Unity --- 如何简单的判断图片是否含有 alpha channel

var texImporter = AssetImporter.GetAtPath(assetPath) as TextureImporter;
if (texImporter.DoesSourceTextureHaveAlpha())
{
    Debug.Log("textures source image don't have alpha channel ");
}
else
{
    Debug.Log("textures source image have alpha channel ");
}