public bool IsModified(object asset)
{
var renderTex = asset as RenderTexture;
var changed = false;
if (renderTex.wrapMode != this.wrapMode) changed = true;
if (renderTex.filterMode != this.filterMode) changed = true;
if (renderTex.anisoLevel != this.anisoLevel) changed = true;
return changed;
}