Grid finally working and understood

Scenes/Main/grid_display.gd

@@ -0,0 +1,17 @@
+extends Control
+
+var grid: AStarGrid2D:
+	set(v): grid = v; queue_redraw()
+var show_grid_display: bool:
+	set(v): show_grid_display = v; queue_redraw()
+	
+func toggle_grid_display(on: bool):
+	show_grid_display = on
+
+func _draw():
+	if not grid or not show_grid_display: return
+	for x in grid.region.size.x:
+		for y in grid.region.size.y:
+			var p = Vector2(x, y)
+			var col = Color(1,0,0,0.3) if grid.is_point_solid(p) else Color(0,1,0,0.3)
+			draw_rect(Rect2(p*grid.cell_size, grid.cell_size), col)