Vuforia在Unity中屏幕坐标转世界坐标,并使用lineRender画线，手指画线，选中物体并拖拽

前段时间一直在琢磨vuforia for android ,考虑在这样的情况下：世界坐标中有多个物体，选中其中某个物体开始连线到另一个物体，没想到vuforia for android 太坑了，花了很长时间也没有实现。在vuforia for android中使用的是OPENGL.ES2.0实现画各种图形，vuforia会得到一个最终矩阵，把它传入OPENGL，再传入要画的图形的坐标，就可以画出ar的效果，但是得不到经过以上过程后图形的最终坐标，所以点击的时候无法做出点击时间。无奈之下换成vuforia for unity，之前的问题都很容易解决了。

1.选中物体：在世界坐标下在多个物体中通过点击选中某个物体

2.拖拽物体：在世界坐标下选中某个物体并让物体跟着手指移动

3.手指画线：使用linerender，实现手指画线

选中物体

void Update () {
Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
RaycastHit hit ;
if (Physics.Raycast(ray, out hit))
{

Debug.Log("产生碰撞，并且碰撞体的名字是:"+hit.collider.name);
}
else {
Debug.Log("没有碰撞");
}
}

想要点击的物体要添加碰撞体如box collider，如果是sphere，添加sphere collider等。。

拖拽物体：

using UnityEngine;
using System.Collections;
public class DragObject : MonoBehaviour
{
private Transform pickedObject = null;
private Vector3 lastPlanePoint;
// Use this for initialization
void Start()
{
}
// Update is called once per frame
void Update()
{
//创建一个平面
Plane targetPlane = new Plane(transform.up, transform.position);
foreach (Touch touch in Input.touches)
{
//获取摄像头近平面到屏幕触摸点的射线
Ray ray = Camera.main.ScreenPointToRay(touch.position);
//获取射线沿着plane的距离
float dist = 0.0f;
targetPlane.Raycast(ray, out dist);
//获取沿着射线在距离dist位置的点
Vector3 planePoint = ray.GetPoint(dist);
//Debug.Log("Point=" + planePoint);
//按下手指触碰屏幕
if (touch.phase == TouchPhase.Began)
{
RaycastHit hit = new RaycastHit();
// 判断是否有碰撞到对象
if (Physics.Raycast(ray, out hit, 1000))
{
pickedObject = hit.transform;
lastPlanePoint = planePoint;
}
else
{
pickedObject = null;
}
//选中模型后拖拽
}
else if (touch.phase == TouchPhase.Moved)
{
if (pickedObject != null)
{
pickedObject.position += planePoint - lastPlanePoint;
lastPlanePoint = planePoint;
}
//释放
}
else if (touch.phase == TouchPhase.Ended)
{
pickedObject = null;
}
}
}
}

给想要拖拽的物体绑定碰撞体，否则上述代码没用

**

手指画线

**

创建一个空物体，添加lienrender组件，修改名字为Line，上个有色材质,再创建一个Plane物体，给Plane添加碰撞体，上个透明材质，这样点击后产生的射线才有可能产生碰撞

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
public class LineHelper3 : MonoBehaviour {
int lineSeg = 1;
RaycastHit rh ;
List<GameObject> pointPos;
LineRenderer lr;
GameObject pointer ;
bool start_point = true;
void Start()
{
pointer = new GameObject();
gameObject.SetActive(true);
lr = gameObject.GetComponent(typeof(LineRenderer)) as LineRenderer;
lr.SetWidth(1f, 1f);
}

// Update is called once per frame
void Update()
{
if (Input.GetTouch(0).phase == TouchPhase.Began)
{
Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
rh = new RaycastHit();
lr.SetVertexCount(1);
if (Physics.Raycast(ray, out rh))
{
pointPos.Add(DrawLine(rh, 0));
}
}
if (Input.GetTouch(0).phase == TouchPhase.Moved)
{

Ray ray = Camera.main.ScreenPointToRay(Input.GetTouch(0).position);
rh = new RaycastHit();
lr.SetVertexCount(2);
if (Physics.Raycast(ray, out rh))
{
pointPos.Add(DrawLine(rh, 1));
}

}
if (Input.GetTouch(0).phase == TouchPhase.Ended)
{
start_point = true;
lr.SetVertexCount(0);
lr.SetPosition(0, new Vector3(0, 0, 0));
lr.SetPosition(1, new Vector3(0, 0, 0));

}

}

GameObject DrawLine(RaycastHit pointPos,int start_or_end)
{

//Display point
GameObject gb_pointer = GameObject.Instantiate(pointer) as GameObject;
gb_pointer.transform.position = pointPos.point + (transform.position - pointPos.point) * 0.01f;
gb_pointer.transform.rotation = Quaternion.LookRotation(pointPos.normal, Camera.main.transform.up);
Vector3 laserpos = new Vector3();
laserpos.x = 90.0f;
laserpos.y = gb_pointer.transform.position.y;
laserpos.z = gb_pointer.transform.position.z;
gb_pointer.transform.eulerAngles = laserpos;
lr.SetPosition(start_or_end, pointPos.point);   //设置目标点的坐标，使用的是world坐标系
//lineSeg++;
return gb_pointer;
}

void DestroyLine()
{
int arrayLength = pointPos.Count;
if (arrayLength > 0)
{
GameObject.Destroy(pointPos[arrayLength - 1]);
pointPos.RemoveAt(arrayLength - 1);
//lr.SetVertexCount(--lineSeg);

}
}
}