4-9 Having Character Build Themselves

這次重構要來修剪Player擁有太多的Component，概念是為了讓遊戲設計師方便調整Player的參數。畢竟Player擁有的Component有Nav Mesh Agent、Capsule Collider、Rigidbody．．．等，且這些Component又都有自帶的參數需要設定，某些設定不需要開放讓設計師調整。

所以本次要讓Character.cs產生大多數的Component。首先將CharacterMovement改名為Character。

在Player新增Character。

以下提供Character.cs修改後的程式碼：

using System;
using UnityEngine;
using UnityEngine.AI;
using RPG.CameraUI;

namespace RPG.Character{
 [SelectionBase]
 public class Character : MonoBehaviour
 {
  [Header("Audio")]
  [Range(0.0f, 1.0f)][SerializeField] float spatialBlend = 1f;

  [Header("Capsule Collider")]
  [SerializeField] Vector3 colliderCenter = new Vector3(0, 1, 0);
  [SerializeField] float colliderRadius = 0.3f;
  [SerializeField] float colliderHeight = 1.5f;

  [Header("Animator")]
  [SerializeField] RuntimeAnimatorController animatorController;
  [SerializeField] AnimatorOverrideController animatorOverrideController;
  [SerializeField] Avatar avatar;

  [Header("Movement")]
  [SerializeField] float walkMoveStopRadius = 0.2f;
  [SerializeField] float attackMoveStopRadius = 5f;
  [SerializeField] float moveSpeedMultiplier = 1f;
  [SerializeField] float animationSpeedMultiplier = 1f;
  [SerializeField] float movingTurnSpeed = 1800;
  [SerializeField] float stationaryTurnSpeed = 1800;
  [SerializeField] float moveThreshold = 1f;

  [Header("Nav Mesh Agent")]
  [SerializeField] float steeringSpeed = 1.0f;

  NavMeshAgent navMeshAgent = null;
  Animator animator = null;
  Rigidbody myRigidbody = null;
  float turnAmount;
  float forwardAmount;

  void Awake(){
   AddRequiredComponents ();
  }

  private void AddRequiredComponents(){
   CapsuleCollider capsuleCollider = gameObject.AddComponent ();
   capsuleCollider.center = colliderCenter;
   capsuleCollider.radius = colliderRadius;
   capsuleCollider.height = colliderHeight;

   myRigidbody = gameObject.AddComponent ();
   myRigidbody.collisionDetectionMode = CollisionDetectionMode.Continuous;
   myRigidbody.constraints = RigidbodyConstraints.FreezeRotation;

   AudioSource audioSource = gameObject.AddComponent ();
   audioSource.spatialBlend = spatialBlend;

   animator = gameObject.AddComponent ();
   animator.runtimeAnimatorController = animatorController;
   animator.avatar = avatar;

   navMeshAgent = gameObject.AddComponent ();
   navMeshAgent.updateRotation = false;
   navMeshAgent.updatePosition = true;
   navMeshAgent.speed = steeringSpeed;
  }

  void Start()
  {
   CameraRaycaster cameraRaycaster = Camera.main.GetComponent();
   cameraRaycaster.onMouseOverWalkable += OnMouseOverWalkable;
   cameraRaycaster.onMouseOverEnemy += OnMouseOverEnemy;
  }

  void Update(){
   if (navMeshAgent.remainingDistance > navMeshAgent.stoppingDistance) {
    Move(navMeshAgent.desiredVelocity);
   } else {
    Move (Vector3.zero);
   }
  }

  public void Move(Vector3 movement)
  {
   SetForwardAndTurn (movement);
   ApplyExtraTurnRotation();
   UpdateAnimator();
  }

  public void Kill(){
   // TODO 需要禁止角色移動
  }

  public void SetDestinaition(Vector3 worldPos){
   navMeshAgent.SetDestination = worldPos;
  }

  private void SetForwardAndTurn(Vector3 movement){
   // 將Wolrd相對的向量轉換成Local相對的向量
   if (movement.magnitude > moveThreshold) {
    movement.Normalize ();
   }
   // 將Worldspace的方向轉換成LocalSpace
   Vector3 localMovement = transform.InverseTransformDirection(movement);
   turnAmount = Mathf.Atan2(localMovement.x, localMovement.z);
   forwardAmount = localMovement.z;
  }

  void UpdateAnimator()
  {
   // update the animator parameters
   animator.SetFloat("Forward", forwardAmount, 0.1f, Time.deltaTime);
   animator.SetFloat("Turn", turnAmount, 0.1f, Time.deltaTime);
   animator.speed = animationSpeedMultiplier;
  }

  void ApplyExtraTurnRotation()
  {
   // help the character turn faster (this is in addition to root rotation in the animation)
   float turnSpeed = Mathf.Lerp(stationaryTurnSpeed, movingTurnSpeed, forwardAmount);
   transform.Rotate(0, turnAmount * turnSpeed * Time.deltaTime, 0);
  }

  void OnMouseOverWalkable(Vector3 destination){
   if (Input.GetMouseButton (0)) {
    // 設置地點為滑鼠點擊的位置
    navMeshAgent.SetDestination(destination);
    navMeshAgent.stoppingDistance = walkMoveStopRadius;
   }
  }

  void OnMouseOverEnemy(Enemy enemy){
   if (Input.GetMouseButton (0)) {
    // 設置地點為Enemy的位置
    navMeshAgent.SetDestination(enemy.transform.position);
    navMeshAgent.stoppingDistance = attackMoveStopRadius;
   }
  }

  void OnAnimatorMove(){
   if (Time.deltaTime > 0) {
    Vector3 velocity = (animator.deltaPosition * moveSpeedMultiplier) / Time.deltaTime;
    // 保持y軸的速度不變
    velocity.y = myRigidbody.velocity.y;
    myRigidbody.velocity = velocity;
   }
  }

  void OnDrawGizmos(){
   //繪製攻擊範圍
   Gizmos.color = new Color(255f, 0f, 0f, 0.5f);
   Gizmos.DrawWireSphere (transform.position, attackMoveStopRadius);
  }
 }
}

修改完成後，便可以將Player其他的組件都刪除啦！如下圖這樣刪除Component。

最後讓Player保持乾淨，只剩下Transform跟我們撰寫的Script。後面的重構會再將Movement的部分移出來，往後不管是Player、Enemy、NPC等角色，只要依據需求引入我們撰寫的Script即可，比方說NPC不需要技能也不需要血量，就引入Character、NPCAI、Movement。Enemy也可以視需求選擇引入Special Abilities等等。

所以，將這些功能解構出來的好處顯而易見！

Character打開後的屬性設定視窗如下圖。

執行遊戲以後，Character便會在Player底下自動新增組件。