While Writing a vertex shader- Is is mandatory to have a **gl_Position** value for each vetex of Geometry? Or we can use **“if”** Statement as follows:

if( pos_current.z < depth + L0)

gl_Position = position_ES;

to give gl_Position value for only certain vertex of Geometry.

I am Trying to implement Random Subset Algorithm for transparency in which I divide geometry in three subsets(In vertex shader) And then render them deferred And blend them to get final result.