xref: /netbsd-src/games/hack/hack.mklev.c (revision 404fbe5fb94ca1e054339640cabb2801ce52dd30)
1 /*	$NetBSD: hack.mklev.c,v 1.6 2003/04/02 18:36:38 jsm Exp $	*/
2 
3 /*
4  * Copyright (c) 1985, Stichting Centrum voor Wiskunde en Informatica,
5  * Amsterdam
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions are
10  * met:
11  *
12  * - Redistributions of source code must retain the above copyright notice,
13  * this list of conditions and the following disclaimer.
14  *
15  * - Redistributions in binary form must reproduce the above copyright
16  * notice, this list of conditions and the following disclaimer in the
17  * documentation and/or other materials provided with the distribution.
18  *
19  * - Neither the name of the Stichting Centrum voor Wiskunde en
20  * Informatica, nor the names of its contributors may be used to endorse or
21  * promote products derived from this software without specific prior
22  * written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
25  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
27  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
28  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
29  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
30  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
31  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
33  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
34  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 
37 /*
38  * Copyright (c) 1982 Jay Fenlason <hack@gnu.org>
39  * All rights reserved.
40  *
41  * Redistribution and use in source and binary forms, with or without
42  * modification, are permitted provided that the following conditions
43  * are met:
44  * 1. Redistributions of source code must retain the above copyright
45  *    notice, this list of conditions and the following disclaimer.
46  * 2. Redistributions in binary form must reproduce the above copyright
47  *    notice, this list of conditions and the following disclaimer in the
48  *    documentation and/or other materials provided with the distribution.
49  * 3. The name of the author may not be used to endorse or promote products
50  *    derived from this software without specific prior written permission.
51  *
52  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
53  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
54  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
55  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
56  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
57  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
58  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
59  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
60  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
61  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
62  */
63 
64 #include <sys/cdefs.h>
65 #ifndef lint
66 __RCSID("$NetBSD: hack.mklev.c,v 1.6 2003/04/02 18:36:38 jsm Exp $");
67 #endif				/* not lint */
68 
69 #include <unistd.h>
70 #include <stdlib.h>
71 #include "hack.h"
72 #include "extern.h"
73 
74 #define somex() ((random()%(croom->hx-croom->lx+1))+croom->lx)
75 #define somey() ((random()%(croom->hy-croom->ly+1))+croom->ly)
76 
77 #include "def.mkroom.h"
78 #define	XLIM	4		/* define minimum required space around a
79 				 * room */
80 #define	YLIM	3
81 boolean         secret;		/* TRUE while making a vault: increase
82 				 * [XY]LIM */
83 int             smeq[MAXNROFROOMS + 1];
84 int             doorindex;
85 struct rm       zerorm;
86 schar           nxcor;
87 boolean         goldseen;
88 int             nroom;
89 
90 /* Definitions used by makerooms() and addrs() */
91 #define	MAXRS	50		/* max lth of temp rectangle table -
92 				 * arbitrary */
93 struct rectangle {
94 	xchar           rlx, rly, rhx, rhy;
95 }               rs[MAXRS + 1];
96 int             rscnt, rsmax;	/* 0..rscnt-1: currently under consideration */
97 /* rscnt..rsmax: discarded */
98 
99 void
100 makelevel()
101 {
102 	struct mkroom  *croom, *troom;
103 	unsigned        tryct;
104 	int x, y;
105 
106 	nroom = 0;
107 	doorindex = 0;
108 	rooms[0].hx = -1;	/* in case we are in a maze */
109 
110 	for (x = 0; x < COLNO; x++)
111 		for (y = 0; y < ROWNO; y++)
112 			levl[x][y] = zerorm;
113 
114 	oinit();		/* assign level dependent obj probabilities */
115 
116 	if (dlevel >= rn1(3, 26)) {	/* there might be several mazes */
117 		makemaz();
118 		return;
119 	}
120 	/* construct the rooms */
121 	nroom = 0;
122 	secret = FALSE;
123 	(void) makerooms();
124 
125 	/* construct stairs (up and down in different rooms if possible) */
126 	croom = &rooms[rn2(nroom)];
127 	xdnstair = somex();
128 	ydnstair = somey();
129 	levl[xdnstair][ydnstair].scrsym = '>';
130 	levl[xdnstair][ydnstair].typ = STAIRS;
131 	if (nroom > 1) {
132 		troom = croom;
133 		croom = &rooms[rn2(nroom - 1)];
134 		if (croom >= troom)
135 			croom++;
136 	}
137 	xupstair = somex();	/* %% < and > might be in the same place */
138 	yupstair = somey();
139 	levl[xupstair][yupstair].scrsym = '<';
140 	levl[xupstair][yupstair].typ = STAIRS;
141 
142 	/* for each room: put things inside */
143 	for (croom = rooms; croom->hx > 0; croom++) {
144 
145 		/* put a sleeping monster inside */
146 		/*
147 		 * Note: monster may be on the stairs. This cannot be
148 		 * avoided: maybe the player fell through a trapdoor while a
149 		 * monster was on the stairs. Conclusion: we have to check
150 		 * for monsters on the stairs anyway.
151 		 */
152 		if (!rn2(3))
153 			(void)
154 				makemon((struct permonst *) 0, somex(), somey());
155 
156 		/* put traps and mimics inside */
157 		goldseen = FALSE;
158 		while (!rn2(8 - (dlevel / 6)))
159 			mktrap(0, 0, croom);
160 		if (!goldseen && !rn2(3))
161 			mkgold(0L, somex(), somey());
162 		if (!rn2(3)) {
163 			(void) mkobj_at(0, somex(), somey());
164 			tryct = 0;
165 			while (!rn2(5)) {
166 				if (++tryct > 100) {
167 					printf("tryct overflow4\n");
168 					break;
169 				}
170 				(void) mkobj_at(0, somex(), somey());
171 			}
172 		}
173 	}
174 
175 	qsort((char *) rooms, nroom, sizeof(struct mkroom), comp);
176 	makecorridors();
177 	make_niches();
178 
179 	/* make a secret treasure vault, not connected to the rest */
180 	if (nroom <= (2 * MAXNROFROOMS / 3))
181 		if (rn2(3)) {
182 			troom = &rooms[nroom];
183 			secret = TRUE;
184 			if (makerooms()) {
185 				troom->rtype = VAULT;	/* treasure vault */
186 				for (x = troom->lx; x <= troom->hx; x++)
187 					for (y = troom->ly; y <= troom->hy; y++)
188 						mkgold((long) (rnd(dlevel * 100) + 50), x, y);
189 				if (!rn2(3))
190 					makevtele();
191 			}
192 		}
193 #ifndef QUEST
194 #ifdef WIZARD
195 	if (wizard && getenv("SHOPTYPE"))
196 		mkshop();
197 	else
198 #endif	/* WIZARD */
199 	if (dlevel > 1 && dlevel < 20 && rn2(dlevel) < 3)
200 		mkshop();
201 	else if (dlevel > 6 && !rn2(7))
202 		mkzoo(ZOO);
203 	else if (dlevel > 9 && !rn2(5))
204 		mkzoo(BEEHIVE);
205 	else if (dlevel > 11 && !rn2(6))
206 		mkzoo(MORGUE);
207 	else if (dlevel > 18 && !rn2(6))
208 		mkswamp();
209 #endif	/* QUEST */
210 }
211 
212 int
213 makerooms()
214 {
215 	struct rectangle *rsp;
216 	int             lx, ly, hx, hy, lowx, lowy, hix, hiy, dx, dy;
217 	int             tryct = 0, xlim, ylim;
218 
219 	/* init */
220 	xlim = XLIM + secret;
221 	ylim = YLIM + secret;
222 	if (nroom == 0) {
223 		rsp = rs;
224 		rsp->rlx = rsp->rly = 0;
225 		rsp->rhx = COLNO - 1;
226 		rsp->rhy = ROWNO - 1;
227 		rsmax = 1;
228 	}
229 	rscnt = rsmax;
230 
231 	/* make rooms until satisfied */
232 	while (rscnt > 0 && nroom < MAXNROFROOMS - 1) {
233 		if (!secret && nroom > (MAXNROFROOMS / 3) &&
234 		    !rn2((MAXNROFROOMS - nroom) * (MAXNROFROOMS - nroom)))
235 			return (0);
236 
237 		/* pick a rectangle */
238 		rsp = &rs[rn2(rscnt)];
239 		hx = rsp->rhx;
240 		hy = rsp->rhy;
241 		lx = rsp->rlx;
242 		ly = rsp->rly;
243 
244 		/* find size of room */
245 		if (secret)
246 			dx = dy = 1;
247 		else {
248 			dx = 2 + rn2((hx - lx - 8 > 20) ? 12 : 8);
249 			dy = 2 + rn2(4);
250 			if (dx * dy > 50)
251 				dy = 50 / dx;
252 		}
253 
254 		/* look whether our room will fit */
255 		if (hx - lx < dx + dx / 2 + 2 * xlim || hy - ly < dy + dy / 3 + 2 * ylim) {
256 			/* no, too small */
257 			/* maybe we throw this area out */
258 			if (secret || !rn2(MAXNROFROOMS + 1 - nroom - tryct)) {
259 				rscnt--;
260 				rs[rsmax] = *rsp;
261 				*rsp = rs[rscnt];
262 				rs[rscnt] = rs[rsmax];
263 				tryct = 0;
264 			} else
265 				tryct++;
266 			continue;
267 		}
268 		lowx = lx + xlim + rn2(hx - lx - dx - 2 * xlim + 1);
269 		lowy = ly + ylim + rn2(hy - ly - dy - 2 * ylim + 1);
270 		hix = lowx + dx;
271 		hiy = lowy + dy;
272 
273 		if (maker(lowx, dx, lowy, dy)) {
274 			if (secret)
275 				return (1);
276 			addrs(lowx - 1, lowy - 1, hix + 1, hiy + 1);
277 			tryct = 0;
278 		} else if (tryct++ > 100)
279 			break;
280 	}
281 	return (0);		/* failed to make vault - very strange */
282 }
283 
284 void
285 addrs(lowx, lowy, hix, hiy)
286 	int             lowx, lowy, hix, hiy;
287 {
288 	struct rectangle *rsp;
289 	int             lx, ly, hx, hy, xlim, ylim;
290 	boolean         discarded;
291 
292 	xlim = XLIM + secret;
293 	ylim = YLIM + secret;
294 
295 	/* walk down since rscnt and rsmax change */
296 	for (rsp = &rs[rsmax - 1]; rsp >= rs; rsp--) {
297 
298 		if ((lx = rsp->rlx) > hix || (ly = rsp->rly) > hiy ||
299 		    (hx = rsp->rhx) < lowx || (hy = rsp->rhy) < lowy)
300 			continue;
301 		if ((discarded = (rsp >= &rs[rscnt]))) {
302 			*rsp = rs[--rsmax];
303 		} else {
304 			rsmax--;
305 			rscnt--;
306 			*rsp = rs[rscnt];
307 			if (rscnt != rsmax)
308 				rs[rscnt] = rs[rsmax];
309 		}
310 		if (lowy - ly > 2 * ylim + 4)
311 			addrsx(lx, ly, hx, lowy - 2, discarded);
312 		if (lowx - lx > 2 * xlim + 4)
313 			addrsx(lx, ly, lowx - 2, hy, discarded);
314 		if (hy - hiy > 2 * ylim + 4)
315 			addrsx(lx, hiy + 2, hx, hy, discarded);
316 		if (hx - hix > 2 * xlim + 4)
317 			addrsx(hix + 2, ly, hx, hy, discarded);
318 	}
319 }
320 
321 void
322 addrsx(lx, ly, hx, hy, discarded)
323 	int             lx, ly, hx, hy;
324 	boolean         discarded;	/* piece of a discarded area */
325 {
326 	struct rectangle *rsp;
327 
328 	/* check inclusions */
329 	for (rsp = rs; rsp < &rs[rsmax]; rsp++) {
330 		if (lx >= rsp->rlx && hx <= rsp->rhx &&
331 		    ly >= rsp->rly && hy <= rsp->rhy)
332 			return;
333 	}
334 
335 	/* make a new entry */
336 	if (rsmax >= MAXRS) {
337 #ifdef WIZARD
338 		if (wizard)
339 			pline("MAXRS may be too small.");
340 #endif	/* WIZARD */
341 		return;
342 	}
343 	rsmax++;
344 	if (!discarded) {
345 		*rsp = rs[rscnt];
346 		rsp = &rs[rscnt];
347 		rscnt++;
348 	}
349 	rsp->rlx = lx;
350 	rsp->rly = ly;
351 	rsp->rhx = hx;
352 	rsp->rhy = hy;
353 }
354 
355 int
356 comp(vx, vy)
357 	const void *vx, *vy;
358 {
359 	const struct mkroom  *x = vx, *y = vy;
360 	if (x->lx < y->lx)
361 		return (-1);
362 	return (x->lx > y->lx);
363 }
364 
365 coord
366 finddpos(int xl, int yl, int xh, int yh)
367 {
368 	coord           ff;
369 	int x, y;
370 
371 	x = (xl == xh) ? xl : (xl + rn2(xh - xl + 1));
372 	y = (yl == yh) ? yl : (yl + rn2(yh - yl + 1));
373 	if (okdoor(x, y))
374 		goto gotit;
375 
376 	for (x = xl; x <= xh; x++)
377 		for (y = yl; y <= yh; y++)
378 			if (okdoor(x, y))
379 				goto gotit;
380 
381 	for (x = xl; x <= xh; x++)
382 		for (y = yl; y <= yh; y++)
383 			if (levl[x][y].typ == DOOR || levl[x][y].typ == SDOOR)
384 				goto gotit;
385 	/* cannot find something reasonable -- strange */
386 	x = xl;
387 	y = yh;
388 gotit:
389 	ff.x = x;
390 	ff.y = y;
391 	return (ff);
392 }
393 
394 /* see whether it is allowable to create a door at [x,y] */
395 int
396 okdoor(x, y)
397 	int x, y;
398 {
399 	if (levl[x - 1][y].typ == DOOR || levl[x + 1][y].typ == DOOR ||
400 	    levl[x][y + 1].typ == DOOR || levl[x][y - 1].typ == DOOR ||
401 	    levl[x - 1][y].typ == SDOOR || levl[x + 1][y].typ == SDOOR ||
402 	    levl[x][y - 1].typ == SDOOR || levl[x][y + 1].typ == SDOOR ||
403 	    (levl[x][y].typ != HWALL && levl[x][y].typ != VWALL) ||
404 	    doorindex >= DOORMAX)
405 		return (0);
406 	return (1);
407 }
408 
409 void
410 dodoor(x, y, aroom)
411 	int x, y;
412 	struct mkroom  *aroom;
413 {
414 	if (doorindex >= DOORMAX) {
415 		impossible("DOORMAX exceeded?");
416 		return;
417 	}
418 	if (!okdoor(x, y) && nxcor)
419 		return;
420 	dosdoor(x, y, aroom, rn2(8) ? DOOR : SDOOR);
421 }
422 
423 void
424 dosdoor(x, y, aroom, type)
425 	int x, y;
426 	struct mkroom  *aroom;
427 	int type;
428 {
429 	struct mkroom  *broom;
430 	int tmp;
431 
432 	if (!IS_WALL(levl[x][y].typ))	/* avoid SDOORs with '+' as scrsym */
433 		type = DOOR;
434 	levl[x][y].typ = type;
435 	if (type == DOOR)
436 		levl[x][y].scrsym = '+';
437 	aroom->doorct++;
438 	broom = aroom + 1;
439 	if (broom->hx < 0)
440 		tmp = doorindex;
441 	else
442 		for (tmp = doorindex; tmp > broom->fdoor; tmp--)
443 			doors[tmp] = doors[tmp - 1];
444 	doorindex++;
445 	doors[tmp].x = x;
446 	doors[tmp].y = y;
447 	for (; broom->hx >= 0; broom++)
448 		broom->fdoor++;
449 }
450 
451 /* Only called from makerooms() */
452 int
453 maker(lowx, ddx, lowy, ddy)
454 	schar           lowx, ddx, lowy, ddy;
455 {
456 	struct mkroom  *croom;
457 	int x, y, hix = lowx + ddx, hiy = lowy + ddy;
458 	int xlim = XLIM + secret, ylim = YLIM + secret;
459 
460 	if (nroom >= MAXNROFROOMS)
461 		return (0);
462 	if (lowx < XLIM)
463 		lowx = XLIM;
464 	if (lowy < YLIM)
465 		lowy = YLIM;
466 	if (hix > COLNO - XLIM - 1)
467 		hix = COLNO - XLIM - 1;
468 	if (hiy > ROWNO - YLIM - 1)
469 		hiy = ROWNO - YLIM - 1;
470 chk:
471 	if (hix <= lowx || hiy <= lowy)
472 		return (0);
473 
474 	/* check area around room (and make room smaller if necessary) */
475 	for (x = lowx - xlim; x <= hix + xlim; x++) {
476 		for (y = lowy - ylim; y <= hiy + ylim; y++) {
477 			if (levl[x][y].typ) {
478 #ifdef WIZARD
479 				if (wizard && !secret)
480 					pline("Strange area [%d,%d] in maker().", x, y);
481 #endif	/* WIZARD */
482 				if (!rn2(3))
483 					return (0);
484 				if (x < lowx)
485 					lowx = x + xlim + 1;
486 				else
487 					hix = x - xlim - 1;
488 				if (y < lowy)
489 					lowy = y + ylim + 1;
490 				else
491 					hiy = y - ylim - 1;
492 				goto chk;
493 			}
494 		}
495 	}
496 
497 	croom = &rooms[nroom];
498 
499 	/* on low levels the room is lit (usually) */
500 	/* secret vaults are always lit */
501 	if ((rnd(dlevel) < 10 && rn2(77)) || (ddx == 1 && ddy == 1)) {
502 		for (x = lowx - 1; x <= hix + 1; x++)
503 			for (y = lowy - 1; y <= hiy + 1; y++)
504 				levl[x][y].lit = 1;
505 		croom->rlit = 1;
506 	} else
507 		croom->rlit = 0;
508 	croom->lx = lowx;
509 	croom->hx = hix;
510 	croom->ly = lowy;
511 	croom->hy = hiy;
512 	croom->rtype = croom->doorct = croom->fdoor = 0;
513 
514 	for (x = lowx - 1; x <= hix + 1; x++)
515 		for (y = lowy - 1; y <= hiy + 1; y += (hiy - lowy + 2)) {
516 			levl[x][y].scrsym = '-';
517 			levl[x][y].typ = HWALL;
518 		}
519 	for (x = lowx - 1; x <= hix + 1; x += (hix - lowx + 2))
520 		for (y = lowy; y <= hiy; y++) {
521 			levl[x][y].scrsym = '|';
522 			levl[x][y].typ = VWALL;
523 		}
524 	for (x = lowx; x <= hix; x++)
525 		for (y = lowy; y <= hiy; y++) {
526 			levl[x][y].scrsym = '.';
527 			levl[x][y].typ = ROOM;
528 		}
529 
530 	smeq[nroom] = nroom;
531 	croom++;
532 	croom->hx = -1;
533 	nroom++;
534 	return (1);
535 }
536 
537 void
538 makecorridors()
539 {
540 	int a, b;
541 
542 	nxcor = 0;
543 	for (a = 0; a < nroom - 1; a++)
544 		join(a, a + 1);
545 	for (a = 0; a < nroom - 2; a++)
546 		if (smeq[a] != smeq[a + 2])
547 			join(a, a + 2);
548 	for (a = 0; a < nroom; a++)
549 		for (b = 0; b < nroom; b++)
550 			if (smeq[a] != smeq[b])
551 				join(a, b);
552 	if (nroom > 2)
553 		for (nxcor = rn2(nroom) + 4; nxcor; nxcor--) {
554 			a = rn2(nroom);
555 			b = rn2(nroom - 2);
556 			if (b >= a)
557 				b += 2;
558 			join(a, b);
559 		}
560 }
561 
562 void
563 join(a, b)
564 	int a, b;
565 {
566 	coord           cc, tt;
567 	int tx, ty, xx, yy;
568 	struct rm      *crm;
569 	struct mkroom  *croom, *troom;
570 	int dx, dy, dix, diy, cct;
571 
572 	croom = &rooms[a];
573 	troom = &rooms[b];
574 
575 	/*
576 	 * find positions cc and tt for doors in croom and troom and
577 	 * direction for a corridor between them
578 	 */
579 
580 	if (troom->hx < 0 || croom->hx < 0 || doorindex >= DOORMAX)
581 		return;
582 	if (troom->lx > croom->hx) {
583 		dx = 1;
584 		dy = 0;
585 		xx = croom->hx + 1;
586 		tx = troom->lx - 1;
587 		cc = finddpos(xx, croom->ly, xx, croom->hy);
588 		tt = finddpos(tx, troom->ly, tx, troom->hy);
589 	} else if (troom->hy < croom->ly) {
590 		dy = -1;
591 		dx = 0;
592 		yy = croom->ly - 1;
593 		cc = finddpos(croom->lx, yy, croom->hx, yy);
594 		ty = troom->hy + 1;
595 		tt = finddpos(troom->lx, ty, troom->hx, ty);
596 	} else if (troom->hx < croom->lx) {
597 		dx = -1;
598 		dy = 0;
599 		xx = croom->lx - 1;
600 		tx = troom->hx + 1;
601 		cc = finddpos(xx, croom->ly, xx, croom->hy);
602 		tt = finddpos(tx, troom->ly, tx, troom->hy);
603 	} else {
604 		dy = 1;
605 		dx = 0;
606 		yy = croom->hy + 1;
607 		ty = troom->ly - 1;
608 		cc = finddpos(croom->lx, yy, croom->hx, yy);
609 		tt = finddpos(troom->lx, ty, troom->hx, ty);
610 	}
611 	xx = cc.x;
612 	yy = cc.y;
613 	tx = tt.x - dx;
614 	ty = tt.y - dy;
615 	if (nxcor && levl[xx + dx][yy + dy].typ)
616 		return;
617 	dodoor(xx, yy, croom);
618 
619 	cct = 0;
620 	while (xx != tx || yy != ty) {
621 		xx += dx;
622 		yy += dy;
623 
624 		/* loop: dig corridor at [xx,yy] and find new [xx,yy] */
625 		if (cct++ > 500 || (nxcor && !rn2(35)))
626 			return;
627 
628 		if (xx == COLNO - 1 || xx == 0 || yy == 0 || yy == ROWNO - 1)
629 			return;	/* impossible */
630 
631 		crm = &levl[xx][yy];
632 		if (!(crm->typ)) {
633 			if (rn2(100)) {
634 				crm->typ = CORR;
635 				crm->scrsym = CORR_SYM;
636 				if (nxcor && !rn2(50))
637 					(void) mkobj_at(ROCK_SYM, xx, yy);
638 			} else {
639 				crm->typ = SCORR;
640 				crm->scrsym = ' ';
641 			}
642 		} else if (crm->typ != CORR && crm->typ != SCORR) {
643 			/* strange ... */
644 			return;
645 		}
646 		/* find next corridor position */
647 		dix = abs(xx - tx);
648 		diy = abs(yy - ty);
649 
650 		/* do we have to change direction ? */
651 		if (dy && dix > diy) {
652 			int ddx = (xx > tx) ? -1 : 1;
653 
654 			crm = &levl[xx + ddx][yy];
655 			if (!crm->typ || crm->typ == CORR || crm->typ == SCORR) {
656 				dx = ddx;
657 				dy = 0;
658 				continue;
659 			}
660 		} else if (dx && diy > dix) {
661 			int ddy = (yy > ty) ? -1 : 1;
662 
663 			crm = &levl[xx][yy + ddy];
664 			if (!crm->typ || crm->typ == CORR || crm->typ == SCORR) {
665 				dy = ddy;
666 				dx = 0;
667 				continue;
668 			}
669 		}
670 		/* continue straight on? */
671 		crm = &levl[xx + dx][yy + dy];
672 		if (!crm->typ || crm->typ == CORR || crm->typ == SCORR)
673 			continue;
674 
675 		/* no, what must we do now?? */
676 		if (dx) {
677 			dx = 0;
678 			dy = (ty < yy) ? -1 : 1;
679 			crm = &levl[xx + dx][yy + dy];
680 			if (!crm->typ || crm->typ == CORR || crm->typ == SCORR)
681 				continue;
682 			dy = -dy;
683 			continue;
684 		} else {
685 			dy = 0;
686 			dx = (tx < xx) ? -1 : 1;
687 			crm = &levl[xx + dx][yy + dy];
688 			if (!crm->typ || crm->typ == CORR || crm->typ == SCORR)
689 				continue;
690 			dx = -dx;
691 			continue;
692 		}
693 	}
694 
695 	/* we succeeded in digging the corridor */
696 	dodoor(tt.x, tt.y, troom);
697 
698 	if (smeq[a] < smeq[b])
699 		smeq[b] = smeq[a];
700 	else
701 		smeq[a] = smeq[b];
702 }
703 
704 void
705 make_niches()
706 {
707 	int             ct = rnd(nroom / 2 + 1);
708 	while (ct--)
709 		makeniche(FALSE);
710 }
711 
712 void
713 makevtele()
714 {
715 	makeniche(TRUE);
716 }
717 
718 void
719 makeniche(with_trap)
720 	boolean         with_trap;
721 {
722 	struct mkroom  *aroom;
723 	struct rm      *rm;
724 	int             vct = 8;
725 	coord           dd;
726 	int		dy, xx, yy;
727 	struct trap    *ttmp;
728 
729 	if (doorindex < DOORMAX)
730 		while (vct--) {
731 			aroom = &rooms[rn2(nroom - 1)];
732 			if (aroom->rtype != 0)
733 				continue;	/* not an ordinary room */
734 			if (aroom->doorct == 1 && rn2(5))
735 				continue;
736 			if (rn2(2)) {
737 				dy = 1;
738 				dd = finddpos(aroom->lx, aroom->hy + 1, aroom->hx, aroom->hy + 1);
739 			} else {
740 				dy = -1;
741 				dd = finddpos(aroom->lx, aroom->ly - 1, aroom->hx, aroom->ly - 1);
742 			}
743 			xx = dd.x;
744 			yy = dd.y;
745 			if ((rm = &levl[xx][yy + dy])->typ)
746 				continue;
747 			if (with_trap || !rn2(4)) {
748 				rm->typ = SCORR;
749 				rm->scrsym = ' ';
750 				if (with_trap) {
751 					ttmp = maketrap(xx, yy + dy, TELEP_TRAP);
752 					ttmp->once = 1;
753 					make_engr_at(xx, yy - dy, "ad ae?ar um");
754 				}
755 				dosdoor(xx, yy, aroom, SDOOR);
756 			} else {
757 				rm->typ = CORR;
758 				rm->scrsym = CORR_SYM;
759 				if (rn2(7))
760 					dosdoor(xx, yy, aroom, rn2(5) ? SDOOR : DOOR);
761 				else {
762 					mksobj_at(SCR_TELEPORTATION, xx, yy + dy);
763 					if (!rn2(3))
764 						(void) mkobj_at(0, xx, yy + dy);
765 				}
766 			}
767 			return;
768 		}
769 }
770 
771 /* make a trap somewhere (in croom if mazeflag = 0) */
772 void
773 mktrap(num, mazeflag, croom)
774 	int num, mazeflag;
775 	struct mkroom  *croom;
776 {
777 	struct trap    *ttmp;
778 	int             kind, nopierc, nomimic, fakedoor, fakegold, tryct = 0;
779 	xchar           mx, my;
780 
781 	if (!num || num >= TRAPNUM) {
782 		nopierc = (dlevel < 4) ? 1 : 0;
783 		nomimic = (dlevel < 9 || goldseen) ? 1 : 0;
784 		if (strchr(fut_geno, 'M'))
785 			nomimic = 1;
786 		kind = rn2(TRAPNUM - nopierc - nomimic);
787 		/* note: PIERC = 7, MIMIC = 8, TRAPNUM = 9 */
788 	} else
789 		kind = num;
790 
791 	if (kind == MIMIC) {
792 		struct monst   *mtmp;
793 
794 		fakedoor = (!rn2(3) && !mazeflag);
795 		fakegold = (!fakedoor && !rn2(2));
796 		if (fakegold)
797 			goldseen = TRUE;
798 		do {
799 			if (++tryct > 200)
800 				return;
801 			if (fakedoor) {
802 				/* note: fakedoor maybe on actual door */
803 				if (rn2(2)) {
804 					if (rn2(2))
805 						mx = croom->hx + 1;
806 					else
807 						mx = croom->lx - 1;
808 					my = somey();
809 				} else {
810 					if (rn2(2))
811 						my = croom->hy + 1;
812 					else
813 						my = croom->ly - 1;
814 					mx = somex();
815 				}
816 			} else if (mazeflag) {
817 				coord           mm;
818 				mm = mazexy();
819 				mx = mm.x;
820 				my = mm.y;
821 			} else {
822 				mx = somex();
823 				my = somey();
824 			}
825 		} while (m_at(mx, my) || levl[mx][my].typ == STAIRS);
826 		if ((mtmp = makemon(PM_MIMIC, mx, my)) != NULL) {
827 			mtmp->mimic = 1;
828 			mtmp->mappearance =
829 				fakegold ? '$' : fakedoor ? '+' :
830 				(mazeflag && rn2(2)) ? AMULET_SYM :
831 				"=/)%?![<>"[rn2(9)];
832 		}
833 		return;
834 	}
835 	do {
836 		if (++tryct > 200)
837 			return;
838 		if (mazeflag) {
839 			coord           mm;
840 			mm = mazexy();
841 			mx = mm.x;
842 			my = mm.y;
843 		} else {
844 			mx = somex();
845 			my = somey();
846 		}
847 	} while (t_at(mx, my) || levl[mx][my].typ == STAIRS);
848 	ttmp = maketrap(mx, my, kind);
849 	if (mazeflag && !rn2(10) && ttmp->ttyp < PIERC)
850 		ttmp->tseen = 1;
851 }
852