unity官方demo学习之Stealth（二十）敌人视听范围

using UnityEngine;
using System.Collections;

public class DoneEnemySight : MonoBehaviour
{
public float fieldOfViewAngle = 110f;				// Number of degrees, centred on forward, for the enemy see.
public bool playerInSight;							// Whether or not the player is currently sighted.
public Vector3 personalLastSighting;				// Last place this enemy spotted the player.

private NavMeshAgent nav;							// Reference to the NavMeshAgent component.
private SphereCollider col;							// Reference to the sphere collider trigger component.
private Animator anim;								// Reference to the Animator.
private DoneLastPlayerSighting lastPlayerSighting;	// Reference to last global sighting of the player.
private GameObject player;							// Reference to the player.
private Animator playerAnim;						// Reference to the player's animator component.
private DonePlayerHealth playerHealth;				// Reference to the player's health script.
private DoneHashIDs hash;							// Reference to the HashIDs.
private Vector3 previousSighting;					// Where the player was sighted last frame.

void Awake ()
{
// Setting up the references.
nav = GetComponent<NavMeshAgent>();
col = GetComponent<SphereCollider>();
anim = GetComponent<Animator>();
lastPlayerSighting = GameObject.FindGameObjectWithTag(DoneTags.gameController).GetComponent<DoneLastPlayerSighting>();
player = GameObject.FindGameObjectWithTag(DoneTags.player);
playerAnim = player.GetComponent<Animator>();
playerHealth = player.GetComponent<DonePlayerHealth>();
hash = GameObject.FindGameObjectWithTag(DoneTags.gameController).GetComponent<DoneHashIDs>();

// Set the personal sighting and the previous sighting to the reset position.
personalLastSighting = lastPlayerSighting.resetPosition;
previousSighting = lastPlayerSighting.resetPosition;
}

void Update ()
{
// If the last global sighting of the player has changed...
if(lastPlayerSighting.position != previousSighting)
// ... then update the personal sighting to be the same as the global sighting.
personalLastSighting = lastPlayerSighting.position;

// Set the previous sighting to the be the sighting from this frame.
previousSighting = lastPlayerSighting.position;

// If the player is alive...
if(playerHealth.health > 0f)
// ... set the animator parameter to whether the player is in sight or not.
anim.SetBool(hash.playerInSightBool, playerInSight);
else
// ... set the animator parameter to false.
anim.SetBool(hash.playerInSightBool, false);
}

void OnTriggerStay (Collider other)
{
// If the player has entered the trigger sphere...
if(other.gameObject == player)
{
// By default the player is not in sight.
playerInSight = false;

// Create a vector from the enemy to the player and store the angle between it and forward.
Vector3 direction = other.transform.position - transform.position;
float angle = Vector3.Angle(direction, transform.forward);

// If the angle between forward and where the player is, is less than half the angle of view...
if(angle < fieldOfViewAngle * 0.5f)
{
RaycastHit hit;

// ... and if a raycast towards the player hits something...
if(Physics.Raycast(transform.position + transform.up, direction.normalized, out hit, col.radius))
{
// ... and if the raycast hits the player...
if(hit.collider.gameObject == player)
{
// ... the player is in sight.
playerInSight = true;

// Set the last global sighting is the players current position.
lastPlayerSighting.position = player.transform.position;
}
}
}

// Store the name hashes of the current states.
int playerLayerZeroStateHash = playerAnim.GetCurrentAnimatorStateInfo(0).nameHash;
int playerLayerOneStateHash = playerAnim.GetCurrentAnimatorStateInfo(1).nameHash;

// If the player is running or is attracting attention...
if(playerLayerZeroStateHash == hash.locomotionState || playerLayerOneStateHash == hash.shoutState)
{
// ... and if the player is within hearing range...
if(CalculatePathLength(player.transform.position) <= col.radius)
// ... set the last personal sighting of the player to the player's current position.
personalLastSighting = player.transform.position;
}
}
}

void OnTriggerExit (Collider other)
{
// If the player leaves the trigger zone...
if(other.gameObject == player)
// ... the player is not in sight.
playerInSight = false;
}

float CalculatePathLength (Vector3 targetPosition)
{
// Create a path and set it based on a target position.
NavMeshPath path = new NavMeshPath();
if(nav.enabled)
nav.CalculatePath(targetPosition, path);

// Create an array of points which is the length of the number of corners in the path + 2.
Vector3 [] allWayPoints = new Vector3[path.corners.Length + 2];

// The first point is the enemy's position.
allWayPoints[0] = transform.position;

// The last point is the target position.
allWayPoints[allWayPoints.Length - 1] = targetPosition;

// The points inbetween are the corners of the path.
for(int i = 0; i < path.corners.Length; i++)
{
allWayPoints[i + 1] = path.corners[i];
}

// Create a float to store the path length that is by default 0.
float pathLength = 0;

// Increment the path length by an amount equal to the distance between each waypoint and the next.
for(int i = 0; i < allWayPoints.Length - 1; i++)
{
pathLength += Vector3.Distance(allWayPoints[i], allWayPoints[i + 1]);
}

return pathLength;
}
}