: TileMapLayer = $Obstacles
+# Maybe a SubClass that is a Singleton, so we can create one grid
+# and then change it per Map
+var astarGrid: AStarGrid2D
+
+# Called when the node enters the scene tree for the first time.
+func _ready() -> void:
+	#astarGrid = generateSimpleGrid()
+	astarGrid = generateObstacleGrid()
+	%GridDisplay.grid = astarGrid
+
+func generateSimpleGrid() -> AStarGrid2D:
+	var grid = AStarGrid2D.new()
+	grid.cell_size = Vector2(GroundLayer.tile_set.tile_size)
+	grid.region = GroundLayer.get_used_rect()
+	grid.update()
+	
+	for id in GroundLayer.get_used_cells():
+		var data: TileData = GroundLayer.get_cell_tile_data(id)
+		if data and data.get_custom_data('obstacle'):
+			grid.set_point_solid(id)
+	
+	return grid
+
+func generateObstacleGrid() -> AStarGrid2D:
+	astarGrid = AStarGrid2D.new()
+	astarGrid.cell_size = Vector2(GroundLayer.tile_set.tile_size)
+	astarGrid.region = GroundLayer.get_used_rect()
+	astarGrid.update()
+	
+	var layers = ObstacleLayer.get_children()
+	for layer in layers:
+		for id in layer.get_used_cells():
+			var data: TileData = layer.get_cell_tile_data(id)
+			if data and data.get_custom_data('obstacle'):
+				astarGrid.set_point_solid(id)
+	
+	return astarGrid
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta: float) -> void:
+	pass

Scenes/Map/map_new.gd.uid

@@ -0,0 +1 @@
+uid://dlnu7a7viuh8a