server/random_maps/maze_gen.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008,2009 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) Crossfire Development Team (restored, original file without copyright notice)
 * 
 * Deliantra is free software: you can redistribute it and/or modify it under
 * the terms of the Affero GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the Affero GNU General Public License
 * and the GNU General Public License along with this program. If not, see
 * <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <support@deliantra.net>
 */

/* peterm@langmuir.eecs.berkeley.edu:  this function generates a random
blocked maze with the property that there is only one path from one spot
to any other, and there is always a path from one spot to any other.

input:  xsize, ysize;
output:  a char** array with # and . for closed and open respectively.

a char value of 0 represents a blank space:  a '#' is
a wall.

*/

/* we need to maintain a list of wall points to generate
   reasonable mazes:  a straightforward recursive random walk maze
   generator would generate a map with a trivial circle-the-outer-wall solution */

#include <vector>

#include <global.h>

#include "random_map.h"
#include "rproto.h"

struct point
{
  short x;
  short y;

  point ()
  {
  }

  point (int x, int y)
  : x(x), y(y)
  {
  }
};

/* global variables that everyone needs:  don't want to pass them in
   as parameters every time. */
static point *seed_list;
static int seed_max, seed_size;
static int xsize, ysize;
static char **maze;

static void
push (point p)
{
  assert (seed_size < seed_max);

  seed_list [seed_size++] = p;

  maze [p.x][p.y] = '#';
}

/*  the free wall points are those outer points which aren't corners or
    near corners, and don't have a maze wall growing out of them already. */
static void
push_walls ()
{
  /* top and bottom wall */
  for (int x = 2; x < xsize - 2; x++)
    {
      push (point (x,         0));
      push (point (x, ysize - 1));
    }

  /* left and right wall */
  for (int y = 2; y < ysize - 2; y++)
    {
      push (point (        0, y));
      push (point (xsize - 1, y));
    }
}

/* randomly returns one of the elements from the wall point list */
static point
pop_rand ()
{
  int index = rmg_rndm (seed_size);

  point p = seed_list [index];

  /* write the last array point here */
  seed_list [index] = seed_list [--seed_size];

  return p;
}

/* find free point:  randomly look for a square adjacent to this one where
we can place a new block without closing a path.  We may only look
up, down, right, or left. */
static int
find_free_point (point &p, point pc)
{
  /* we will randomly pick from this list, 1=up,2=down,3=right,4=left */
  int dirlist[4];
  int count = 0;                /* # elements in dirlist */

  int xc = pc.x;
  int yc = pc.y;

  /* look up */
  if (yc < ysize - 2 && xc > 2 && xc < xsize - 2)       /* it is valid to look up */
    {
      int cleartest = maze[xc][yc + 1] + maze[xc - 1][yc + 1] + maze[xc + 1][yc + 1]
                    + maze[xc][yc + 2] + maze[xc - 1][yc + 2] + maze[xc + 1][yc + 2];

      if (cleartest == 0)
        dirlist[count++] = 1;
    }

  /* look down */
  if (yc > 2 && xc > 2 && xc < xsize - 2)       /* it is valid to look down */
    {
      int cleartest = maze[xc][yc - 1] + maze[xc - 1][yc - 1] + maze[xc + 1][yc - 1]
                    + maze[xc][yc - 2] + maze[xc - 1][yc - 2] + maze[xc + 1][yc - 2];

      if (cleartest == 0)
        dirlist[count++] = 2;
    }

  /* look right */
  if (xc < xsize - 2 && yc > 2 && yc < ysize - 2)       /* it is valid to look left */
    {
      int cleartest = maze[xc + 1][yc] + maze[xc + 1][yc - 1] + maze[xc + 1][yc + 1]
                    + maze[xc + 2][yc] + maze[xc + 2][yc - 1] + maze[xc + 2][yc + 1];

      if (cleartest == 0)
        dirlist[count++] = 3;
    }

  /* look left */
  if (xc > 2 && yc > 2 && yc < ysize - 2)       /* it is valid to look down */
    {
      int cleartest = maze[xc - 1][yc] + maze[xc - 1][yc - 1] + maze[xc - 1][yc + 1]
                    + maze[xc - 2][yc] + maze[xc - 2][yc - 1] + maze[xc - 2][yc + 1];

      if (cleartest == 0)
        dirlist[count++] = 4;
    }

  if (count == 0)
    return -1;                  /* failed to find any clear points */

  /* choose a random direction */
  switch (dirlist [rmg_rndm (count)])
    {
      case 1:                  /* up */
        p.x = xc;
        p.y = yc + 1;
        break;

      case 2:                  /* down */
        p.x = xc;
        p.y = yc - 1;
        break;

      case 3:                  /* right */
        p.x = xc + 1;
        p.y = yc;
        break;
        
      case 4:                  /* left */
        p.x = xc - 1;
        p.y = yc;
        break;
    }

  return 1;
}

/* the outsize interface routine:  accepts sizes, returns a char
** maze.  option is a flag for either a sparse or a full maze. Sparse
mazes have sizable rooms. option = 3=full, 2=braided, 1=sparse, 0=rooms.*/
void
maze_gen (Layout maze, int subtype)
{
  xsize = maze->w;
  ysize = maze->h;
  ::maze = maze;

  maze->clear ();
  maze->border ();

  if (xsize < 4 || ysize < 4)
    return;

  seed_max = xsize * ysize;
  seed_size = 0;
  seed_list = salloc<point> (seed_max);

  if (subtype > 0)
    push_walls ();

  if (subtype == 0 || subtype == 2)
    for (int i = (xsize + ysize) / 2; i; --i)
      push (point (rmg_rndm (1, xsize - 2), rmg_rndm (1, ysize - 2)));

  bool full = subtype == 3;

  /* recursively generate the walls of the maze */
  /* first pop a random starting point */
  while (seed_size)
    {
      point p = pop_rand ();

      for (;;)
        {
          point pc;

          maze [p.x][p.y] = '#';

          if (find_free_point (pc, p) < 0)
            break;

          if (full)
            push (p);

          if (!rmg_rndm (8))
            {
              if (!full)
                push (pc);

              break;
            }

          p = pc;
        }
    }

  /* clean up our intermediate data structures. */
  sfree (seed_list, seed_max);
}

#if 0
static struct demo
{
  demo ()
  {
    Layout layout (30, 30);
    rmg_rndm.seed (time (0));

    for(int i=1;i<10;++i)
      {
        maze_gen (layout, 3);
        layout.print ();
      }
    exit (1);
  }
} demo;
#endif
Revision:	1.21
Committed:	Tue Jun 29 16:52:53 2010 UTC (13 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.20:	+59 -58 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3	*
4	* Copyright (©) 2005,2006,2007,2008,2009 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	* Copyright (©) Crossfire Development Team (restored, original file without copyright notice)
6	*
7	* Deliantra is free software: you can redistribute it and/or modify it under
8	* the terms of the Affero GNU General Public License as published by the
9	* Free Software Foundation, either version 3 of the License, or (at your
10	* option) any later version.
11	*
12	* This program is distributed in the hope that it will be useful,
13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15	* GNU General Public License for more details.
16	*
17	* You should have received a copy of the Affero GNU General Public License
18	* and the GNU General Public License along with this program. If not, see
19	* <http://www.gnu.org/licenses/>.
20	*
21	* The authors can be reached via e-mail to <support@deliantra.net>
22	*/
23
24	/* peterm@langmuir.eecs.berkeley.edu: this function generates a random
25	blocked maze with the property that there is only one path from one spot
26	to any other, and there is always a path from one spot to any other.
27
28	input: xsize, ysize;
29	output: a char** array with # and . for closed and open respectively.
30
31	a char value of 0 represents a blank space: a '#' is
32	a wall.
33
34	*/
35
36	/* we need to maintain a list of wall points to generate
37	reasonable mazes: a straightforward recursive random walk maze
38	generator would generate a map with a trivial circle-the-outer-wall solution */
39
40	#include <vector>
41
42	#include <global.h>
43
44	#include "random_map.h"
45	#include "rproto.h"
46
47	struct point
48	{
49	short x;
50	short y;
51
52	point ()
53	{
54	}
55
56	point (int x, int y)
57	: x(x), y(y)
58	{
59	}
60	};
61
62	/* global variables that everyone needs: don't want to pass them in
63	as parameters every time. */
64	static point *seed_list;
65	static int seed_max, seed_size;
66	static int xsize, ysize;
67	static char **maze;
68
69	static void
70	push (point p)
71	{
72	assert (seed_size < seed_max);
73
74	seed_list [seed_size++] = p;
75
76	maze [p.x][p.y] = '#';
77	}
78
79	/* the free wall points are those outer points which aren't corners or
80	near corners, and don't have a maze wall growing out of them already. */
81	static void
82	push_walls ()
83	{
84	/* top and bottom wall */
85	for (int x = 2; x < xsize - 2; x++)
86	{
87	push (point (x, 0));
88	push (point (x, ysize - 1));
89	}
90
91	/* left and right wall */
92	for (int y = 2; y < ysize - 2; y++)
93	{
94	push (point ( 0, y));
95	push (point (xsize - 1, y));
96	}
97	}
98
99	/* randomly returns one of the elements from the wall point list */
100	static point
101	pop_rand ()
102	{
103	int index = rmg_rndm (seed_size);
104
105	point p = seed_list [index];
106
107	/* write the last array point here */
108	seed_list [index] = seed_list [--seed_size];
109
110	return p;
111	}
112
113	/* find free point: randomly look for a square adjacent to this one where
114	we can place a new block without closing a path. We may only look
115	up, down, right, or left. */
116	static int
117	find_free_point (point &p, point pc)
118	{
119	/* we will randomly pick from this list, 1=up,2=down,3=right,4=left */
120	int dirlist[4];
121	int count = 0; /* # elements in dirlist */
122
123	int xc = pc.x;
124	int yc = pc.y;
125
126	/* look up */
127	if (yc < ysize - 2 && xc > 2 && xc < xsize - 2) /* it is valid to look up */
128	{
129	int cleartest = maze[xc][yc + 1] + maze[xc - 1][yc + 1] + maze[xc + 1][yc + 1]
130	+ maze[xc][yc + 2] + maze[xc - 1][yc + 2] + maze[xc + 1][yc + 2];
131
132	if (cleartest == 0)
133	dirlist[count++] = 1;
134	}
135
136	/* look down */
137	if (yc > 2 && xc > 2 && xc < xsize - 2) /* it is valid to look down */
138	{
139	int cleartest = maze[xc][yc - 1] + maze[xc - 1][yc - 1] + maze[xc + 1][yc - 1]
140	+ maze[xc][yc - 2] + maze[xc - 1][yc - 2] + maze[xc + 1][yc - 2];
141
142	if (cleartest == 0)
143	dirlist[count++] = 2;
144	}
145
146	/* look right */
147	if (xc < xsize - 2 && yc > 2 && yc < ysize - 2) /* it is valid to look left */
148	{
149	int cleartest = maze[xc + 1][yc] + maze[xc + 1][yc - 1] + maze[xc + 1][yc + 1]
150	+ maze[xc + 2][yc] + maze[xc + 2][yc - 1] + maze[xc + 2][yc + 1];
151
152	if (cleartest == 0)
153	dirlist[count++] = 3;
154	}
155
156	/* look left */
157	if (xc > 2 && yc > 2 && yc < ysize - 2) /* it is valid to look down */
158	{
159	int cleartest = maze[xc - 1][yc] + maze[xc - 1][yc - 1] + maze[xc - 1][yc + 1]
160	+ maze[xc - 2][yc] + maze[xc - 2][yc - 1] + maze[xc - 2][yc + 1];
161
162	if (cleartest == 0)
163	dirlist[count++] = 4;
164	}
165
166	if (count == 0)
167	return -1; /* failed to find any clear points */
168
169	/* choose a random direction */
170	switch (dirlist [rmg_rndm (count)])
171	{
172	case 1: /* up */
173	p.x = xc;
174	p.y = yc + 1;
175	break;
176
177	case 2: /* down */
178	p.x = xc;
179	p.y = yc - 1;
180	break;
181
182	case 3: /* right */
183	p.x = xc + 1;
184	p.y = yc;
185	break;
186
187	case 4: /* left */
188	p.x = xc - 1;
189	p.y = yc;
190	break;
191	}
192
193	return 1;
194	}
195
196	/* the outsize interface routine: accepts sizes, returns a char
197	** maze. option is a flag for either a sparse or a full maze. Sparse
198	mazes have sizable rooms. option = 3=full, 2=braided, 1=sparse, 0=rooms.*/
199	void
200	maze_gen (Layout maze, int subtype)
201	{
202	xsize = maze->w;
203	ysize = maze->h;
204	::maze = maze;
205
206	maze->clear ();
207	maze->border ();
208
209	if (xsize < 4 \|\| ysize < 4)
210	return;
211
212	seed_max = xsize * ysize;
213	seed_size = 0;
214	seed_list = salloc<point> (seed_max);
215
216	if (subtype > 0)
217	push_walls ();
218
219	if (subtype == 0 \|\| subtype == 2)
220	for (int i = (xsize + ysize) / 2; i; --i)
221	push (point (rmg_rndm (1, xsize - 2), rmg_rndm (1, ysize - 2)));
222
223	bool full = subtype == 3;
224
225	/* recursively generate the walls of the maze */
226	/* first pop a random starting point */
227	while (seed_size)
228	{
229	point p = pop_rand ();
230
231	for (;;)
232	{
233	point pc;
234
235	maze [p.x][p.y] = '#';
236
237	if (find_free_point (pc, p) < 0)
238	break;
239
240	if (full)
241	push (p);
242
243	if (!rmg_rndm (8))
244	{
245	if (!full)
246	push (pc);
247
248	break;
249	}
250
251	p = pc;
252	}
253	}
254
255	/* clean up our intermediate data structures. */
256	sfree (seed_list, seed_max);
257	}
258
259	#if 0
260	static struct demo
261	{
262	demo ()
263	{
264	Layout layout (30, 30);
265	rmg_rndm.seed (time (0));
266
267	for(int i=1;i<10;++i)
268	{
269	maze_gen (layout, 3);
270	layout.print ();
271	}
272	exit (1);
273	}
274	} demo;
275	#endif