Unity3D实现人物转向与移动

using UnityEngine;
using System.Collections;
using System.Linq;
public class move: MonoBehaviour
{
 private int State;//角色状态
 private int oldState=0;//前一次角色的状态
 private int UP = 0;//角色状态向前
 private int RIGHT =1;//角色状态向右
 private int DOWN = 2;//角色状态向后
 private int LEFT = 3;//角色状态向左
 
 public float speed=8;
 
 void Start()
 {
 }
 void Update()
 {
 if (Input.GetKey("w"))
 {
  setState(UP);
 }
 else if (Input.GetKey("s"))
 {
  setState(DOWN);
 }
 
 if (Input.GetKey("a"))
 {
  setState(LEFT);
 }
 else if (Input.GetKey("d"))
 {
  setState(RIGHT);
 }
 
 }
 
 
 void setState(int currState)
 {
 Vector3 transformValue = new Vector3();//定义平移向量
 int rotateValue = (currState - State) * 90;
 transform.animation.Play("walk");//播放角色行走动画
 switch (currState)
 {
 case 0://角色状态向前时，角色不断向前缓慢移动
  transformValue = Vector3.forward * Time.deltaTime * speed;
  break;
 case 1://角色状态向右时。角色不断向右缓慢移动
  transformValue = Vector3.right * Time.deltaTime * speed;
  break;
 case 2://角色状态向后时。角色不断向后缓慢移动
  transformValue = Vector3.back * Time.deltaTime * speed;
  break;
 case 3://角色状态向左时，角色不断向左缓慢移动
  transformValue = Vector3.left * Time.deltaTime * speed;
  break;
 }
 transform.Rotate(Vector3.up, rotateValue);//旋转角色
 transform.Translate(transformValue, Space.World);//平移角色
 oldState = State;//赋值，方便下一次计算
 State = currState;//赋值，方便下一次计算
 }
 
 
}