UnityLeapMotion流程记录

突然接到一个LeapMotion的项目，回想起上次做LeapMotion还是在几年前，但是当时没有去记录，所以这次就相当于是重新走了一遍流程。很苦恼，赶紧记录下来。防止之后忘记。这次的需求还是比较简单的，用手滑动控制图片序列播放。

准备

• Unity版本2021.3.19f1c1
• LeapMotion一台

开始接入

Downloads – Page Array – Ultraleap

首先来到官网下载LeapMotion的必备组件

选择对应的设备，我这台设备是比较旧的。

无脑安装

安装好后还需要来到github页面下载unity-leapmotion的插件

https://github.com/ultraleap/UnityPlugin

然后导入到unity工程中

导入后找到Capsule Hands场景就是官方的示例

针对需求查看了官网文档。有两种想法：

1. 通过XRXRI and XRHands Integration - Ultraleap documentation

去用手滑动UI。

1. 获取手部追踪数据，用程序去判断，得到值，然后去改变视频的帧。

最终选择了第二种方法，觉得第二种比较简单。

创建HandControl.cs脚本

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
 
using Leap;
using Leap.Unity;
 
public class HandControl : MonoBehaviour
{
 
	public static bool Gesture_left = false;
	public static bool Gesture_right = false;
	public static bool Gesture_up = false;
	public static bool Gesture_down = false;
	public static bool Gesture_zoom = false;
	public static float movePOs = 0.0f;
 
	private LeapProvider mProvider;
	private Frame mFrame;
	private Hand mHand;
 
	public ImageSwitcher imageSwitcher;
 
 
	private Vector3 leftPosition;
	private Vector3 rightPosition;
	public static float zoom = 1.0f;
	[Tooltip("Velocity (m/s) of Palm ")]
 
	public float smallestVelocity = 1.45f;//手掌移动的最小速度
 
	[Tooltip("Velocity (m/s) of Single Direction ")]
	[Range(0, 1)]
	public float deltaVelocity = 1.0f;//单方向上手掌移动的速度
 
	// Use this for initialization
	void Start()
	{
		mProvider = FindObjectOfType<LeapProvider>() as LeapProvider;
	}
 
	// Update is called once per frame
	void Update()
	{
 
		mFrame = mProvider.CurrentFrame;//获取当前帧
										//获得手的个数
										//print ("hand num are " + mFrame.Hands.Count);
 
		if (mFrame.Hands.Count > 0)
		{
			
			if (mFrame.Hands.Count == 2)
				zoom = CalcuateDistance(mFrame);
 
			if (mFrame.Hands.Count == 1)
				LRUDGestures(mFrame, ref movePOs);
		}
	}
 
 
	float CalcuateDistance(Frame mFrame)
	{
		Gesture_zoom = true;
		Gesture_left = false;
		Gesture_right = false;
 
		float distance = 0f;
		//print ("Two hands");
		foreach (var itemHands in mFrame.Hands)
		{
			if (itemHands.IsLeft)
			{
				leftPosition = itemHands.PalmPosition;
				//print ("leftPosition" + leftPosition);
			}
			if (itemHands.IsRight)
			{
				rightPosition = itemHands.PalmPosition;
				//print ("rightPosition" + rightPosition);
			}
		}
 
		if (leftPosition != Vector3.zero && rightPosition != Vector3.zero)
		{
 
			Vector3 leftPos = new Vector3(leftPosition.x, leftPosition.y, leftPosition.z);
			Vector3 rightPos = new Vector3(rightPosition.x, rightPosition.y, rightPosition.z);
 
			distance = 10 * Vector3.Distance(leftPos, rightPos);
			//print("distance" + distance);
		}
 
		if (distance != 0)
			return distance;
		else
			return distance = 1;
	}
 
 
 
 
	void LRUDGestures(Frame mFrame, ref float movePOs)
	{
		Gesture_zoom = false;
		foreach (var item in mFrame.Hands)
		{
			int numFinger = item.Fingers.Count;
			//print ("item is  " + numFinger);
 
			//print("hand are " + isOpenFullHand (item));
			// print ("isOpenFullHands is  " + isOpenFullHands(item));
 
 
			if (item.GrabStrength == 1)
			{
				
 
			}
			else if (item.GrabStrength == 0)
			{
				//print ("num is 5, open your hand");
				//print("PalmVelocity" + item.PalmVelocity);
				//print("PalmPosition" + item.PalmPosition);
				movePOs = item.PalmPosition.x;
				if (isMoveLeft(item))
				{
					Gesture_left = true;
					Gesture_right = false;
					//print("move left");
 
				}
				else if (isMoveRight(item))
				{
					Gesture_left = false;
					Gesture_right = true;
					//print("move Right");
 
				}
				else if (isMoveUp(item))
				{
					Gesture_left = false;
					Gesture_right = false;
					print("move Up");
					imageSwitcher.PreviousImage();
				}
				else if (isMoveDown(item))
				{
					Gesture_left = false;
					Gesture_right = false;
					print("move Down");
					imageSwitcher.NextImage();
 
				}
				else if (isMoveForward(item))
				{
					Gesture_left = false;
					Gesture_right = false;
					print("move Forward");
					imageSwitcher.PreviousImage();
				}
				else if (isMoveBack(item))
				{
					Gesture_left = false;
					Gesture_right = false;
					print("move back");
					imageSwitcher.NextImage();
				}
			}
		}
	}
 
 
 
	private bool isStone(Hand hand)
	{
		//print ("hand.GrabAngle" + hand.GrabAngle);
		return hand.GrabStrength > 2.0f;
	}
	//是否抓取
	public bool isGrabHand(Hand hand)
	{
		return hand.GrabStrength > 0.8f;        //抓取力 
	}
 
 
	//hand move four direction
	public bool isMoveRight(Hand hand)
	{
 
		return hand.PalmVelocity.x > deltaVelocity && !isStationary(hand);
	}
 
	// 手划向右边
	public bool isMoveLeft(Hand hand)
	{
 
		//print (hand.PalmVelocity.x );
		return hand.PalmVelocity.x < -deltaVelocity && !isStationary(hand);
	}
 
	//手向上 
	public bool isMoveUp(Hand hand)
	{
		//print ("hand.PalmVelocity.y" + hand.PalmVelocity.y);
 
		return hand.PalmVelocity.y > deltaVelocity && !isStationary(hand);
	}
 
	//手向下  
	public bool isMoveDown(Hand hand)
	{
		return hand.PalmVelocity.y < -deltaVelocity && !isStationary(hand);
	}
 
 
	//手向前
	public bool isMoveForward(Hand hand)
	{
		//print (hand.PalmVelocity.z);
		return hand.PalmVelocity.z > deltaVelocity && !isStationary(hand);
	}
 
	//手向后 
	public bool isMoveBack(Hand hand)
	{
		return hand.PalmVelocity.z < -deltaVelocity && !isStationary(hand);
	}
 
	//固定不动的
	public bool isStationary(Hand hand)
	{
		return hand.PalmVelocity.magnitude < smallestVelocity;      //Vector3.Magnitude返回向量的长度
	}
 
 
}
 

创建ImageSwitcher.cs脚本

using UnityEngine;
using UnityEngine.UI; // 引入UI命名空间
 
public class ImageSwitcher : MonoBehaviour
{
    public Image displayImage; // 用于显示图片的Image组件
    public Sprite[] images; // 存储所有图片的数组
    private int currentImageIndex = 0; // 当前显示的图片索引
 
    void Start()
    {
        // 初始化时显示第一张图片
        if (images.Length > 0)
        {
            displayImage.sprite = images[currentImageIndex];
        }
    }
 
    // 切换到下一张图片
    public void NextImage()
    {
        if (images.Length > 0)
        {
            currentImageIndex = (currentImageIndex + 1) % images.Length; // 使用模运算确保索引循环
            displayImage.sprite = images[currentImageIndex];
        }
    }
 
    // 切换到上一张图片
    public void PreviousImage()
    {
        if (images.Length > 0)
        {
            currentImageIndex = (currentImageIndex - 1 + images.Length) % images.Length; // 使用模运算确保索引循环
            displayImage.sprite = images[currentImageIndex];
        }
    }
}

将两个脚本挂载在场景中并赋值

image switcher中的images将准备好的序列帧拖入

创建Canvas和Image。将image拖入image Switcher中

最终场景是这样的结构。使用的场景是官方的Capsule Hands。

成功运行。这个项目比较简单，开发的时候也没有遇到坑，在此记录下防止后面忘了流程。

官方文档

Get started with our plugins for XR developers - Ultraleap documentation