【Unity渲染】Camera RenderToCubemap 渲染到立方体纹理

Unity圣典 传送门：http://www.ceeger.com/Script/Camera/Camera.RenderToCubemap.html

Camera.RenderToCubemap 有4个重载

（1）bool  RenderToCubemap(Cubemap cubemap)

　　  bool  RenderToCubemap(Cubemap cubemap,int faceMask)

　　可以用于在编辑器中生成场景静态立方体贴图。faceMask是一个bitfield比特数，表示那个立方贴图面应该被渲染，每个位对

应于一个面。比特数是Cubemapface枚举的整型值。默认的所有六个立方贴图面都被渲染（默认值63的低6位是打开的）。

 // Render scene from a given point into a static cube map.
 //从给定的点渲染场景到以静态立方贴图
 // Place this script in Editor folder of your project.
 //放置这个脚本到工程的Editor文件夹中
 // Then use the cubemap with one of Reflective shaders!
 //然后用一个Reflective shaders 来使用这个立方贴图
 class RenderCubemapWizard extends ScriptableWizard {
     var renderFromPosition : Transform;
     var cubemap : Cubemap;

     function OnWizardUpdate () {
         helpString = "Select transform to render from and cubemap to render into";
         isValid = (renderFromPosition != null) && (cubemap != null);
     }

     function OnWizardCreate () {
         // create temporary camera for rendering
         //为渲染创建临时相机
         var go = new GameObject( "CubemapCamera", Camera );
         // place it on the object
         //放置它到物体上
         go.transform.position = renderFromPosition.position;
         go.transform.rotation = Quaternion.identity;

         // render into cubemap
         //渲染到立方贴图
         go.camera.RenderToCubemap( cubemap );

         // destroy temporary camera
         //销毁临时相机
         DestroyImmediate( go );
     }

     @MenuItem("GameObject/Render into Cubemap")
     static function RenderCubemap () {
         ScriptableWizard.DisplayWizard.<RenderCubemapWizard>(
         "Render cubemap", "Render!");
     }
 }

（2）bool  RenderToCubemap(RenderTexture cubemap)

bool  RenderToCubemap(RenderTexture cubemap,int faceMask)

这个用于实时反射到立方贴图渲染纹理。这是非常耗时的，尤其是所有六个立方贴图面在每一帧中都被渲染。

如果渲染失败这个函数将返回false，某些显卡不支持这个函数。

　　同时,一定要将 RenderTexture.isCubemap = true

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 using UnityEditor;

 // Attach this script to an object that uses a Reflective shader.
 // Realtime reflective cubemaps!
 //附加这个脚本到使用了Reflective shader的物体上
 //实时反射立方贴图
 [ExecuteInEditMode]
 public class RealtimeCubemap :MonoBehaviour
 {
     int cubemapSize = ;
     //一帧渲染一面
     bool oneFacePerFrame = false;
     Camera cam = null;
     RenderTexture cubemap = null;
     Material mat = null;

     void Start()
     {
         //在启动时渲染所有六个面
         UpdateCubemap();
     }

     void LateUpdate()
     {
         if (oneFacePerFrame)
         {
             int faceToRender = Time.frameCount % ;
             int faceMask =  << faceToRender;
             UpdateCubemap(faceMask);
         }
         else
         {
             //所有六个面
             UpdateCubemap();
         }
     }

 void UpdateCubemap (int faceMask )
 {
     if (cam == null)
     {
         GameObject go = new GameObject("CubemapCamera", typeof(Camera));

         //隐藏在场景中
         go.hideFlags = HideFlags.HideAndDontSave;
         go.transform.position = transform.position;
         go.transform.rotation = Quaternion.identity;
         cam = go.GetComponent<Camera>();

         ///不要渲染较远的部分
         cam.farClipPlane = ;
         cam.enabled = false;
     }
     if (mat == null)
     {
         mat = new Material(Shader.Find("Custom/RealtimeCubemap"));
         mat.hideFlags = HideFlags.HideAndDontSave;
         GetComponent<Renderer>().material = mat;
     }

     if (cubemap == null)
     {
         cubemap = new RenderTexture(cubemapSize, cubemapSize, );
         cubemap.isPowerOfTwo = true;
         cubemap.isCubemap = true;
         cubemap.hideFlags = HideFlags.HideAndDontSave;
         mat.SetTexture("_Cubemap", cubemap);
     }

     cam.transform.position = transform.position;
     cam.RenderToCubemap(cubemap, faceMask);
 }

     void OnDisable()
     {
         DestroyImmediate(cam);
         DestroyImmediate(cubemap);
     }

 }