1. 简介

在PC上开发时，其天空盒的效果很好，但是为Android平台Build之后，其效果简直没法看。

更为恼火的是，之后PC上的纹理效果也变差了，新加入的纹理效果都会变差，看其纹理格式，使用ETC进行了压缩。

2. Unity3D默认纹理格式问题

2.1 在导入时是否自动压缩

Edit->Preferences...

当选择此选项之后，每当导入新的纹理（无论是拖入或在文件管理器中copy），Unity3D都会根据当前平台的设置进行自动转换，此纹理转换，并不是把纹理文件进行修改，纹理文件是不动的，而是增加了一个.meta文件（如Sunny4_back.tif对应Sunny4_back.tif.meta），其中定义了很多与纹理相关的参数，其中决定此纹理格式的参数为：textureType，此文件内容如下：

fileFormatVersion: 2guid: e658bdd655d56c64eb2bf011d186cdedTextureImporter:  serializedVersion: 2  mipmaps:    mipMapMode: 0    enableMipMap: 1    linearTexture: 0    correctGamma: 0    fadeOut: 0    borderMipMap: 0    mipMapFadeDistanceStart: 1    mipMapFadeDistanceEnd: 3  bumpmap:    convertToNormalMap: 0    externalNormalMap: 0    heightScale: .25    normalMapFilter: 0  isReadable: 0  grayScaleToAlpha: 0  generateCubemap: 0  seamlessCubemap: 0  textureFormat: 4  maxTextureSize: 1024  textureSettings:    filterMode: -1    aniso: -1    mipBias: -1    wrapMode: -1  nPOTScale: 1  lightmap: 0  compressionQuality: 50  spriteMode: 0  spriteExtrude: 1  spriteMeshType: 1  alignment: 0  spritePivot: {x: .5, y: .5}  spriteBorder: {x: 0, y: 0, z: 0, w: 0}  spritePixelsToUnits: 100  alphaIsTransparency: 0  textureType: -1  buildTargetSettings: []  spriteSheet:    sprites: []  spritePackingTag:   userData:

2.2 Unity3D设置纹理格式

1) 选中纹理，纹理的Inspector窗口如下图所示：

上图显示的为Default设置，若Android平台没有单独设置，则此纹理在Anroid平台采用默认设置，若Android平台单独设置了，则采用Android平台设置的格式。Unity3D只能设置三种纹理格式：Compressed、16bits、Truecolor，若要设置其它纹理格式，则Unity3D无能为力。

2.3 在Unity3D中自定义设置纹理格式

把ChangeTextureImportSettings.cs放于Assets/Editor目录下，ChangeTextureImportSettings.cs内容如下：

using UnityEngine;using UnityEditor;// ///////////////////////////////////////////////////////////////////////////////////////////////////////////// Batch Texture import settings modifier.//// Modifies all selected textures in the project window and applies the requested modification on the// textures. Idea was to have the same choices for multiple files as you would have if you open the// import settings of a single texture. Put this into Assets/Editor and once compiled by Unity you find// the new functionality in Custom -> Texture. Enjoy! :-)//// Based on the great work of benblo in this thread:// http://forum.unity3d.com/viewtopic.php?t=16079&start=0&postdays=0&postorder=asc&highlight=textureimporter//// Developed by Martin Schultz, Decane in August 2009// e-mail: [email protected]//// Updated for Unity 3.0 by col000r in August 2010// http://col000r.blogspot.com//// /////////////////////////////////////////////////////////////////////////////////////////////////////////public class ChangeTextureImportSettingsUnity3 : ScriptableObject {    [MenuItem ("Custom/Texture/Change Texture Format/Auto Compressed")]  static void ChangeTextureFormat_AutoCompressed() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.AutomaticCompressed);   }    [MenuItem ("Custom/Texture/Change Texture Format/Auto 16bit")]  static void ChangeTextureFormat_Auto16Bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.Automatic16bit);   }    [MenuItem ("Custom/Texture/Change Texture Format/Auto Truecolor")]  static void ChangeTextureFormat_AutoTruecolor() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.AutomaticTruecolor);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGB Compressed DXT1")]  static void ChangeTextureFormat_RGB_DXT1() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.DXT1);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGB Compressed DXT5")]  static void ChangeTextureFormat_RGB_DXT5() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.DXT5);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGB 16 bit")]  static void ChangeTextureFormat_RGB_16bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.RGB16);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGB 24 bit")]  static void ChangeTextureFormat_RGB_24bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.RGB24);   }    [MenuItem ("Custom/Texture/Change Texture Format/Alpha 8 bit")]  static void ChangeTextureFormat_Alpha_8bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.Alpha8);   }    [MenuItem ("Custom/Texture/Change Texture Format/ARGB 16 bit")]  static void ChangeTextureFormat_RGBA_16bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.ARGB16);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGBA 32 bit")]  static void ChangeTextureFormat_RGBA_32bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.RGBA32);   }    [MenuItem ("Custom/Texture/Change Texture Format/ARGB 32 bit")]  static void ChangeTextureFormat_ARGB_32bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.ARGB32);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGB PVRTC 2bit")]  static void ChangeTextureFormat_RGB_PVRTC_2bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.PVRTC_RGB2);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGBA PVRTC 2bit")]  static void ChangeTextureFormat_RGBA_PVRTC_2bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.PVRTC_RGBA2);   }        [MenuItem ("Custom/Texture/Change Texture Format/RGB PVRTC 4bit")]  static void ChangeTextureFormat_RGB_PVRTC_4bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.PVRTC_RGB4);   }    [MenuItem ("Custom/Texture/Change Texture Format/RGBA PVRTC 4bit")]  static void ChangeTextureFormat_RGBA_PVRTC_4bit() {    SelectedChangeTextureFormatSettings(TextureImporterFormat.PVRTC_RGBA4);   }    // ----------------------------------------------------------------------------    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/32")]  static void ChangeTextureSize_32() {    SelectedChangeMaxTextureSize(32);   }    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/64")]  static void ChangeTextureSize_64() {    SelectedChangeMaxTextureSize(64);   }    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/128")]  static void ChangeTextureSize_128() {    SelectedChangeMaxTextureSize(128);   }    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/256")]  static void ChangeTextureSize_256() {    SelectedChangeMaxTextureSize(256);   }    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/512")]  static void ChangeTextureSize_512() {    SelectedChangeMaxTextureSize(512);   }    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/1024")]  static void ChangeTextureSize_1024() {    SelectedChangeMaxTextureSize(1024);   }    [MenuItem ("Custom/Texture/Change Texture Size/Change Max Texture Size/2048")]  static void ChangeTextureSize_2048() {    SelectedChangeMaxTextureSize(2048);   }    // ----------------------------------------------------------------------------    [MenuItem ("Custom/Texture/Change MipMap/Enable MipMap")]  static void ChangeMipMap_On() {    SelectedChangeMimMap(true);   }    [MenuItem ("Custom/Texture/Change MipMap/Disable MipMap")]  static void ChangeMipMap_Off() {    SelectedChangeMimMap(false);   }    // ----------------------------------------------------------------------------      [MenuItem ("Custom/Texture/Change Non Power of 2/None")]  static void ChangeNPOT_None() {    SelectedChangeNonPowerOf2(TextureImporterNPOTScale.None);   }    [MenuItem ("Custom/Texture/Change Non Power of 2/ToNearest")]  static void ChangeNPOT_ToNearest() {    SelectedChangeNonPowerOf2(TextureImporterNPOTScale.ToNearest);   }    [MenuItem ("Custom/Texture/Change Non Power of 2/ToLarger")]  static void ChangeNPOT_ToLarger() {    SelectedChangeNonPowerOf2(TextureImporterNPOTScale.ToLarger);   }    [MenuItem ("Custom/Texture/Change Non Power of 2/ToSmaller")]  static void ChangeNPOT_ToSmaller() {    SelectedChangeNonPowerOf2(TextureImporterNPOTScale.ToSmaller);   }        // ----------------------------------------------------------------------------    [MenuItem ("Custom/Texture/Change Is Readable/Enable")]  static void ChangeIsReadable_Yes() {    SelectedChangeIsReadable(true);   }    [MenuItem ("Custom/Texture/Change Is Readable/Disable")]  static void ChangeIsReadable_No() {    SelectedChangeIsReadable(false);   }    //Unity3D教程手册：www.unitymanual.com    // ----------------------------------------------------------------------------    static void SelectedChangeIsReadable(bool enabled) {        Object[] textures = GetSelectedTextures();    Selection.objects = new Object[0];    foreach (Texture2D texture in textures)  {      string path = AssetDatabase.GetAssetPath(texture);      TextureImporter textureImporter = AssetImporter.GetAtPath(path) as TextureImporter;      textureImporter.isReadable = enabled;          AssetDatabase.ImportAsset(path);     }   }      static void SelectedChangeNonPowerOf2(TextureImporterNPOTScale npot) {        Object[] textures = GetSelectedTextures();    Selection.objects = new Object[0];    foreach (Texture2D texture in textures)  {      string path = AssetDatabase.GetAssetPath(texture);      TextureImporter textureImporter = AssetImporter.GetAtPath(path) as TextureImporter;      textureImporter.npotScale = npot;          AssetDatabase.ImportAsset(path);     }   }    static void SelectedChangeMimMap(bool enabled) {        Object[] textures = GetSelectedTextures();    Selection.objects = new Object[0];    foreach (Texture2D texture in textures)  {      string path = AssetDatabase.GetAssetPath(texture);      TextureImporter textureImporter = AssetImporter.GetAtPath(path) as TextureImporter;      textureImporter.mipmapEnabled = enabled;          AssetDatabase.ImportAsset(path);     }   }  //Unity3D教程手册：www.unitymanual.com  static void SelectedChangeMaxTextureSize(int size) {        Object[] textures = GetSelectedTextures();    Selection.objects = new Object[0];    foreach (Texture2D texture in textures)  {      string path = AssetDatabase.GetAssetPath(texture);      TextureImporter textureImporter = AssetImporter.GetAtPath(path) as TextureImporter;      textureImporter.maxTextureSize = size;        AssetDatabase.ImportAsset(path);     }   }    static void SelectedChangeTextureFormatSettings(TextureImporterFormat newFormat) {        Object[] textures = GetSelectedTextures();    Selection.objects = new Object[0];    foreach (Texture2D texture in textures)  {      string path = AssetDatabase.GetAssetPath(texture);      //Debug.Log("path: " + path);      TextureImporter textureImporter = AssetImporter.GetAtPath(path) as TextureImporter;      textureImporter.textureFormat = newFormat;        AssetDatabase.ImportAsset(path);     }   }    static Object[] GetSelectedTextures()   {    return Selection.GetFiltered(typeof(Texture2D), SelectionMode.DeepAssets);   } }

以上代码参考：Unity3d：批量修改贴图导入设置工具脚本

然后，Unity3D界面如下：

在Project窗口中选中需要设置的纹理（可多选），然后点菜单命令执行对应的转换即可。

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