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Source:NetHack 3.4.0/display.c

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Below is the full text to display.c from the source code of NetHack 3.4.0. To link to a particular line, write [[NetHack 3.4.0/display.c#line123]], for example.

Warning! This is the source code from an old release. For the latest release, see Source code

The NetHack General Public License applies to screenshots, source code and other content from NetHack.
1.    /*	SCCS Id: @(#)display.c	3.4	2000/07/27	*/
2.    /* Copyright (c) Dean Luick, with acknowledgements to Kevin Darcy */
3.    /* and Dave Cohrs, 1990.					  */
4.    /* NetHack may be freely redistributed.  See license for details. */
5.    
6.    /*
7.     *			THE NEW DISPLAY CODE
8.     *
9.     * The old display code has been broken up into three parts: vision, display,
10.    * and drawing.  Vision decides what locations can and cannot be physically
11.    * seen by the hero.  Display decides _what_ is displayed at a given location.
12.    * Drawing decides _how_ to draw a monster, fountain, sword, etc.
13.    *
14.    * The display system uses information from the vision system to decide
15.    * what to draw at a given location.  The routines for the vision system
16.    * can be found in vision.c and vision.h.  The routines for display can
17.    * be found in this file (display.c) and display.h.  The drawing routines
18.    * are part of the window port.  See doc/window.doc for the drawing
19.    * interface.
20.    *
21.    * The display system deals with an abstraction called a glyph.  Anything
22.    * that could possibly be displayed has a unique glyph identifier.
23.    *
24.    * What is seen on the screen is a combination of what the hero remembers
25.    * and what the hero currently sees.  Objects and dungeon features (walls
26.    * doors, etc) are remembered when out of sight.  Monsters and temporary
27.    * effects are not remembered.  Each location on the level has an
28.    * associated glyph.  This is the hero's _memory_ of what he or she has
29.    * seen there before.
30.    *
31.    * Display rules:
32.    *
33.    *	If the location is in sight, display in order:
34.    *		visible (or sensed) monsters
35.    *		visible objects
36.    *		known traps
37.    *		background
38.    *
39.    *	If the location is out of sight, display in order:
40.    *		sensed monsters (telepathy)
41.    *		memory
42.    *
43.    *
44.    *
45.    * Here is a list of the major routines in this file to be used externally:
46.    *
47.    * newsym
48.    *
49.    * Possibly update the screen location (x,y).  This is the workhorse routine.
50.    * It is always correct --- where correct means following the in-sight/out-
51.    * of-sight rules.  **Most of the code should use this routine.**  This
52.    * routine updates the map and displays monsters.
53.    *
54.    *
55.    * map_background
56.    * map_object
57.    * map_trap
58.    * map_invisible
59.    * unmap_object
60.    *
61.    * If you absolutely must override the in-sight/out-of-sight rules, there
62.    * are two possibilities.  First, you can mess with vision to force the
63.    * location in sight then use newsym(), or you can  use the map_* routines.
64.    * The first has not been tried [no need] and the second is used in the
65.    * detect routines --- detect object, magic mapping, etc.  The map_*
66.    * routines *change* what the hero remembers.  All changes made by these
67.    * routines will be sticky --- they will survive screen redraws.  Do *not*
68.    * use these for things that only temporarily change the screen.  These
69.    * routines are also used directly by newsym().  unmap_object is used to
70.    * clear a remembered object when/if detection reveals it isn't there.
71.    *
72.    *
73.    * show_glyph
74.    *
75.    * This is direct (no processing in between) buffered access to the screen.
76.    * Temporary screen effects are run through this and its companion,
77.    * flush_screen().  There is yet a lower level routine, print_glyph(),
78.    * but this is unbuffered and graphic dependent (i.e. it must be surrounded
79.    * by graphic set-up and tear-down routines).  Do not use print_glyph().
80.    *
81.    *
82.    * see_monsters
83.    * see_objects
84.    * see_traps
85.    *
86.    * These are only used when something affects all of the monsters or
87.    * objects or traps.  For objects and traps, the only thing is hallucination.
88.    * For monsters, there are hallucination and changing from/to blindness, etc.
89.    *
90.    *
91.    * tmp_at
92.    *
93.    * This is a useful interface for displaying temporary items on the screen.
94.    * Its interface is different than previously, so look at it carefully.
95.    *
96.    *
97.    *
98.    * Parts of the rm structure that are used:
99.    *
100.   *	typ	- What is really there.
101.   *	glyph	- What the hero remembers.  This will never be a monster.
102.   *		  Monsters "float" above this.
103.   *	lit	- True if the position is lit.  An optimization for
104.   *		  lit/unlit rooms.
105.   *	waslit	- True if the position was *remembered* as lit.
106.   *	seenv	- A vector of bits representing the directions from which the
107.   *		  hero has seen this position.  The vector's primary use is
108.   *		  determining how walls are seen.  E.g. a wall sometimes looks
109.   *		  like stone on one side, but is seen as a wall from the other.
110.   *		  Other uses are for unmapping detected objects and felt
111.   *		  locations, where we need to know if the hero has ever
112.   *		  seen the location.
113.   *	flags   - Additional information for the typ field.  Different for
114.   *		  each typ.
115.   *	horizontal - Indicates whether the wall or door is horizontal or
116.   *		     vertical.
117.   */
118.  #include "hack.h"
119.  #include "region.h"
120.  
121.  STATIC_DCL void FDECL(display_monster,(XCHAR_P,XCHAR_P,struct monst *,int,XCHAR_P));
122.  STATIC_DCL int FDECL(swallow_to_glyph, (int, int));
123.  STATIC_DCL void FDECL(display_warning,(struct monst *));
124.  
125.  STATIC_DCL int FDECL(check_pos, (int, int, int));
126.  #ifdef WA_VERBOSE
127.  STATIC_DCL boolean FDECL(more_than_one, (int, int, int, int, int));
128.  #endif
129.  STATIC_DCL int FDECL(set_twall, (int,int, int,int, int,int, int,int));
130.  STATIC_DCL int FDECL(set_wall, (int, int, int));
131.  STATIC_DCL int FDECL(set_corn, (int,int, int,int, int,int, int,int));
132.  STATIC_DCL int FDECL(set_crosswall, (int, int));
133.  STATIC_DCL void FDECL(set_seenv, (struct rm *, int, int, int, int));
134.  STATIC_DCL void FDECL(t_warn, (struct rm *));
135.  STATIC_DCL int FDECL(wall_angle, (struct rm *));
136.  
137.  #ifdef INVISIBLE_OBJECTS
138.  /*
139.   * vobj_at()
140.   *
141.   * Returns a pointer to an object if the hero can see an object at the
142.   * given location.  This takes care of invisible objects.  NOTE, this
143.   * assumes that the hero is not blind and on top of the object pile.
144.   * It does NOT take into account that the location is out of sight, or,
145.   * say, one can see blessed, etc.
146.   */
147.  struct obj *
148.  vobj_at(x,y)
149.      xchar x,y;
150.  {
151.      register struct obj *obj = level.objects[x][y];
152.  
153.      while (obj) {
154.  	if (!obj->oinvis || See_invisible) return obj;
155.  	obj = obj->nexthere;
156.      }
157.      return ((struct obj *) 0);
158.  }
159.  #endif	/* else vobj_at() is defined in display.h */
160.  
161.  /*
162.   * magic_map_background()
163.   *
164.   * This function is similar to map_background (see below) except we pay
165.   * attention to and correct unexplored, lit ROOM and CORR spots.
166.   */
167.  void
168.  magic_map_background(x, y, show)
169.      xchar x,y;
170.      int  show;
171.  {
172.      int glyph = back_to_glyph(x,y);	/* assumes hero can see x,y */
173.      struct rm *lev = &levl[x][y];
174.  
175.      /*
176.       * Correct for out of sight lit corridors and rooms that the hero
177.       * doesn't remember as lit.
178.       */
179.      if (!cansee(x,y) && !lev->waslit) {
180.  	/* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
181.  	if (lev->typ == ROOM && glyph == cmap_to_glyph(S_room))
182.  	    glyph = cmap_to_glyph(S_stone);
183.  	else if (lev->typ == CORR && glyph == cmap_to_glyph(S_litcorr))
184.  	    glyph = cmap_to_glyph(S_corr);
185.      }
186.      if (level.flags.hero_memory)
187.  	lev->glyph = glyph;
188.      if (show) show_glyph(x,y, glyph);
189.  }
190.  
191.  /*
192.   * The routines map_background(), map_object(), and map_trap() could just
193.   * as easily be:
194.   *
195.   *	map_glyph(x,y,glyph,show)
196.   *
197.   * Which is called with the xx_to_glyph() in the call.  Then I can get
198.   * rid of 3 routines that don't do very much anyway.  And then stop
199.   * having to create fake objects and traps.  However, I am reluctant to
200.   * make this change.
201.   */
202.  /* FIXME: some of these use xchars for x and y, and some use ints.  Make
203.   * this consistent.
204.   */
205.  
206.  /*
207.   * map_background()
208.   *
209.   * Make the real background part of our map.  This routine assumes that
210.   * the hero can physically see the location.  Update the screen if directed.
211.   */
212.  void
213.  map_background(x, y, show)
214.      register xchar x,y;
215.      register int  show;
216.  {
217.      register int glyph = back_to_glyph(x,y);
218.  
219.      if (level.flags.hero_memory)
220.  	levl[x][y].glyph = glyph;
221.      if (show) show_glyph(x,y, glyph);
222.  }
223.  
224.  /*
225.   * map_trap()
226.   *
227.   * Map the trap and print it out if directed.  This routine assumes that the
228.   * hero can physically see the location.
229.   */
230.  void
231.  map_trap(trap, show)
232.      register struct trap *trap;
233.      register int	 show;
234.  {
235.      register int x = trap->tx, y = trap->ty;
236.      register int glyph = trap_to_glyph(trap);
237.  
238.      if (level.flags.hero_memory)
239.  	levl[x][y].glyph = glyph;
240.      if (show) show_glyph(x, y, glyph);
241.  }
242.  
243.  /*
244.   * map_object()
245.   *
246.   * Map the given object.  This routine assumes that the hero can physically
247.   * see the location of the object.  Update the screen if directed.
248.   */
249.  void
250.  map_object(obj, show)
251.      register struct obj *obj;
252.      register int	show;
253.  {
254.      register int x = obj->ox, y = obj->oy;
255.      register int glyph = obj_to_glyph(obj);
256.  
257.      if (level.flags.hero_memory)
258.  	levl[x][y].glyph = glyph;
259.      if (show) show_glyph(x, y, glyph);
260.  }
261.  
262.  /*
263.   * map_invisible()
264.   *
265.   * Make the hero remember that a square contains an invisible monster.
266.   * This is a special case in that the square will continue to be displayed
267.   * this way even when the hero is close enough to see it.  To get rid of
268.   * this and display the square's actual contents, use unmap_object() followed
269.   * by newsym() if necessary.
270.   */
271.  void
272.  map_invisible(x, y)
273.  register xchar x, y;
274.  {
275.      if (level.flags.hero_memory)
276.  	levl[x][y].glyph = GLYPH_INVISIBLE;
277.      show_glyph(x, y, GLYPH_INVISIBLE);
278.  }
279.  
280.  /*
281.   * unmap_object()
282.   *
283.   * Remove something from the map when the hero realizes it's not there any
284.   * more.  Replace it with background or known trap, but not with any other
285.   * If this is used for detection, a full screen update is imminent anyway;
286.   * if this is used to get rid of an invisible monster notation, we might have
287.   * to call newsym().
288.   */
289.  void
290.  unmap_object(x, y)
291.      register int x, y;
292.  {
293.      register struct trap *trap;
294.  
295.      if (!level.flags.hero_memory) return;
296.  
297.      if ((trap = t_at(x,y)) != 0 && trap->tseen && !covers_traps(x,y))
298.  	map_trap(trap, 0);
299.      else if (levl[x][y].seenv) {
300.  	struct rm *lev = &levl[x][y];
301.  
302.  	map_background(x, y, 0);
303.  
304.  	/* turn remembered dark room squares dark */
305.  	if (!lev->waslit && lev->glyph == cmap_to_glyph(S_room) &&
306.  							    lev->typ == ROOM)
307.  	    lev->glyph = cmap_to_glyph(S_stone);
308.      } else
309.  	levl[x][y].glyph = cmap_to_glyph(S_stone);	/* default val */
310.  }
311.  
312.  
313.  /*
314.   * map_location()
315.   *
316.   * Make whatever at this location show up.  This is only for non-living
317.   * things.  This will not handle feeling invisible objects correctly.
318.   *
319.   * Internal to display.c, this is a #define for speed.
320.   */
321.  #define _map_location(x,y,show)						\
322.  {									\
323.      register struct obj   *obj;						\
324.      register struct trap  *trap;					\
325.  									\
326.      if ((obj = vobj_at(x,y)) && !covers_objects(x,y))			\
327.  	map_object(obj,show);						\
328.      else if ((trap = t_at(x,y)) && trap->tseen && !covers_traps(x,y))	\
329.  	map_trap(trap,show);						\
330.      else								\
331.  	map_background(x,y,show);					\
332.  }
333.  
334.  void map_location(x,y,show)
335.      int x, y, show;
336.  {
337.      _map_location(x,y,show);
338.  }
339.  
340.  #define DETECTED 	2
341.  #define PHYSICALLY_SEEN 1
342.  #define is_worm_tail(mon)	((mon) && ((x != (mon)->mx)  || (y != (mon)->my)))
343.  
344.  /*
345.   * display_monster()
346.   *
347.   * Note that this is *not* a map_XXXX() function!  Monsters sort of float
348.   * above everything.
349.   *
350.   * Yuck.  Display body parts by recognizing that the display position is
351.   * not the same as the monster position.  Currently the only body part is
352.   * a worm tail.
353.   *
354.   */
355.  STATIC_OVL void
356.  display_monster(x, y, mon, sightflags, worm_tail)
357.      register xchar x, y;	/* display position */
358.      register struct monst *mon;	/* monster to display */
359.      int sightflags;		/* 1 if the monster is physically seen */
360.      				/* 2 if detected using Detect_monsters */
361.      register xchar worm_tail;	/* mon is actually a worm tail */
362.  {
363.      register boolean mon_mimic = (mon->m_ap_type != M_AP_NOTHING);
364.      register int sensed = mon_mimic &&
365.  	(Protection_from_shape_changers || sensemon(mon));
366.      /*
367.       * We must do the mimic check first.  If the mimic is mimicing something,
368.       * and the location is in sight, we have to change the hero's memory
369.       * so that when the position is out of sight, the hero remembers what
370.       * the mimic was mimicing.
371.       */
372.  
373.      if (mon_mimic && sightflags) {
374.  	switch (mon->m_ap_type) {
375.  	    default:
376.  		impossible("display_monster:  bad m_ap_type value [ = %d ]",
377.  							(int) mon->m_ap_type);
378.  	    case M_AP_NOTHING:
379.  		show_glyph(x, y, mon_to_glyph(mon));
380.  		break;
381.  
382.  	    case M_AP_FURNITURE: {
383.  		/*
384.  		 * This is a poor man's version of map_background().  I can't
385.  		 * use map_background() because we are overriding what is in
386.  		 * the 'typ' field.  Maybe have map_background()'s parameters
387.  		 * be (x,y,glyph) instead of just (x,y).
388.  		 *
389.  		 * mappearance is currently set to an S_ index value in
390.  		 * makemon.c.
391.  		 */
392.  		register int glyph = cmap_to_glyph(mon->mappearance);
393.  		levl[x][y].glyph = glyph;
394.  		if (!sensed) show_glyph(x,y, glyph);
395.  		break;
396.  	    }
397.  
398.  	    case M_AP_OBJECT: {
399.  		struct obj obj;	/* Make a fake object to send	*/
400.  				/* to map_object().		*/
401.  		obj.ox = x;
402.  		obj.oy = y;
403.  		obj.otyp = mon->mappearance;
404.  		obj.corpsenm = PM_TENGU;	/* if mimicing a corpse */
405.  		map_object(&obj,!sensed);
406.  		break;
407.  	    }
408.  
409.  	    case M_AP_MONSTER:
410.  		show_glyph(x,y, monnum_to_glyph(what_mon((int)mon->mappearance)));
411.  		break;
412.  	}
413.  	
414.      }
415.  
416.      /* If the mimic is unsucessfully mimicing something, display the monster */
417.      if (!mon_mimic || sensed) {
418.  	int num;
419.  
420.  	/* [ALI] Only use detected glyphs when monster wouldn't be
421.  	 * visible by any other means.
422.  	 */
423.  	if (sightflags == DETECTED) {
424.  	    if (worm_tail)
425.  		num = detected_monnum_to_glyph(what_mon(PM_LONG_WORM_TAIL));
426.  	    else
427.  		num = detected_mon_to_glyph(mon);
428.  	} else if (mon->mtame && !Hallucination) {
429.  	    if (worm_tail)
430.  		num = petnum_to_glyph(PM_LONG_WORM_TAIL);
431.  	    else
432.  		num = pet_to_glyph(mon);
433.  	} else {
434.  	    if (worm_tail)
435.  		num = monnum_to_glyph(what_mon(PM_LONG_WORM_TAIL));
436.  	    else
437.  		num = mon_to_glyph(mon);
438.  	}
439.  	show_glyph(x,y,num);
440.      }
441.  }
442.  
443.  /*
444.   * display_warning()
445.   *
446.   * This is also *not* a map_XXXX() function!  Monster warnings float
447.   * above everything just like monsters do, but only if the monster
448.   * is not showing.
449.   *
450.   * Do not call for worm tails.
451.   */
452.  STATIC_OVL void
453.  display_warning(mon)
454.      register struct monst *mon;
455.  {
456.      int x = mon->mx, y = mon->my;
457.      int wl = (int) (mon->m_lev / 4);
458.      int glyph;
459.  
460.      if (mon_warning(mon)) {
461.          if (wl > WARNCOUNT - 1) wl = WARNCOUNT - 1;
462.          glyph = warning_to_glyph(wl);
463.      } else if (MATCH_WARN_OF_MON(mon)) {
464.  	glyph = mon_to_glyph(mon);
465.      } else {
466.      	impossible("display_warning did not match warning type?");
467.          return;
468.      }
469.      show_glyph(x, y, glyph);
470.  }
471.  
472.  /*
473.   * feel_location()
474.   *
475.   * Feel the given location.  This assumes that the hero is blind and that
476.   * the given position is either the hero's or one of the eight squares
477.   * adjacent to the hero (except for a boulder push).
478.   * If an invisible monster has gone away, that will be discovered.  If an
479.   * invisible monster has appeared, this will _not_ be discovered since
480.   * searching only finds one monster per turn so we must check that separately.
481.   */
482.  void
483.  feel_location(x, y)
484.      xchar x, y;
485.  {
486.      struct rm *lev = &(levl[x][y]);
487.      struct obj *boulder;
488.      register struct monst *mon;
489.  
490.      /* If the hero's memory of an invisible monster is accurate, we want to keep
491.       * him from detecting the same monster over and over again on each turn.
492.       * We must return (so we don't erase the monster).  (We must also, in the
493.       * search function, be sure to skip over previously detected 'I's.)
494.       */
495.      if (glyph_is_invisible(levl[x][y].glyph) && m_at(x,y)) return;
496.  
497.      /* The hero can't feel non pool locations while under water. */
498.      if (Underwater && !Is_waterlevel(&u.uz) && ! is_pool(x,y))
499.  	return;
500.  
501.      /* Set the seen vector as if the hero had seen it.  It doesn't matter */
502.      /* if the hero is levitating or not.				  */
503.      set_seenv(lev, u.ux, u.uy, x, y);
504.  
505.      if (Levitation && !Is_airlevel(&u.uz) && !Is_waterlevel(&u.uz)) {
506.  	/*
507.  	 * Levitation Rules.  It is assumed that the hero can feel the state
508.  	 * of the walls around herself and can tell if she is in a corridor,
509.  	 * room, or doorway.  Boulders are felt because they are large enough.
510.  	 * Anything else is unknown because the hero can't reach the ground.
511.  	 * This makes things difficult.
512.  	 *
513.  	 * Check (and display) in order:
514.  	 *
515.  	 *	+ Stone, walls, and closed doors.
516.  	 *	+ Boulders.  [see a boulder before a doorway]
517.  	 *	+ Doors.
518.  	 *	+ Room/water positions
519.  	 *	+ Everything else (hallways!)
520.  	 */
521.  	if (IS_ROCK(lev->typ) || (IS_DOOR(lev->typ) &&
522.  				(lev->doormask & (D_LOCKED | D_CLOSED)))) {
523.  	    map_background(x, y, 1);
524.  	} else if ((boulder = sobj_at(BOULDER,x,y)) != 0) {
525.  	    map_object(boulder, 1);
526.  	} else if (IS_DOOR(lev->typ)) {
527.  	    map_background(x, y, 1);
528.  	} else if (IS_ROOM(lev->typ) || IS_POOL(lev->typ)) {
529.  	    /*
530.  	     * An open room or water location.  Normally we wouldn't touch
531.  	     * this, but we have to get rid of remembered boulder symbols.
532.  	     * This will only occur in rare occations when the hero goes
533.  	     * blind and doesn't find a boulder where expected (something
534.  	     * came along and picked it up).  We know that there is not a
535.  	     * boulder at this location.  Show fountains, pools, etc.
536.  	     * underneath if already seen.  Otherwise, show the appropriate
537.  	     * floor symbol.
538.  	     *
539.  	     * This isn't quite correct.  If the boulder was on top of some
540.  	     * other objects they should be seen once the boulder is removed.
541.  	     * However, we have no way of knowing that what is there now
542.  	     * was there then.  So we let the hero have a lapse of memory.
543.  	     * We could also just display what is currently on the top of the
544.  	     * object stack (if anything).
545.  	     */
546.  	    if (lev->glyph == objnum_to_glyph(BOULDER)) {
547.  		if (lev->typ != ROOM && lev->seenv) {
548.  		    map_background(x, y, 1);
549.  		} else {
550.  		    lev->glyph = lev->waslit ? cmap_to_glyph(S_room) :
551.  					       cmap_to_glyph(S_stone);
552.  		    show_glyph(x,y,lev->glyph);
553.  		}
554.  	    }
555.  	} else {
556.  	    /* We feel it (I think hallways are the only things left). */
557.  	    map_background(x, y, 1);
558.  	    /* Corridors are never felt as lit (unless remembered that way) */
559.  	    /* (lit_corridor only).					    */
560.  	    if (lev->typ == CORR &&
561.  		    lev->glyph == cmap_to_glyph(S_litcorr) && !lev->waslit)
562.  		show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
563.  	}
564.      } else {
565.  	_map_location(x, y, 1);
566.  
567.  	if (Punished) {
568.  	    /*
569.  	     * A ball or chain is only felt if it is first on the object
570.  	     * location list.  Otherwise, we need to clear the felt bit ---
571.  	     * something has been dropped on the ball/chain.  If the bit is
572.  	     * not cleared, then when the ball/chain is moved it will drop
573.  	     * the wrong glyph.
574.  	     */
575.  	    if (uchain->ox == x && uchain->oy == y) {
576.  		if (level.objects[x][y] == uchain)
577.  		    u.bc_felt |= BC_CHAIN;
578.  		else
579.  		    u.bc_felt &= ~BC_CHAIN;	/* do not feel the chain */
580.  	    }
581.  	    if (!carried(uball) && uball->ox == x && uball->oy == y) {
582.  		if (level.objects[x][y] == uball)
583.  		    u.bc_felt |= BC_BALL;
584.  		else
585.  		    u.bc_felt &= ~BC_BALL;	/* do not feel the ball */
586.  	    }
587.  	}
588.  
589.  	/* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
590.  	if (lev->typ == ROOM &&
591.  		    lev->glyph == cmap_to_glyph(S_room) && !lev->waslit)
592.  	    show_glyph(x,y, lev->glyph = cmap_to_glyph(S_stone));
593.  	else if (lev->typ == CORR &&
594.  		    lev->glyph == cmap_to_glyph(S_litcorr) && !lev->waslit)
595.  	    show_glyph(x,y, lev->glyph = cmap_to_glyph(S_corr));
596.      }
597.      /* draw monster on top if we can sense it */
598.      if ((x != u.ux || y != u.uy) && (mon = m_at(x,y)) && sensemon(mon))
599.  	display_monster(x, y, mon,
600.  		(tp_sensemon(mon) || MATCH_WARN_OF_MON(mon)) ? PHYSICALLY_SEEN : DETECTED,
601.  		is_worm_tail(mon));
602.  }
603.  
604.  /*
605.   * newsym()
606.   *
607.   * Possibly put a new glyph at the given location.
608.   */
609.  void
610.  newsym(x,y)
611.      register int x,y;
612.  {
613.      register struct monst *mon;
614.      register struct rm *lev = &(levl[x][y]);
615.      register int see_it;
616.      register xchar worm_tail;
617.  
618.      if (in_mklev) return;
619.  
620.      /* only permit updating the hero when swallowed */
621.      if (u.uswallow) {
622.  	if (x == u.ux && y == u.uy) display_self();
623.  	return;
624.      }
625.      if (Underwater && !Is_waterlevel(&u.uz)) {
626.  	/* don't do anything unless (x,y) is an adjacent underwater position */
627.  	int dx, dy;
628.  	if (!is_pool(x,y)) return;
629.  	dx = x - u.ux;	if (dx < 0) dx = -dx;
630.  	dy = y - u.uy;	if (dy < 0) dy = -dy;
631.  	if (dx > 1 || dy > 1) return;
632.      }
633.  
634.      /* Can physically see the location. */
635.      if (cansee(x,y)) {
636.          NhRegion* reg = visible_region_at(x,y);
637.  	/*
638.  	 * Don't use templit here:  E.g.
639.  	 *
640.  	 *	lev->waslit = !!(lev->lit || templit(x,y));
641.  	 *
642.  	 * Otherwise we have the "light pool" problem, where non-permanently
643.  	 * lit areas just out of sight stay remembered as lit.  They should
644.  	 * re-darken.
645.  	 *
646.  	 * Perhaps ALL areas should revert to their "unlit" look when
647.  	 * out of sight.
648.  	 */
649.  	lev->waslit = (lev->lit!=0);	/* remember lit condition */
650.  
651.  	if (reg != NULL && ACCESSIBLE(lev->typ)) {
652.  	    show_region(reg,x,y);
653.  	    return;
654.  	}
655.  	if (x == u.ux && y == u.uy) {
656.  	    if (canseeself()) {
657.  		_map_location(x,y,0);	/* map *under* self */
658.  		display_self();
659.  	    } else
660.  		/* we can see what is there */
661.  		_map_location(x,y,1);
662.  	}
663.  	else {
664.  	    mon = m_at(x,y);
665.  	    worm_tail = is_worm_tail(mon);
666.  	    see_it = mon && (worm_tail
667.  		? (!mon->minvis || See_invisible)
668.  		: (mon_visible(mon)) || tp_sensemon(mon) || MATCH_WARN_OF_MON(mon));
669.  	    if (mon && (see_it || (!worm_tail && Detect_monsters))) {
670.  		if (mon->mtrapped) {
671.  		    struct trap *trap = t_at(x, y);
672.  		    int tt = trap ? trap->ttyp : NO_TRAP;
673.  
674.  		    /* if monster is in a physical trap, you see the trap too */
675.  		    if (tt == BEAR_TRAP || tt == PIT ||
676.  			tt == SPIKED_PIT ||tt == WEB) {
677.  			trap->tseen = TRUE;
678.  		    }
679.  		}
680.  		_map_location(x,y,0);	/* map under the monster */
681.  		/* also gets rid of any invisibility glyph */
682.  		display_monster(x, y, mon, see_it ? PHYSICALLY_SEEN : DETECTED, worm_tail);
683.  	    }
684.  	    else if (mon && mon_warning(mon) && !is_worm_tail(mon))
685.  	        display_warning(mon);
686.  	    else if (glyph_is_invisible(levl[x][y].glyph))
687.  		map_invisible(x, y);
688.  	    else
689.  		_map_location(x,y,1);	/* map the location */
690.  	}
691.      }
692.  
693.      /* Can't see the location. */
694.      else {
695.  	if (x == u.ux && y == u.uy) {
696.  	    feel_location(u.ux, u.uy);		/* forces an update */
697.  
698.  	    if (canseeself()) display_self();
699.  	}
700.  	else if ((mon = m_at(x,y))
701.  		&& ((see_it = (tp_sensemon(mon) || MATCH_WARN_OF_MON(mon)
702.  		    		|| (see_with_infrared(mon) && mon_visible(mon))))
703.  		    || Detect_monsters)
704.  		&& !is_worm_tail(mon)) {
705.  	    /* Monsters are printed every time. */
706.  	    /* This also gets rid of any invisibility glyph */
707.  	    display_monster(x, y, mon, see_it ? 0 : DETECTED, 0);
708.  	}
709.  	else if ((mon = m_at(x,y)) && mon_warning(mon) &&
710.  		 !is_worm_tail(mon)) {
711.  	        display_warning(mon);
712.  	}		
713.  
714.  	/*
715.  	 * If the location is remembered as being both dark (waslit is false)
716.  	 * and lit (glyph is a lit room or lit corridor) then it was either:
717.  	 *
718.  	 *	(1) A dark location that the hero could see through night
719.  	 *	    vision.
720.  	 *
721.  	 *	(2) Darkened while out of the hero's sight.  This can happen
722.  	 *	    when cursed scroll of light is read.
723.  	 *
724.  	 * In either case, we have to manually correct the hero's memory to
725.  	 * match waslit.  Deciding when to change waslit is non-trivial.
726.  	 *
727.  	 *  Note:  If flags.lit_corridor is set, then corridors act like room
728.  	 *	   squares.  That is, they light up if in night vision range.
729.  	 *	   If flags.lit_corridor is not set, then corridors will
730.  	 *	   remain dark unless lit by a light spell.
731.  	 *
732.  	 * These checks and changes must be here and not in back_to_glyph().
733.  	 * They are dependent on the position being out of sight.
734.  	 */
735.  	else if (!lev->waslit) {
736.  	    if (flags.lit_corridor && lev->glyph == cmap_to_glyph(S_litcorr) &&
737.  							    lev->typ == CORR)
738.  		show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
739.  	    else if (lev->glyph == cmap_to_glyph(S_room) && lev->typ == ROOM)
740.  		show_glyph(x, y, lev->glyph = cmap_to_glyph(S_stone));
741.  	    else
742.  		goto show_mem;
743.  	} else {
744.  show_mem:
745.  	    show_glyph(x, y, lev->glyph);
746.  	}
747.      }
748.  }
749.  
750.  #undef is_worm_tail
751.  
752.  /*
753.   * shieldeff()
754.   *
755.   * Put magic shield pyrotechnics at the given location.  This *could* be
756.   * pulled into a platform dependent routine for fancier graphics if desired.
757.   */
758.  void
759.  shieldeff(x,y)
760.      xchar x,y;
761.  {
762.      register int i;
763.  
764.      if (!flags.sparkle) return;
765.      if (cansee(x,y)) {	/* Don't see anything if can't see the location */
766.  	for (i = 0; i < SHIELD_COUNT; i++) {
767.  	    show_glyph(x, y, cmap_to_glyph(shield_static[i]));
768.  	    flush_screen(1);	/* make sure the glyph shows up */
769.  	    delay_output();
770.  	}
771.  	newsym(x,y);		/* restore the old information */
772.      }
773.  }
774.  
775.  
776.  /*
777.   * tmp_at()
778.   *
779.   * Temporarily place glyphs on the screen.  Do not call delay_output().  It
780.   * is up to the caller to decide if it wants to wait [presently, everyone
781.   * but explode() wants to delay].
782.   *
783.   * Call:
784.   *	(DISP_BEAM,   glyph)	open, initialize glyph
785.   *	(DISP_FLASH,  glyph)	open, initialize glyph
786.   *	(DISP_ALWAYS, glyph)	open, initialize glyph
787.   *	(DISP_CHANGE, glyph)	change glyph
788.   *	(DISP_END,    0)	close & clean up (second argument doesn't
789.   *				matter)
790.   *	(DISP_FREEMEM, 0)	only used to prevent memory leak during
791.   *				exit)
792.   *	(x, y)			display the glyph at the location
793.   *
794.   * DISP_BEAM  - Display the given glyph at each location, but do not erase
795.   *		any until the close call.
796.   * DISP_FLASH - Display the given glyph at each location, but erase the
797.   *		previous location's glyph.
798.   * DISP_ALWAYS- Like DISP_FLASH, but vision is not taken into account.
799.   */
800.  
801.  static struct tmp_glyph {
802.      coord saved[COLNO];	/* previously updated positions */
803.      int sidx;		/* index of next unused slot in saved[] */
804.      int style;		/* either DISP_BEAM or DISP_FLASH or DISP_ALWAYS */
805.      int glyph;		/* glyph to use when printing */
806.      struct tmp_glyph *prev;
807.  } tgfirst;
808.  
809.  void
810.  tmp_at(x, y)
811.      int x, y;
812.  {
813.      static struct tmp_glyph *tglyph = (struct tmp_glyph *)0;
814.      struct tmp_glyph *tmp;
815.  
816.      switch (x) {
817.  	case DISP_BEAM:
818.  	case DISP_FLASH:
819.  	case DISP_ALWAYS:
820.  	    if (!tglyph)
821.  		tmp = &tgfirst;
822.  	    else	/* nested effect; we need dynamic memory */
823.  		tmp = (struct tmp_glyph *)alloc(sizeof (struct tmp_glyph));
824.  	    tmp->prev = tglyph;
825.  	    tglyph = tmp;
826.  	    tglyph->sidx = 0;
827.  	    tglyph->style = x;
828.  	    tglyph->glyph = y;
829.  	    flush_screen(0);	/* flush buffered glyphs */
830.  	    return;
831.  
832.  	case DISP_FREEMEM:  /* in case game ends with tmp_at() in progress */
833.  	    while (tglyph) {
834.  		tmp = tglyph->prev;
835.  		if (tglyph != &tgfirst) free((genericptr_t)tglyph);
836.  		tglyph = tmp;
837.  	    }
838.  	    return;
839.  
840.  	default:
841.  	    break;
842.      }
843.  
844.      if (!tglyph) panic("tmp_at: tglyph not initialized");
845.  
846.      switch (x) {
847.  	case DISP_CHANGE:
848.  	    tglyph->glyph = y;
849.  	    break;
850.  
851.  	case DISP_END:
852.  	    if (tglyph->style == DISP_BEAM) {
853.  		register int i;
854.  
855.  		/* Erase (reset) from source to end */
856.  		for (i = 0; i < tglyph->sidx; i++)
857.  		    newsym(tglyph->saved[i].x, tglyph->saved[i].y);
858.  	    } else {		/* DISP_FLASH or DISP_ALWAYS */
859.  		if (tglyph->sidx)	/* been called at least once */
860.  		    newsym(tglyph->saved[0].x, tglyph->saved[0].y);
861.  	    }
862.  	 /* tglyph->sidx = 0; -- about to be freed, so not necessary */
863.  	    tmp = tglyph->prev;
864.  	    if (tglyph != &tgfirst) free((genericptr_t)tglyph);
865.  	    tglyph = tmp;
866.  	    break;
867.  
868.  	default:	/* do it */
869.  	    if (tglyph->style == DISP_BEAM) {
870.  		if (!cansee(x,y)) break;
871.  		/* save pos for later erasing */
872.  		tglyph->saved[tglyph->sidx].x = x;
873.  		tglyph->saved[tglyph->sidx].y = y;
874.  		tglyph->sidx += 1;
875.  	    } else {	/* DISP_FLASH/ALWAYS */
876.  		if (tglyph->sidx) { /* not first call, so reset previous pos */
877.  		    newsym(tglyph->saved[0].x, tglyph->saved[0].y);
878.  		    tglyph->sidx = 0;	/* display is presently up to date */
879.  		}
880.  		if (!cansee(x,y) && tglyph->style != DISP_ALWAYS) break;
881.  		tglyph->saved[0].x = x;
882.  		tglyph->saved[0].y = y;
883.  		tglyph->sidx = 1;
884.  	    }
885.  
886.  	    show_glyph(x, y, tglyph->glyph);	/* show it */
887.  	    flush_screen(0);			/* make sure it shows up */
888.  	    break;
889.      } /* end case */
890.  }
891.  
892.  
893.  /*
894.   * swallowed()
895.   *
896.   * The hero is swallowed.  Show a special graphics sequence for this.  This
897.   * bypasses all of the display routines and messes with buffered screen
898.   * directly.  This method works because both vision and display check for
899.   * being swallowed.
900.   */
901.  void
902.  swallowed(first)
903.      int first;
904.  {
905.      static xchar lastx, lasty;	/* last swallowed position */
906.      int swallower, left_ok, rght_ok;
907.  
908.      if (first)
909.  	cls();
910.      else {
911.  	register int x, y;
912.  
913.  	/* Clear old location */
914.  	for (y = lasty-1; y <= lasty+1; y++)
915.  	    for (x = lastx-1; x <= lastx+1; x++)
916.  		if (isok(x,y)) show_glyph(x,y,cmap_to_glyph(S_stone));
917.      }
918.  
919.      swallower = monsndx(u.ustuck->data);
920.      /* assume isok(u.ux,u.uy) */
921.      left_ok = isok(u.ux-1,u.uy);
922.      rght_ok = isok(u.ux+1,u.uy);
923.      /*
924.       *  Display the hero surrounded by the monster's stomach.
925.       */
926.      if(isok(u.ux, u.uy-1)) {
927.  	if (left_ok)
928.  	show_glyph(u.ux-1, u.uy-1, swallow_to_glyph(swallower, S_sw_tl));
929.  	show_glyph(u.ux  , u.uy-1, swallow_to_glyph(swallower, S_sw_tc));
930.  	if (rght_ok)
931.  	show_glyph(u.ux+1, u.uy-1, swallow_to_glyph(swallower, S_sw_tr));
932.      }
933.  
934.      if (left_ok)
935.      show_glyph(u.ux-1, u.uy  , swallow_to_glyph(swallower, S_sw_ml));
936.      display_self();
937.      if (rght_ok)
938.      show_glyph(u.ux+1, u.uy  , swallow_to_glyph(swallower, S_sw_mr));
939.  
940.      if(isok(u.ux, u.uy+1)) {
941.  	if (left_ok)
942.  	show_glyph(u.ux-1, u.uy+1, swallow_to_glyph(swallower, S_sw_bl));
943.  	show_glyph(u.ux  , u.uy+1, swallow_to_glyph(swallower, S_sw_bc));
944.  	if (rght_ok)
945.  	show_glyph(u.ux+1, u.uy+1, swallow_to_glyph(swallower, S_sw_br));
946.      }
947.  
948.      /* Update the swallowed position. */
949.      lastx = u.ux;
950.      lasty = u.uy;
951.  }
952.  
953.  /*
954.   * under_water()
955.   *
956.   * Similar to swallowed() in operation.  Shows hero when underwater
957.   * except when in water level.  Special routines exist for that.
958.   */
959.  void
960.  under_water(mode)
961.      int mode;
962.  {
963.      static xchar lastx, lasty;
964.      static boolean dela;
965.      register int x, y;
966.  
967.      /* swallowing has a higher precedence than under water */
968.      if (Is_waterlevel(&u.uz) || u.uswallow) return;
969.  
970.      /* full update */
971.      if (mode == 1 || dela) {
972.  	cls();
973.  	dela = FALSE;
974.      }
975.      /* delayed full update */
976.      else if (mode == 2) {
977.  	dela = TRUE;
978.  	return;
979.      }
980.      /* limited update */
981.      else {
982.  	for (y = lasty-1; y <= lasty+1; y++)
983.  	    for (x = lastx-1; x <= lastx+1; x++)
984.  		if (isok(x,y))
985.  		    show_glyph(x,y,cmap_to_glyph(S_stone));
986.      }
987.      for (x = u.ux-1; x <= u.ux+1; x++)
988.  	for (y = u.uy-1; y <= u.uy+1; y++)
989.  	    if (isok(x,y) && is_pool(x,y)) {
990.  		if (Blind && !(x == u.ux && y == u.uy))
991.  		    show_glyph(x,y,cmap_to_glyph(S_stone));
992.  		else	
993.  		    newsym(x,y);
994.  	    }
995.      lastx = u.ux;
996.      lasty = u.uy;
997.  }
998.  
999.  /*
1000.  *	under_ground()
1001.  *
1002.  *	Very restricted display.  You can only see yourself.
1003.  */
1004. void
1005. under_ground(mode)
1006.     int mode;
1007. {
1008.     static boolean dela;
1009. 
1010.     /* swallowing has a higher precedence than under ground */
1011.     if (u.uswallow) return;
1012. 
1013.     /* full update */
1014.     if (mode == 1 || dela) {
1015. 	cls();
1016. 	dela = FALSE;
1017.     }
1018.     /* delayed full update */
1019.     else if (mode == 2) {
1020. 	dela = TRUE;
1021. 	return;
1022.     }
1023.     /* limited update */
1024.     else
1025. 	newsym(u.ux,u.uy);
1026. }
1027. 
1028. 
1029. /* ========================================================================= */
1030. 
1031. /*
1032.  * Loop through all of the monsters and update them.  Called when:
1033.  *	+ going blind & telepathic
1034.  *	+ regaining sight & telepathic
1035.  *      + getting and losing infravision 
1036.  *	+ hallucinating
1037.  *	+ doing a full screen redraw
1038.  *	+ see invisible times out or a ring of see invisible is taken off
1039.  *	+ when a potion of see invisible is quaffed or a ring of see
1040.  *	  invisible is put on
1041.  *	+ gaining telepathy when blind [givit() in eat.c, pleased() in pray.c]
1042.  *	+ losing telepathy while blind [xkilled() in mon.c, attrcurse() in
1043.  *	  sit.c]
1044.  */
1045. void
1046. see_monsters()
1047. {
1048.     register struct monst *mon;
1049.     for (mon = fmon; mon; mon = mon->nmon) {
1050. 	if (DEADMONSTER(mon)) continue;
1051. 	newsym(mon->mx,mon->my);
1052. 	if (mon->wormno) see_wsegs(mon);
1053.     }
1054. }
1055. 
1056. /*
1057.  * Block/unblock light depending on what a mimic is mimicing and if it's
1058.  * invisible or not.  Should be called only when the state of See_invisible
1059.  * changes.
1060.  */
1061. void
1062. set_mimic_blocking()
1063. {
1064.     register struct monst *mon;
1065.     for (mon = fmon; mon; mon = mon->nmon)
1066. 	if(!DEADMONSTER(mon) && mon->minvis &&
1067. 	   ((mon->m_ap_type == M_AP_FURNITURE &&
1068. 	      (mon->mappearance == S_vcdoor || mon->mappearance == S_hcdoor))||
1069. 	    (mon->m_ap_type == M_AP_OBJECT && mon->mappearance == BOULDER))) {
1070. 	    if(See_invisible)
1071. 		block_point(mon->mx, mon->my);
1072. 	    else
1073. 		unblock_point(mon->mx, mon->my);
1074. 	}
1075. }
1076. 
1077. /*
1078.  * Loop through all of the object *locations* and update them.  Called when
1079.  *	+ hallucinating.
1080.  */
1081. void
1082. see_objects()
1083. {
1084.     register struct obj *obj;
1085.     for(obj = fobj; obj; obj = obj->nobj)
1086. 	if (vobj_at(obj->ox,obj->oy) == obj) newsym(obj->ox, obj->oy);
1087. }
1088. 
1089. /*
1090.  * Update hallucinated traps.
1091.  */
1092. void
1093. see_traps()
1094. {
1095.     struct trap *trap;
1096.     int glyph;
1097. 
1098.     for (trap = ftrap; trap; trap = trap->ntrap) {
1099. 	glyph = glyph_at(trap->tx, trap->ty);
1100. 	if (glyph_is_trap(glyph))
1101. 	    newsym(trap->tx, trap->ty);
1102.     }
1103. }
1104. 
1105. /*
1106.  * Put the cursor on the hero.  Flush all accumulated glyphs before doing it.
1107.  */
1108. void
1109. curs_on_u()
1110. {
1111.     flush_screen(1);	/* Flush waiting glyphs & put cursor on hero */
1112. }
1113. 
1114. int
1115. doredraw()
1116. {
1117.     docrt();
1118.     return 0;
1119. }
1120. 
1121. void
1122. docrt()
1123. {
1124.     register int x,y;
1125.     register struct rm *lev;
1126. 
1127.     if (!u.ux) return; /* display isn't ready yet */
1128. 
1129.     if (u.uswallow) {
1130. 	swallowed(1);
1131. 	return;
1132.     }
1133.     if (Underwater && !Is_waterlevel(&u.uz)) {
1134. 	under_water(1);
1135. 	return;
1136.     }
1137.     if (u.uburied) {
1138. 	under_ground(1);
1139. 	return;
1140.     }
1141. 
1142.     /* shut down vision */
1143.     vision_recalc(2);
1144. 
1145.     /*
1146.      * This routine assumes that cls() does the following:
1147.      *      + fills the physical screen with the symbol for rock
1148.      *      + clears the glyph buffer
1149.      */
1150.     cls();
1151. 
1152.     /* display memory */
1153.     for (x = 1; x < COLNO; x++) {
1154. 	lev = &levl[x][0];
1155. 	for (y = 0; y < ROWNO; y++, lev++)
1156. 	    if (lev->glyph != cmap_to_glyph(S_stone))
1157. 		show_glyph(x,y,lev->glyph);
1158.     }
1159. 
1160.     /* see what is to be seen */
1161.     vision_recalc(0);
1162. 
1163.     /* overlay with monsters */
1164.     see_monsters();
1165. 
1166.     flags.botlx = 1;	/* force a redraw of the bottom line */
1167. }
1168. 
1169. 
1170. /* ========================================================================= */
1171. /* Glyph Buffering (3rd screen) ============================================ */
1172. 
1173. typedef struct {
1174.     xchar new;		/* perhaps move this bit into the rm strucure. */
1175.     int   glyph;
1176. } gbuf_entry;
1177. 
1178. static gbuf_entry gbuf[ROWNO][COLNO];
1179. static char gbuf_start[ROWNO];
1180. static char gbuf_stop[ROWNO];
1181. 
1182. /*
1183.  * Store the glyph in the 3rd screen for later flushing.
1184.  */
1185. void
1186. show_glyph(x,y,glyph)
1187.     int x, y, glyph;
1188. {
1189.     /*
1190.      * Check for bad positions and glyphs.
1191.      */
1192.     if (!isok(x, y)) {
1193. 	const char *text;
1194. 	int  offset;
1195. 
1196. 	/* column 0 is invalid, but it's often used as a flag, so ignore it */
1197. 	if (x == 0) return;
1198. 
1199. 	/*
1200. 	 *  This assumes an ordering of the offsets.  See display.h for
1201. 	 *  the definition.
1202. 	 */
1203. 
1204. 	if (glyph >= GLYPH_WARNING_OFF) {	/* a warning */
1205. 	    text = "warning";		offset = glyph - GLYPH_WARNING_OFF;
1206. 	} else if (glyph >= GLYPH_SWALLOW_OFF) {	/* swallow border */
1207. 	    text = "swallow border";	offset = glyph - GLYPH_SWALLOW_OFF;
1208. 	} else if (glyph >= GLYPH_ZAP_OFF) {		/* zap beam */
1209. 	    text = "zap beam";		offset = glyph - GLYPH_ZAP_OFF;
1210. 	} else if (glyph >= GLYPH_EXPLODE_OFF) {	/* explosion */
1211. 	    text = "explosion";		offset = glyph - GLYPH_EXPLODE_OFF;
1212. 	} else if (glyph >= GLYPH_CMAP_OFF) {		/* cmap */
1213. 	    text = "cmap_index";	offset = glyph - GLYPH_CMAP_OFF;
1214. 	} else if (glyph >= GLYPH_OBJ_OFF) {		/* object */
1215. 	    text = "object";		offset = glyph - GLYPH_OBJ_OFF;
1216. 	} else if (glyph >= GLYPH_RIDDEN_OFF) {		/* ridden mon */
1217. 	    text = "ridden mon";	offset = glyph - GLYPH_RIDDEN_OFF;
1218. 	} else if (glyph >= GLYPH_BODY_OFF) {		/* a corpse */
1219. 	    text = "corpse";		offset = glyph - GLYPH_BODY_OFF;
1220. 	} else if (glyph >= GLYPH_DETECT_OFF) {		/* detected mon */
1221. 	    text = "detected mon";	offset = glyph - GLYPH_DETECT_OFF;
1222. 	} else if (glyph >= GLYPH_INVIS_OFF) {		/* invisible mon */
1223. 	    text = "invisible mon";	offset = glyph - GLYPH_INVIS_OFF;
1224. 	} else if (glyph >= GLYPH_PET_OFF) {		/* a pet */
1225. 	    text = "pet";		offset = glyph - GLYPH_PET_OFF;
1226. 	} else {					/* a monster */
1227. 	    text = "monster";		offset = glyph;
1228. 	}
1229. 
1230. 	impossible("show_glyph:  bad pos %d %d with glyph %d [%s %d].",
1231. 						x, y, glyph, text, offset);
1232. 	return;
1233.     }
1234. 
1235.     if (glyph >= MAX_GLYPH) {
1236. 	impossible("show_glyph:  bad glyph %d [max %d] at (%d,%d).",
1237. 					glyph, MAX_GLYPH, x, y);
1238. 	return;
1239.     }
1240. 
1241.     if (gbuf[y][x].glyph != glyph) {
1242. 	gbuf[y][x].glyph = glyph;
1243. 	gbuf[y][x].new   = 1;
1244. 	if (gbuf_start[y] > x) gbuf_start[y] = x;
1245. 	if (gbuf_stop[y]  < x) gbuf_stop[y]  = x;
1246.     }
1247. }
1248. 
1249. 
1250. /*
1251.  * Reset the changed glyph borders so that none of the 3rd screen has
1252.  * changed.
1253.  */
1254. #define reset_glyph_bbox()			\
1255.     {						\
1256. 	int i;					\
1257. 						\
1258. 	for (i = 0; i < ROWNO; i++) {		\
1259. 	    gbuf_start[i] = COLNO-1;		\
1260. 	    gbuf_stop[i]  = 0;			\
1261. 	}					\
1262.     }
1263. 
1264. 
1265. static gbuf_entry nul_gbuf = { 0, cmap_to_glyph(S_stone) };
1266. /*
1267.  * Turn the 3rd screen into stone.
1268.  */
1269. void
1270. clear_glyph_buffer()
1271. {
1272.     register int x, y;
1273.     register gbuf_entry *gptr;
1274. 
1275.     for (y = 0; y < ROWNO; y++) {
1276. 	gptr = &gbuf[y][0];
1277. 	for (x = COLNO; x; x--) {
1278. 	    *gptr++ = nul_gbuf;
1279. 	}
1280.     }
1281.     reset_glyph_bbox();
1282. }
1283. 
1284. /*
1285.  * Assumes that the indicated positions are filled with S_stone glyphs.
1286.  */
1287. void
1288. row_refresh(start,stop,y)
1289.     int start,stop,y;
1290. {
1291.     register int x;
1292. 
1293.     for (x = start; x <= stop; x++)
1294. 	if (gbuf[y][x].glyph != cmap_to_glyph(S_stone))
1295. 	    print_glyph(WIN_MAP,x,y,gbuf[y][x].glyph);
1296. }
1297. 
1298. void
1299. cls()
1300. {
1301.     display_nhwindow(WIN_MESSAGE, FALSE); /* flush messages */
1302.     flags.botlx = 1;		/* force update of botl window */
1303.     clear_nhwindow(WIN_MAP);	/* clear physical screen */
1304. 
1305.     clear_glyph_buffer();	/* this is sort of an extra effort, but OK */
1306. }
1307. 
1308. /*
1309.  * Synch the third screen with the display.
1310.  */
1311. void
1312. flush_screen(cursor_on_u)
1313.     int cursor_on_u;
1314. {
1315.     /* Prevent infinite loops on errors:
1316.      *	    flush_screen->print_glyph->impossible->pline->flush_screen
1317.      */
1318.     static   boolean flushing = 0;
1319.     register int x,y;
1320. 
1321.     if (flushing) return;	/* if already flushing then return */
1322.     flushing = 1;
1323. 
1324.     for (y = 0; y < ROWNO; y++) {
1325. 	register gbuf_entry *gptr = &gbuf[y][x = gbuf_start[y]];
1326. 	for (; x <= gbuf_stop[y]; gptr++, x++)
1327. 	    if (gptr->new) {
1328. 		print_glyph(WIN_MAP,x,y,gptr->glyph);
1329. 		gptr->new = 0;
1330. 	    }
1331.     }
1332. 
1333.     if (cursor_on_u) curs(WIN_MAP, u.ux,u.uy); /* move cursor to the hero */
1334.     display_nhwindow(WIN_MAP, FALSE);
1335.     reset_glyph_bbox();
1336.     flushing = 0;
1337.     if(flags.botl || flags.botlx) bot();
1338. }
1339. 
1340. /* ========================================================================= */
1341. 
1342. /*
1343.  * back_to_glyph()
1344.  *
1345.  * Use the information in the rm structure at the given position to create
1346.  * a glyph of a background.
1347.  *
1348.  * I had to add a field in the rm structure (horizontal) so that we knew
1349.  * if open doors and secret doors were horizontal or vertical.  Previously,
1350.  * the screen symbol had the horizontal/vertical information set at
1351.  * level generation time.
1352.  *
1353.  * I used the 'ladder' field (really doormask) for deciding if stairwells
1354.  * were up or down.  I didn't want to check the upstairs and dnstairs
1355.  * variables.
1356.  */
1357. int
1358. back_to_glyph(x,y)
1359.     xchar x,y;
1360. {
1361.     int idx;
1362.     struct rm *ptr = &(levl[x][y]);
1363. 
1364.     switch (ptr->typ) {
1365. 	case SCORR:
1366. 	case STONE:
1367. 	    idx = level.flags.arboreal ? S_tree : S_stone;
1368. 	    break;
1369. 	case ROOM:		idx = S_room;	  break;
1370. 	case CORR:
1371. 	    idx = (ptr->waslit || flags.lit_corridor) ? S_litcorr : S_corr;
1372. 	    break;
1373. 	case HWALL:
1374. 	case VWALL:
1375. 	case TLCORNER:
1376. 	case TRCORNER:
1377. 	case BLCORNER:
1378. 	case BRCORNER:
1379. 	case CROSSWALL:
1380. 	case TUWALL:
1381. 	case TDWALL:
1382. 	case TLWALL:
1383. 	case TRWALL:
1384. 	case SDOOR:
1385. 	    idx = ptr->seenv ? wall_angle(ptr) : S_stone;
1386. 	    break;
1387. 	case DOOR:
1388. 	    if (ptr->doormask) {
1389. 		if (ptr->doormask & D_BROKEN)
1390. 		    idx = S_ndoor;
1391. 		else if (ptr->doormask & D_ISOPEN)
1392. 		    idx = (ptr->horizontal) ? S_hodoor : S_vodoor;
1393. 		else			/* else is closed */
1394. 		    idx = (ptr->horizontal) ? S_hcdoor : S_vcdoor;
1395. 	    } else
1396. 		idx = S_ndoor;
1397. 	    break;
1398. 	case IRONBARS:	idx = S_bars;     break;
1399. 	case TREE:		idx = S_tree;     break;
1400. 	case POOL:
1401. 	case MOAT:		idx = S_pool;	  break;
1402. 	case STAIRS:
1403. 	    idx = (ptr->ladder & LA_DOWN) ? S_dnstair : S_upstair;
1404. 	    break;
1405. 	case LADDER:
1406. 	    idx = (ptr->ladder & LA_DOWN) ? S_dnladder : S_upladder;
1407. 	    break;
1408. 	case FOUNTAIN:		idx = S_fountain; break;
1409. 	case SINK:		idx = S_sink;     break;
1410. 	case ALTAR:		idx = S_altar;    break;
1411. 	case GRAVE:		idx = S_grave;    break;
1412. 	case THRONE:		idx = S_throne;   break;
1413. 	case LAVAPOOL:		idx = S_lava;	  break;
1414. 	case ICE:		idx = S_ice;      break;
1415. 	case AIR:		idx = S_air;	  break;
1416. 	case CLOUD:		idx = S_cloud;	  break;
1417. 	case WATER:		idx = S_water;	  break;
1418. 	case DBWALL:
1419. 	    idx = (ptr->horizontal) ? S_hcdbridge : S_vcdbridge;
1420. 	    break;
1421. 	case DRAWBRIDGE_UP:
1422. 	    switch(ptr->drawbridgemask & DB_UNDER) {
1423. 	    case DB_MOAT:  idx = S_pool; break;
1424. 	    case DB_LAVA:  idx = S_lava; break;
1425. 	    case DB_ICE:   idx = S_ice;  break;
1426. 	    case DB_FLOOR: idx = S_room; break;
1427. 	    default:
1428. 		impossible("Strange db-under: %d",
1429. 			   ptr->drawbridgemask & DB_UNDER);
1430. 		idx = S_room; /* something is better than nothing */
1431. 		break;
1432. 	    }
1433. 	    break;
1434. 	case DRAWBRIDGE_DOWN:
1435. 	    idx = (ptr->horizontal) ? S_hodbridge : S_vodbridge;
1436. 	    break;
1437. 	default:
1438. 	    impossible("back_to_glyph:  unknown level type [ = %d ]",ptr->typ);
1439. 	    idx = S_room;
1440. 	    break;
1441.     }
1442. 
1443.     return cmap_to_glyph(idx);
1444. }
1445. 
1446. 
1447. /*
1448.  * swallow_to_glyph()
1449.  *
1450.  * Convert a monster number and a swallow location into the correct glyph.
1451.  * If you don't want a patchwork monster while hallucinating, decide on
1452.  * a random monster in swallowed() and don't use what_mon() here.
1453.  */
1454. STATIC_OVL int
1455. swallow_to_glyph(mnum, loc)
1456.     int mnum;
1457.     int loc;
1458. {
1459.     if (loc < S_sw_tl || S_sw_br < loc) {
1460. 	impossible("swallow_to_glyph: bad swallow location");
1461. 	loc = S_sw_br;
1462.     }
1463.     return ((int) (what_mon(mnum)<<3) | (loc - S_sw_tl)) + GLYPH_SWALLOW_OFF;
1464. }
1465. 
1466. 
1467. 
1468. /*
1469.  * zapdir_to_glyph()
1470.  *
1471.  * Change the given zap direction and beam type into a glyph.  Each beam
1472.  * type has four glyphs, one for each of the symbols below.  The order of
1473.  * the zap symbols [0-3] as defined in rm.h are:
1474.  *
1475.  *	|  S_vbeam	( 0, 1) or ( 0,-1)
1476.  *	-  S_hbeam	( 1, 0) or (-1,	0)
1477.  *	\  S_lslant	( 1, 1) or (-1,-1)
1478.  *	/  S_rslant	(-1, 1) or ( 1,-1)
1479.  */
1480. int
1481. zapdir_to_glyph(dx, dy, beam_type)
1482.     register int dx, dy;
1483.     int beam_type;
1484. {
1485.     if (beam_type >= NUM_ZAP) {
1486. 	impossible("zapdir_to_glyph:  illegal beam type");
1487. 	beam_type = 0;
1488.     }
1489.     dx = (dx == dy) ? 2 : (dx && dy) ? 3 : dx ? 1 : 0;
1490. 
1491.     return ((int) ((beam_type << 2) | dx)) + GLYPH_ZAP_OFF;
1492. }
1493. 
1494. 
1495. /*
1496.  * Utility routine for dowhatis() used to find out the glyph displayed at
1497.  * the location.  This isn't necessarily the same as the glyph in the levl
1498.  * structure, so we must check the "third screen".
1499.  */
1500. int
1501. glyph_at(x, y)
1502.     xchar x,y;
1503. {
1504.     if(x < 0 || y < 0 || x >= COLNO || y >= ROWNO)
1505. 	return cmap_to_glyph(S_room);			/* XXX */
1506.     return gbuf[y][x].glyph;
1507. }
1508. 
1509. 
1510. /* ------------------------------------------------------------------------- */
1511. /* Wall Angle -------------------------------------------------------------- */
1512. 
1513. /*#define WA_VERBOSE*/	/* give (x,y) locations for all "bad" spots */
1514. 
1515. #ifdef WA_VERBOSE
1516. 
1517. static const char *FDECL(type_to_name, (int));
1518. static void FDECL(error4, (int,int,int,int,int,int));
1519. 
1520. static int bad_count[MAX_TYPE]; /* count of positions flagged as bad */
1521. static const char *type_names[MAX_TYPE] = {
1522. 	"STONE",	"VWALL",	"HWALL",	"TLCORNER",
1523. 	"TRCORNER",	"BLCORNER",	"BRCORNER",	"CROSSWALL",
1524. 	"TUWALL",	"TDWALL",	"TLWALL",	"TRWALL",
1525. 	"DBWALL",	"SDOOR",	"SCORR",	"POOL",
1526. 	"MOAT",		"WATER",	"DRAWBRIDGE_UP","LAVAPOOL",
1527. 	"DOOR",		"CORR",		"ROOM",		"STAIRS",
1528. 	"LADDER",	"FOUNTAIN",	"THRONE",	"SINK",
1529. 	"ALTAR",	"ICE",		"DRAWBRIDGE_DOWN","AIR",
1530. 	"CLOUD"
1531. };
1532. 
1533. 
1534. static const char *
1535. type_to_name(type)
1536.     int type;
1537. {
1538.     return (type < 0 || type > MAX_TYPE) ? "unknown" : type_names[type];
1539. }
1540. 
1541. static void
1542. error4(x, y, a, b, c, dd)
1543.     int x, y, a, b, c, dd;
1544. {
1545.     pline("set_wall_state: %s @ (%d,%d) %s%s%s%s",
1546. 	type_to_name(levl[x][y].typ), x, y,
1547. 	a ? "1":"", b ? "2":"", c ? "3":"", dd ? "4":"");
1548.     bad_count[levl[x][y].typ]++;
1549. }
1550. #endif /* WA_VERBOSE */
1551. 
1552. /*
1553.  * Return 'which' if position is implies an unfinshed exterior.  Return
1554.  * zero otherwise.  Unfinished implies outer area is rock or a corridor.
1555.  *
1556.  * Things that are ambigious: lava
1557.  */
1558. STATIC_OVL int
1559. check_pos(x, y, which)
1560.     int x, y, which;
1561. {
1562.     int type;
1563.     if (!isok(x,y)) return which;
1564.     type = levl[x][y].typ;
1565.     if (IS_ROCK(type) || type == CORR || type == SCORR) return which;
1566.     return 0;
1567. }
1568. 
1569. /* Return TRUE if more than one is non-zero. */
1570. /*ARGSUSED*/
1571. #ifdef WA_VERBOSE
1572. STATIC_OVL boolean
1573. more_than_one(x, y, a, b, c)
1574.     int x, y, a, b, c;
1575. {
1576.     if ((a && (b|c)) || (b && (a|c)) || (c && (a|b))) {
1577. 	error4(x,y,a,b,c,0);
1578. 	return TRUE;
1579.     }
1580.     return FALSE;
1581. }
1582. #else
1583. #define more_than_one(x, y, a, b, c) (((a) && ((b)|(c))) || ((b) && ((a)|(c))) || ((c) && ((a)|(b))))
1584. #endif
1585. 
1586. /* Return the wall mode for a T wall. */
1587. STATIC_OVL int
1588. set_twall(x0,y0, x1,y1, x2,y2, x3,y3)
1589. int x0,y0, x1,y1, x2,y2, x3,y3;
1590. {
1591.     int wmode, is_1, is_2, is_3;
1592. 
1593.     is_1 = check_pos(x1, y1, WM_T_LONG);
1594.     is_2 = check_pos(x2, y2, WM_T_BL);
1595.     is_3 = check_pos(x3, y3, WM_T_BR);
1596.     if (more_than_one(x0, y0, is_1, is_2, is_3)) {
1597. 	wmode = 0;
1598.     } else {
1599. 	wmode = is_1 + is_2 + is_3;
1600.     }
1601.     return wmode;
1602. }
1603. 
1604. /* Return wall mode for a horizontal or vertical wall. */
1605. STATIC_OVL int
1606. set_wall(x, y, horiz)
1607.     int x, y, horiz;
1608. {
1609.     int wmode, is_1, is_2;
1610. 
1611.     if (horiz) {
1612. 	is_1 = check_pos(x,y-1, WM_W_TOP);
1613. 	is_2 = check_pos(x,y+1, WM_W_BOTTOM);
1614.     } else {
1615. 	is_1 = check_pos(x-1,y, WM_W_LEFT);
1616. 	is_2 = check_pos(x+1,y, WM_W_RIGHT);
1617.     }
1618.     if (more_than_one(x, y, is_1, is_2, 0)) {
1619. 	wmode = 0;
1620.     } else {
1621. 	wmode = is_1 + is_2;
1622.     }
1623.     return wmode;
1624. }
1625. 
1626. 
1627. /* Return a wall mode for a corner wall. (x4,y4) is the "inner" position. */
1628. STATIC_OVL int
1629. set_corn(x1,y1, x2,y2, x3,y3, x4,y4)
1630. 	int x1, y1, x2, y2, x3, y3, x4, y4;
1631. {
1632.     int wmode, is_1, is_2, is_3, is_4;
1633. 
1634.     is_1 = check_pos(x1, y1, 1);
1635.     is_2 = check_pos(x2, y2, 1);
1636.     is_3 = check_pos(x3, y3, 1);
1637.     is_4 = check_pos(x4, y4, 1);	/* inner location */
1638. 
1639.     /*
1640.      * All 4 should not be true.  So if the inner location is rock,
1641.      * use it.  If all of the outer 3 are true, use outer.  We currently
1642.      * can't cover the case where only part of the outer is rock, so
1643.      * we just say that all the walls are finished (if not overridden
1644.      * by the inner section).
1645.      */
1646.     if (is_4) {
1647. 	wmode = WM_C_INNER;
1648.     } else if (is_1 && is_2 && is_3)
1649. 	wmode = WM_C_OUTER;
1650.      else
1651. 	wmode = 0;	/* finished walls on all sides */
1652. 
1653.     return wmode;
1654. }
1655. 
1656. /* Return mode for a crosswall. */
1657. STATIC_OVL int
1658. set_crosswall(x, y)
1659.     int x, y;
1660. {
1661.     int wmode, is_1, is_2, is_3, is_4;
1662. 
1663.     is_1 = check_pos(x-1, y-1, 1);
1664.     is_2 = check_pos(x+1, y-1, 1);
1665.     is_3 = check_pos(x+1, y+1, 1);
1666.     is_4 = check_pos(x-1, y+1, 1);
1667. 
1668.     wmode = is_1+is_2+is_3+is_4;
1669.     if (wmode > 1) {
1670. 	if (is_1 && is_3 && (is_2+is_4 == 0)) {
1671. 	    wmode = WM_X_TLBR;
1672. 	} else if (is_2 && is_4 && (is_1+is_3 == 0)) {
1673. 	    wmode = WM_X_BLTR;
1674. 	} else {
1675. #ifdef WA_VERBOSE
1676. 	    error4(x,y,is_1,is_2,is_3,is_4);
1677. #endif
1678. 	    wmode = 0;
1679. 	}
1680.     } else if (is_1)
1681. 	wmode = WM_X_TL;
1682.     else if (is_2)
1683. 	wmode = WM_X_TR;
1684.     else if (is_3)
1685. 	wmode = WM_X_BR;
1686.     else if (is_4)
1687. 	wmode = WM_X_BL;
1688. 
1689.     return wmode;
1690. }
1691. 
1692. /* Called from mklev.  Scan the level and set the wall modes. */
1693. void
1694. set_wall_state()
1695. {
1696.     int x, y;
1697.     int wmode;
1698.     struct rm *lev;
1699. 
1700. #ifdef WA_VERBOSE
1701.     for (x = 0; x < MAX_TYPE; x++) bad_count[x] = 0;
1702. #endif
1703. 
1704.     for (x = 0; x < COLNO; x++)
1705. 	for (lev = &levl[x][0], y = 0; y < ROWNO; y++, lev++) {
1706. 	    switch (lev->typ) {
1707. 		case SDOOR:
1708. 		    wmode = set_wall(x, y, (int) lev->horizontal);
1709. 		    break;
1710. 		case VWALL:
1711. 		    wmode = set_wall(x, y, 0);
1712. 		    break;
1713. 		case HWALL:
1714. 		    wmode = set_wall(x, y, 1);
1715. 		    break;
1716. 		case TDWALL:
1717. 		    wmode = set_twall(x,y, x,y-1, x-1,y+1, x+1,y+1);
1718. 		    break;
1719. 		case TUWALL:
1720. 		    wmode = set_twall(x,y, x,y+1, x+1,y-1, x-1,y-1);
1721. 		    break;
1722. 		case TLWALL:
1723. 		    wmode = set_twall(x,y, x+1,y, x-1,y-1, x-1,y+1);
1724. 		    break;
1725. 		case TRWALL:
1726. 		    wmode = set_twall(x,y, x-1,y, x+1,y+1, x+1,y-1);
1727. 		    break;
1728. 		case TLCORNER:
1729. 		    wmode = set_corn(x-1,y-1, x,y-1, x-1,y, x+1,y+1);
1730. 		    break;
1731. 		case TRCORNER:
1732. 		    wmode = set_corn(x,y-1, x+1,y-1, x+1,y, x-1,y+1);
1733. 		    break;
1734. 		case BLCORNER:
1735. 		    wmode = set_corn(x,y+1, x-1,y+1, x-1,y, x+1,y-1);
1736. 		    break;
1737. 		case BRCORNER:
1738. 		    wmode = set_corn(x+1,y, x+1,y+1, x,y+1, x-1,y-1);
1739. 		    break;
1740. 		case CROSSWALL:
1741. 		    wmode = set_crosswall(x, y);
1742. 		    break;
1743. 
1744. 		default:
1745. 		    wmode = -1;	/* don't set wall info */
1746. 		    break;
1747. 	    }
1748. 
1749. 	if (wmode >= 0)
1750. 	    lev->wall_info = (lev->wall_info & ~WM_MASK) | wmode;
1751. 	}
1752. 
1753. #ifdef WA_VERBOSE
1754.     /* check if any bad positions found */
1755.     for (x = y = 0; x < MAX_TYPE; x++)
1756. 	if (bad_count[x]) {
1757. 	    if (y == 0) {
1758. 		y = 1;	/* only print once */
1759. 		pline("set_wall_type: wall mode problems with: ");
1760. 	    }
1761. 	    pline("%s %d;", type_names[x], bad_count[x]);
1762. 	}
1763. #endif /* WA_VERBOSE */
1764. }
1765. 
1766. /* ------------------------------------------------------------------------- */
1767. /* This matrix is used here and in vision.c. */
1768. unsigned char seenv_matrix[3][3] = { {SV2,   SV1, SV0},
1769. 				     {SV3, SVALL, SV7},
1770. 				     {SV4,   SV5, SV6} };
1771. 
1772. #define sign(z) ((z) < 0 ? -1 : ((z) > 0 ? 1 : 0))
1773. 
1774. /* Set the seen vector of lev as if seen from (x0,y0) to (x,y). */
1775. STATIC_OVL void
1776. set_seenv(lev, x0, y0, x, y)
1777.     struct rm *lev;
1778.     int x0, y0, x, y;	/* from, to */
1779. {
1780.     int dx = x-x0, dy = y0-y;
1781.     lev->seenv |= seenv_matrix[sign(dy)+1][sign(dx)+1];
1782. }
1783. 
1784. /* ------------------------------------------------------------------------- */
1785. 
1786. /* T wall types, one for each row in wall_matrix[][]. */
1787. #define T_d 0
1788. #define T_l 1
1789. #define T_u 2
1790. #define T_r 3
1791. 
1792. /*
1793.  * These are the column names of wall_matrix[][].  They are the "results"
1794.  * of a tdwall pattern match.  All T walls are rotated so they become
1795.  * a tdwall.  Then we do a single pattern match, but return the
1796.  * correct result for the original wall by using different rows for
1797.  * each of the wall types.
1798.  */
1799. #define T_stone  0
1800. #define T_tlcorn 1
1801. #define T_trcorn 2
1802. #define T_hwall  3
1803. #define T_tdwall 4
1804. 
1805. static const int wall_matrix[4][5] = {
1806.     { S_stone, S_tlcorn, S_trcorn, S_hwall, S_tdwall },	/* tdwall */
1807.     { S_stone, S_trcorn, S_brcorn, S_vwall, S_tlwall },	/* tlwall */
1808.     { S_stone, S_brcorn, S_blcorn, S_hwall, S_tuwall },	/* tuwall */
1809.     { S_stone, S_blcorn, S_tlcorn, S_vwall, S_trwall },	/* trwall */
1810. };
1811. 
1812. 
1813. /* Cross wall types, one for each "solid" quarter.  Rows of cross_matrix[][]. */
1814. #define C_bl 0
1815. #define C_tl 1
1816. #define C_tr 2
1817. #define C_br 3
1818. 
1819. /*
1820.  * These are the column names for cross_matrix[][].  They express results
1821.  * in C_br (bottom right) terms.  All crosswalls with a single solid
1822.  * quarter are rotated so the solid section is at the bottom right.
1823.  * We pattern match on that, but return the correct result depending
1824.  * on which row we'ere looking at.
1825.  */
1826. #define C_trcorn 0
1827. #define C_brcorn 1
1828. #define C_blcorn 2
1829. #define C_tlwall 3
1830. #define C_tuwall 4
1831. #define C_crwall 5
1832. 
1833. static const int cross_matrix[4][6] = {
1834.     { S_brcorn, S_blcorn, S_tlcorn, S_tuwall, S_trwall, S_crwall },
1835.     { S_blcorn, S_tlcorn, S_trcorn, S_trwall, S_tdwall, S_crwall },
1836.     { S_tlcorn, S_trcorn, S_brcorn, S_tdwall, S_tlwall, S_crwall },
1837.     { S_trcorn, S_brcorn, S_blcorn, S_tlwall, S_tuwall, S_crwall },
1838. };
1839. 
1840. 
1841. /* Print out a T wall warning and all interesting info. */
1842. STATIC_OVL void
1843. t_warn(lev)
1844.     struct rm *lev;
1845. {
1846.     static const char *warn_str = "wall_angle: %s: case %d: seenv = 0x%x";
1847.     const char *wname;
1848. 
1849.     if (lev->typ == TUWALL) wname = "tuwall";
1850.     else if (lev->typ == TLWALL) wname = "tlwall";
1851.     else if (lev->typ == TRWALL) wname = "trwall";
1852.     else if (lev->typ == TDWALL) wname = "tdwall";
1853.     else wname = "unknown";
1854.     impossible(warn_str, wname, lev->wall_info & WM_MASK,
1855. 	(unsigned int) lev->seenv);
1856. }
1857. 
1858. 
1859. /*
1860.  * Return the correct graphics character index using wall type, wall mode,
1861.  * and the seen vector.  It is expected that seenv is non zero.
1862.  *
1863.  * All T-wall vectors are rotated to be TDWALL.  All single crosswall
1864.  * blocks are rotated to bottom right.  All double crosswall are rotated
1865.  * to W_X_BLTR.  All results are converted back.
1866.  *
1867.  * The only way to understand this is to take out pen and paper and
1868.  * draw diagrams.  See rm.h for more details on the wall modes and
1869.  * seen vector (SV).
1870.  */
1871. STATIC_OVL int
1872. wall_angle(lev)
1873.     struct rm *lev;
1874. {
1875.     register unsigned int seenv = lev->seenv & 0xff;
1876.     const int *row;
1877.     int col, idx;
1878. 
1879. #define only(sv, bits)	(((sv) & (bits)) && ! ((sv) & ~(bits)))
1880.     switch (lev->typ) {
1881. 	case TUWALL:
1882. 		row = wall_matrix[T_u];
1883. 		seenv = (seenv >> 4 | seenv << 4) & 0xff;/* rotate to tdwall */
1884. 		goto do_twall;
1885. 	case TLWALL:
1886. 		row = wall_matrix[T_l];
1887. 		seenv = (seenv >> 2 | seenv << 6) & 0xff;/* rotate to tdwall */
1888. 		goto do_twall;
1889. 	case TRWALL:
1890. 		row = wall_matrix[T_r];
1891. 		seenv = (seenv >> 6 | seenv << 2) & 0xff;/* rotate to tdwall */
1892. 		goto do_twall;
1893. 	case TDWALL:
1894. 		row = wall_matrix[T_d];
1895. do_twall:
1896. 		switch (lev->wall_info & WM_MASK) {
1897. 		    case 0:
1898. 			if (seenv == SV4) {
1899. 			    col = T_tlcorn;
1900. 			} else if (seenv == SV6) {
1901. 			    col = T_trcorn;
1902. 			} else if (seenv & (SV3|SV5|SV7) ||
1903. 					    ((seenv & SV4) && (seenv & SV6))) {
1904. 			    col = T_tdwall;
1905. 			} else if (seenv & (SV0|SV1|SV2)) {
1906. 			    col = (seenv & (SV4|SV6) ? T_tdwall : T_hwall);
1907. 			} else {
1908. 			    t_warn(lev);
1909. 			    col = T_stone;
1910. 			}
1911. 			break;
1912. 		    case WM_T_LONG:
1913. 			if (seenv & (SV3|SV4) && !(seenv & (SV5|SV6|SV7))) {
1914. 			    col = T_tlcorn;
1915. 			} else if (seenv&(SV6|SV7) && !(seenv&(SV3|SV4|SV5))) {
1916. 			    col = T_trcorn;
1917. 			} else if ((seenv & SV5) ||
1918. 				((seenv & (SV3|SV4)) && (seenv & (SV6|SV7)))) {
1919. 			    col = T_tdwall;
1920. 			} else {
1921. 			    /* only SV0|SV1|SV2 */
1922. 			    if (! only(seenv, SV0|SV1|SV2) )
1923. 				t_warn(lev);
1924. 			    col = T_stone;
1925. 			}
1926. 			break;
1927. 		    case WM_T_BL:
1928. #if 0	/* older method, fixed */
1929. 			if (only(seenv, SV4|SV5)) {
1930. 			    col = T_tlcorn;
1931. 			} else if ((seenv & (SV0|SV1|SV2)) &&
1932. 					only(seenv, SV0|SV1|SV2|SV6|SV7)) {
1933. 			    col = T_hwall;
1934. 			} else if (seenv & SV3 ||
1935. 			    ((seenv & (SV0|SV1|SV2)) && (seenv & (SV4|SV5)))) {
1936. 			    col = T_tdwall;
1937. 			} else {
1938. 			    if (seenv != SV6)
1939. 				t_warn(lev);
1940. 			    col = T_stone;
1941. 			}
1942. #endif	/* 0 */
1943. 			if (only(seenv, SV4|SV5))
1944. 			    col = T_tlcorn;
1945. 			else if ((seenv & (SV0|SV1|SV2|SV7)) &&
1946. 					!(seenv & (SV3|SV4|SV5)))
1947. 			    col = T_hwall;
1948. 			else if (only(seenv, SV6))
1949. 			    col = T_stone;
1950. 			else
1951. 			    col = T_tdwall;
1952. 			break;
1953. 		    case WM_T_BR:
1954. #if 0	/* older method, fixed */
1955. 			if (only(seenv, SV5|SV6)) {
1956. 			    col = T_trcorn;
1957. 			} else if ((seenv & (SV0|SV1|SV2)) &&
1958. 					    only(seenv, SV0|SV1|SV2|SV3|SV4)) {
1959. 			    col = T_hwall;
1960. 			} else if (seenv & SV7 ||
1961. 			    ((seenv & (SV0|SV1|SV2)) && (seenv & (SV5|SV6)))) {
1962. 			    col = T_tdwall;
1963. 			} else {
1964. 			    if (seenv != SV4)
1965. 				t_warn(lev);
1966. 			    col = T_stone;
1967. 			}
1968. #endif	/* 0 */
1969. 			if (only(seenv, SV5|SV6))
1970. 			    col = T_trcorn;
1971. 			else if ((seenv & (SV0|SV1|SV2|SV3)) &&
1972. 					!(seenv & (SV5|SV6|SV7)))
1973. 			    col = T_hwall;
1974. 			else if (only(seenv, SV4))
1975. 			    col = T_stone;
1976. 			else
1977. 			    col = T_tdwall;
1978. 
1979. 			break;
1980. 		    default:
1981. 			impossible("wall_angle: unknown T wall mode %d",
1982. 				lev->wall_info & WM_MASK);
1983. 			col = T_stone;
1984. 			break;
1985. 		}
1986. 		idx = row[col];
1987. 		break;
1988. 
1989. 	case SDOOR:
1990. 		if (lev->horizontal) goto horiz;
1991. 		/* fall through */
1992. 	case VWALL:
1993. 		switch (lev->wall_info & WM_MASK) {
1994. 		    case 0: idx = seenv ? S_vwall : S_stone; break;
1995. 		    case 1: idx = seenv & (SV1|SV2|SV3|SV4|SV5) ? S_vwall :
1996. 								  S_stone;
1997. 			    break;
1998. 		    case 2: idx = seenv & (SV0|SV1|SV5|SV6|SV7) ? S_vwall :
1999. 								  S_stone;
2000. 			    break;
2001. 		    default:
2002. 			impossible("wall_angle: unknown vwall mode %d",
2003. 				lev->wall_info & WM_MASK);
2004. 			idx = S_stone;
2005. 			break;
2006. 		}
2007. 		break;
2008. 
2009. 	case HWALL:
2010. horiz:
2011. 		switch (lev->wall_info & WM_MASK) {
2012. 		    case 0: idx = seenv ? S_hwall : S_stone; break;
2013. 		    case 1: idx = seenv & (SV3|SV4|SV5|SV6|SV7) ? S_hwall :
2014. 								  S_stone;
2015. 			    break;
2016. 		    case 2: idx = seenv & (SV0|SV1|SV2|SV3|SV7) ? S_hwall :
2017. 								  S_stone;
2018. 			    break;
2019. 		    default:
2020. 			impossible("wall_angle: unknown hwall mode %d",
2021. 				lev->wall_info & WM_MASK);
2022. 			idx = S_stone;
2023. 			break;
2024. 		}
2025. 		break;
2026. 
2027. #define set_corner(idx, lev, which, outer, inner, name)	\
2028.     switch ((lev)->wall_info & WM_MASK) {				    \
2029. 	case 0:		 idx = which; break;				    \
2030. 	case WM_C_OUTER: idx = seenv &  (outer) ? which : S_stone; break;   \
2031. 	case WM_C_INNER: idx = seenv & ~(inner) ? which : S_stone; break;   \
2032. 	default:							    \
2033. 	    impossible("wall_angle: unknown %s mode %d", name,		    \
2034. 		(lev)->wall_info & WM_MASK);				    \
2035. 	    idx = S_stone;						    \
2036. 	    break;							    \
2037.     }
2038. 
2039. 	case TLCORNER:
2040. 	    set_corner(idx, lev, S_tlcorn, (SV3|SV4|SV5), SV4, "tlcorn");
2041. 	    break;
2042. 	case TRCORNER:
2043. 	    set_corner(idx, lev, S_trcorn, (SV5|SV6|SV7), SV6, "trcorn");
2044. 	    break;
2045. 	case BLCORNER:
2046. 	    set_corner(idx, lev, S_blcorn, (SV1|SV2|SV3), SV2, "blcorn");
2047. 	    break;
2048. 	case BRCORNER:
2049. 	    set_corner(idx, lev, S_brcorn, (SV7|SV0|SV1), SV0, "brcorn");
2050. 	    break;
2051. 
2052. 
2053. 	case CROSSWALL:
2054. 		switch (lev->wall_info & WM_MASK) {
2055. 		    case 0:
2056. 			if (seenv == SV0)
2057. 			    idx = S_brcorn;
2058. 			else if (seenv == SV2)
2059. 			    idx = S_blcorn;
2060. 			else if (seenv == SV4)
2061. 			    idx = S_tlcorn;
2062. 			else if (seenv == SV6)
2063. 			    idx = S_trcorn;
2064. 			else if (!(seenv & ~(SV0|SV1|SV2)) &&
2065. 					(seenv & SV1 || seenv == (SV0|SV2)))
2066. 			    idx = S_tuwall;
2067. 			else if (!(seenv & ~(SV2|SV3|SV4)) &&
2068. 					(seenv & SV3 || seenv == (SV2|SV4)))
2069. 			    idx = S_trwall;
2070. 			else if (!(seenv & ~(SV4|SV5|SV6)) &&
2071. 					(seenv & SV5 || seenv == (SV4|SV6)))
2072. 			    idx = S_tdwall;
2073. 			else if (!(seenv & ~(SV0|SV6|SV7)) &&
2074. 					(seenv & SV7 || seenv == (SV0|SV6)))
2075. 			    idx = S_tlwall;
2076. 			else
2077. 			    idx = S_crwall;
2078. 			break;
2079. 
2080. 		    case WM_X_TL:
2081. 			row = cross_matrix[C_tl];
2082. 			seenv = (seenv >> 4 | seenv << 4) & 0xff;
2083. 			goto do_crwall;
2084. 		    case WM_X_TR:
2085. 			row = cross_matrix[C_tr];
2086. 			seenv = (seenv >> 6 | seenv << 2) & 0xff;
2087. 			goto do_crwall;
2088. 		    case WM_X_BL:
2089. 			row = cross_matrix[C_bl];
2090. 			seenv = (seenv >> 2 | seenv << 6) & 0xff;
2091. 			goto do_crwall;
2092. 		    case WM_X_BR:
2093. 			row = cross_matrix[C_br];
2094. do_crwall:
2095. 			if (seenv == SV4)
2096. 			    idx = S_stone;
2097. 			else {
2098. 			    seenv = seenv & ~SV4;	/* strip SV4 */
2099. 			    if (seenv == SV0) {
2100. 				col = C_brcorn;
2101. 			    } else if (seenv & (SV2|SV3)) {
2102. 				if (seenv & (SV5|SV6|SV7))
2103. 				    col = C_crwall;
2104. 				else if (seenv & (SV0|SV1))
2105. 				    col = C_tuwall;
2106. 				else
2107. 				    col = C_blcorn;
2108. 			    } else if (seenv & (SV5|SV6)) {
2109. 				if (seenv & (SV1|SV2|SV3))
2110. 				    col = C_crwall;
2111. 				else if (seenv & (SV0|SV7))
2112. 				    col = C_tlwall;
2113. 				else
2114. 				    col = C_trcorn;
2115. 			    } else if (seenv & SV1) {
2116. 				col = seenv & SV7 ? C_crwall : C_tuwall;
2117. 			    } else if (seenv & SV7) {
2118. 				col = seenv & SV1 ? C_crwall : C_tlwall;
2119. 			    } else {
2120. 				impossible(
2121. 				    "wall_angle: bottom of crwall check");
2122. 				col = C_crwall;
2123. 			    }
2124. 
2125. 			    idx = row[col];
2126. 			}
2127. 			break;
2128. 
2129. 		    case WM_X_TLBR:
2130. 			if ( only(seenv, SV1|SV2|SV3) )
2131. 			    idx = S_blcorn;
2132. 			else if ( only(seenv, SV5|SV6|SV7) )
2133. 			    idx = S_trcorn;
2134. 			else if ( only(seenv, SV0|SV4) )
2135. 			    idx = S_stone;
2136. 			else
2137. 			    idx = S_crwall;
2138. 			break;
2139. 
2140. 		    case WM_X_BLTR:
2141. 			if ( only(seenv, SV0|SV1|SV7) )
2142. 			    idx = S_brcorn;
2143. 			else if ( only(seenv, SV3|SV4|SV5) )
2144. 			    idx = S_tlcorn;
2145. 			else if ( only(seenv, SV2|SV6) )
2146. 			    idx = S_stone;
2147. 			else
2148. 			    idx = S_crwall;
2149. 			break;
2150. 
2151. 		    default:
2152. 			impossible("wall_angle: unknown crosswall mode");
2153. 			idx = S_stone;
2154. 			break;
2155. 		}
2156. 		break;
2157. 
2158. 	default:
2159. 	    impossible("wall_angle: unexpected wall type %d", lev->typ);
2160. 	    idx = S_stone;
2161.     }
2162.     return idx;
2163. }
2164. 
2165. /*display.c*/

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