ICTS_Denmark/Assets/GameObjects/Pickups/SpermicidalWaveFollower.cs

using UnityEngine;
using System.Collections;

/// <summary>
/// This component is attached to a particle system which is not the UI root, because otherwise
/// the shuriken particle system will freak out due to scaling (it will not render when transform is not visible)
/// So this makes the particle system follow a target without the need of being under the scaling
/// of the UI root.
/// </summary>
public class SpermicidalWaveFollower : MonoBehaviour
{
	Transform _target;

	Transform _cachedTransform;

	float _originalZPosition;

	void Awake()
	{
		_cachedTransform = transform;
		_originalZPosition = _cachedTransform.position.z;
		NotificationCenter.AddListener(OnGameOver, NotificationType.GameOver);
		NotificationCenter.AddListener(OnGamePause, NotificationType.GamePause);
		NotificationCenter.AddListener(OnGameResume, NotificationType.GameResume);
	}

	void OnDestroy()
	{
		NotificationCenter.RemoveListener(OnGameOver, NotificationType.GameOver);
		NotificationCenter.RemoveListener(OnGamePause, NotificationType.GamePause);
		NotificationCenter.RemoveListener(OnGameResume, NotificationType.GameResume);
	}

	void OnEnable()
	{
		//Just in case it was previously hidden
		ChangeZPosition(_originalZPosition);
	}

	void LateUpdate()
	{
		if (_target != null)
		{
			if (_target.gameObject.activeSelf)
			{
				Vector3 newPos = _target.position;
				newPos.z = _cachedTransform.position.z;
				_cachedTransform.position = newPos;
			} else
			{
				StopFollowing();
			}
		}
	}

	void OnGameOver(Notification note)
	{
		StopFollowing();
	}

	void OnGamePause(Notification note)
	{
		//This is to hide it, so it doesn't conflict with the pause menu.
		//This is a hack due to mixing 2D with 3D
		ChangeZPosition(5);
	}

	void OnGameResume(Notification note)
	{
		ChangeZPosition(_originalZPosition);
	}

	public void StartFollowing(Transform target)
	{
		_target = target;
		var m = GetComponent<ParticleSystem>().emission;
		m.enabled = true;
	}

	void StopFollowing()
	{
		_target = null;
		var m = GetComponent<ParticleSystem>().emission;
		m.enabled = false;
	}

	void ChangeZPosition(float newZ)
	{
		Vector3 newPos = _cachedTransform.position;
		newPos.z = newZ;
		_cachedTransform.position = newPos;

	}

}