1 /* $NetBSD: makemaze.c,v 1.12 2021/05/02 12:50:45 rillig 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 1.12 2021/05/02 12:50:45 rillig 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 #if 0 44 45 #define NPERM 24 46 #define NDIR 4 47 48 static const int dirs[NPERM][NDIR] = { 49 {0,1,2,3}, {3,0,1,2}, {0,2,3,1}, {0,3,2,1}, 50 {1,0,2,3}, {2,3,0,1}, {0,2,1,3}, {2,3,1,0}, 51 {1,0,3,2}, {1,2,0,3}, {3,1,2,0}, {2,0,3,1}, 52 {1,3,0,2}, {0,3,1,2}, {1,3,2,0}, {2,0,1,3}, 53 {0,1,3,2}, {3,1,0,2}, {2,1,0,3}, {1,2,3,0}, 54 {2,1,3,0}, {3,0,2,1}, {3,2,0,1}, {3,2,1,0} 55 }; 56 57 static const int incr[NDIR][2] = { 58 {0, 1}, {1, 0}, {0, -1}, {-1, 0} 59 }; 60 61 62 /* 63 * candig: 64 * Is it legal to clear this spot? 65 */ 66 static bool 67 candig(int y, int x) 68 { 69 int i; 70 71 if (ODD(x) && ODD(y)) 72 return false; /* can't touch ODD spots */ 73 74 if (y < UBOUND || y >= DBOUND) 75 return false; /* Beyond vertical bounds, NO */ 76 if (x < LBOUND || x >= RBOUND) 77 return false; /* Beyond horizontal bounds, NO */ 78 79 if (ISCLEAR(y, x)) 80 return false; /* Already clear, NO */ 81 82 i = ISCLEAR(y, x + 1); 83 i += ISCLEAR(y, x - 1); 84 if (i > 1) 85 return false; /* Introduces cycle, NO */ 86 i += ISCLEAR(y + 1, x); 87 if (i > 1) 88 return false; /* Introduces cycle, NO */ 89 i += ISCLEAR(y - 1, x); 90 if (i > 1) 91 return false; /* Introduces cycle, NO */ 92 93 return true; /* OK */ 94 } 95 96 static void 97 dig(int y, int x) 98 { 99 const int *dp; 100 const int *ip; 101 int ny, nx; 102 const int *endp; 103 104 Maze[y][x] = SPACE; /* Clear this spot */ 105 dp = dirs[rand_num(NPERM)]; 106 endp = &dp[NDIR]; 107 while (dp < endp) { 108 ip = &incr[*dp++][0]; 109 ny = y + *ip++; 110 nx = x + *ip; 111 if (candig(ny, nx)) 112 dig(ny, nx); 113 } 114 } 115 #endif 116 117 static void 118 dig_maze(int x, int y) 119 { 120 int tx, ty; 121 int i, j; 122 int order[4]; 123 #define MNORTH 0x1 124 #define MSOUTH 0x2 125 #define MEAST 0x4 126 #define MWEST 0x8 127 128 tx = ty = 0; 129 Maze[y][x] = SPACE; 130 order[0] = MNORTH; 131 for (i = 1; i < 4; i++) { 132 j = rand_num(i + 1); 133 order[i] = order[j]; 134 order[j] = 0x1 << i; 135 } 136 for (i = 0; i < 4; i++) { 137 switch (order[i]) { 138 case MNORTH: 139 tx = x; 140 ty = y - 2; 141 break; 142 case MSOUTH: 143 tx = x; 144 ty = y + 2; 145 break; 146 case MEAST: 147 tx = x + 2; 148 ty = y; 149 break; 150 case MWEST: 151 tx = x - 2; 152 ty = y; 153 break; 154 } 155 if (tx < 0 || ty < 0 || tx >= WIDTH || ty >= HEIGHT) 156 continue; 157 if (Maze[ty][tx] == SPACE) 158 continue; 159 Maze[(y + ty) / 2][(x + tx) / 2] = SPACE; 160 dig_maze(tx, ty); 161 } 162 } 163 164 static void 165 remap(void) 166 { 167 int y, x; 168 char *sp; 169 int stat; 170 171 for (y = 0; y < HEIGHT; y++) 172 for (x = 0; x < WIDTH; x++) { 173 sp = &Maze[y][x]; 174 if (*sp == SPACE) 175 continue; 176 stat = 0; 177 if (y - 1 >= 0 && Maze[y - 1][x] != SPACE) 178 stat |= NORTH; 179 if (y + 1 < HEIGHT && Maze[y + 1][x] != SPACE) 180 stat |= SOUTH; 181 if (x + 1 < WIDTH && Maze[y][x + 1] != SPACE) 182 stat |= EAST; 183 if (x - 1 >= 0 && Maze[y][x - 1] != SPACE) 184 stat |= WEST; 185 switch (stat) { 186 case WEST | EAST: 187 case EAST: 188 case WEST: 189 *sp = WALL1; 190 break; 191 case NORTH | SOUTH: 192 case NORTH: 193 case SOUTH: 194 *sp = WALL2; 195 break; 196 case 0: 197 #ifdef RANDOM 198 *sp = DOOR; 199 #endif 200 #ifdef REFLECT 201 *sp = rand_num(2) ? WALL4 : WALL5; 202 #endif 203 break; 204 default: 205 *sp = WALL3; 206 break; 207 } 208 } 209 memcpy(Orig_maze, Maze, sizeof Maze); 210 } 211 212 void 213 makemaze(void) 214 { 215 char *sp; 216 int y, x; 217 218 /* 219 * fill maze with walls 220 */ 221 sp = &Maze[0][0]; 222 while (sp < &Maze[HEIGHT - 1][WIDTH]) 223 *sp++ = DOOR; 224 225 x = rand_num(WIDTH / 2) * 2 + 1; 226 y = rand_num(HEIGHT / 2) * 2 + 1; 227 dig_maze(x, y); 228 remap(); 229 } 230
Indexes created Thu Sep 25 16:09:42 GMT 2025