Window Textured Portal Lighting - concept by Paul Mandell
                                  (paul.mandell@telewest.co.uk)

The QuakeLab - http://www.in2nett.com/stevefu/QuakeLab

        TEXTURES:

        Any WINDOW texture (eg. the stained glass dragons.)

        ENTITIES:

        func_train, path_corner, light

        WHAT TO DO:

        Make a room. Make a room whose walls are the size of the window
        you wish to put into the room. This 'window-sized' room should
        be joined up with the original room. Make the window brush and
        put it into position, and texture it correctly. Put the window
        fairly deep into the 'window-sized' room, away from the main room.

        Next, make a light entity and put it in front of the window brush.
        You may wish to compile and test out the lighting at this point to
        make sure that you are getting the appearance you want.

        Now make the window brush into a func_train. Make a path_corner. Have
        the func_train 'window' target the path_corner. Set the path_corner's
        'wait' to -1. Set the 'target' of the path_corner to itself. Position
        the path_corner so that it will spawn the func_train 'window' at the
        window's intended position. You may need to move the path_corner
        around a bit before you get the window correctly aligned in the
        window frame when you run the level.

        Explanation: Func_trains are always lit where they are placed
        originally, but move to their targeted path_corners as soon as the
        level starts, or if they are targeted, as soon as they are triggered.
        The 'wait' of -1 makes the window stop at the path_corner - all of
        this movement happens right at the outset of the level and thus you
        don't see anything except a fully lit window and an appropriate
        portal lighting effect.

        OPTIONS:

        The portal lighting will probably seem a little too stark/contrasted.
        To offset this, make a few more lights of reduced intensity; set
        their 'light' fields to about 150. Place these at regular intervals
        where they will brighten up the particularly dark shadows created by
        the lighting effect. This evens things out a bit and makes it look
        more natural.