导入贴图操作：处理贴图MaxSize和Format

using UnityEngine;
using System.Collections;
using UnityEditor;
public class ImportModflyTextures : AssetPostprocessor{

    private uint m_Version = 0;
    public override uint GetVersion() {return m_Version;}

    public void OnPostprocessTexture(Texture2D tex){

        TextureImporter importerTexture = (TextureImporter)assetImporter;

        if(importerTexture.DoesSourceTextureHaveAlpha() ==  true){
                if(tex.width >= tex.height )
                    importerTexture.maxTextureSize = tex.width/2;
                else importerTexture.maxTextureSize = tex.height/2;

            importerTexture.textureFormat = TextureImporterFormat.AutomaticTruecolor;
        }else{
            if(tex.width >= tex.height )
                importerTexture.maxTextureSize = tex.width;
            else importerTexture.maxTextureSize = tex.height;

            importerTexture.textureFormat = TextureImporterFormat.AutomaticCompressed;
        }
        //AssetDatabase.Refresh(ImportAssetOptions.ForceUpdate);
    }
}