AssetPostprocessor.OnPostprocessTexture(Texture2D)

Description

Add this function to a subclass to get a notification when a texture has completed importing just before.

The texture is optionally compressed and saved to disk.

At this point it is too late to choose compression format, it is still possible to compress the texture using texture.Compress but this is not advised and the compression format will not be displayed in the editor. Use OnPreprocessTexture if you wish to change compression format based on filename or other attributes of the texture.

Note that you should avoid modifying the TextureImporter settings in this manner as it would have no effect on the texture that is currently being imported but would apply the next time the texture is imported. This behavior is nondeterministic and therefore undesirable.

using UnityEditor;
using UnityEngine;
using System.Collections;

// Postprocesses all textures that are placed in a folder
// "invert color" to have their colors inverted.
public class InvertColor : AssetPostprocessor
{
    void OnPostprocessTexture(Texture2D texture)
    {
        // Only post process textures if they are in a folder
        // "invert color" or a sub folder of it.
        string lowerCaseAssetPath = assetPath.ToLower();
        if (lowerCaseAssetPath.IndexOf("/invert color/") == -1)
            return;

        for (int m = 0; m < texture.mipmapCount; m++)
        {
            Color[] c = texture.GetPixels(m);

            for (int i = 0; i < c.Length; i++)
            {
                c[i].r = 1 - c[i].r;
                c[i].g = 1 - c[i].g;
                c[i].b = 1 - c[i].b;
            }
            texture.SetPixels(c, m);
        }
        // Instead of setting pixels for each mip map levels, you can also
        // modify only the pixels in the highest mip level. And then simply use
        // texture.Apply(true); to generate lower mip levels.
    }
}