Cool! I am gonna work on a solution (4.17 also uses public virtual functions). Will keep you guys updated (if someone wants to collab, highly appreciated).
Update: I got it working, yet any background texture (plane, 3d widget etc) will also be affected. Since I am trying to find a way to project something on a webcam texture I tried to modify scenecapture2d which does not work yet My question here!
As some guy mentioned showed here it can work. But I couldn’t figure it out yet.