Unity 手指上下左右滑动的判定

using UnityEngine;
using System.Collections;

public class jarodInputController : MonoBehaviour {


private float fingerActionSensitivity = Screen.width * 0.05f; //手指动作的敏感度，这里设定为 二十分之一的屏幕宽度.
//
private float fingerBeginX;
private float fingerBeginY;
private float fingerCurrentX;
private float fingerCurrentY;
private float fingerSegmentX;
private float fingerSegmentY;
//
private int fingerTouchState;
//
private int FINGER_STATE_NULL = 0;
private int FINGER_STATE_TOUCH = 1;
private int FINGER_STATE_ADD = 2;
// Use this for initialization
void Start () 
{
fingerActionSensitivity = Screen.width * 0.05f;

fingerBeginX = 0;
fingerBeginY = 0;
fingerCurrentX = 0;
fingerCurrentY = 0;
fingerSegmentX = 0;
fingerSegmentY = 0;

fingerTouchState = FINGER_STATE_NULL;
}
// Update is called once per frame
void Update ()
{

if (Input.GetKeyDown (KeyCode.Mouse0)) 
{

if(fingerTouchState == FINGER_STATE_NULL)
{
fingerTouchState = FINGER_STATE_TOUCH;
fingerBeginX = Input.mousePosition.x;
fingerBeginY = Input.mousePosition.y;
}

}

if(fingerTouchState == FINGER_STATE_TOUCH)
{
fingerCurrentX = Input.mousePosition.x;
fingerCurrentY = Input.mousePosition.y;
fingerSegmentX = fingerCurrentX - fingerBeginX;
fingerSegmentY = fingerCurrentY - fingerBeginY;

}


if (fingerTouchState == FINGER_STATE_TOUCH) 
{
float fingerDistance = fingerSegmentX*fingerSegmentX + fingerSegmentY*fingerSegmentY; 

if (fingerDistance > (fingerActionSensitivity*fingerActionSensitivity))
{
toAddFingerAction();
}
}

if (Input.GetKeyUp(KeyCode.Mouse0))
{
fingerTouchState = FINGER_STATE_NULL;
}
}

private void toAddFingerAction()
{

fingerTouchState = FINGER_STATE_ADD;

if (Mathf.Abs (fingerSegmentX) > Mathf.Abs (fingerSegmentY)) 
{
fingerSegmentY = 0;
} 
else 
{
fingerSegmentX = 0;
}

if (fingerSegmentX == 0) 
{
if (fingerSegmentY > 0) 
{
Debug.Log ("up");
} 
else {
Debug.Log ("down");
}
} 
else if(fingerSegmentY == 0) 
{
if(fingerSegmentX > 0)
{
Debug.Log ("right");
}
else
{
Debug.Log("left");
}
}

}
}