unity5 JoyJoystick分析

参考雨松momo 的《Unity3D研究院之IOS自定义游戏摇杆与飞机平滑的移动（十一）》一文

地址：http://www.xuanyusong.com/archives/526

文中的JoyJoystick脚本是Unity自带的比较旧的脚本，我这儿是针对Unity新的脚本进行分析；

Joystick.cs是官方提供的脚本，具体代码如下:

using System;
using UnityEngine;
using UnityEngine.EventSystems;

namespace UnityStandardAssets.CrossPlatformInput
{
	public class Joystick : MonoBehaviour, IPointerDownHandler, IPointerUpHandler, IDragHandler
	{
		public enum AxisOption
		{
			// Options for which axes to use
			Both, // Use both
			OnlyHorizontal, // Only horizontal
			OnlyVertical // Only vertical
		}

		public int MovementRange = 100;
		public AxisOption axesToUse = AxisOption.Both; // The options for the axes that the still will use
		public string horizontalAxisName = "Horizontal"; // The name given to the horizontal axis for the cross platform input
		public string verticalAxisName = "Vertical"; // The name given to the vertical axis for the cross platform input

		Vector3 m_StartPos;
		bool m_UseX; // Toggle for using the x axis
		bool m_UseY; // Toggle for using the Y axis
		CrossPlatformInputManager.VirtualAxis m_HorizontalVirtualAxis; // Reference to the joystick in the cross platform input
		CrossPlatformInputManager.VirtualAxis m_VerticalVirtualAxis; // Reference to the joystick in the cross platform input

		void OnEnable()
		{
			CreateVirtualAxes();
		}

        void Start()
        {
            m_StartPos = transform.position;
        }

		void UpdateVirtualAxes(Vector3 value)
		{
			var delta = m_StartPos - value;          
			delta.y = -delta.y;
			delta /= MovementRange;

            //圆形           
            if (Vector3.SqrMagnitude(delta)>1)
            {
                delta = delta.normalized;
            }
           // Debug.Log(Vector3.SqrMagnitude(delta));


            if (m_UseX)
			{
				m_HorizontalVirtualAxis.Update(-delta.x);
			}

			if (m_UseY)
			{
				m_VerticalVirtualAxis.Update(delta.y);
			}
		}

		void CreateVirtualAxes()
		{
			// set axes to use
			m_UseX = (axesToUse == AxisOption.Both || axesToUse == AxisOption.OnlyHorizontal);
			m_UseY = (axesToUse == AxisOption.Both || axesToUse == AxisOption.OnlyVertical);

			// create new axes based on axes to use
			if (m_UseX)
			{
				m_HorizontalVirtualAxis = new CrossPlatformInputManager.VirtualAxis(horizontalAxisName);
				CrossPlatformInputManager.RegisterVirtualAxis(m_HorizontalVirtualAxis);
			}
			if (m_UseY)
			{
				m_VerticalVirtualAxis = new CrossPlatformInputManager.VirtualAxis(verticalAxisName);
				CrossPlatformInputManager.RegisterVirtualAxis(m_VerticalVirtualAxis);
			}
		}


		public void OnDrag(PointerEventData data)
		{
			Vector3 newPos = Vector3.zero;

			if (m_UseX)
			{
				int delta = (int)(data.position.x - m_StartPos.x);
				delta = Mathf.Clamp(delta, - MovementRange, MovementRange);
				newPos.x = delta;
			}

			if (m_UseY)
			{
				int delta = (int)(data.position.y - m_StartPos.y);
				delta = Mathf.Clamp(delta, -MovementRange, MovementRange);
				newPos.y = delta;
			}
			transform.position = new Vector3(m_StartPos.x + newPos.x, m_StartPos.y + newPos.y, m_StartPos.z + newPos.z);
			UpdateVirtualAxes(transform.position);
		}


		public void OnPointerUp(PointerEventData data)
		{
			transform.position = m_StartPos;
			UpdateVirtualAxes(m_StartPos);
		}


		public void OnPointerDown(PointerEventData data) { }

		void OnDisable()
		{
			// remove the joysticks from the cross platform input
			if (m_UseX)
			{
				m_HorizontalVirtualAxis.Remove();
			}
			if (m_UseY)
			{
				m_VerticalVirtualAxis.Remove();
			}
		}
	}
}

我这里是对原文 Main.js 的改编，我这里用的语言是C#：

using UnityEngine;
using System.Collections;
using UnityStandardAssets.CrossPlatformInput;
using UnityEngine.UI;
public class Main : MonoBehaviour {
    public Joystick moveJoystick;
    public Image plan;//飞机贴图
    //飞机在屏幕中的坐标
    float x = 0.0f;
    float y = 0.0f;
    //避免飞机飞出屏幕，分别是X，Y最大坐标 ，最小坐标是0，0
    float cross_x = 0;
    float cross_y = 0;

    float planSpeed = 20.0f;//飞机移动速度

    // Use this for initialization
    void Start()
    {
        x = 200.0f;
        y = 200.0f;

        cross_x = Screen.width - plan.GetComponent().rect.width * 0.5f;
        cross_y = Screen.height - plan.GetComponent().rect.height*0.5f;     
    }

    // Update is called once per frame
    void Update()
    {
        //得到游戏摇杆的反馈信息  得到是-1到1之间  
        //官方CrossPlatformInput核心是提出了PC和手机输入的兼容方案
        float touchKey_x = CrossPlatformInputManager.GetAxis(moveJoystick.horizontalAxisName);
        float touchKey_y = CrossPlatformInputManager.GetAxis(moveJoystick.verticalAxisName);
        //摇杆向左
        if (touchKey_x<0)
        {
            x -= planSpeed;
        }
        else if (touchKey_x>0)
        {
            x += planSpeed;
        }
        //摇杆向xia
        if (touchKey_y <0)
        {
            y -= planSpeed;
        }
        else if (touchKey_y >0)
        {
            y+= planSpeed;
        }

        //防止飞机飞出屏幕，出界检测
        if (x < 50)
        {
            x = 50;
        }
        else if (x > cross_x)
        {
            x = cross_x;
        }

        if (y < 150)
        {
            y = 150;
        }
        else if (y > cross_y)
        {
            y = cross_y;
        }
        plan.GetComponent().position= new Vector3(x,y,0);
    }
}

这里需要注意的几点是：

引用需要增加

using UnityStandardAssets.CrossPlatformInput;
using UnityEngine.UI;

另外就是获取游戏摇杆的反馈信息这儿

 float touchKey_x = CrossPlatformInputManager.GetAxis(moveJoystick.horizontalAxisName);
        float touchKey_y = CrossPlatformInputManager.GetAxis(moveJoystick.verticalAxisName);