解决Unity鼠标坐标点转成世界坐标系坐标点

第一种：

这是一种发射线，获取当前点击的物体（具有碰撞器）的坐标点（也就是碰撞器范围的坐标点）

if (Input.GetMouseButtonDown(0))

{

RaycastHit hitt = new RaycastHit();

Ray ray =Camera.main.ScreenPointToRay(Input.mousePosition);

Physics.Raycast(ray, out hitt);

Debug.Log(hitt.point);

//Debug.Log(Camera.main.ScreenToWorldPoint(Input.mousePosition));

}

第二种：
Camera TempC;//定义摄像机变量

private void Start()

{
TempC = this.GetComponent<Camera>();//获取摄像机的组件
Camera

}

void Update()

{

if(Input.GetMouseButtonDown(0))

{

Debug.Log(TempC.ScreenToWorldPoint(new Vector3(Input.mousePosition.x,Input.mousePosition.y, 10.0f)));

}

}
注意：这里容易出现的问题是，从鼠标坐标点转成世界坐标点的时候，新的三维向量Z轴的赋值必须不能是0.0f，因为，屏幕坐 标点的Z轴，其实是相对于当前摄像机的，如果是0，只能转一次世界坐标系，剩下的不管点哪里都是一个值，所以不能把Z值设为和摄像机的Z坐标重合，我们需要设置一个非0的数字，最后转成世界坐标系后的值是，摄像机的Z轴加上所设置的值。例如当前摄像机Z坐标是10f，我所设置的Z值是10f，最后转成世界坐标系后的Z值就是20；下面是老外的经典回复。

Thereare two problems here. The first one is that you need a 'new' in front of yourVector3() in C#. The second is that the 'z' parameter must be the distance infront of the camera. In perspective mode at least, passing 0 will
causeScreenToWorldPoint() to always return the position of the camera. So the callwill look something like:

worldPos
=
Camera.main.ScreenToWorldPoint(new
Vector3(Input.mousePosition.x,Input.mousePosition.y,
10.0f));

Notethe measurement for the 'z' parameter is from camera plane to the playingsurface plane. It is not the distance between the camera and the object. If thecamera is aligned with the axes, then the distance is easy to calculate.
If thecamera is at an angle (i.e. not axes aligned), then ScreenToWorldPoint() is notthe way to go.

来自 <http://answers.unity3d.com/questions/599097/need-help-understanding-screentoworldpoint.html?sort=votes>