games/hunt/huntd/makemaze.c

   1 /*      $NetBSD: makemaze.c,v 1.6 2009/07/04 04:29:55 dholland Exp $    */
   2 /*
   3  * Copyright (c) 1983-2003, Regents of the University of California.
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are
   8  * met:
   9  *
  10  * + Redistributions of source code must retain the above copyright
  11  *   notice, this list of conditions and the following disclaimer.
  12  * + Redistributions in binary form must reproduce the above copyright
  13  *   notice, this list of conditions and the following disclaimer in the
  14  *   documentation and/or other materials provided with the distribution.
  15  * + Neither the name of the University of California, San Francisco nor
  16  *   the names of its contributors may be used to endorse or promote
  17  *   products derived from this software without specific prior written
  18  *   permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  21  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  23  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 #include <sys/cdefs.h>
  34 #ifndef lint
  35 __RCSID("$NetBSD: makemaze.c,v 1.6 2009/07/04 04:29:55 dholland Exp $");
  36 #endif /* not lint */
  37
  38 #include "hunt.h"
  39
  40 #define ISCLEAR(y,x)    (Maze[y][x] == SPACE)
  41 #define ODD(n)          ((n) & 01)
  42
  43 static int candig(int, int);
  44 static void dig(int, int);
  45 static void dig_maze(int, int);
  46 static void remap(void);
  47
  48 void
  49 makemaze(void)
  50 {
  51         char *sp;
  52         int y, x;
  53
  54         /*
  55          * fill maze with walls
  56          */
  57         sp = &Maze[0][0];
  58         while (sp < &Maze[HEIGHT - 1][WIDTH])
  59                 *sp++ = DOOR;
  60
  61         x = rand_num(WIDTH / 2) * 2 + 1;
  62         y = rand_num(HEIGHT / 2) * 2 + 1;
  63         dig_maze(x, y);
  64         remap();
  65 }
  66
  67 #define NPERM   24
  68 #define NDIR    4
  69
  70 static int dirs[NPERM][NDIR] = {
  71         {0,1,2,3},      {3,0,1,2},      {0,2,3,1},      {0,3,2,1},
  72         {1,0,2,3},      {2,3,0,1},      {0,2,1,3},      {2,3,1,0},
  73         {1,0,3,2},      {1,2,0,3},      {3,1,2,0},      {2,0,3,1},
  74         {1,3,0,2},      {0,3,1,2},      {1,3,2,0},      {2,0,1,3},
  75         {0,1,3,2},      {3,1,0,2},      {2,1,0,3},      {1,2,3,0},
  76         {2,1,3,0},      {3,0,2,1},      {3,2,0,1},      {3,2,1,0}
  77 };
  78
  79 static int incr[NDIR][2] = {
  80         {0, 1}, {1, 0}, {0, -1}, {-1, 0}
  81 };
  82
  83 static void
  84 dig(int y, int x)
  85 {
  86         int *dp;
  87         int *ip;
  88         int ny, nx;
  89         int *endp;
  90
  91         Maze[y][x] = SPACE;                     /* Clear this spot */
  92         dp = dirs[rand_num(NPERM)];
  93         endp = &dp[NDIR];
  94         while (dp < endp) {
  95                 ip = &incr[*dp++][0];
  96                 ny = y + *ip++;
  97                 nx = x + *ip;
  98                 if (candig(ny, nx))
  99                         dig(ny, nx);
 100         }
 101 }
 102
 103 /*
 104  * candig:
 105  *      Is it legal to clear this spot?
 106  */
 107 static int
 108 candig(int y, int x)
 109 {
 110         int i;
 111
 112         if (ODD(x) && ODD(y))
 113                 return FALSE;           /* can't touch ODD spots */
 114
 115         if (y < UBOUND || y >= DBOUND)
 116                 return FALSE;           /* Beyond vertical bounds, NO */
 117         if (x < LBOUND || x >= RBOUND)
 118                 return FALSE;           /* Beyond horizontal bounds, NO */
 119
 120         if (ISCLEAR(y, x))
 121                 return FALSE;           /* Already clear, NO */
 122
 123         i = ISCLEAR(y, x + 1);
 124         i += ISCLEAR(y, x - 1);
 125         if (i > 1)
 126                 return FALSE;           /* Introduces cycle, NO */
 127         i += ISCLEAR(y + 1, x);
 128         if (i > 1)
 129                 return FALSE;           /* Introduces cycle, NO */
 130         i += ISCLEAR(y - 1, x);
 131         if (i > 1)
 132                 return FALSE;           /* Introduces cycle, NO */
 133
 134         return TRUE;                    /* OK */
 135 }
 136
 137 void
 138 dig_maze(int x, int y)
 139 {
 140         int tx, ty;
 141         int i, j;
 142         int order[4];
 143 #define MNORTH  0x1
 144 #define MSOUTH  0x2
 145 #define MEAST   0x4
 146 #define MWEST   0x8
 147
 148         tx = ty = 0;
 149         Maze[y][x] = SPACE;
 150         order[0] = MNORTH;
 151         for (i = 1; i < 4; i++) {
 152                 j = rand_num(i + 1);
 153                 order[i] = order[j];
 154                 order[j] = 0x1 << i;
 155         }
 156         for (i = 0; i < 4; i++) {
 157                 switch (order[i]) {
 158                   case MNORTH:
 159                         tx = x;
 160                         ty = y - 2;
 161                         break;
 162                   case MSOUTH:
 163                         tx = x;
 164                         ty = y + 2;
 165                         break;
 166                   case MEAST:
 167                         tx = x + 2;
 168                         ty = y;
 169                         break;
 170                   case MWEST:
 171                         tx = x - 2;
 172                         ty = y;
 173                         break;
 174                 }
 175                 if (tx < 0 || ty < 0 || tx >= WIDTH || ty >= HEIGHT)
 176                         continue;
 177                 if (Maze[ty][tx] == SPACE)
 178                         continue;
 179                 Maze[(y + ty) / 2][(x + tx) / 2] = SPACE;
 180                 dig_maze(tx, ty);
 181         }
 182 }
 183
 184 void
 185 remap(void)
 186 {
 187         int y, x;
 188         char *sp;
 189         int stat;
 190
 191         for (y = 0; y < HEIGHT; y++)
 192                 for (x = 0; x < WIDTH; x++) {
 193                         sp = &Maze[y][x];
 194                         if (*sp == SPACE)
 195                                 continue;
 196                         stat = 0;
 197                         if (y - 1 >= 0 && Maze[y - 1][x] != SPACE)
 198                                 stat |= NORTH;
 199                         if (y + 1 < HEIGHT && Maze[y + 1][x] != SPACE)
 200                                 stat |= SOUTH;
 201                         if (x + 1 < WIDTH && Maze[y][x + 1] != SPACE)
 202                                 stat |= EAST;
 203                         if (x - 1 >= 0 && Maze[y][x - 1] != SPACE)
 204                                 stat |= WEST;
 205                         switch (stat) {
 206                           case WEST | EAST:
 207                           case EAST:
 208                           case WEST:
 209                                 *sp = WALL1;
 210                                 break;
 211                           case NORTH | SOUTH:
 212                           case NORTH:
 213                           case SOUTH:
 214                                 *sp = WALL2;
 215                                 break;
 216                           case 0:
 217 #ifdef RANDOM
 218                                 *sp = DOOR;
 219 #endif
 220 #ifdef REFLECT
 221                                 *sp = rand_num(2) ? WALL4 : WALL5;
 222 #endif
 223                                 break;
 224                           default:
 225                                 *sp = WALL3;
 226                                 break;
 227                         }
 228                 }
 229         memcpy(Orig_maze, Maze, sizeof Maze);
 230 }