summaryrefslogtreecommitdiffstats
path: root/hunt/huntd/makemaze.c
blob: d0e889600f126b1f354f2db688f4c355d3d28dce (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/*
 *  Hunt
 *  Copyright (c) 1985 Conrad C. Huang, Gregory S. Couch, Kenneth C.R.C. Arnold
 *  San Francisco, California
 */

# include	"hunt.h"

# define	ISCLEAR(y,x)	(Maze[y][x] == SPACE)
# define	ODD(n)		((n) & 01)

makemaze()
{
	register char	*sp;
	register int	y, x;

	/*
	 * fill maze with walls
	 */
	sp = &Maze[0][0];
	while (sp < &Maze[HEIGHT - 1][WIDTH])
		*sp++ = DOOR;

	x = rand_num(WIDTH / 2) * 2 + 1;
	y = rand_num(HEIGHT / 2) * 2 + 1;
	dig_maze(x, y);
	remap();
}

# define	NPERM	24
# define	NDIR	4

int	dirs[NPERM][NDIR] = {
		{0,1,2,3},	{3,0,1,2},	{0,2,3,1},	{0,3,2,1},
		{1,0,2,3},	{2,3,0,1},	{0,2,1,3},	{2,3,1,0},
		{1,0,3,2},	{1,2,0,3},	{3,1,2,0},	{2,0,3,1},
		{1,3,0,2},	{0,3,1,2},	{1,3,2,0},	{2,0,1,3},
		{0,1,3,2},	{3,1,0,2},	{2,1,0,3},	{1,2,3,0},
		{2,1,3,0},	{3,0,2,1},	{3,2,0,1},	{3,2,1,0}
	};

int	incr[NDIR][2] = {
		{0, 1}, {1, 0}, {0, -1}, {-1, 0}
	};

dig(y, x)
int	y, x;
{
	register int	*dp;
	register int	*ip;
	register int	ny, nx;
	register int	*endp;

	Maze[y][x] = SPACE;			/* Clear this spot */
	dp = dirs[rand_num(NPERM)];
	endp = &dp[NDIR];
	while (dp < endp) {
		ip = &incr[*dp++][0];
		ny = y + *ip++;
		nx = x + *ip;
		if (candig(ny, nx))
			dig(ny, nx);
	}
}

/*
 * candig:
 *	Is it legal to clear this spot?
 */
candig(y, x)
register int	y, x;
{
	register int	i;

	if (ODD(x) && ODD(y))
		return FALSE;		/* can't touch ODD spots */

	if (y < UBOUND || y >= DBOUND)
		return FALSE;		/* Beyond vertical bounds, NO */
	if (x < LBOUND || x >= RBOUND)
		return FALSE;		/* Beyond horizontal bounds, NO */

	if (ISCLEAR(y, x))
		return FALSE;		/* Already clear, NO */

	i = ISCLEAR(y, x + 1);
	i += ISCLEAR(y, x - 1);
	if (i > 1)
		return FALSE;		/* Introduces cycle, NO */
	i += ISCLEAR(y + 1, x);
	if (i > 1)
		return FALSE;		/* Introduces cycle, NO */
	i += ISCLEAR(y - 1, x);
	if (i > 1)
		return FALSE;		/* Introduces cycle, NO */

	return TRUE;			/* OK */
}

dig_maze(x, y)
int	x, y;
{
	register int	tx, ty;
	register int	i, j;
	int		order[4];
#define	MNORTH	0x1
#define	MSOUTH	0x2
#define	MEAST	0x4
#define	MWEST	0x8

	Maze[y][x] = SPACE;
	order[0] = MNORTH;
	for (i = 1; i < 4; i++) {
		j = rand_num(i + 1);
		order[i] = order[j];
		order[j] = 0x1 << i;
	}
	for (i = 0; i < 4; i++) {
		switch (order[i]) {
		  case MNORTH:
			tx = x;
			ty = y - 2;
			break;
		  case MSOUTH:
			tx = x;
			ty = y + 2;
			break;
		  case MEAST:
			tx = x + 2;
			ty = y;
			break;
		  case MWEST:
			tx = x - 2;
			ty = y;
			break;
		}
		if (tx < 0 || ty < 0 || tx >= WIDTH || ty >= HEIGHT)
			continue;
		if (Maze[ty][tx] == SPACE)
			continue;
		Maze[(y + ty) / 2][(x + tx) / 2] = SPACE;
		dig_maze(tx, ty);
	}
}

remap()
{
	register int	y, x;
	register char	*sp;
	register int	stat;

	for (y = 0; y < HEIGHT; y++)
		for (x = 0; x < WIDTH; x++) {
			sp = &Maze[y][x];
			if (*sp == SPACE)
				continue;
			stat = 0;
			if (y - 1 >= 0 && Maze[y - 1][x] != SPACE)
				stat |= NORTH;
			if (y + 1 < HEIGHT && Maze[y + 1][x] != SPACE)
				stat |= SOUTH;
			if (x + 1 < WIDTH && Maze[y][x + 1] != SPACE)
				stat |= EAST;
			if (x - 1 >= 0 && Maze[y][x - 1] != SPACE)
				stat |= WEST;
			switch (stat) {
			  case WEST | EAST:
			  case EAST:
			  case WEST:
				*sp = WALL1;
				break;
			  case NORTH | SOUTH:
			  case NORTH:
			  case SOUTH:
				*sp = WALL2;
				break;
			  case 0:
# ifdef RANDOM
				*sp = DOOR;
# endif
# ifdef REFLECT
				*sp = rand_num(2) ? WALL4 : WALL5;
# endif
				break;
			  default:
				*sp = WALL3;
				break;
			}
		}
	memcpy(Orig_maze, Maze, sizeof Maze);
}