GLSL - Paint fragments in a certain view position

Hi,

I'm receiving from Unity a pixel in view coordinates (X,Y) given by a simple call to Camera.WorldToScreenPoint() (where position (0,0) is at bottom left of the screen as Unity documentation states). But now I want to make a condition like this in my fragment shader:

Pseudo code: IF(my_frag_position_in_view == (X,Y)) then gl_FragColor = pink; ELSE gl_FragColor = blue;

So I'm asking if the current fragment being processed is in the same pixel position as the pixel unity gave me, if so color it pink.

My problem is, I cant figure out "my_frag_position_in_camera", that corresponds to the current fragment's position in the view coordinates.