added keep shield ui onscreen option

Scripts/enemy_goal.gd

@@ -1,10 +1,36 @@
 class_name EnemyGoal
 extends Node3D
 
+signal goal_cleared()
+signal goal_occupied()
+
 @export var audio_player: AudioStreamPlayer3D
 
+var enemies_inside: int
+
 
 func _on_area_3d_body_entered(body: Node3D) -> void:
 	if body is EnemyController:
 		body.goal_entered()
 		audio_player.play()
+
+
+func enemy_entered_shield_range(body: Node3D) -> void:
+	if body is EnemyController:
+		if enemies_inside == 0:
+			goal_occupied.emit()
+		enemies_inside += 1
+		body.died.connect(enemy_died)
+		body.reached_goal.connect(enemy_reached_goal)
+
+
+func enemy_died(enemy: Enemy) -> void:
+	enemies_inside -= 1
+	if enemies_inside == 0:
+		goal_cleared.emit()
+
+
+func enemy_reached_goal(enemy: Enemy, penalty: int) -> void:
+	enemies_inside -= 1
+	if enemies_inside == 0:
+		goal_cleared.emit()