Navigation：是通过 enum 和 switch 来进行状态机的转换从而实现AI巡逻和攻击以及追踪
private GameObject playerUnit; //获取玩家单位
private Animator thisAnimator; //自身动画组件
private Vector3 initialPosition; //初始位置
public float wanderRadius; //游走半径，移动状态下，如果超出游走半径会返回出生位置
public float alertRadius; //警戒半径，玩家进入后怪物会发出警告，并一直面朝玩家
public float defendRadius; //自卫半径，玩家进入后怪物会追击玩家，当距离<攻击距离则会发动攻击（或者触发战斗）
public float chaseRadius; //追击半径，当怪物超出追击半径后会放弃追击，返回追击起始位置
public float attackRange; //攻击距离
public float walkSpeed; //移动速度
public float runSpeed; //跑动速度
public float turnSpeed; //转身速度，建议0.1
private enum MonsterState
{
STAND, //原地呼吸
CHECK, //原地观察
WALK, //移动
WARN, //盯着玩家
CHASE, //追击玩家
RETURN //超出追击范围后返回
}
private MonsterState currentState = MonsterState.STAND; //默认状态为原地呼吸
public float[] actionWeight = { 3000, 3000, 4000 }; //设置待机时各种动作的权重，顺序依次为呼吸、观察、移动
public float actRestTme; //更换待机指令的间隔时间
private float lastActTime; //最近一次指令时间
private float diatanceToPlayer; //怪物与玩家的距离
private float diatanceToInitial; //怪物与初始位置的距离
private Quaternion targetRotation; //怪物的目标朝向
private bool is_Warned = false;
private bool is_Running = false;
void Start()
{
playerUnit = GameObject.FindGameObjectWithTag("Player");
thisAnimator = GetComponent<Animator>();
//保存初始位置信息
initialPosition = gameObject.GetComponent<Transform>().position;
//检查并修正怪物设置
//1. 自卫半径不大于警戒半径，否则就无法触发警戒状态，直接开始追击了
defendRadius = Mathf.Min(alertRadius, defendRadius);
//2. 攻击距离不大于自卫半径，否则就无法触发追击状态，直接开始战斗了
attackRange = Mathf.Min(defendRadius, attackRange);
//3. 游走半径不大于追击半径，否则怪物可能刚刚开始追击就返回出生点
wanderRadius = Mathf.Min(chaseRadius, wanderRadius);
//随机一个待机动作
RandomAction();
}
/// <summary>
/// 根据权重随机待机指令
/// </summary>
void RandomAction()
{
//更新行动时间
lastActTime = Time.time;
//根据权重随机
float number = Random.Range(0, actionWeight[0] + actionWeight[1] + actionWeight[2]);
if (number <= actionWeight[0])
{
currentState = MonsterState.STAND;
thisAnimator.SetTrigger("Stand");
}
else if (actionWeight[0] < number && number <= actionWeight[0] + actionWeight[1])
{
currentState = MonsterState.CHECK;
thisAnimator.SetTrigger("Check");
}
if (actionWeight[0] + actionWeight[1] < number && number <= actionWeight[0] + actionWeight[1] + actionWeight[2])
{
currentState = MonsterState.WALK;
//随机一个朝向
targetRotation = Quaternion.Euler(0, Random.Range(1, 5) * 90, 0);
thisAnimator.SetTrigger("Walk");
}
}
void Update()
{
switch (currentState)
{
//待机状态，等待actRestTme后重新随机指令
case MonsterState.STAND:
if (Time.time - lastActTime > actRestTme)
{
RandomAction(); //随机切换指令
}
//该状态下的检测指令
EnemyDistanceCheck();
break;
//待机状态，由于观察动画时间较长，并希望动画完整播放，故等待时间是根据一个完整动画的播放长度，而不是指令间隔时间
case MonsterState.CHECK:
if (Time.time - lastActTime > thisAnimator.GetCurrentAnimatorStateInfo(0).length)
{
RandomAction(); //随机切换指令
}
//该状态下的检测指令
EnemyDistanceCheck();
break;
//游走，根据状态随机时生成的目标位置修改朝向，并向前移动
case MonsterState.WALK:
transform.Translate(Vector3.forward * Time.deltaTime * walkSpeed);
transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, turnSpeed);
if (Time.time - lastActTime > actRestTme)
{
RandomAction(); //随机切换指令
}
//该状态下的检测指令
WanderRadiusCheck();
break;
//警戒状态，播放一次警告动画和声音，并持续朝向玩家位置
case MonsterState.WARN:
if (!is_Warned)
{
thisAnimator.SetTrigger("Warn");
gameObject.GetComponent<AudioSource>().Play();
is_Warned = true;
}
//持续朝向玩家位置
targetRotation = Quaternion.LookRotation(playerUnit.transform.position - transform.position, Vector3.up);
transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, turnSpeed);
//该状态下的检测指令
WarningCheck();
break;
//追击状态，朝着玩家跑去
case MonsterState.CHASE:
if (!is_Running)
{
thisAnimator.SetTrigger("Run");
is_Running = true;
}
transform.Translate(Vector3.forward * Time.deltaTime * runSpeed);
//朝向玩家位置
targetRotation = Quaternion.LookRotation(playerUnit.transform.position - transform.position, Vector3.up);
transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, turnSpeed);
//该状态下的检测指令
ChaseRadiusCheck();
break;
//返回状态，超出追击范围后返回出生位置
case MonsterState.RETURN:
//朝向初始位置移动
targetRotation = Quaternion.LookRotation(initialPosition - transform.position, Vector3.up);
transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, turnSpeed);
transform.Translate(Vector3.forward * Time.deltaTime * runSpeed);
//该状态下的检测指令
ReturnCheck();
break;
}
}
/// <summary>
/// 原地呼吸、观察状态的检测
/// </summary>
void EnemyDistanceCheck()
{
diatanceToPlayer = Vector3.Distance(playerUnit.transform.position, transform.position);
if (diatanceToPlayer < attackRange)
{
SceneManager.LoadScene("Battle");
}
else if (diatanceToPlayer < defendRadius)
{
currentState = MonsterState.CHASE;
}
else if (diatanceToPlayer < alertRadius)
{
currentState = MonsterState.WARN;
}
}
/// <summary>
/// 警告状态下的检测，用于启动追击及取消警戒状态
/// </summary>
void WarningCheck()
{
diatanceToPlayer = Vector3.Distance(playerUnit.transform.position, transform.position);
if (diatanceToPlayer < defendRadius)
{
is_Warned = false;
currentState = MonsterState.CHASE;
}
if (diatanceToPlayer > alertRadius)
{
is_Warned = false;
RandomAction();
}
}
/// <summary>
/// 游走状态检测，检测敌人距离及游走是否越界
/// </summary>
void WanderRadiusCheck()
{
diatanceToPlayer = Vector3.Distance(playerUnit.transform.position, transform.position);
diatanceToInitial = Vector3.Distance(transform.position, initialPosition);
if (diatanceToPlayer < attackRange)
{
SceneManager.LoadScene("Battle");
}
else if (diatanceToPlayer < defendRadius)
{
currentState = MonsterState.CHASE;
}
else if (diatanceToPlayer < alertRadius)
{
currentState = MonsterState.WARN;
}
if (diatanceToInitial > wanderRadius)
{
//朝向调整为初始方向
targetRotation = Quaternion.LookRotation(initialPosition - transform.position, Vector3.up);
}
}
/// <summary>
/// 追击状态检测，检测敌人是否进入攻击范围以及是否离开警戒范围
/// </summary>
void ChaseRadiusCheck()
{
diatanceToPlayer = Vector3.Distance(playerUnit.transform.position, transform.position);
diatanceToInitial = Vector3.Distance(transform.position, initialPosition);
if (diatanceToPlayer < attackRange)
{
SceneManager.LoadScene("Battle");
}
//如果超出追击范围或者敌人的距离超出警戒距离就返回
if (diatanceToInitial > chaseRadius || diatanceToPlayer > alertRadius)
{
currentState = MonsterState.RETURN;
}
}
/// <summary>
/// 超出追击半径，返回状态的检测，不再检测敌人距离
/// </summary>
void ReturnCheck()
{
diatanceToInitial = Vector3.Distance(transform.position, initialPosition);
//如果已经接近初始位置，则随机一个待机状态
if (diatanceToInitial < 0.5f)
{
is_Running = false;
RandomAction();
}
}
