Fragment vs Surface Difference (Simple Question)

Ok i'm still shader noob, but why those are different? I tried a lot but cant get this sparkles work on surface.

 

I don’t know a reason why your surface shader wouldn’t work. The IN.viewDir should perfectly match the viewDir value you have in the vertex fragment shader, as should the worldPos.

Make sure there are no warnings or errors showing up when you select the shaders in the project view?

 

Yes they were same indeed but i had a logic error at somewhere else. Surface couldnt get its properties correct. Thanks.