MAZE 3D


          Picture a large cube, filled with cube-shaped rooms, five rooms
      high, five deep, and five wide. The rooms have doors opening into
      adjacent rooms, but not all walls have doors, and not all rooms
      have doors on the same walls.

          You are lost somewhere inside this cubical maze. There is only
      one exit. Your goal is to find your way out as fast as possible. Your
      method is to go through the doors from one room to the next until
      you find yourself outside the cube. 

          The left-hand side of your screen displays the room you are in,
      and the doors through which you can move. The top line on the right-
      hand side shows which way you are facing. The second line displays
      the keypresses you have available to navigate through the maze.
      Press "N" to move north, "S" for south, "E" for east, "W" for west,
      "U" for up, and "D" for down. If you want to change the direction you
      are facing, press "F" and answer the prompt by pressing N, S, E, or W
      for the direction you want to face. As a last resort, the coordinates
      for your present position and/or the coordinates for the exit may be
      displayed. Press "*" to turn on the position display, and press "?"
      to turn on the exit display. You can turn these displays off by
      pressing the same keys a second time. These coordinates are displayed
      in terms of one to five along the east/west, north/south, and up/down
      directions. (The "fives" are all the way east, north, and up.)

          When you run MAZE 3D, it takes a little while to initialize.
      Think of everything it's doing to set up a challenging maze! Function
      keys F4 (RUN) and F8 (MENU) retain their function during the game, so
      you can bail out or start over at any time without having to BREAK.
      However, if you do break, type GOTO 315, so the function keys will be
      restored to BASIC.



                             PROGRAM DOCUMENTATION


          MAZE 3D is based upon the program "Caves of Ice", originally
      written for the Apple, Atari, and Commodore computers by Robert Tsuk,
      and published in COMPUTE! magazine. It was about 90 percent
      rewritten by Tim Ekdom to run on the TRS-80 Model 100.

          The main program is contained in lines 100. Execution first
      branches to lines 200 for set-up. Subroutines are line numbers below
      100. The wrap-up is in line numbers 300. Comments in the code explain
      briefly what each section does.

          The maze is stored in the array MZ() with each array subscript
      representing one wall. Doors are placed in the walls at random
      locations by stepping through the maze one cell at a time, generating
      a random number, and setting the array subscript for the appropriate
      wall to a value of one if the random number exceeds a fixed value.
      And the array subscript for the wall of the adjacent cell is also set
      to one so there is a "doorway" on both sides of the wall.









          Then a random exit point is generated by setting one of the
      location coordinates to the outside of the cube (0 or 4, internal
      values) and generating random values for the other two coordinates.
      And a random starting position is calculated in the same way.

          A second array contains orientation values so that the proper
      room display will be drawn when the direction facing is changed. This
      occurs in line 110.

          The program is a little over 5600 bytes long tokenized (.BA) and
      almost 6900 bytes ASCII (.DO). I have not done all I could have done
      to compress it in order to maintain legibility for those interested
      in its operation. You are certainly welcome to try. The comments
      should be deleted in your saved copy, and there are certainly a few
      frills that could be cut out if memory is a problem; for instance:
      the "nasty message" subroutine 50, the "highlight choice"
      subroutines 71-79, and most of the winner's display following
      line 300.


      Variable list:

        A$    = Keypress input
        DI    = Direction of movement
        DR$   = Direction facing prompt
        EE    = Exit coordinate
        EN    = Exit coordinate
        EU    = Exit coordinate
        EW    = East/west position
        EX    = Exit display on/off flag
        FA    = Direction facing value
        FC()  = Room orientation
        I     = Wall value to generate pointer into maze array
        M1    = Minutes calculation
        M2    = Minutes calculation
        MI$   = Minutes display
        MZ()  = Maze array
        N     = Counter
        NS    = North/south position
        P$    = Inverse video on
        PO    = Position display on/off flag
        Q$    = Inverse video off
        RA!   = Random number
        S1    = Seconds calculation
        S2    = Seconds calculation
        SE$   = Seconds display
        T1$   = Start time
        T2$   = Stop time
        UD    = Up/down direction
        WA    = Wall number
        X1    = Graphics display
        X2    = Graphics display
        Y1    = Graphics display


      Tim Ekdom
      72575,1473