unity摄像机投影

摄像机分为两种，一种是正交摄像机还有一种是透视摄像机。正交摄像机无论远近它的视口范围永远是固定的，但是透视摄像机是由原点向外扩散性发射，也就是距离越远它的视口区域也就越大。那么我们如何获取距离摄像机任意距离的视口区域呢？如下图所示，分别用红色和黄色两种颜色将计算出来的视口区域标记了出来。

 

下面上代码，把如下脚本挂在摄像机出直接运行游戏即可看到。

using UnityEngine;using System.Collections;public class Demo : MonoBehaviour{    private Camera theCamera;    //距离摄像机8.5米 用黄色表示    public float upperDistance = 1.0f;    //距离摄像机30米 用红色表示    public float lowerDistance = 20.0f;    private Transform tx;    private bool isFirst = true;    void Start()    {        if (!theCamera)        {            theCamera = Camera.main;        }        tx = theCamera.transform;    }    void Update()    {        FindUpperCorners();        FindLowerCorners();    }    void FindUpperCorners()    {        Vector3[] corners = GetCorners(upperDistance);        // for debugging        Debug.DrawLine(corners[0], corners[1], Color.yellow); // UpperLeft -> UpperRight        Debug.DrawLine(corners[1], corners[3], Color.yellow); // UpperRight -> LowerRight        Debug.DrawLine(corners[3], corners[2], Color.yellow); // LowerRight -> LowerLeft        Debug.DrawLine(corners[2], corners[0], Color.yellow); // LowerLeft -> UpperLeft    }    void FindLowerCorners()    {        Vector3[] corners = GetCorners(lowerDistance);        // for debugging        Debug.DrawLine(corners[0], corners[1], Color.red);        Debug.DrawLine(corners[1], corners[3], Color.red);        Debug.DrawLine(corners[3], corners[2], Color.red);        Debug.DrawLine(corners[2], corners[0], Color.red);        //if (isFirst == false)        //    return;        Vector3 cornersFirst = (corners[0] + corners[1])/2;        Vector3 cornersSecord = (corners[2] + corners[3])/2;        Vector3 finalCorners = (cornersFirst + cornersSecord) / 2;        Debug.LogWarning("finalCorners.x = " + finalCorners.x + ",finalCorners.y =" + finalCorners.y + ",finalCorners.z = " + finalCorners.z);        GameObject obj = GameObject.FindWithTag("BattleBg");        obj.transform.position = finalCorners;        GameObject cameraParent = GameObject.Find("SmartCamera");        if (null == cameraParent)            return;        Debug.LogWarning("world , UpperLeft, corners[0].x = " + corners[0].x + ",[0].y = " + corners[0].y + ",[0].z = " + corners[0].z);        Debug.LogWarning("world , UpperRight, corners[1].x = " + corners[1].x + ",[1].y = " + corners[1].y + ",[1].z = " + corners[1].z);        Debug.LogWarning("world,  LowerLeft,  corners[2].x = " + corners[2].x + ",[2].y = " + corners[2].y + ",[2].z = " + corners[2].z);        Debug.LogWarning("world , LowerRight,corners[3].x = " + corners[3].x + ",[3].y = " + corners[3].y + ",[3].z = " + corners[3].z);        Vector3 screenPoint1 = Camera.main.WorldToScreenPoint(corners[0]);        Vector3 screenPoint2 = Camera.main.WorldToScreenPoint(corners[1]);        Vector3 screenPoint3 = Camera.main.WorldToScreenPoint(corners[2]);        Vector3 screenPoint4 = Camera.main.WorldToScreenPoint(corners[3]);        Debug.LogWarning("screen , UpperLeft,  screenPoint1.x = " + screenPoint1.x + ",y = " + screenPoint1.y + ",z = " + screenPoint1.z);        Debug.LogWarning("screen , UpperRight, screenPoint2.x = " + screenPoint2.x + ",y = " + screenPoint2.y + ",z = " + screenPoint2.z);        Debug.LogWarning("screen,  LowerLeft,  screenPoint3.x = " + screenPoint3.x + ",y = " + screenPoint3.y + ",z = " + screenPoint3.z);        Debug.LogWarning("screen , LowerRight, screenPoint4.x = " + screenPoint4.x + ",y = " + screenPoint4.y + ",z = " + screenPoint4.z);        Vector3 meshVec = obj.GetComponent<MeshFilter>().mesh.bounds.size;        Vector3 meshRender = obj.GetComponent<MeshRenderer>().bounds.size;        //Old        Quaternion quaternion = cameraParent.transform.rotation;        Vector3 euler = quaternion.eulerAngles;        Vector3 finalVec = new Vector3(90 - euler.x, euler.y - 180, euler.z);        quaternion = Quaternion.Euler(finalVec);        obj.transform.rotation = quaternion;        //New error        //obj.transform.LookAt(cameraParent.transform);        //Quaternion quaternion = obj.transform.rotation;        //Vector3 euler = quaternion.eulerAngles;        //Vector3 finalVec = new Vector3(euler.x , euler.y , euler.z);        //quaternion = Quaternion.Euler(finalVec);        //obj.transform.rotation = quaternion;        //TODO        //obj.transform.localScale = new Vector3(2.81f, 1f, 1.27f);        float finalHeight = 1.27f;        float finalWidth = theCamera.aspect * finalHeight;                obj.transform.localScale = new Vector3(finalWidth, 1f, finalHeight);        //isFirst =false;    }    Vector3[] GetCorners(float distance)    {        Vector3[] corners = new Vector3[4];        float halfFOV = (theCamera.fieldOfView * 0.5f) * Mathf.Deg2Rad;        float aspect = theCamera.aspect;        float height = distance * Mathf.Tan(halfFOV);        float width = height * aspect;        // UpperLeft        corners[0] = tx.position - (tx.right * width);        corners[0] += tx.up * height;        corners[0] += tx.forward * distance;        // UpperRight        corners[1] = tx.position + (tx.right * width);        corners[1] += tx.up * height;        corners[1] += tx.forward * distance;        // LowerLeft        corners[2] = tx.position - (tx.right * width);        corners[2] -= tx.up * height;        corners[2] += tx.forward * distance;        // LowerRight        corners[3] = tx.position + (tx.right * width);        corners[3] -= tx.up * height;        corners[3] += tx.forward * distance;        return corners;    }}

这个脚本是我在逛国外网站无意间发现的，我这里翻译成了C#语言。http://answers.unity3d.com/questions/509466/scale-box-collider-to-camera-view-1.html?sort=oldest

我们可以根据文章里的算法计算出视口3D的坐标点，有了坐标信息那么想干什么都好干了，呵呵。

 

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