MissileTest

using UnityEngine;
using System.Collections;

public enum eMissilePhase
{
    MoveForward,
    MoveOnCircle,
    ChaseTarget,
}
public class MissileTest : MonoBehaviour
{
    public float Radius = 5;
    public Transform bullet;
    public Transform target;
    public Vector3 OriginPos;
    public float speed = 3;
    public float distance;

    private eMissilePhase mState=eMissilePhase.MoveForward;
    public float ForwardTime = 1;
    private float mCurForwardTime = 0;
    public float angle;
    public float turnSpeed = 3;
	// Use this for initialization
	void Start () {
	
	}
	
	// Update is called once per frame
	void Update ()
	{

	    if (mState == eMissilePhase.MoveForward)
	    {
	        Vector3 dir = Vector3.right;
	        bullet.position += dir*Time.deltaTime*speed;
	        bullet.rotation = Quaternion.LookRotation(dir, Vector3.up);
	        mCurForwardTime += Time.deltaTime;
	        if (mCurForwardTime >= ForwardTime)
	        {
	            mState=eMissilePhase.MoveOnCircle;
	            OriginPos = bullet.position + Vector3.up*Radius;
	        }

	    }else if (mState == eMissilePhase.MoveOnCircle)
	    {
	        distance += Time.deltaTime*speed;
	        angle = (0.5f*distance/Radius);
	        Vector3 targetPos = Vector3.zero;
	        targetPos.x = Mathf.Sin(angle)*Radius;
	        targetPos.y = -Mathf.Cos(angle)*Radius;
            targetPos=OriginPos+ targetPos;
	        bullet.position = targetPos;
            //忽略Z  轴， 所以可以这样算出圆上点的切线方向
	        Vector3 tangentDir = Vector3.Cross(Vector3.forward, (targetPos - OriginPos).normalized);
            bullet.rotation = Quaternion.LookRotation(tangentDir, Vector3.forward);
	        if (angle >= Mathf.PI)
	        {
	            mState=eMissilePhase.ChaseTarget;
	        }
	    }
	    else
	    {
            Quaternion newRotation = Quaternion.LookRotation(target.position - bullet.position, Vector3.up);
            bullet.rotation = Quaternion.Slerp(bullet.rotation, newRotation, Time.deltaTime * turnSpeed);

//	        Vector3 dir = (target.position - bullet.position).normalized;
            Vector3 dir = bullet.forward;
	        bullet.position += dir*speed*Time.deltaTime;
          

	    }
	}



   
}