摄像机碰到后面物体缩进视口（消隐，滚轴，距离）

var camera1:Camera;           //摄像机

var mousescrollwheel:float;      //鼠标中间滚轮，不要修改默认值
var sensitivityW:float=5;         //鼠标滚轮敏捷性

var nearview:float=0;              //鼠标滚轮滚动 控制摄像机离设定点的最近距离
var farview:float=-10;              //鼠标滚轮滚动 控制摄像机离设定点的最远距离
function Start ()
{
    mousescrollwheel=camera1.transform.localPosition.z;
}

function Update () {
    if (camera1==null){
        return;
    }
    mousescrollwheel += Input.GetAxis("Mouse ScrollWheel")*sensitivityW;
    if(mousescrollwheel>nearview)
    {
        mousescrollwheel=nearview;
    }
    else if(mousescrollwheel<farview)
    {
        mousescrollwheel=farview;
    }
    camera1.transform.localPosition.z=mousescrollwheel;
    var fwd = -transform.TransformDirection (Vector3.forward);

    var hit : RaycastHit;
    if (Physics.Raycast (transform.position, fwd, hit, -farview))
    {
    if(hit.transform.tag!="renwu")     //当检查到的物体的标签不为人物的时候。
    {
        var cameraz =(hit.point- transform.position).magnitude;
        print(cameraz);
        if(-cameraz>mousescrollwheel)      //摄像机与背后物体的距离大于滚轴的距离时
        {
            camera1.transform.localPosition.z=-cameraz;
        }
    }
}

//人物透明
if(camera1.transform.localPosition.z>=-1.5&&camera1.transform.localPosition.z<=-0.8)
{
    renderer.material.color.a = 0.3;
}
else if(camera1.transform.localPosition.z>-0.8)
{
    renderer.material.color.a = 0;
}
else
{
    renderer.material.color.a =1;
}

}