一个摄像机选择碰壁脚本（初步）

var camera1:Camera;               //摄像机
var detectpoint:Transform;       //设定点
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 pnearview:float=-1;            //碰到物体后摄像机离设定点的距离
var meetdistance:float=3;         //人物靠近物体的距离

var nearview:float=-1;              //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 () {

    mousescrollwheel += Input.GetAxis("Mouse ScrollWheel")*sensitivityW;
    if(mousescrollwheel>nearview){mousescrollwheel=nearview;}
    else if(mousescrollwheel<farview){mousescrollwheel=farview;}
    camera1.transform.localPosition.z=mousescrollwheel;

    //print(camera1.transform.localPosition.z);
    
    var fwd = detectpoint.transform.TransformDirection (-(Vector3.forward));
    if (Physics.Raycast (detectpoint.transform.position, fwd, meetdistance)) {
        camera1.transform.localPosition.z=pnearview;
    }
}