Blur CubeMap

有時候會需要Blur CubeMap
例如 要用 CubeMap的Mip Map表現 roughness時
但一般自動產生的mip map邊緣會不連續

這時候可以用cubemapgen/產生連續的mip map結果

產生出來的圖，再到Unity裡讀進來，建立CubeMap

 using UnityEngine;  
 using System.Collections;  
 using System;  
 public class BlurCubeMap : MonoBehaviour {  
      public Cubemap TextureCube;  
      public Texture2D [] mTexture;  
      CubemapFace[] faces = {CubemapFace.PositiveX, CubemapFace.NegativeX, CubemapFace.PositiveY, CubemapFace.NegativeY, CubemapFace.PositiveZ, CubemapFace.NegativeZ };  
      // Use this for initialization  
      void Start () {  
       int miplevel = 0;  
       if(mTexture.Length > 0)  
       {  
           miplevel = mTexture[0].mipmapCount;  
       }  
      // TextureCube = new Cubemap (256, TextureFormat.ARGB32, true);  
       for(int i = 0; i <6 ; ++i){  
                for(int m = 0 ; m < miplevel; ++m)  
                {  
                     Color[] c = mTexture[i].GetPixels(m);  
                     //mip map level 6 is stranger   
                     if(m == 6)  
                     {  
                          if(i == 0)  
                               c = mTexture[1].GetPixels(m);  
                          if(i == 1)  
                               c = mTexture[0].GetPixels(m);                                
                     }  
                     if(m == 6) //mirror it  
                     {  
                          Color[] c2 = mTexture[i].GetPixels(m);  
                          int width =(int)Math.Sqrt(c.Length);  
                          int currentidx = 0;  
                          for(int idx = 0; idx < width; ++idx)  
                          {  
                               for(int idx2 = 0; idx2 < width; ++idx2)  
                               {  
                                    int switchidx = currentidx + (width -1 -(idx2 * 2));  
                                    c[currentidx] = c2[switchidx];  
                                    currentidx++;  
                               }  
                          }  
                     }  
                     else{  
                          Array.Reverse(c);  
                     }  
                     TextureCube.SetPixels(c,faces[i], m);  
                     //Debug.Log(m);  
                }  
           }  
      TextureCube.Apply(false);  
      }  
      // Update is called once per frame  
      void Update () {  
      }  
 }