Sliding Door    Semicharm  1998

The map has a sample room to demonstrate each step.  I did the glass door in the same room to save
time.  Since some of these steps may be a little tricky, I've included a movable box to show how
simple this effect really is.

1.  Make the area where the door is going to go.  It doesn't have to be the typical short hallway 
    between two rooms.  
2.  In 2D mode, make a long rectangular sector and make it a double sided, red sector.
3.  Make the sector a sliding door by giving it a sector tag of 25.  Place a sector effector in the   
    sector.  Give it a low tag of 15 and a unique high tag.  If you want to make more than one door 
    move at once, then give them the same high tag.  Now point the effector sprite in the direction 
    the door will move when it closes.
4.  Make the door the way you want it to look.  
    If you want it to be a solid door, just raise the floor to the ceiling.  
    
    Glass doors are a little harder.  Make two white sectors inside the main door sector at each end 
    and make a sector in between the two white sectors.  Now turn the grid locking off and zoom in as
    close as possible.  Place the walls of the inside sectors next to the walls of the main sector.  
    Be careful not to overlap the walls!  Place the effector sprite between the walls of sectors.  
    This will require turning the tags off by pressing ctrl+t in order to position it properly.
    Now in 3D mode, lower the ceiling and raise the floor of the inside sector.  Make a mask wall and
    give it a glass texture.
5.  In 2-D, make add a few points on the wall where the door will slide into.  Bend the wall to make a 
    narrow passageway.  Make sure that it is slightly wider and longer than the door or else the walls 
    will overlap when the door opens.
6.  If you want to adjust how far the door will open, place a GPSpeed sprite in main door sector and set the
    low tag to half the distance you want it to move.

Debugging.
  If the door seems to disappear or has visual glitching, make sure that the path where the door will slide
  into is wider and longer than the door.  Also if it's a glass door, make sure none of the walls are 
  overlapping.
  If it doesn't move, make sure that the sector tag of the main door sector is 25.  Also make sure that the
  sector effector is inside the main sector and that its low tag is set to 15.
