server/random_maps/maze_gen.C

/*
 * This file is part of Deliantra, the Roguelike Realtime MMORPG.
 * 
 * Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
 * Copyright (©) 1994-2004 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 <rmg.h>
#include "rproto.h"

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

static void
push (point p)
{
  seeds.push (p);
  maze [p.x][p.y] = '#';
}

/* randomly returns one of the elements from the wall point list */
static point
pop_rand ()
{
  return seeds.remove (rmg_rndm (seeds.size));
}

/*  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));
    }
}

/* 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;

  seeds.reset (xsize * ysize);

  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 (seeds.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;
        }
    }

  seeds.free ();
}

Revision:	1.28
Committed:	Tue Jan 3 11:25:34 2012 UTC (12 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.27:	+1 -1 lines
Log Message:	update copyrights to 2012
#	User	Rev	Content
1	root	1.16	/*
2			* This file is part of Deliantra, the Roguelike Realtime MMORPG.
3			*
4	root	1.28	* Copyright (©) 2005,2006,2007,2008,2009,2010,2011,2012 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
5	root	1.27	* Copyright (©) 1994-2004 Crossfire Development Team (restored, original file without copyright notice)
6	root	1.16	*
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	root	1.5
24	elmex	1.1	/* 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	root	1.20	#include <vector>
41
42	elmex	1.1	#include <global.h>
43	root	1.3
44	root	1.26	#include <rmg.h>
45	root	1.8	#include "rproto.h"
46	elmex	1.1
47			/* global variables that everyone needs: don't want to pass them in
48			as parameters every time. */
49	root	1.23	static fixed_stack<point> seeds;
50	root	1.19	static int xsize, ysize;
51	root	1.20	static char **maze;
52	elmex	1.1
53	root	1.21	static void
54			push (point p)
55			{
56	root	1.23	seeds.push (p);
57			maze [p.x][p.y] = '#';
58			}
59	root	1.21
60	root	1.23	/* randomly returns one of the elements from the wall point list */
61			static point
62			pop_rand ()
63			{
64			return seeds.remove (rmg_rndm (seeds.size));
65	root	1.21	}
66
67	elmex	1.1	/* the free wall points are those outer points which aren't corners or
68			near corners, and don't have a maze wall growing out of them already. */
69	root	1.14	static void
70	root	1.21	push_walls ()
71	root	1.3	{
72	elmex	1.1	/* top and bottom wall */
73	root	1.20	for (int x = 2; x < xsize - 2; x++)
74	root	1.3	{
75	root	1.21	push (point (x, 0));
76			push (point (x, ysize - 1));
77	root	1.3	}
78	elmex	1.1
79			/* left and right wall */
80	root	1.20	for (int y = 2; y < ysize - 2; y++)
81	root	1.3	{
82	root	1.21	push (point ( 0, y));
83			push (point (xsize - 1, y));
84	root	1.3	}
85	elmex	1.1	}
86
87			/* find free point: randomly look for a square adjacent to this one where
88			we can place a new block without closing a path. We may only look
89			up, down, right, or left. */
90	root	1.14	static int
91	root	1.20	find_free_point (point &p, point pc)
92	root	1.3	{
93	root	1.12	/* we will randomly pick from this list, 1=up,2=down,3=right,4=left */
94	root	1.3	int dirlist[4];
95			int count = 0; /* # elements in dirlist */
96	elmex	1.1
97	root	1.20	int xc = pc.x;
98			int yc = pc.y;
99
100	elmex	1.1	/* look up */
101	root	1.3	if (yc < ysize - 2 && xc > 2 && xc < xsize - 2) /* it is valid to look up */
102	elmex	1.1	{
103	root	1.17	int cleartest = maze[xc][yc + 1] + maze[xc - 1][yc + 1] + maze[xc + 1][yc + 1]
104			+ maze[xc][yc + 2] + maze[xc - 1][yc + 2] + maze[xc + 1][yc + 2];
105	root	1.3
106			if (cleartest == 0)
107	root	1.12	dirlist[count++] = 1;
108	elmex	1.1	}
109
110			/* look down */
111	root	1.3	if (yc > 2 && xc > 2 && xc < xsize - 2) /* it is valid to look down */
112	elmex	1.1	{
113	root	1.17	int cleartest = maze[xc][yc - 1] + maze[xc - 1][yc - 1] + maze[xc + 1][yc - 1]
114			+ maze[xc][yc - 2] + maze[xc - 1][yc - 2] + maze[xc + 1][yc - 2];
115	root	1.3
116			if (cleartest == 0)
117	root	1.12	dirlist[count++] = 2;
118	elmex	1.1	}
119
120			/* look right */
121	root	1.3	if (xc < xsize - 2 && yc > 2 && yc < ysize - 2) /* it is valid to look left */
122	elmex	1.1	{
123	root	1.17	int cleartest = maze[xc + 1][yc] + maze[xc + 1][yc - 1] + maze[xc + 1][yc + 1]
124			+ maze[xc + 2][yc] + maze[xc + 2][yc - 1] + maze[xc + 2][yc + 1];
125	root	1.3
126			if (cleartest == 0)
127	root	1.12	dirlist[count++] = 3;
128	elmex	1.1	}
129
130			/* look left */
131	root	1.3	if (xc > 2 && yc > 2 && yc < ysize - 2) /* it is valid to look down */
132	elmex	1.1	{
133	root	1.17	int cleartest = maze[xc - 1][yc] + maze[xc - 1][yc - 1] + maze[xc - 1][yc + 1]
134			+ maze[xc - 2][yc] + maze[xc - 2][yc - 1] + maze[xc - 2][yc + 1];
135	root	1.2
136	root	1.3	if (cleartest == 0)
137	root	1.12	dirlist[count++] = 4;
138	elmex	1.1	}
139
140	root	1.3	if (count == 0)
141			return -1; /* failed to find any clear points */
142	elmex	1.1
143			/* choose a random direction */
144	root	1.12	switch (dirlist [rmg_rndm (count)])
145	elmex	1.1	{
146	root	1.5	case 1: /* up */
147	root	1.20	p.x = xc;
148			p.y = yc + 1;
149	root	1.12	break;
150
151	root	1.5	case 2: /* down */
152	root	1.20	p.x = xc;
153			p.y = yc - 1;
154	root	1.12	break;
155
156	root	1.5	case 3: /* right */
157	root	1.20	p.x = xc + 1;
158			p.y = yc;
159	root	1.12	break;
160
161	root	1.5	case 4: /* left */
162	root	1.20	p.x = xc - 1;
163			p.y = yc;
164	root	1.12	break;
165	elmex	1.1	}
166	root	1.12
167	elmex	1.1	return 1;
168			}
169
170	root	1.13	/* the outsize interface routine: accepts sizes, returns a char
171			** maze. option is a flag for either a sparse or a full maze. Sparse
172	root	1.21	mazes have sizable rooms. option = 3=full, 2=braided, 1=sparse, 0=rooms.*/
173	root	1.13	void
174	root	1.25	maze_gen (layout &maze, int subtype)
175	root	1.13	{
176	root	1.24	xsize = maze.w;
177			ysize = maze.h;
178	root	1.20	::maze = maze;
179	root	1.19
180	root	1.24	maze.clear ();
181			maze.border ();
182	root	1.13
183	root	1.20	if (xsize < 4 \|\| ysize < 4)
184			return;
185	root	1.13
186	root	1.23	seeds.reset (xsize * ysize);
187	root	1.21
188			if (subtype > 0)
189			push_walls ();
190
191			if (subtype == 0 \|\| subtype == 2)
192			for (int i = (xsize + ysize) / 2; i; --i)
193			push (point (rmg_rndm (1, xsize - 2), rmg_rndm (1, ysize - 2)));
194
195			bool full = subtype == 3;
196	root	1.13
197			/* recursively generate the walls of the maze */
198			/* first pop a random starting point */
199	root	1.23	while (seeds.size)
200	root	1.21	{
201			point p = pop_rand ();
202
203			for (;;)
204			{
205			point pc;
206
207			maze [p.x][p.y] = '#';
208
209			if (find_free_point (pc, p) < 0)
210			break;
211
212			if (full)
213			push (p);
214
215			if (!rmg_rndm (8))
216			{
217			if (!full)
218			push (pc);
219
220			break;
221			}
222
223			p = pc;
224			}
225			}
226	root	1.13
227	root	1.23	seeds.free ();
228	root	1.13	}
229