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
dig_maze(int x,int y)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
remap(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
makemaze(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