#!/usr/bin/env -S awk -f

BEGIN {mode = "any"; lineno = 1;}

{lineno++;}

/@@/ {mode = "any"; $0 = ("#line " lineno);}
/%%/ {mode = "vert";}
/##/ {mode = "frag"; $0 = ("#line " lineno);}

mode == "any"
mode == "frag"