Ui shader doesn't consider alpha from spirit image.

Hi guys,

I download a shader code file from github, the idea is use grab pass and normal file to make a frosted glass ui effect, while the effect works very well, but from the image above, the alpha from spirit has been totally ignored, I am not quite good at writing shader code, so anybody can help me with it, many thanks.

 

I end up with solving the problem, I just fetch alpha from MainTex and use it as the alpha of final output.