Use Tokyo glass texture with surface flags trans66 and solid

Yeah sry Nott - that does not work - you can still shoot through the glass

You can get the effect you are after though by making a normal brush the same size as the window, I used texture armoury 1_2_subfloor - put this next to the glass like a sandwich and put the flag nodraw on this brush.....

You can then only see the tokyo glass but you cannot shoot through it because of the "wall" that you cannot see in the map

I messed around with tokyo glass and you can make it bulletproof by deselecting "Alpha tex" in surface properties

You may find that the view of the player on the other side can disappear if you are close up to the glass and near the edge of the brush - you may be able to insert the edges inside a wall brush to fix this - I remember in the kill-bill windows this error was present in the fast-vis but not the full-vis

np - I will pm you