| 1 |
|
| 2 |
/* peterm@langmuir.eecs.berkeley.edu: this function generates a random |
| 3 |
blocked maze with the property that there is only one path from one spot |
| 4 |
to any other, and there is always a path from one spot to any other. |
| 5 |
|
| 6 |
input: xsize, ysize; |
| 7 |
output: a char** array with # and . for closed and open respectively. |
| 8 |
|
| 9 |
a char value of 0 represents a blank space: a '#' is |
| 10 |
a wall. |
| 11 |
|
| 12 |
*/ |
| 13 |
|
| 14 |
/* we need to maintain a list of wall points to generate |
| 15 |
reasonable mazes: a straightforward recursive random walk maze |
| 16 |
generator would generate a map with a trivial circle-the-outer-wall solution */ |
| 17 |
|
| 18 |
#include <stdio.h> |
| 19 |
#include <global.h> |
| 20 |
|
| 21 |
/*#include <random_map.h>*/ |
| 22 |
#include <maze_gen.h> |
| 23 |
#include <time.h> |
| 24 |
|
| 25 |
|
| 26 |
/* this include solely, and only, is needed for the definition of RANDOM */ |
| 27 |
|
| 28 |
|
| 29 |
|
| 30 |
/* global variables that everyone needs: don't want to pass them in |
| 31 |
as parameters every time. */ |
| 32 |
int *wall_x_list = 0; |
| 33 |
int *wall_y_list = 0; |
| 34 |
int wall_free_size = 0; |
| 35 |
|
| 36 |
/* heuristically, we need to change wall_chance based on the size of |
| 37 |
the maze. */ |
| 38 |
|
| 39 |
int wall_chance; |
| 40 |
|
| 41 |
/* the outsize interface routine: accepts sizes, returns a char |
| 42 |
** maze. option is a flag for either a sparse or a full maze. Sparse |
| 43 |
mazes have sizable rooms. option = 1, full, 0, sparse.*/ |
| 44 |
|
| 45 |
char ** |
| 46 |
maze_gen (int xsize, int ysize, int option) |
| 47 |
{ |
| 48 |
int i, j; |
| 49 |
|
| 50 |
/* allocate that array, set it up */ |
| 51 |
char **maze = (char **) calloc (sizeof (char *), xsize); |
| 52 |
|
| 53 |
for (i = 0; i < xsize; i++) |
| 54 |
{ |
| 55 |
maze[i] = (char *) calloc (sizeof (char), ysize); |
| 56 |
} |
| 57 |
|
| 58 |
/* write the outer walls */ |
| 59 |
for (i = 0; i < xsize; i++) |
| 60 |
maze[i][0] = maze[i][ysize - 1] = '#'; |
| 61 |
for (j = 0; j < ysize; j++) |
| 62 |
maze[0][j] = maze[xsize - 1][j] = '#'; |
| 63 |
|
| 64 |
|
| 65 |
/* find how many free wall spots there are */ |
| 66 |
wall_free_size = 2 * (xsize - 4) + 2 * (ysize - 4); |
| 67 |
|
| 68 |
make_wall_free_list (xsize, ysize); |
| 69 |
|
| 70 |
/* return the empty maze */ |
| 71 |
if (wall_free_size <= 0) |
| 72 |
return maze; |
| 73 |
|
| 74 |
/* recursively generate the walls of the maze */ |
| 75 |
/* first pop a random starting point */ |
| 76 |
while (wall_free_size > 0) |
| 77 |
{ |
| 78 |
pop_wall_point (&i, &j); |
| 79 |
if (option) |
| 80 |
fill_maze_full (maze, i, j, xsize, ysize); |
| 81 |
else |
| 82 |
fill_maze_sparse (maze, i, j, xsize, ysize); |
| 83 |
} |
| 84 |
|
| 85 |
/* clean up our intermediate data structures. */ |
| 86 |
|
| 87 |
free (wall_x_list); |
| 88 |
free (wall_y_list); |
| 89 |
|
| 90 |
return maze; |
| 91 |
} |
| 92 |
|
| 93 |
|
| 94 |
|
| 95 |
/* the free wall points are those outer points which aren't corners or |
| 96 |
near corners, and don't have a maze wall growing out of them already. */ |
| 97 |
|
| 98 |
void |
| 99 |
make_wall_free_list (int xsize, int ysize) |
| 100 |
{ |
| 101 |
int i, j, count; |
| 102 |
|
| 103 |
count = 0; /* entries already placed in the free list */ |
| 104 |
/*allocate it */ |
| 105 |
if (wall_free_size < 0) |
| 106 |
return; |
| 107 |
wall_x_list = (int *) calloc (sizeof (int), wall_free_size); |
| 108 |
wall_y_list = (int *) calloc (sizeof (int), wall_free_size); |
| 109 |
|
| 110 |
|
| 111 |
/* top and bottom wall */ |
| 112 |
for (i = 2; i < xsize - 2; i++) |
| 113 |
{ |
| 114 |
wall_x_list[count] = i; |
| 115 |
wall_y_list[count] = 0; |
| 116 |
count++; |
| 117 |
wall_x_list[count] = i; |
| 118 |
wall_y_list[count] = ysize - 1; |
| 119 |
count++; |
| 120 |
} |
| 121 |
|
| 122 |
/* left and right wall */ |
| 123 |
for (j = 2; j < ysize - 2; j++) |
| 124 |
{ |
| 125 |
wall_x_list[count] = 0; |
| 126 |
wall_y_list[count] = j; |
| 127 |
count++; |
| 128 |
wall_x_list[count] = xsize - 1; |
| 129 |
wall_y_list[count] = j; |
| 130 |
count++; |
| 131 |
} |
| 132 |
} |
| 133 |
|
| 134 |
|
| 135 |
|
| 136 |
/* randomly returns one of the elements from the wall point list */ |
| 137 |
|
| 138 |
void |
| 139 |
pop_wall_point (int *x, int *y) |
| 140 |
{ |
| 141 |
int index = RANDOM () % wall_free_size; |
| 142 |
|
| 143 |
*x = wall_x_list[index]; |
| 144 |
*y = wall_y_list[index]; |
| 145 |
/* write the last array point here */ |
| 146 |
wall_x_list[index] = wall_x_list[wall_free_size - 1]; |
| 147 |
wall_y_list[index] = wall_y_list[wall_free_size - 1]; |
| 148 |
wall_free_size--; |
| 149 |
} |
| 150 |
|
| 151 |
|
| 152 |
|
| 153 |
/* find free point: randomly look for a square adjacent to this one where |
| 154 |
we can place a new block without closing a path. We may only look |
| 155 |
up, down, right, or left. */ |
| 156 |
|
| 157 |
int |
| 158 |
find_free_point (char **maze, int *x, int *y, int xc, int yc, int xsize, int ysize) |
| 159 |
{ |
| 160 |
|
| 161 |
/* we will randomly pick from this list, 1=up,2=down,3=right,4=left */ |
| 162 |
int dirlist[4]; |
| 163 |
int count = 0; /* # elements in dirlist */ |
| 164 |
|
| 165 |
/* look up */ |
| 166 |
if (yc < ysize - 2 && xc > 2 && xc < xsize - 2) /* it is valid to look up */ |
| 167 |
{ |
| 168 |
int cleartest = (int) maze[xc][yc + 1] + (int) maze[xc - 1][yc + 1] + (int) maze[xc + 1][yc + 1]; |
| 169 |
|
| 170 |
cleartest += (int) maze[xc][yc + 2] + (int) maze[xc - 1][yc + 2] + (int) maze[xc + 1][yc + 2]; |
| 171 |
|
| 172 |
if (cleartest == 0) |
| 173 |
{ |
| 174 |
dirlist[count] = 1; |
| 175 |
count++; |
| 176 |
} |
| 177 |
} |
| 178 |
|
| 179 |
|
| 180 |
/* look down */ |
| 181 |
if (yc > 2 && xc > 2 && xc < xsize - 2) /* it is valid to look down */ |
| 182 |
{ |
| 183 |
int cleartest = (int) maze[xc][yc - 1] + (int) maze[xc - 1][yc - 1] + (int) maze[xc + 1][yc - 1]; |
| 184 |
|
| 185 |
cleartest += (int) maze[xc][yc - 2] + (int) maze[xc - 1][yc - 2] + (int) maze[xc + 1][yc - 2]; |
| 186 |
|
| 187 |
if (cleartest == 0) |
| 188 |
{ |
| 189 |
dirlist[count] = 2; |
| 190 |
count++; |
| 191 |
} |
| 192 |
} |
| 193 |
|
| 194 |
|
| 195 |
/* look right */ |
| 196 |
if (xc < xsize - 2 && yc > 2 && yc < ysize - 2) /* it is valid to look left */ |
| 197 |
{ |
| 198 |
int cleartest = (int) maze[xc + 1][yc] + (int) maze[xc + 1][yc - 1] + (int) maze[xc + 1][yc + 1]; |
| 199 |
|
| 200 |
cleartest += (int) maze[xc + 2][yc] + (int) maze[xc + 2][yc - 1] + (int) maze[xc + 2][yc + 1]; |
| 201 |
|
| 202 |
if (cleartest == 0) |
| 203 |
{ |
| 204 |
dirlist[count] = 3; |
| 205 |
count++; |
| 206 |
} |
| 207 |
} |
| 208 |
|
| 209 |
|
| 210 |
/* look left */ |
| 211 |
if (xc > 2 && yc > 2 && yc < ysize - 2) /* it is valid to look down */ |
| 212 |
{ |
| 213 |
int cleartest = (int) maze[xc - 1][yc] + (int) maze[xc - 1][yc - 1] + (int) maze[xc - 1][yc + 1]; |
| 214 |
|
| 215 |
cleartest += (int) maze[xc - 2][yc] + (int) maze[xc - 2][yc - 1] + (int) maze[xc - 2][yc + 1]; |
| 216 |
|
| 217 |
if (cleartest == 0) |
| 218 |
{ |
| 219 |
dirlist[count] = 4; |
| 220 |
count++; |
| 221 |
} |
| 222 |
} |
| 223 |
|
| 224 |
if (count == 0) |
| 225 |
return -1; /* failed to find any clear points */ |
| 226 |
|
| 227 |
/* choose a random direction */ |
| 228 |
if (count > 1) |
| 229 |
count = RANDOM () % count; |
| 230 |
else |
| 231 |
count = 0; |
| 232 |
switch (dirlist[count]) |
| 233 |
{ |
| 234 |
case 1: /* up */ |
| 235 |
{ |
| 236 |
*y = yc + 1; |
| 237 |
*x = xc; |
| 238 |
break; |
| 239 |
}; |
| 240 |
case 2: /* down */ |
| 241 |
{ |
| 242 |
*y = yc - 1; |
| 243 |
*x = xc; |
| 244 |
break; |
| 245 |
}; |
| 246 |
case 3: /* right */ |
| 247 |
{ |
| 248 |
*y = yc; |
| 249 |
*x = xc + 1; |
| 250 |
break; |
| 251 |
} |
| 252 |
case 4: /* left */ |
| 253 |
{ |
| 254 |
*x = xc - 1; |
| 255 |
*y = yc; |
| 256 |
break; |
| 257 |
} |
| 258 |
default: /* ??? */ |
| 259 |
{ |
| 260 |
return -1; |
| 261 |
} |
| 262 |
} |
| 263 |
return 1; |
| 264 |
} |
| 265 |
|
| 266 |
/* recursive routine which will fill every available space in the maze |
| 267 |
with walls*/ |
| 268 |
|
| 269 |
void |
| 270 |
fill_maze_full (char **maze, int x, int y, int xsize, int ysize) |
| 271 |
{ |
| 272 |
int xc, yc; |
| 273 |
|
| 274 |
/* write a wall here */ |
| 275 |
maze[x][y] = '#'; |
| 276 |
|
| 277 |
/* decide if we're going to pick from the wall_free_list */ |
| 278 |
if (RANDOM () % 4 && wall_free_size > 0) |
| 279 |
{ |
| 280 |
pop_wall_point (&xc, &yc); |
| 281 |
fill_maze_full (maze, xc, yc, xsize, ysize); |
| 282 |
} |
| 283 |
|
| 284 |
/* change the if to a while for a complete maze. */ |
| 285 |
while (find_free_point (maze, &xc, &yc, x, y, xsize, ysize) != -1) |
| 286 |
{ |
| 287 |
fill_maze_full (maze, xc, yc, xsize, ysize); |
| 288 |
} |
| 289 |
} |
| 290 |
|
| 291 |
|
| 292 |
/* recursive routine which will fill much of the maze, but will leave |
| 293 |
some free spots (possibly large) toward the center.*/ |
| 294 |
|
| 295 |
void |
| 296 |
fill_maze_sparse (char **maze, int x, int y, int xsize, int ysize) |
| 297 |
{ |
| 298 |
int xc, yc; |
| 299 |
|
| 300 |
/* write a wall here */ |
| 301 |
maze[x][y] = '#'; |
| 302 |
|
| 303 |
/* decide if we're going to pick from the wall_free_list */ |
| 304 |
if (RANDOM () % 4 && wall_free_size > 0) |
| 305 |
{ |
| 306 |
pop_wall_point (&xc, &yc); |
| 307 |
fill_maze_sparse (maze, xc, yc, xsize, ysize); |
| 308 |
} |
| 309 |
|
| 310 |
/* change the if to a while for a complete maze. */ |
| 311 |
if (find_free_point (maze, &xc, &yc, x, y, xsize, ysize) != -1) |
| 312 |
{ |
| 313 |
fill_maze_sparse (maze, xc, yc, xsize, ysize); |
| 314 |
} |
| 315 |
} |
