Eye.cs

using UnityEngine;
#if UNITY_EDITOR
using UnityEditor;
#endif
using UnityEngine.Assertions;
using System.Collections.Generic;

public class Eye : MonoBehaviour
{
	// public for debugging
	public List<Unit> eyeRangeUnits;
	public RaycastHit hit;

	Unit _unit;
	UnitSight _unitSight;
	int _unitBodyLayer;
	int _obstacleLayer;
	LayerMask _layerMask;

	void Awake()
	{
		_unitBodyLayer = LayerMask.NameToLayer("Body");
		_obstacleLayer = LayerMask.NameToLayer("Obstacle");
		_layerMask = (1 << _obstacleLayer) | (1 << _unitBodyLayer);
		_unit = GetComponentInParent<Unit> ();
		_unitSight = GetComponentInParent<UnitSight> ();
		eyeRangeUnits = new List<Unit> ();
	}

	void OnTriggerEnter(Collider other)
	{
		// only look for the 'body' of a unit ( the collider of the  it's 3D model ) a unit may have
		// multiple colliders on it, for vision, for detecting touch in a wider area, etc.)
		if (other.name != "Body")
			return;

//		Debug.Log (string.Format ("{0}.OnTriggerEnter: {1} ", name, other.name));
		Unit otherUnit = other.GetComponentInParent<Unit> ();
		if (otherUnit != null && otherUnit.troopId != _unit.troopId)
		{
			Assert.IsFalse (eyeRangeUnits.Contains (otherUnit));
			eyeRangeUnits.Add (otherUnit);

		}
	}

	void OnTriggerExit(Collider other)
	{
		if (other.name != "Body")
			return;

//		Debug.Log (string.Format ("{0}.OnTriggerExit: {1}", name, other.name));
		Unit otherUnit = other.GetComponentInParent<Unit> ();
		if (otherUnit && otherUnit.troopId != _unit.troopId)
		{
			Assert.IsTrue (eyeRangeUnits.Contains (otherUnit));
			eyeRangeUnits.Remove (otherUnit);
		}
	}

	// loop through the units in range of the 'eye' collider and add / remove them from the
	// unit sight 'watching' list (they could go in and out of sight behind obstacles, other
	// units etc.)
	void Update()
	{
		foreach (var unit in eyeRangeUnits)
		{
			// line-of-sight vector from this to other unit
			var direction = unit.transform.position - _unit.transform.position;

			// make sure that there is no obstacle blocking our direct line of sight (add a 
			// little buffer so raycast doesn't interesect with this unit's 'body' collider)
			Ray ray = new Ray(_unit.transform.position + _unit.transform.forward * .5f, direction); // HARDCODE
			if (Physics.Raycast (ray, out hit, 100f, _layerMask)) // HARDCODE
			{
				string hitLayerName = LayerMask.LayerToName (hit.transform.gameObject.layer);

				// remove the unit if it is being watched but we can no longer see it
				if (hit.transform.gameObject.layer == _obstacleLayer)
				{
					if (_unitSight.watching.Contains (unit)) {
						_unitSight.watching.Remove (unit);
						_unitSight.WatchingChange.Invoke ();
					}
				}
				// add the unit if it wasn't being watched already
				else if (hit.transform.gameObject.layer == _unitBodyLayer)
				{
					if (!_unitSight.watching.Contains (unit)) {
						_unitSight.watching.Add (unit);
						_unitSight.WatchingChange.Invoke ();
					}
				} else {
					// safty-check: layer mask *should* only have two layers, so we shouldn't get here
					Debug.LogWarning (string.Format ("Eye.Update: hitLayerName = {0} ({1})", hitLayerName, hit.transform.name));
				}
			}
		}
	}
}