NetNews Usenet Archive 1992 #16/NN_1992_16.iso/spool/comp/programm/2121

Text File | 1992-07-28 | 3.2 KB | 80 lines

Newsgroups: comp.programming
Path: sparky!uunet!darwin.sura.net!jvnc.net!yale.edu!ira.uka.de!math.fu-berlin.de!informatik.tu-muenchen.de!stumpf
From: [e-mail] (Markus Stumpf)
Subject: Re: MAZE
References:  <[e-mail]>
Originator: [e-mail]
Sender: [e-mail] (USENET Newssystem)
Organization: Technische Universitaet Muenchen, Germany
Date: Tue, 28 Jul 1992 16:07:21 GMT
Message-ID: <[e-mail]>
Lines: 67


In article <[e-mail]>, [e-mail] (Peter Pui Tak Chiu) writes:
|> I am trying to write a 3D maze in which the player can move around as if
|> he/she is "inside" the maze.  (something like the adventure game ULTIMA
|> when you are inside a dungeon...)
|>
|> I wrote a version but it is extremely slow.  First I transform the 2D maze
|> into 3D coordinates.  Then for every move, I redraw the maze with appropriate
|> transformation, rotations and hidden surface eliminations...  and as you can
|> tell it takes a lot of TIME!!!

Hmmm, did this in BASIC on a TRS-80 Model I some years ago!
Thats how I solved it:

asume maze is  m * n squares;
the maze layout is saved as a m * n matrix
the values of the single cells are bitwise OR of the following values:
    1 = exit to east
    2 = exit to north
    4 = exit to west
    8 = exit to south

(a way without corners or crossing would eg. have values of 5 (east-west
passage or 10 north-south passage)

Calculate the next square that can be seen by adding/subtracting 1 to the
row/column, depending on which is the current direction the player is looking.

Have some graphics for a way to the left in distance one/two/three/four/...
same for right, wall left, wall right.

Draw the appropiate graphics for each distance.
Stop as soon as row (resp. column) is < 0 or is > m (resp. n),
as soon as you encounter a wall in the direction the player looks or as
soon as you have reached the max distance the player can look (usually
5 cells in Ultima, if I can remember correctly)

Whether there is an exit or a wall to be drawn can be determined by bitwise
ANDing the value of the matrix cell with EAST/NORTH/WEST, that is
(draw exit for xxx if xxx_exit is TRUE, draw a wall for xxx otherwise)

(in C notation:)
left_exit = maze[player_x + distance_x, player_y + distance_y] & EAST;
ahead_exit = maze[player_x + distance_x, player_y + distance_y] & NORTH;
right_exit = maze[player_x + distance_x, player_y + distance_y] & WEST;
/* do not need backward_exit as it can't be seen */

where EAST, WEST, NORTH are set according to

player looks east:
    EAST=8;  NORTH=1;  WEST=2;
player looks north:
    EAST=1;  NORTH=2;  WEST=4;
player looks west:
    EAST=2;  NORTH=4;  WEST=8;
player looks south:
    EAST=4;  NORTH=8;  WEST=1;

Hope that helps and was what you where looking for.

    \Maex

P.S. you can use the values 16, 32, 64 and 128 bitwise to the maxtrix cell
     to indicated something special for that position (trapdoors, boxes ...)
--
______________________________________________________________________________
 Markus Stumpf                        [e-mail]