xref: /netbsd-src/games/hunt/huntd/shots.c (revision 2de962bd804263c16657f586aa00f1704045df8e)
1 /*	$NetBSD: shots.c,v 1.6 2006/03/17 23:34:37 abs Exp $	*/
2 /*
3  * Copyright (c) 1983-2003, Regents of the University of California.
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions are
8  * met:
9  *
10  * + Redistributions of source code must retain the above copyright
11  *   notice, this list of conditions and the following disclaimer.
12  * + Redistributions in binary form must reproduce the above copyright
13  *   notice, this list of conditions and the following disclaimer in the
14  *   documentation and/or other materials provided with the distribution.
15  * + Neither the name of the University of California, San Francisco nor
16  *   the names of its contributors may be used to endorse or promote
17  *   products derived from this software without specific prior written
18  *   permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
21  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
23  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 #ifndef lint
35 __RCSID("$NetBSD: shots.c,v 1.6 2006/03/17 23:34:37 abs Exp $");
36 #endif /* not lint */
37 
38 # include	<err.h>
39 # include	<signal.h>
40 # include	<stdlib.h>
41 # include	"hunt.h"
42 
43 # define	PLUS_DELTA(x, max)	if (x < max) x++; else x--
44 # define	MINUS_DELTA(x, min)	if (x > min) x--; else x++
45 
46 static	void	chkshot(BULLET *, BULLET *);
47 static	void	chkslime(BULLET *, BULLET *);
48 static	void	explshot(BULLET *, int, int);
49 static	void	find_under(BULLET *, BULLET *);
50 static	int	iswall(int, int);
51 static	void	mark_boot(BULLET *);
52 static	void	mark_player(BULLET *);
53 #ifdef DRONE
54 static	void	move_drone(BULLET *);
55 #endif
56 static	void	move_flyer(PLAYER *);
57 static	int	move_normal_shot(BULLET *);
58 static	void	move_slime(BULLET *, int, BULLET *);
59 static	void	save_bullet(BULLET *);
60 static	void	zapshot(BULLET *, BULLET *);
61 
62 /*
63  * moveshots:
64  *	Move the shots already in the air, taking explosions into account
65  */
66 void
67 moveshots()
68 {
69 	BULLET	*bp, *next;
70 	PLAYER	*pp;
71 	int	x, y;
72 	BULLET	*blist;
73 
74 	rollexpl();
75 	if (Bullets == NULL)
76 		goto ret;
77 
78 	/*
79 	 * First we move through the bullet list BULSPD times, looking
80 	 * for things we may have run into.  If we do run into
81 	 * something, we set up the explosion and disappear, checking
82 	 * for damage to any player who got in the way.
83 	 */
84 
85 	blist = Bullets;
86 	Bullets = NULL;
87 	for (bp = blist; bp != NULL; bp = next) {
88 		next = bp->b_next;
89 		x = bp->b_x;
90 		y = bp->b_y;
91 		Maze[y][x] = bp->b_over;
92 		for (pp = Player; pp < End_player; pp++)
93 			check(pp, y, x);
94 # ifdef MONITOR
95 		for (pp = Monitor; pp < End_monitor; pp++)
96 			check(pp, y, x);
97 # endif
98 
99 		switch (bp->b_type) {
100 		  case SHOT:
101 		  case GRENADE:
102 		  case SATCHEL:
103 		  case BOMB:
104 			if (move_normal_shot(bp)) {
105 				bp->b_next = Bullets;
106 				Bullets = bp;
107 			}
108 			break;
109 # ifdef OOZE
110 		  case SLIME:
111 			if (bp->b_expl || move_normal_shot(bp)) {
112 				bp->b_next = Bullets;
113 				Bullets = bp;
114 			}
115 			break;
116 # endif
117 # ifdef DRONE
118 		  case DSHOT:
119 			if (move_drone(bp)) {
120 				bp->b_next = Bullets;
121 				Bullets = bp;
122 			}
123 			break;
124 # endif
125 		  default:
126 			bp->b_next = Bullets;
127 			Bullets = bp;
128 			break;
129 		}
130 	}
131 
132 	blist = Bullets;
133 	Bullets = NULL;
134 	for (bp = blist; bp != NULL; bp = next) {
135 		next = bp->b_next;
136 		if (!bp->b_expl) {
137 			save_bullet(bp);
138 # ifdef MONITOR
139 			for (pp = Monitor; pp < End_monitor; pp++)
140 				check(pp, bp->b_y, bp->b_x);
141 # endif
142 # ifdef DRONE
143 			if (bp->b_type == DSHOT)
144 				for (pp = Player; pp < End_player; pp++)
145 					if (pp->p_scan >= 0)
146 						check(pp, bp->b_y, bp->b_x);
147 # endif
148 			continue;
149 		}
150 
151 		chkshot(bp, next);
152 		free((char *) bp);
153 	}
154 
155 	for (pp = Player; pp < End_player; pp++)
156 		Maze[pp->p_y][pp->p_x] = pp->p_face;
157 
158 ret:
159 # ifdef BOOTS
160 	for (pp = Boot; pp < &Boot[NBOOTS]; pp++)
161 		if (pp->p_flying >= 0)
162 			move_flyer(pp);
163 # endif
164 	for (pp = Player; pp < End_player; pp++) {
165 # ifdef FLY
166 		if (pp->p_flying >= 0)
167 			move_flyer(pp);
168 # endif
169 		sendcom(pp, REFRESH);	/* Flush out the explosions */
170 		look(pp);
171 		sendcom(pp, REFRESH);
172 	}
173 # ifdef MONITOR
174 	for (pp = Monitor; pp < End_monitor; pp++)
175 		sendcom(pp, REFRESH);
176 # endif
177 
178 	return;
179 }
180 
181 /*
182  * move_normal_shot:
183  *	Move a normal shot along its trajectory
184  */
185 static int
186 move_normal_shot(bp)
187 	BULLET	*bp;
188 {
189 	int	i, x, y;
190 	PLAYER	*pp;
191 
192 	for (i = 0; i < BULSPD; i++) {
193 		if (bp->b_expl)
194 			break;
195 
196 		x = bp->b_x;
197 		y = bp->b_y;
198 
199 		switch (bp->b_face) {
200 		  case LEFTS:
201 			x--;
202 			break;
203 		  case RIGHT:
204 			x++;
205 			break;
206 		  case ABOVE:
207 			y--;
208 			break;
209 		  case BELOW:
210 			y++;
211 			break;
212 		}
213 
214 		switch (Maze[y][x]) {
215 		  case SHOT:
216 			if (rand_num(100) < 5) {
217 				zapshot(Bullets, bp);
218 				zapshot(bp->b_next, bp);
219 			}
220 			break;
221 		  case GRENADE:
222 			if (rand_num(100) < 10) {
223 				zapshot(Bullets, bp);
224 				zapshot(bp->b_next, bp);
225 			}
226 			break;
227 # ifdef	REFLECT
228 		  case WALL4:	/* reflecting walls */
229 			switch (bp->b_face) {
230 			  case LEFTS:
231 				bp->b_face = BELOW;
232 				break;
233 			  case RIGHT:
234 				bp->b_face = ABOVE;
235 				break;
236 			  case ABOVE:
237 				bp->b_face = RIGHT;
238 				break;
239 			  case BELOW:
240 				bp->b_face = LEFTS;
241 				break;
242 			}
243 			Maze[y][x] = WALL5;
244 # ifdef MONITOR
245 			for (pp = Monitor; pp < End_monitor; pp++)
246 				check(pp, y, x);
247 # endif
248 			break;
249 		  case WALL5:
250 			switch (bp->b_face) {
251 			  case LEFTS:
252 				bp->b_face = ABOVE;
253 				break;
254 			  case RIGHT:
255 				bp->b_face = BELOW;
256 				break;
257 			  case ABOVE:
258 				bp->b_face = LEFTS;
259 				break;
260 			  case BELOW:
261 				bp->b_face = RIGHT;
262 				break;
263 			}
264 			Maze[y][x] = WALL4;
265 # ifdef MONITOR
266 			for (pp = Monitor; pp < End_monitor; pp++)
267 				check(pp, y, x);
268 # endif
269 			break;
270 # endif
271 # ifdef RANDOM
272 		  case DOOR:
273 			switch (rand_num(4)) {
274 			  case 0:
275 				bp->b_face = ABOVE;
276 				break;
277 			  case 1:
278 				bp->b_face = BELOW;
279 				break;
280 			  case 2:
281 				bp->b_face = LEFTS;
282 				break;
283 			  case 3:
284 				bp->b_face = RIGHT;
285 				break;
286 			}
287 			break;
288 # endif
289 # ifdef FLY
290 		  case FLYER:
291 			pp = play_at(y, x);
292 			message(pp, "Zing!");
293 			break;
294 # endif
295 		  case LEFTS:
296 		  case RIGHT:
297 		  case BELOW:
298 		  case ABOVE:
299 			/*
300 			 * give the person a chance to catch a
301 			 * grenade if s/he is facing it
302 			 */
303 			pp = play_at(y, x);
304 			pp->p_ident->i_shot += bp->b_charge;
305 			if (opposite(bp->b_face, Maze[y][x])) {
306 			    if (rand_num(100) < 10) {
307 				if (bp->b_owner != NULL)
308 					message(bp->b_owner,
309 					    "Your charge was absorbed!");
310 				if (bp->b_score != NULL)
311 					bp->b_score->i_robbed += bp->b_charge;
312 				pp->p_ammo += bp->b_charge;
313 				if (pp->p_damage + bp->b_size * MINDAM
314 				    > pp->p_damcap)
315 					pp->p_ident->i_saved++;
316 				message(pp, "Absorbed charge (good shield!)");
317 				pp->p_ident->i_absorbed += bp->b_charge;
318 				free((char *) bp);
319 				(void) sprintf(Buf, "%3d", pp->p_ammo);
320 				cgoto(pp, STAT_AMMO_ROW, STAT_VALUE_COL);
321 				outstr(pp, Buf, 3);
322 				return FALSE;
323 			    }
324 			    pp->p_ident->i_faced += bp->b_charge;
325 			}
326 			/*
327 			 * Small chance that the bullet just misses the
328 			 * person.  If so, the bullet just goes on its
329 			 * merry way without exploding.
330 			 */
331 			if (rand_num(100) < 5) {
332 				pp->p_ident->i_ducked += bp->b_charge;
333 				if (pp->p_damage + bp->b_size * MINDAM
334 				    > pp->p_damcap)
335 					pp->p_ident->i_saved++;
336 				if (bp->b_score != NULL)
337 					bp->b_score->i_missed += bp->b_charge;
338 				message(pp, "Zing!");
339 				if (bp->b_owner == NULL)
340 					break;
341 				message(bp->b_owner, bp->b_score &&
342 					((bp->b_score->i_missed & 0x7) == 0x7) ?
343 					"My!  What a bad shot you are!" :
344 					"Missed him");
345 				break;
346 			}
347 			/*
348 			 * The shot hit that sucker!  Blow it up.
349 			 */
350 			/* FALLTHROUGH */
351 # ifndef RANDOM
352 		  case DOOR:
353 # endif
354 		  case WALL1:
355 		  case WALL2:
356 		  case WALL3:
357 			bp->b_expl = TRUE;
358 			break;
359 		}
360 
361 		bp->b_x = x;
362 		bp->b_y = y;
363 	}
364 	return TRUE;
365 }
366 
367 # ifdef	DRONE
368 /*
369  * move_drone:
370  *	Move the drone to the next square
371  */
372 static void
373 move_drone(bp)
374 	BULLET	*bp;
375 {
376 	int	mask, count;
377 	int	n, dir;
378 	PLAYER	*pp;
379 
380 	/*
381 	 * See if we can give someone a blast
382 	 */
383 	if (isplayer(Maze[bp->b_y][bp->b_x - 1])) {
384 		dir = WEST;
385 		goto drone_move;
386 	}
387 	if (isplayer(Maze[bp->b_y - 1][bp->b_x])) {
388 		dir = NORTH;
389 		goto drone_move;
390 	}
391 	if (isplayer(Maze[bp->b_y + 1][bp->b_x])) {
392 		dir = SOUTH;
393 		goto drone_move;
394 	}
395 	if (isplayer(Maze[bp->b_y][bp->b_x + 1])) {
396 		dir = EAST;
397 		goto drone_move;
398 	}
399 
400 	/*
401 	 * Find out what directions are clear
402 	 */
403 	mask = count = 0;
404 	if (!iswall(bp->b_y, bp->b_x - 1))
405 		mask |= WEST, count++;
406 	if (!iswall(bp->b_y - 1, bp->b_x))
407 		mask |= NORTH, count++;
408 	if (!iswall(bp->b_y + 1, bp->b_x))
409 		mask |= SOUTH, count++;
410 	if (!iswall(bp->b_y, bp->b_x + 1))
411 		mask |= EAST, count++;
412 
413 	/*
414 	 * All blocked up, just you wait
415 	 */
416 	if (count == 0)
417 		return TRUE;
418 
419 	/*
420 	 * Only one way to go.
421 	 */
422 	if (count == 1) {
423 		dir = mask;
424 		goto drone_move;
425 	}
426 
427 	/*
428 	 * Get rid of the direction that we came from
429 	 */
430 	switch (bp->b_face) {
431 	  case LEFTS:
432 		if (mask & EAST)
433 			mask &= ~EAST, count--;
434 		break;
435 	  case RIGHT:
436 		if (mask & WEST)
437 			mask &= ~WEST, count--;
438 		break;
439 	  case ABOVE:
440 		if (mask & SOUTH)
441 			mask &= ~SOUTH, count--;
442 		break;
443 	  case BELOW:
444 		if (mask & NORTH)
445 			mask &= ~NORTH, count--;
446 		break;
447 	}
448 
449 	/*
450 	 * Pick one of the remaining directions
451 	 */
452 	n = rand_num(count);
453 	if (n >= 0 && mask & NORTH)
454 		dir = NORTH, n--;
455 	if (n >= 0 && mask & SOUTH)
456 		dir = SOUTH, n--;
457 	if (n >= 0 && mask & EAST)
458 		dir = EAST, n--;
459 	if (n >= 0 && mask & WEST)
460 		dir = WEST, n--;
461 
462 	/*
463 	 * Now that we know the direction of movement,
464 	 * just update the position of the drone
465 	 */
466 drone_move:
467 	switch (dir) {
468 	  case WEST:
469 		bp->b_x--;
470 		bp->b_face = LEFTS;
471 		break;
472 	  case EAST:
473 		bp->b_x++;
474 		bp->b_face = RIGHT;
475 		break;
476 	  case NORTH:
477 		bp->b_y--;
478 		bp->b_face = ABOVE;
479 		break;
480 	  case SOUTH:
481 		bp->b_y++;
482 		bp->b_face = BELOW;
483 		break;
484 	}
485 	switch (Maze[bp->b_y][bp->b_x]) {
486 	  case LEFTS:
487 	  case RIGHT:
488 	  case BELOW:
489 	  case ABOVE:
490 		/*
491 		 * give the person a chance to catch a
492 		 * drone if s/he is facing it
493 		 */
494 		if (rand_num(100) < 1 &&
495 		opposite(bp->b_face, Maze[bp->b_y][bp->b_x])) {
496 			pp = play_at(bp->b_y, bp->b_x);
497 			pp->p_ammo += bp->b_charge;
498 			message(pp, "**** Absorbed drone ****");
499 			free((char *) bp);
500 			(void) sprintf(Buf, "%3d", pp->p_ammo);
501 			cgoto(pp, STAT_AMMO_ROW, STAT_VALUE_COL);
502 			outstr(pp, Buf, 3);
503 			return FALSE;
504 		}
505 		bp->b_expl = TRUE;
506 		break;
507 	}
508 	return TRUE;
509 }
510 # endif
511 
512 /*
513  * save_bullet:
514  *	Put this bullet back onto the bullet list
515  */
516 static void
517 save_bullet(bp)
518 	BULLET	*bp;
519 {
520 	bp->b_over = Maze[bp->b_y][bp->b_x];
521 	switch (bp->b_over) {
522 	  case SHOT:
523 	  case GRENADE:
524 	  case SATCHEL:
525 	  case BOMB:
526 # ifdef OOZE
527 	  case SLIME:
528 # ifdef VOLCANO
529 	  case LAVA:
530 # endif
531 # endif
532 # ifdef DRONE
533 	  case DSHOT:
534 # endif
535 		find_under(Bullets, bp);
536 		break;
537 	}
538 
539 	switch (bp->b_over) {
540 	  case LEFTS:
541 	  case RIGHT:
542 	  case ABOVE:
543 	  case BELOW:
544 # ifdef FLY
545 	  case FLYER:
546 # endif
547 		mark_player(bp);
548 		break;
549 # ifdef BOOTS
550 	  case BOOT:
551 	  case BOOT_PAIR:
552 		mark_boot(bp);
553 # endif
554 
555 	  default:
556 		Maze[bp->b_y][bp->b_x] = bp->b_type;
557 		break;
558 	}
559 
560 	bp->b_next = Bullets;
561 	Bullets = bp;
562 }
563 
564 /*
565  * move_flyer:
566  *	Update the position of a player in flight
567  */
568 static void
569 move_flyer(pp)
570 	PLAYER	*pp;
571 {
572 	int	x, y;
573 
574 	if (pp->p_undershot) {
575 		fixshots(pp->p_y, pp->p_x, pp->p_over);
576 		pp->p_undershot = FALSE;
577 	}
578 	Maze[pp->p_y][pp->p_x] = pp->p_over;
579 	x = pp->p_x + pp->p_flyx;
580 	y = pp->p_y + pp->p_flyy;
581 	if (x < 1) {
582 		x = 1 - x;
583 		pp->p_flyx = -pp->p_flyx;
584 	}
585 	else if (x > WIDTH - 2) {
586 		x = (WIDTH - 2) - (x - (WIDTH - 2));
587 		pp->p_flyx = -pp->p_flyx;
588 	}
589 	if (y < 1) {
590 		y = 1 - y;
591 		pp->p_flyy = -pp->p_flyy;
592 	}
593 	else if (y > HEIGHT - 2) {
594 		y = (HEIGHT - 2) - (y - (HEIGHT - 2));
595 		pp->p_flyy = -pp->p_flyy;
596 	}
597 again:
598 	switch (Maze[y][x]) {
599 	  default:
600 		switch (rand_num(4)) {
601 		  case 0:
602 			PLUS_DELTA(x, WIDTH - 2);
603 			break;
604 		  case 1:
605 			MINUS_DELTA(x, 1);
606 			break;
607 		  case 2:
608 			PLUS_DELTA(y, HEIGHT - 2);
609 			break;
610 		  case 3:
611 			MINUS_DELTA(y, 1);
612 			break;
613 		}
614 		goto again;
615 	  case WALL1:
616 	  case WALL2:
617 	  case WALL3:
618 # ifdef	REFLECT
619 	  case WALL4:
620 	  case WALL5:
621 # endif
622 # ifdef	RANDOM
623 	  case DOOR:
624 # endif
625 		if (pp->p_flying == 0)
626 			pp->p_flying++;
627 		break;
628 	  case SPACE:
629 		break;
630 	}
631 	pp->p_y = y;
632 	pp->p_x = x;
633 	if (pp->p_flying-- == 0) {
634 # ifdef BOOTS
635 		if (pp->p_face != BOOT && pp->p_face != BOOT_PAIR) {
636 # endif
637 			checkdam(pp, (PLAYER *) NULL, (IDENT *) NULL,
638 				rand_num(pp->p_damage / 5), FALL);
639 			pp->p_face = rand_dir();
640 			showstat(pp);
641 # ifdef BOOTS
642 		}
643 		else {
644 			if (Maze[y][x] == BOOT)
645 				pp->p_face = BOOT_PAIR;
646 			Maze[y][x] = SPACE;
647 		}
648 # endif
649 	}
650 	pp->p_over = Maze[y][x];
651 	Maze[y][x] = pp->p_face;
652 	showexpl(y, x, pp->p_face);
653 }
654 
655 /*
656  * chkshot
657  *	Handle explosions
658  */
659 static void
660 chkshot(bp, next)
661 	BULLET	*bp;
662 	BULLET	*next;
663 {
664 	int	y, x;
665 	int	dy, dx, absdy;
666 	int	delta, damage;
667 	char	expl;
668 	PLAYER	*pp;
669 
670 	delta = 0;
671 	switch (bp->b_type) {
672 	  case SHOT:
673 	  case MINE:
674 	  case GRENADE:
675 	  case GMINE:
676 	  case SATCHEL:
677 	  case BOMB:
678 		delta = bp->b_size - 1;
679 		break;
680 # ifdef	OOZE
681 	  case SLIME:
682 # ifdef VOLCANO
683 	  case LAVA:
684 # endif
685 		chkslime(bp, next);
686 		return;
687 # endif
688 # ifdef DRONE
689 	  case DSHOT:
690 		bp->b_type = SLIME;
691 		chkslime(bp, next);
692 		return;
693 # endif
694 	}
695 	for (y = bp->b_y - delta; y <= bp->b_y + delta; y++) {
696 		if (y < 0 || y >= HEIGHT)
697 			continue;
698 		dy = y - bp->b_y;
699 		absdy = (dy < 0) ? -dy : dy;
700 		for (x = bp->b_x - delta; x <= bp->b_x + delta; x++) {
701 			if (x < 0 || x >= WIDTH)
702 				continue;
703 			dx = x - bp->b_x;
704 			if (dx == 0)
705 				expl = (dy == 0) ? '*' : '|';
706 			else if (dy == 0)
707 				expl = '-';
708 			else if (dx == dy)
709 				expl = '\\';
710 			else if (dx == -dy)
711 				expl = '/';
712 			else
713 				expl = '*';
714 			showexpl(y, x, expl);
715 			switch (Maze[y][x]) {
716 			  case LEFTS:
717 			  case RIGHT:
718 			  case ABOVE:
719 			  case BELOW:
720 # ifdef FLY
721 			  case FLYER:
722 # endif
723 				if (dx < 0)
724 					dx = -dx;
725 				if (absdy > dx)
726 					damage = bp->b_size - absdy;
727 				else
728 					damage = bp->b_size - dx;
729 				pp = play_at(y, x);
730 				checkdam(pp, bp->b_owner, bp->b_score,
731 					damage * MINDAM, bp->b_type);
732 				break;
733 			  case GMINE:
734 			  case MINE:
735 				add_shot((Maze[y][x] == GMINE) ?
736 					GRENADE : SHOT,
737 					y, x, LEFTS,
738 					(Maze[y][x] == GMINE) ?
739 					GRENREQ : BULREQ,
740 					(PLAYER *) NULL, TRUE, SPACE);
741 				Maze[y][x] = SPACE;
742 				break;
743 			}
744 		}
745 	}
746 }
747 
748 # ifdef	OOZE
749 /*
750  * chkslime:
751  *	handle slime shot exploding
752  */
753 static void
754 chkslime(bp, next)
755 	BULLET	*bp;
756 	BULLET	*next;
757 {
758 	BULLET	*nbp;
759 
760 	switch (Maze[bp->b_y][bp->b_x]) {
761 	  case WALL1:
762 	  case WALL2:
763 	  case WALL3:
764 # ifdef	REFLECT
765 	  case WALL4:
766 	  case WALL5:
767 # endif
768 # ifdef	RANDOM
769 	  case DOOR:
770 # endif
771 		switch (bp->b_face) {
772 		  case LEFTS:
773 			bp->b_x++;
774 			break;
775 		  case RIGHT:
776 			bp->b_x--;
777 			break;
778 		  case ABOVE:
779 			bp->b_y++;
780 			break;
781 		  case BELOW:
782 			bp->b_y--;
783 			break;
784 		}
785 		break;
786 	}
787 	nbp = (BULLET *) malloc(sizeof (BULLET));
788 	*nbp = *bp;
789 # ifdef VOLCANO
790 	move_slime(nbp, nbp->b_type == SLIME ? SLIMESPEED : LAVASPEED, next);
791 # else
792 	move_slime(nbp, SLIMESPEED, next);
793 # endif
794 }
795 
796 /*
797  * move_slime:
798  *	move the given slime shot speed times and add it back if
799  *	it hasn't fizzled yet
800  */
801 void
802 move_slime(bp, speed, next)
803 	BULLET	*bp;
804 	int	speed;
805 	BULLET	*next;
806 {
807 	int	i, j, dirmask, count;
808 	PLAYER	*pp;
809 	BULLET	*nbp;
810 
811 	if (speed == 0) {
812 		if (bp->b_charge <= 0)
813 			free((char *) bp);
814 		else
815 			save_bullet(bp);
816 		return;
817 	}
818 
819 # ifdef VOLCANO
820 	showexpl(bp->b_y, bp->b_x, bp->b_type == LAVA ? LAVA : '*');
821 # else
822 	showexpl(bp->b_y, bp->b_x, '*');
823 # endif
824 	switch (Maze[bp->b_y][bp->b_x]) {
825 	  case LEFTS:
826 	  case RIGHT:
827 	  case ABOVE:
828 	  case BELOW:
829 # ifdef FLY
830 	  case FLYER:
831 # endif
832 		pp = play_at(bp->b_y, bp->b_x);
833 		message(pp, "You've been slimed.");
834 		checkdam(pp, bp->b_owner, bp->b_score, MINDAM, bp->b_type);
835 		break;
836 	  case SHOT:
837 	  case GRENADE:
838 	  case SATCHEL:
839 	  case BOMB:
840 # ifdef DRONE
841 	  case DSHOT:
842 # endif
843 		explshot(next, bp->b_y, bp->b_x);
844 		explshot(Bullets, bp->b_y, bp->b_x);
845 		break;
846 	}
847 
848 	if (--bp->b_charge <= 0) {
849 		free((char *) bp);
850 		return;
851 	}
852 
853 	dirmask = 0;
854 	count = 0;
855 	switch (bp->b_face) {
856 	  case LEFTS:
857 		if (!iswall(bp->b_y, bp->b_x - 1))
858 			dirmask |= WEST, count++;
859 		if (!iswall(bp->b_y - 1, bp->b_x))
860 			dirmask |= NORTH, count++;
861 		if (!iswall(bp->b_y + 1, bp->b_x))
862 			dirmask |= SOUTH, count++;
863 		if (dirmask == 0)
864 			if (!iswall(bp->b_y, bp->b_x + 1))
865 				dirmask |= EAST, count++;
866 		break;
867 	  case RIGHT:
868 		if (!iswall(bp->b_y, bp->b_x + 1))
869 			dirmask |= EAST, count++;
870 		if (!iswall(bp->b_y - 1, bp->b_x))
871 			dirmask |= NORTH, count++;
872 		if (!iswall(bp->b_y + 1, bp->b_x))
873 			dirmask |= SOUTH, count++;
874 		if (dirmask == 0)
875 			if (!iswall(bp->b_y, bp->b_x - 1))
876 				dirmask |= WEST, count++;
877 		break;
878 	  case ABOVE:
879 		if (!iswall(bp->b_y - 1, bp->b_x))
880 			dirmask |= NORTH, count++;
881 		if (!iswall(bp->b_y, bp->b_x - 1))
882 			dirmask |= WEST, count++;
883 		if (!iswall(bp->b_y, bp->b_x + 1))
884 			dirmask |= EAST, count++;
885 		if (dirmask == 0)
886 			if (!iswall(bp->b_y + 1, bp->b_x))
887 				dirmask |= SOUTH, count++;
888 		break;
889 	  case BELOW:
890 		if (!iswall(bp->b_y + 1, bp->b_x))
891 			dirmask |= SOUTH, count++;
892 		if (!iswall(bp->b_y, bp->b_x - 1))
893 			dirmask |= WEST, count++;
894 		if (!iswall(bp->b_y, bp->b_x + 1))
895 			dirmask |= EAST, count++;
896 		if (dirmask == 0)
897 			if (!iswall(bp->b_y - 1, bp->b_x))
898 				dirmask |= NORTH, count++;
899 		break;
900 	}
901 	if (count == 0) {
902 		/*
903 		 * No place to go.  Just sit here for a while and wait
904 		 * for adjacent squares to clear out.
905 		 */
906 		save_bullet(bp);
907 		return;
908 	}
909 	if (bp->b_charge < count) {
910 		/* Only bp->b_charge paths may be taken */
911 		while (count > bp->b_charge) {
912 			if (dirmask & WEST)
913 				dirmask &= ~WEST;
914 			else if (dirmask & EAST)
915 				dirmask &= ~EAST;
916 			else if (dirmask & NORTH)
917 				dirmask &= ~NORTH;
918 			else if (dirmask & SOUTH)
919 				dirmask &= ~SOUTH;
920 			count--;
921 		}
922 	}
923 
924 	i = bp->b_charge / count;
925 	j = bp->b_charge % count;
926 	if (dirmask & WEST) {
927 		count--;
928 		nbp = create_shot(bp->b_type, bp->b_y, bp->b_x - 1, LEFTS,
929 			i, bp->b_size, bp->b_owner, bp->b_score, TRUE, SPACE);
930 		move_slime(nbp, speed - 1, next);
931 	}
932 	if (dirmask & EAST) {
933 		count--;
934 		nbp = create_shot(bp->b_type, bp->b_y, bp->b_x + 1, RIGHT,
935 			(count < j) ? i + 1 : i, bp->b_size, bp->b_owner,
936 			bp->b_score, TRUE, SPACE);
937 		move_slime(nbp, speed - 1, next);
938 	}
939 	if (dirmask & NORTH) {
940 		count--;
941 		nbp = create_shot(bp->b_type, bp->b_y - 1, bp->b_x, ABOVE,
942 			(count < j) ? i + 1 : i, bp->b_size, bp->b_owner,
943 			bp->b_score, TRUE, SPACE);
944 		move_slime(nbp, speed - 1, next);
945 	}
946 	if (dirmask & SOUTH) {
947 		count--;
948 		nbp = create_shot(bp->b_type, bp->b_y + 1, bp->b_x, BELOW,
949 			(count < j) ? i + 1 : i, bp->b_size, bp->b_owner,
950 			bp->b_score, TRUE, SPACE);
951 		move_slime(nbp, speed - 1, next);
952 	}
953 
954 	free((char *) bp);
955 }
956 
957 /*
958  * iswall:
959  *	returns whether the given location is a wall
960  */
961 static int
962 iswall(y, x)
963 	int	y, x;
964 {
965 	if (y < 0 || x < 0 || y >= HEIGHT || x >= WIDTH)
966 		return TRUE;
967 	switch (Maze[y][x]) {
968 	  case WALL1:
969 	  case WALL2:
970 	  case WALL3:
971 # ifdef	REFLECT
972 	  case WALL4:
973 	  case WALL5:
974 # endif
975 # ifdef	RANDOM
976 	  case DOOR:
977 # endif
978 # ifdef OOZE
979 	  case SLIME:
980 # ifdef VOLCANO
981 	  case LAVA:
982 # endif
983 # endif
984 		return TRUE;
985 	}
986 	return FALSE;
987 }
988 # endif
989 
990 /*
991  * zapshot:
992  *	Take a shot out of the air.
993  */
994 static void
995 zapshot(blist, obp)
996 	BULLET	*blist, *obp;
997 {
998 	BULLET	*bp;
999 	FLAG	explode;
1000 
1001 	explode = FALSE;
1002 	for (bp = blist; bp != NULL; bp = bp->b_next) {
1003 		if (bp->b_x != obp->b_x || bp->b_y != obp->b_y)
1004 			continue;
1005 		if (bp->b_face == obp->b_face)
1006 			continue;
1007 		explode = TRUE;
1008 		break;
1009 	}
1010 	if (!explode)
1011 		return;
1012 	explshot(blist, obp->b_y, obp->b_x);
1013 }
1014 
1015 /*
1016  * explshot -
1017  *	Make all shots at this location blow up
1018  */
1019 void
1020 explshot(blist, y, x)
1021 	BULLET	*blist;
1022 	int	y, x;
1023 {
1024 	BULLET	*bp;
1025 
1026 	for (bp = blist; bp != NULL; bp = bp->b_next)
1027 		if (bp->b_x == x && bp->b_y == y) {
1028 			bp->b_expl = TRUE;
1029 			if (bp->b_owner != NULL)
1030 				message(bp->b_owner, "Shot intercepted");
1031 		}
1032 }
1033 
1034 /*
1035  * play_at:
1036  *	Return a pointer to the player at the given location
1037  */
1038 PLAYER *
1039 play_at(y, x)
1040 	int	y, x;
1041 {
1042 	PLAYER	*pp;
1043 
1044 	for (pp = Player; pp < End_player; pp++)
1045 		if (pp->p_x == x && pp->p_y == y)
1046 			return pp;
1047 	errx(1, "driver: couldn't find player at (%d,%d)", x, y);
1048 	/* NOTREACHED */
1049 }
1050 
1051 /*
1052  * opposite:
1053  *	Return TRUE if the bullet direction faces the opposite direction
1054  *	of the player in the maze
1055  */
1056 int
1057 opposite(face, dir)
1058 	int	face;
1059 	char	dir;
1060 {
1061 	switch (face) {
1062 	  case LEFTS:
1063 		return (dir == RIGHT);
1064 	  case RIGHT:
1065 		return (dir == LEFTS);
1066 	  case ABOVE:
1067 		return (dir == BELOW);
1068 	  case BELOW:
1069 		return (dir == ABOVE);
1070 	  default:
1071 		return FALSE;
1072 	}
1073 }
1074 
1075 /*
1076  * is_bullet:
1077  *	Is there a bullet at the given coordinates?  If so, return
1078  *	a pointer to the bullet, otherwise return NULL
1079  */
1080 BULLET *
1081 is_bullet(y, x)
1082 	int	y, x;
1083 {
1084 	BULLET	*bp;
1085 
1086 	for (bp = Bullets; bp != NULL; bp = bp->b_next)
1087 		if (bp->b_y == y && bp->b_x == x)
1088 			return bp;
1089 	return NULL;
1090 }
1091 
1092 /*
1093  * fixshots:
1094  *	change the underlying character of the shots at a location
1095  *	to the given character.
1096  */
1097 void
1098 fixshots(y, x, over)
1099 	int	y, x;
1100 	char	over;
1101 {
1102 	BULLET	*bp;
1103 
1104 	for (bp = Bullets; bp != NULL; bp = bp->b_next)
1105 		if (bp->b_y == y && bp->b_x == x)
1106 			bp->b_over = over;
1107 }
1108 
1109 /*
1110  * find_under:
1111  *	find the underlying character for a bullet when it lands
1112  *	on another bullet.
1113  */
1114 static void
1115 find_under(blist, bp)
1116 	BULLET	*blist, *bp;
1117 {
1118 	BULLET	*nbp;
1119 
1120 	for (nbp = blist; nbp != NULL; nbp = nbp->b_next)
1121 		if (bp->b_y == nbp->b_y && bp->b_x == nbp->b_x) {
1122 			bp->b_over = nbp->b_over;
1123 			break;
1124 		}
1125 }
1126 
1127 /*
1128  * mark_player:
1129  *	mark a player as under a shot
1130  */
1131 static void
1132 mark_player(bp)
1133 	BULLET	*bp;
1134 {
1135 	PLAYER	*pp;
1136 
1137 	for (pp = Player; pp < End_player; pp++)
1138 		if (pp->p_y == bp->b_y && pp->p_x == bp->b_x) {
1139 			pp->p_undershot = TRUE;
1140 			break;
1141 		}
1142 }
1143 
1144 # ifdef BOOTS
1145 /*
1146  * mark_boot:
1147  *	mark a boot as under a shot
1148  */
1149 static void
1150 mark_boot(bp)
1151 	BULLET	*bp;
1152 {
1153 	PLAYER	*pp;
1154 
1155 	for (pp = Boot; pp < &Boot[NBOOTS]; pp++)
1156 		if (pp->p_y == bp->b_y && pp->p_x == bp->b_x) {
1157 			pp->p_undershot = TRUE;
1158 			break;
1159 		}
1160 }
1161 # endif
1162