src/display.c

   1 /* NetHack 3.6  display.c       $NHDT-Date: 1461979957 2016/04/30 01:32:37 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.83 $ */
   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 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
 120 STATIC_DCL void FDECL(display_monster,
 121                       (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 STATIC_DCL int FDECL(get_bk_glyph, (XCHAR_P, XCHAR_P));
 127
 128 /*#define WA_VERBOSE*/ /* give (x,y) locations for all "bad" spots */
 129 #ifdef WA_VERBOSE
 130 STATIC_DCL boolean FDECL(more_than_one, (int, int, int, int, int));
 131 #endif
 132
 133 STATIC_DCL int FDECL(set_twall, (int, int, int, int, int, int, int, int));
 134 STATIC_DCL int FDECL(set_wall, (int, int, int));
 135 STATIC_DCL int FDECL(set_corn, (int, int, int, int, int, int, int, int));
 136 STATIC_DCL int FDECL(set_crosswall, (int, int));
 137 STATIC_DCL void FDECL(set_seenv, (struct rm *, int, int, int, int));
 138 STATIC_DCL void FDECL(t_warn, (struct rm *));
 139 STATIC_DCL int FDECL(wall_angle, (struct rm *));
 140
 141 #define remember_topology(x, y) (lastseentyp[x][y] = levl[x][y].typ)
 142
 143 /*
 144  * magic_map_background()
 145  *
 146  * This function is similar to map_background (see below) except we pay
 147  * attention to and correct unexplored, lit ROOM and CORR spots.
 148  */
 149 void
 150 magic_map_background(x, y, show)
 151 xchar x, y;
 152 int show;
 153 {
 154     int glyph = back_to_glyph(x, y); /* assumes hero can see x,y */
 155     struct rm *lev = &levl[x][y];
 156
 157     /*
 158      * Correct for out of sight lit corridors and rooms that the hero
 159      * doesn't remember as lit.
 160      */
 161     if (!cansee(x, y) && !lev->waslit) {
 162         /* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
 163         if (lev->typ == ROOM && glyph == cmap_to_glyph(S_room))
 164             glyph = cmap_to_glyph((flags.dark_room && iflags.use_color)
 165                                       ? (DARKROOMSYM)
 166                                       : S_stone);
 167         else if (lev->typ == CORR && glyph == cmap_to_glyph(S_litcorr))
 168             glyph = cmap_to_glyph(S_corr);
 169     }
 170     if (level.flags.hero_memory)
 171         lev->glyph = glyph;
 172     if (show)
 173         show_glyph(x, y, glyph);
 174
 175     remember_topology(x, y);
 176 }
 177
 178 /*
 179  * The routines map_background(), map_object(), and map_trap() could just
 180  * as easily be:
 181  *
 182  *      map_glyph(x,y,glyph,show)
 183  *
 184  * Which is called with the xx_to_glyph() in the call.  Then I can get
 185  * rid of 3 routines that don't do very much anyway.  And then stop
 186  * having to create fake objects and traps.  However, I am reluctant to
 187  * make this change.
 188  */
 189 /* FIXME: some of these use xchars for x and y, and some use ints.  Make
 190  * this consistent.
 191  */
 192
 193 /*
 194  * map_background()
 195  *
 196  * Make the real background part of our map.  This routine assumes that
 197  * the hero can physically see the location.  Update the screen if directed.
 198  */
 199 void
 200 map_background(x, y, show)
 201 register xchar x, y;
 202 register int show;
 203 {
 204     register int glyph = back_to_glyph(x, y);
 205
 206     if (level.flags.hero_memory)
 207         levl[x][y].glyph = glyph;
 208     if (show)
 209         show_glyph(x, y, glyph);
 210 }
 211
 212 /*
 213  * map_trap()
 214  *
 215  * Map the trap and print it out if directed.  This routine assumes that the
 216  * hero can physically see the location.
 217  */
 218 void
 219 map_trap(trap, show)
 220 register struct trap *trap;
 221 register int show;
 222 {
 223     register int x = trap->tx, y = trap->ty;
 224     register int glyph = trap_to_glyph(trap);
 225
 226     if (level.flags.hero_memory)
 227         levl[x][y].glyph = glyph;
 228     if (show)
 229         show_glyph(x, y, glyph);
 230 }
 231
 232 /*
 233  * map_object()
 234  *
 235  * Map the given object.  This routine assumes that the hero can physically
 236  * see the location of the object.  Update the screen if directed.
 237  */
 238 void
 239 map_object(obj, show)
 240 register struct obj *obj;
 241 register int show;
 242 {
 243     register int x = obj->ox, y = obj->oy;
 244     register int glyph = obj_to_glyph(obj);
 245
 246     if (level.flags.hero_memory) {
 247         /* MRKR: While hallucinating, statues are seen as random monsters */
 248         /*       but remembered as random objects.                        */
 249
 250         if (Hallucination && obj->otyp == STATUE) {
 251             levl[x][y].glyph = random_obj_to_glyph();
 252         } else {
 253             levl[x][y].glyph = glyph;
 254         }
 255     }
 256     if (show)
 257         show_glyph(x, y, glyph);
 258 }
 259
 260 /*
 261  * map_invisible()
 262  *
 263  * Make the hero remember that a square contains an invisible monster.
 264  * This is a special case in that the square will continue to be displayed
 265  * this way even when the hero is close enough to see it.  To get rid of
 266  * this and display the square's actual contents, use unmap_object() followed
 267  * by newsym() if necessary.
 268  */
 269 void
 270 map_invisible(x, y)
 271 register xchar x, y;
 272 {
 273     if (x != u.ux || y != u.uy) { /* don't display I at hero's location */
 274         if (level.flags.hero_memory)
 275             levl[x][y].glyph = GLYPH_INVISIBLE;
 276         show_glyph(x, y, GLYPH_INVISIBLE);
 277     }
 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)
 296         return;
 297
 298     if ((trap = t_at(x, y)) != 0 && trap->tseen && !covers_traps(x, y))
 299         map_trap(trap, 0);
 300     else if (levl[x][y].seenv) {
 301         struct rm *lev = &levl[x][y];
 302
 303         map_background(x, y, 0);
 304
 305         /* turn remembered dark room squares dark */
 306         if (!lev->waslit && lev->glyph == cmap_to_glyph(S_room)
 307             && lev->typ == ROOM)
 308             lev->glyph = cmap_to_glyph(S_stone);
 309     } else
 310         levl[x][y].glyph = cmap_to_glyph(S_stone); /* default val */
 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         remember_topology(x, y);                                            \
 334     }
 335
 336 void
 337 map_location(x, y, show)
 338 int x, y, show;
 339 {
 340     _map_location(x, y, show);
 341 }
 342
 343 #define DETECTED 2
 344 #define PHYSICALLY_SEEN 1
 345 #define is_worm_tail(mon) ((mon) && ((x != (mon)->mx) || (y != (mon)->my)))
 346
 347 /*
 348  * display_monster()
 349  *
 350  * Note that this is *not* a map_XXXX() function!  Monsters sort of float
 351  * above everything.
 352  *
 353  * Yuck.  Display body parts by recognizing that the display position is
 354  * not the same as the monster position.  Currently the only body part is
 355  * a worm tail.
 356  *
 357  */
 358 STATIC_OVL void
 359 display_monster(x, y, mon, sightflags, worm_tail)
 360 register xchar x, y;        /* display position */
 361 register struct monst *mon; /* monster to display */
 362 int sightflags;             /* 1 if the monster is physically seen;
 363                                2 if detected using Detect_monsters */
 364 xchar worm_tail;            /* mon is actually a worm tail */
 365 {
 366     boolean mon_mimic = (mon->m_ap_type != M_AP_NOTHING);
 367     int sensed = (mon_mimic && (Protection_from_shape_changers
 368                                 || sensemon(mon)));
 369     /*
 370      * We must do the mimic check first.  If the mimic is mimicing something,
 371      * and the location is in sight, we have to change the hero's memory
 372      * so that when the position is out of sight, the hero remembers what
 373      * the mimic was mimicing.
 374      */
 375
 376     if (mon_mimic && (sightflags == PHYSICALLY_SEEN)) {
 377         switch (mon->m_ap_type) {
 378         default:
 379             impossible("display_monster:  bad m_ap_type value [ = %d ]",
 380                        (int) mon->m_ap_type);
 381         case M_AP_NOTHING:
 382             show_glyph(x, y, mon_to_glyph(mon));
 383             break;
 384
 385         case M_AP_FURNITURE: {
 386             /*
 387              * This is a poor man's version of map_background().  I can't
 388              * use map_background() because we are overriding what is in
 389              * the 'typ' field.  Maybe have map_background()'s parameters
 390              * be (x,y,glyph) instead of just (x,y).
 391              *
 392              * mappearance is currently set to an S_ index value in
 393              * makemon.c.
 394              */
 395             int sym = mon->mappearance, glyph = cmap_to_glyph(sym);
 396
 397             levl[x][y].glyph = glyph;
 398             if (!sensed) {
 399                 show_glyph(x, y, glyph);
 400                 /* override real topology with mimic's fake one */
 401                 lastseentyp[x][y] = cmap_to_type(sym);
 402             }
 403             break;
 404         }
 405
 406         case M_AP_OBJECT: {
 407             /* Make a fake object to send to map_object(). */
 408             struct obj obj;
 409
 410             obj = zeroobj;
 411             obj.ox = x;
 412             obj.oy = y;
 413             obj.otyp = mon->mappearance;
 414             /* might be mimicing a corpse or statue */
 415             obj.corpsenm = has_mcorpsenm(mon) ? MCORPSENM(mon) : PM_TENGU;
 416             map_object(&obj, !sensed);
 417             break;
 418         }
 419
 420         case M_AP_MONSTER:
 421             show_glyph(x, y,
 422                        monnum_to_glyph(what_mon((int) mon->mappearance)));
 423             break;
 424         }
 425     }
 426
 427     /* If the mimic is unsuccessfully mimicing something, display the monster
 428      */
 429     if (!mon_mimic || sensed) {
 430         int num;
 431
 432         /* [ALI] Only use detected glyphs when monster wouldn't be
 433          * visible by any other means.
 434          */
 435         if (sightflags == DETECTED && !mon->mtame) {
 436             if (worm_tail)
 437                 num = detected_monnum_to_glyph(what_mon(PM_LONG_WORM_TAIL));
 438             else
 439                 num = detected_mon_to_glyph(mon);
 440         } else if (mon->mtame && !Hallucination) {
 441             if (worm_tail)
 442                 num = petnum_to_glyph(PM_LONG_WORM_TAIL);
 443             else
 444                 num = pet_to_glyph(mon);
 445         } else {
 446             if (worm_tail)
 447                 num = monnum_to_glyph(what_mon(PM_LONG_WORM_TAIL));
 448             else
 449                 num = mon_to_glyph(mon);
 450         }
 451         show_glyph(x, y, num);
 452     }
 453 }
 454
 455 /*
 456  * display_warning()
 457  *
 458  * This is also *not* a map_XXXX() function!  Monster warnings float
 459  * above everything just like monsters do, but only if the monster
 460  * is not showing.
 461  *
 462  * Do not call for worm tails.
 463  */
 464 STATIC_OVL void
 465 display_warning(mon)
 466 register struct monst *mon;
 467 {
 468     int x = mon->mx, y = mon->my;
 469     int glyph;
 470
 471     if (mon_warning(mon)) {
 472         int wl = Hallucination ? rn1(WARNCOUNT - 1, 1) : warning_of(mon);
 473         glyph = warning_to_glyph(wl);
 474     } else if (MATCH_WARN_OF_MON(mon)) {
 475         glyph = mon_to_glyph(mon);
 476     } else {
 477         impossible("display_warning did not match warning type?");
 478         return;
 479     }
 480     show_glyph(x, y, glyph);
 481 }
 482
 483 int
 484 warning_of(mon)
 485 struct monst *mon;
 486 {
 487     int wl = 0, tmp = 0;
 488     if (mon_warning(mon)) {
 489         tmp = (int) (mon->m_lev / 4);    /* match display.h */
 490         wl = (tmp > WARNCOUNT - 1) ? WARNCOUNT - 1 : tmp;
 491     }
 492     return wl;
 493 }
 494
 495
 496 /*
 497  * feel_newsym()
 498  *
 499  * When hero knows what happened to location, even when blind.
 500  */
 501 void
 502 feel_newsym(x, y)
 503 xchar x, y;
 504 {
 505     if (Blind)
 506         feel_location(x, y);
 507     else
 508         newsym(x, y);
 509 }
 510
 511
 512 /*
 513  * feel_location()
 514  *
 515  * Feel the given location.  This assumes that the hero is blind and that
 516  * the given position is either the hero's or one of the eight squares
 517  * adjacent to the hero (except for a boulder push).
 518  * If an invisible monster has gone away, that will be discovered.  If an
 519  * invisible monster has appeared, this will _not_ be discovered since
 520  * searching only finds one monster per turn so we must check that separately.
 521  */
 522 void
 523 feel_location(x, y)
 524 xchar x, y;
 525 {
 526     struct rm *lev;
 527     struct obj *boulder;
 528     register struct monst *mon;
 529
 530     if (!isok(x, y))
 531         return;
 532     lev = &(levl[x][y]);
 533     /* If the hero's memory of an invisible monster is accurate, we want to
 534      * keep
 535      * him from detecting the same monster over and over again on each turn.
 536      * We must return (so we don't erase the monster).  (We must also, in the
 537      * search function, be sure to skip over previously detected 'I's.)
 538      */
 539     if (glyph_is_invisible(lev->glyph) && m_at(x, y))
 540         return;
 541
 542     /* The hero can't feel non pool locations while under water. */
 543     if (Underwater && !Is_waterlevel(&u.uz) && !is_pool(x, y))
 544         return;
 545
 546     /* Set the seen vector as if the hero had seen it.
 547        It doesn't matter if the hero is levitating or not. */
 548     set_seenv(lev, u.ux, u.uy, x, y);
 549
 550     if (!can_reach_floor(FALSE)) {
 551         /*
 552          * Levitation Rules.  It is assumed that the hero can feel the state
 553          * of the walls around herself and can tell if she is in a corridor,
 554          * room, or doorway.  Boulders are felt because they are large enough.
 555          * Anything else is unknown because the hero can't reach the ground.
 556          * This makes things difficult.
 557          *
 558          * Check (and display) in order:
 559          *
 560          *      + Stone, walls, and closed doors.
 561          *      + Boulders.  [see a boulder before a doorway]
 562          *      + Doors.
 563          *      + Room/water positions
 564          *      + Everything else (hallways!)
 565          */
 566         if (IS_ROCK(lev->typ)
 567             || (IS_DOOR(lev->typ)
 568                 && (lev->doormask & (D_LOCKED | D_CLOSED)))) {
 569             map_background(x, y, 1);
 570         } else if ((boulder = sobj_at(BOULDER, x, y)) != 0) {
 571             map_object(boulder, 1);
 572         } else if (IS_DOOR(lev->typ)) {
 573             map_background(x, y, 1);
 574         } else if (IS_ROOM(lev->typ) || IS_POOL(lev->typ)) {
 575             boolean do_room_glyph;
 576
 577             /*
 578              * An open room or water location.  Normally we wouldn't touch
 579              * this, but we have to get rid of remembered boulder symbols.
 580              * This will only occur in rare occasions when the hero goes
 581              * blind and doesn't find a boulder where expected (something
 582              * came along and picked it up).  We know that there is not a
 583              * boulder at this location.  Show fountains, pools, etc.
 584              * underneath if already seen.  Otherwise, show the appropriate
 585              * floor symbol.
 586              *
 587              * Similarly, if the hero digs a hole in a wall or feels a
 588              * location
 589              * that used to contain an unseen monster.  In these cases,
 590              * there's no reason to assume anything was underneath, so
 591              * just show the appropriate floor symbol.  If something was
 592              * embedded in the wall, the glyph will probably already
 593              * reflect that.  Don't change the symbol in this case.
 594              *
 595              * This isn't quite correct.  If the boulder was on top of some
 596              * other objects they should be seen once the boulder is removed.
 597              * However, we have no way of knowing that what is there now
 598              * was there then.  So we let the hero have a lapse of memory.
 599              * We could also just display what is currently on the top of the
 600              * object stack (if anything).
 601              */
 602             do_room_glyph = FALSE;
 603             if (lev->glyph == objnum_to_glyph(BOULDER)
 604                 || glyph_is_invisible(lev->glyph)) {
 605                 if (lev->typ != ROOM && lev->seenv)
 606                     map_background(x, y, 1);
 607                 else
 608                     do_room_glyph = TRUE;
 609             } else if (lev->glyph >= cmap_to_glyph(S_stone)
 610                        && lev->glyph < cmap_to_glyph(S_darkroom)) {
 611                 do_room_glyph = TRUE;
 612             }
 613             if (do_room_glyph) {
 614                 lev->glyph = (flags.dark_room && iflags.use_color
 615                               && !Is_rogue_level(&u.uz))
 616                                  ? cmap_to_glyph(S_darkroom)
 617                                  : (lev->waslit ? cmap_to_glyph(S_room)
 618                                                 : cmap_to_glyph(S_stone));
 619                 show_glyph(x, y, lev->glyph);
 620             }
 621         } else {
 622             /* We feel it (I think hallways are the only things left). */
 623             map_background(x, y, 1);
 624             /* Corridors are never felt as lit (unless remembered that way) */
 625             /* (lit_corridor only).                                         */
 626             if (lev->typ == CORR && lev->glyph == cmap_to_glyph(S_litcorr)
 627                 && !lev->waslit)
 628                 show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
 629             else if (lev->typ == ROOM && flags.dark_room && iflags.use_color
 630                      && lev->glyph == cmap_to_glyph(S_room))
 631                 show_glyph(x, y, lev->glyph = cmap_to_glyph(S_darkroom));
 632         }
 633     } else {
 634         _map_location(x, y, 1);
 635
 636         if (Punished) {
 637             /*
 638              * A ball or chain is only felt if it is first on the object
 639              * location list.  Otherwise, we need to clear the felt bit ---
 640              * something has been dropped on the ball/chain.  If the bit is
 641              * not cleared, then when the ball/chain is moved it will drop
 642              * the wrong glyph.
 643              */
 644             if (uchain->ox == x && uchain->oy == y) {
 645                 if (level.objects[x][y] == uchain)
 646                     u.bc_felt |= BC_CHAIN;
 647                 else
 648                     u.bc_felt &= ~BC_CHAIN; /* do not feel the chain */
 649             }
 650             if (!carried(uball) && uball->ox == x && uball->oy == y) {
 651                 if (level.objects[x][y] == uball)
 652                     u.bc_felt |= BC_BALL;
 653                 else
 654                     u.bc_felt &= ~BC_BALL; /* do not feel the ball */
 655             }
 656         }
 657
 658         /* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
 659         if (lev->typ == ROOM && lev->glyph == cmap_to_glyph(S_room)
 660             && (!lev->waslit || (flags.dark_room && iflags.use_color)))
 661             show_glyph(x, y, lev->glyph = cmap_to_glyph(
 662                                  flags.dark_room ? S_darkroom : S_stone));
 663         else if (lev->typ == CORR && lev->glyph == cmap_to_glyph(S_litcorr)
 664                  && !lev->waslit)
 665             show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
 666     }
 667     /* draw monster on top if we can sense it */
 668     if ((x != u.ux || y != u.uy) && (mon = m_at(x, y)) && sensemon(mon))
 669         display_monster(x, y, mon,
 670                         (tp_sensemon(mon) || MATCH_WARN_OF_MON(mon))
 671                             ? PHYSICALLY_SEEN
 672                             : DETECTED,
 673                         is_worm_tail(mon));
 674 }
 675
 676 /*
 677  * newsym()
 678  *
 679  * Possibly put a new glyph at the given location.
 680  */
 681 void
 682 newsym(x, y)
 683 register int x, y;
 684 {
 685     register struct monst *mon;
 686     register struct rm *lev = &(levl[x][y]);
 687     register int see_it;
 688     register xchar worm_tail;
 689
 690     if (in_mklev)
 691         return;
 692 #ifdef HANGUPHANDLING
 693     if (program_state.done_hup)
 694         return;
 695 #endif
 696
 697     /* only permit updating the hero when swallowed */
 698     if (u.uswallow) {
 699         if (x == u.ux && y == u.uy)
 700             display_self();
 701         return;
 702     }
 703     if (Underwater && !Is_waterlevel(&u.uz)) {
 704         /* don't do anything unless (x,y) is an adjacent underwater position
 705          */
 706         int dx, dy;
 707         if (!is_pool(x, y))
 708             return;
 709         dx = x - u.ux;
 710         if (dx < 0)
 711             dx = -dx;
 712         dy = y - u.uy;
 713         if (dy < 0)
 714             dy = -dy;
 715         if (dx > 1 || dy > 1)
 716             return;
 717     }
 718
 719     /* Can physically see the location. */
 720     if (cansee(x, y)) {
 721         NhRegion *reg = visible_region_at(x, y);
 722         /*
 723          * Don't use templit here:  E.g.
 724          *
 725          *      lev->waslit = !!(lev->lit || templit(x,y));
 726          *
 727          * Otherwise we have the "light pool" problem, where non-permanently
 728          * lit areas just out of sight stay remembered as lit.  They should
 729          * re-darken.
 730          *
 731          * Perhaps ALL areas should revert to their "unlit" look when
 732          * out of sight.
 733          */
 734         lev->waslit = (lev->lit != 0); /* remember lit condition */
 735
 736         /* normal region shown only on accessible positions, but poison clouds
 737          * also shown above lava, pools and moats.
 738          */
 739         if (reg != NULL && (ACCESSIBLE(lev->typ)
 740                             || (reg->glyph == cmap_to_glyph(S_poisoncloud)
 741                                 && (lev->typ == LAVAPOOL || lev->typ == POOL
 742                                     || lev->typ == MOAT)))) {
 743             show_region(reg, x, y);
 744             return;
 745         }
 746         if (x == u.ux && y == u.uy) {
 747             if (canspotself()) {
 748                 _map_location(x, y, 0); /* map *under* self */
 749                 display_self();
 750             } else
 751                 /* we can see what is there */
 752                 _map_location(x, y, 1);
 753         } else {
 754             mon = m_at(x, y);
 755             worm_tail = is_worm_tail(mon);
 756             see_it =
 757                 mon && (worm_tail ? (!mon->minvis || See_invisible)
 758                                   : (mon_visible(mon)) || tp_sensemon(mon)
 759                                         || MATCH_WARN_OF_MON(mon));
 760             if (mon && (see_it || (!worm_tail && Detect_monsters))) {
 761                 if (mon->mtrapped) {
 762                     struct trap *trap = t_at(x, y);
 763                     int tt = trap ? trap->ttyp : NO_TRAP;
 764
 765                     /* if monster is in a physical trap, you see the trap too
 766                      */
 767                     if (tt == BEAR_TRAP || tt == PIT || tt == SPIKED_PIT
 768                         || tt == WEB) {
 769                         trap->tseen = TRUE;
 770                     }
 771                 }
 772                 _map_location(x, y, 0); /* map under the monster */
 773                 /* also gets rid of any invisibility glyph */
 774                 display_monster(x, y, mon,
 775                                 see_it ? PHYSICALLY_SEEN : DETECTED,
 776                                 worm_tail);
 777             } else if (mon && mon_warning(mon) && !is_worm_tail(mon)) {
 778                 display_warning(mon);
 779             } else if (glyph_is_invisible(levl[x][y].glyph)) {
 780                 map_invisible(x, y);
 781             } else
 782                 _map_location(x, y, 1); /* map the location */\
 783         }
 784
 785     /* Can't see the location. */
 786     } else {
 787         if (x == u.ux && y == u.uy) {
 788             feel_location(u.ux, u.uy); /* forces an update */
 789
 790             if (canspotself())
 791                 display_self();
 792         } else if ((mon = m_at(x, y))
 793                    && ((see_it = (tp_sensemon(mon) || MATCH_WARN_OF_MON(mon)
 794                                   || (see_with_infrared(mon)
 795                                       && mon_visible(mon))))
 796                        || Detect_monsters)) {
 797             /* Monsters are printed every time. */
 798             /* This also gets rid of any invisibility glyph */
 799             display_monster(x, y, mon, see_it ? 0 : DETECTED,
 800                             is_worm_tail(mon) ? TRUE : FALSE);
 801         } else if ((mon = m_at(x, y)) && mon_warning(mon)
 802                    && !is_worm_tail(mon)) {
 803             display_warning(mon);
 804         }
 805
 806         /*
 807          * If the location is remembered as being both dark (waslit is false)
 808          * and lit (glyph is a lit room or lit corridor) then it was either:
 809          *
 810          *      (1) A dark location that the hero could see through night
 811          *          vision.
 812          *
 813          *      (2) Darkened while out of the hero's sight.  This can happen
 814          *          when cursed scroll of light is read.
 815          *
 816          * In either case, we have to manually correct the hero's memory to
 817          * match waslit.  Deciding when to change waslit is non-trivial.
 818          *
 819          *  Note:  If flags.lit_corridor is set, then corridors act like room
 820          *         squares.  That is, they light up if in night vision range.
 821          *         If flags.lit_corridor is not set, then corridors will
 822          *         remain dark unless lit by a light spell and may darken
 823          *         again, as discussed above.
 824          *
 825          * These checks and changes must be here and not in back_to_glyph().
 826          * They are dependent on the position being out of sight.
 827          */
 828         else if (Is_rogue_level(&u.uz)) {
 829             if (lev->glyph == cmap_to_glyph(S_litcorr) && lev->typ == CORR)
 830                 show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
 831             else if (lev->glyph == cmap_to_glyph(S_room) && lev->typ == ROOM
 832                      && !lev->waslit)
 833                 show_glyph(x, y, lev->glyph = cmap_to_glyph(S_stone));
 834             else
 835                 goto show_mem;
 836         }
 837         else if (!lev->waslit || (flags.dark_room && iflags.use_color)) {
 838             if (lev->glyph == cmap_to_glyph(S_litcorr) && lev->typ == CORR)
 839                 show_glyph(x, y, lev->glyph = cmap_to_glyph(S_corr));
 840             else if (lev->glyph == cmap_to_glyph(S_room) && lev->typ == ROOM)
 841                 show_glyph(x, y, lev->glyph = cmap_to_glyph(DARKROOMSYM));
 842             else
 843                 goto show_mem;
 844         } else {
 845         show_mem:
 846             show_glyph(x, y, lev->glyph);
 847         }
 848     }
 849 }
 850
 851 #undef is_worm_tail
 852
 853 /*
 854  * shieldeff()
 855  *
 856  * Put magic shield pyrotechnics at the given location.  This *could* be
 857  * pulled into a platform dependent routine for fancier graphics if desired.
 858  */
 859 void
 860 shieldeff(x, y)
 861 xchar x, y;
 862 {
 863     register int i;
 864
 865     if (!flags.sparkle)
 866         return;
 867     if (cansee(x, y)) { /* Don't see anything if can't see the location */
 868         for (i = 0; i < SHIELD_COUNT; i++) {
 869             show_glyph(x, y, cmap_to_glyph(shield_static[i]));
 870             flush_screen(1); /* make sure the glyph shows up */
 871             delay_output();
 872         }
 873         newsym(x, y); /* restore the old information */
 874     }
 875 }
 876
 877 /*
 878  * tmp_at()
 879  *
 880  * Temporarily place glyphs on the screen.  Do not call delay_output().  It
 881  * is up to the caller to decide if it wants to wait [presently, everyone
 882  * but explode() wants to delay].
 883  *
 884  * Call:
 885  *      (DISP_BEAM,   glyph)    open, initialize glyph
 886  *      (DISP_FLASH,  glyph)    open, initialize glyph
 887  *      (DISP_ALWAYS, glyph)    open, initialize glyph
 888  *      (DISP_CHANGE, glyph)    change glyph
 889  *      (DISP_END,    0)        close & clean up (second argument doesn't
 890  *                              matter)
 891  *      (DISP_FREEMEM, 0)       only used to prevent memory leak during
 892  *                              exit)
 893  *      (x, y)                  display the glyph at the location
 894  *
 895  * DISP_BEAM  - Display the given glyph at each location, but do not erase
 896  *              any until the close call.
 897  * DISP_FLASH - Display the given glyph at each location, but erase the
 898  *              previous location's glyph.
 899  * DISP_ALWAYS- Like DISP_FLASH, but vision is not taken into account.
 900  */
 901
 902 #define TMP_AT_MAX_GLYPHS (COLNO * 2)
 903
 904 static struct tmp_glyph {
 905     coord saved[TMP_AT_MAX_GLYPHS]; /* previously updated positions */
 906     int sidx;                       /* index of next unused slot in saved[] */
 907     int style; /* either DISP_BEAM or DISP_FLASH or DISP_ALWAYS */
 908     int glyph; /* glyph to use when printing */
 909     struct tmp_glyph *prev;
 910 } tgfirst;
 911
 912 void
 913 tmp_at(x, y)
 914 int x, y;
 915 {
 916     static struct tmp_glyph *tglyph = (struct tmp_glyph *) 0;
 917     struct tmp_glyph *tmp;
 918
 919     switch (x) {
 920     case DISP_BEAM:
 921     case DISP_ALL:
 922     case DISP_FLASH:
 923     case DISP_ALWAYS:
 924         if (!tglyph)
 925             tmp = &tgfirst;
 926         else /* nested effect; we need dynamic memory */
 927             tmp = (struct tmp_glyph *) alloc(sizeof(struct tmp_glyph));
 928         tmp->prev = tglyph;
 929         tglyph = tmp;
 930         tglyph->sidx = 0;
 931         tglyph->style = x;
 932         tglyph->glyph = y;
 933         flush_screen(0); /* flush buffered glyphs */
 934         return;
 935
 936     case DISP_FREEMEM: /* in case game ends with tmp_at() in progress */
 937         while (tglyph) {
 938             tmp = tglyph->prev;
 939             if (tglyph != &tgfirst)
 940                 free((genericptr_t) tglyph);
 941             tglyph = tmp;
 942         }
 943         return;
 944
 945     default:
 946         break;
 947     }
 948
 949     if (!tglyph)
 950         panic("tmp_at: tglyph not initialized");
 951
 952     switch (x) {
 953     case DISP_CHANGE:
 954         tglyph->glyph = y;
 955         break;
 956
 957     case DISP_END:
 958         if (tglyph->style == DISP_BEAM || tglyph->style == DISP_ALL) {
 959             register int i;
 960
 961             /* Erase (reset) from source to end */
 962             for (i = 0; i < tglyph->sidx; i++)
 963                 newsym(tglyph->saved[i].x, tglyph->saved[i].y);
 964         } else {              /* DISP_FLASH or DISP_ALWAYS */
 965             if (tglyph->sidx) /* been called at least once */
 966                 newsym(tglyph->saved[0].x, tglyph->saved[0].y);
 967         }
 968         /* tglyph->sidx = 0; -- about to be freed, so not necessary */
 969         tmp = tglyph->prev;
 970         if (tglyph != &tgfirst)
 971             free((genericptr_t) tglyph);
 972         tglyph = tmp;
 973         break;
 974
 975     default: /* do it */
 976         if (!isok(x, y))
 977             break;
 978         if (tglyph->style == DISP_BEAM || tglyph->style == DISP_ALL) {
 979             if (tglyph->style != DISP_ALL && !cansee(x, y))
 980                 break;
 981             if (tglyph->sidx >= TMP_AT_MAX_GLYPHS)
 982                 break; /* too many locations */
 983             /* save pos for later erasing */
 984             tglyph->saved[tglyph->sidx].x = x;
 985             tglyph->saved[tglyph->sidx].y = y;
 986             tglyph->sidx += 1;
 987         } else {                /* DISP_FLASH/ALWAYS */
 988             if (tglyph->sidx) { /* not first call, so reset previous pos */
 989                 newsym(tglyph->saved[0].x, tglyph->saved[0].y);
 990                 tglyph->sidx = 0; /* display is presently up to date */
 991             }
 992             if (!cansee(x, y) && tglyph->style != DISP_ALWAYS)
 993                 break;
 994             tglyph->saved[0].x = x;
 995             tglyph->saved[0].y = y;
 996             tglyph->sidx = 1;
 997         }
 998
 999         show_glyph(x, y, tglyph->glyph); /* show it */
1000         flush_screen(0);                 /* make sure it shows up */
1001         break;
1002     } /* end case */
1003 }
1004
1005 /*
1006  * swallowed()
1007  *
1008  * The hero is swallowed.  Show a special graphics sequence for this.  This
1009  * bypasses all of the display routines and messes with buffered screen
1010  * directly.  This method works because both vision and display check for
1011  * being swallowed.
1012  */
1013 void
1014 swallowed(first)
1015 int first;
1016 {
1017     static xchar lastx, lasty; /* last swallowed position */
1018     int swallower, left_ok, rght_ok;
1019
1020     if (first)
1021         cls();
1022     else {
1023         register int x, y;
1024
1025         /* Clear old location */
1026         for (y = lasty - 1; y <= lasty + 1; y++)
1027             for (x = lastx - 1; x <= lastx + 1; x++)
1028                 if (isok(x, y))
1029                     show_glyph(x, y, cmap_to_glyph(S_stone));
1030     }
1031
1032     swallower = monsndx(u.ustuck->data);
1033     /* assume isok(u.ux,u.uy) */
1034     left_ok = isok(u.ux - 1, u.uy);
1035     rght_ok = isok(u.ux + 1, u.uy);
1036     /*
1037      *  Display the hero surrounded by the monster's stomach.
1038      */
1039     if (isok(u.ux, u.uy - 1)) {
1040         if (left_ok)
1041             show_glyph(u.ux - 1, u.uy - 1,
1042                        swallow_to_glyph(swallower, S_sw_tl));
1043         show_glyph(u.ux, u.uy - 1, swallow_to_glyph(swallower, S_sw_tc));
1044         if (rght_ok)
1045             show_glyph(u.ux + 1, u.uy - 1,
1046                        swallow_to_glyph(swallower, S_sw_tr));
1047     }
1048
1049     if (left_ok)
1050         show_glyph(u.ux - 1, u.uy, swallow_to_glyph(swallower, S_sw_ml));
1051     display_self();
1052     if (rght_ok)
1053         show_glyph(u.ux + 1, u.uy, swallow_to_glyph(swallower, S_sw_mr));
1054
1055     if (isok(u.ux, u.uy + 1)) {
1056         if (left_ok)
1057             show_glyph(u.ux - 1, u.uy + 1,
1058                        swallow_to_glyph(swallower, S_sw_bl));
1059         show_glyph(u.ux, u.uy + 1, swallow_to_glyph(swallower, S_sw_bc));
1060         if (rght_ok)
1061             show_glyph(u.ux + 1, u.uy + 1,
1062                        swallow_to_glyph(swallower, S_sw_br));
1063     }
1064
1065     /* Update the swallowed position. */
1066     lastx = u.ux;
1067     lasty = u.uy;
1068 }
1069
1070 /*
1071  * under_water()
1072  *
1073  * Similar to swallowed() in operation.  Shows hero when underwater
1074  * except when in water level.  Special routines exist for that.
1075  */
1076 void
1077 under_water(mode)
1078 int mode;
1079 {
1080     static xchar lastx, lasty;
1081     static boolean dela;
1082     register int x, y;
1083
1084     /* swallowing has a higher precedence than under water */
1085     if (Is_waterlevel(&u.uz) || u.uswallow)
1086         return;
1087
1088     /* full update */
1089     if (mode == 1 || dela) {
1090         cls();
1091         dela = FALSE;
1092
1093     /* delayed full update */
1094     } else if (mode == 2) {
1095         dela = TRUE;
1096         return;
1097
1098     /* limited update */
1099     } else {
1100         for (y = lasty - 1; y <= lasty + 1; y++)
1101             for (x = lastx - 1; x <= lastx + 1; x++)
1102                 if (isok(x, y))
1103                     show_glyph(x, y, cmap_to_glyph(S_stone));
1104     }
1105
1106     for (x = u.ux - 1; x <= u.ux + 1; x++)
1107         for (y = u.uy - 1; y <= u.uy + 1; y++)
1108             if (isok(x, y) && is_pool(x, y)) {
1109                 if (Blind && !(x == u.ux && y == u.uy))
1110                     show_glyph(x, y, cmap_to_glyph(S_stone));
1111                 else
1112                     newsym(x, y);
1113             }
1114     lastx = u.ux;
1115     lasty = u.uy;
1116 }
1117
1118 /*
1119  *      under_ground()
1120  *
1121  *      Very restricted display.  You can only see yourself.
1122  */
1123 void
1124 under_ground(mode)
1125 int mode;
1126 {
1127     static boolean dela;
1128
1129     /* swallowing has a higher precedence than under ground */
1130     if (u.uswallow)
1131         return;
1132
1133     /* full update */
1134     if (mode == 1 || dela) {
1135         cls();
1136         dela = FALSE;
1137
1138     /* delayed full update */
1139     } else if (mode == 2) {
1140         dela = TRUE;
1141         return;
1142
1143     /* limited update */
1144     } else {
1145         newsym(u.ux, u.uy);
1146     }
1147 }
1148
1149 /* =========================================================================
1150  */
1151
1152 /*
1153  * Loop through all of the monsters and update them.  Called when:
1154  *      + going blind & telepathic
1155  *      + regaining sight & telepathic
1156  *      + getting and losing infravision
1157  *      + hallucinating
1158  *      + doing a full screen redraw
1159  *      + see invisible times out or a ring of see invisible is taken off
1160  *      + when a potion of see invisible is quaffed or a ring of see
1161  *        invisible is put on
1162  *      + gaining telepathy when blind [givit() in eat.c, pleased() in pray.c]
1163  *      + losing telepathy while blind [xkilled() in mon.c, attrcurse() in
1164  *        sit.c]
1165  */
1166 void
1167 see_monsters()
1168 {
1169     register struct monst *mon;
1170     int new_warn_obj_cnt = 0;
1171
1172     if (defer_see_monsters)
1173         return;
1174
1175     for (mon = fmon; mon; mon = mon->nmon) {
1176         if (DEADMONSTER(mon))
1177             continue;
1178         newsym(mon->mx, mon->my);
1179         if (mon->wormno)
1180             see_wsegs(mon);
1181         if (Warn_of_mon && (context.warntype.obj & mon->data->mflags2) != 0L)
1182             new_warn_obj_cnt++;
1183     }
1184     /*
1185      * Make Sting glow blue or stop glowing if required.
1186      */
1187     if (new_warn_obj_cnt != warn_obj_cnt) {
1188         Sting_effects(new_warn_obj_cnt);
1189         warn_obj_cnt = new_warn_obj_cnt;
1190     }
1191
1192     /* when mounted, hero's location gets caught by monster loop */
1193     if (!u.usteed)
1194         newsym(u.ux, u.uy);
1195 }
1196
1197 /*
1198  * Block/unblock light depending on what a mimic is mimicing and if it's
1199  * invisible or not.  Should be called only when the state of See_invisible
1200  * changes.
1201  */
1202 void
1203 set_mimic_blocking()
1204 {
1205     register struct monst *mon;
1206
1207     for (mon = fmon; mon; mon = mon->nmon) {
1208         if (DEADMONSTER(mon))
1209             continue;
1210         if (mon->minvis && is_lightblocker_mappear(mon)) {
1211             if (See_invisible)
1212                 block_point(mon->mx, mon->my);
1213             else
1214                 unblock_point(mon->mx, mon->my);
1215         }
1216     }
1217 }
1218
1219 /*
1220  * Loop through all of the object *locations* and update them.  Called when
1221  *      + hallucinating.
1222  */
1223 void
1224 see_objects()
1225 {
1226     register struct obj *obj;
1227     for (obj = fobj; obj; obj = obj->nobj)
1228         if (vobj_at(obj->ox, obj->oy) == obj)
1229             newsym(obj->ox, obj->oy);
1230 }
1231
1232 /*
1233  * Update hallucinated traps.
1234  */
1235 void
1236 see_traps()
1237 {
1238     struct trap *trap;
1239     int glyph;
1240
1241     for (trap = ftrap; trap; trap = trap->ntrap) {
1242         glyph = glyph_at(trap->tx, trap->ty);
1243         if (glyph_is_trap(glyph))
1244             newsym(trap->tx, trap->ty);
1245     }
1246 }
1247
1248 /*
1249  * Put the cursor on the hero.  Flush all accumulated glyphs before doing it.
1250  */
1251 void
1252 curs_on_u()
1253 {
1254     flush_screen(1); /* Flush waiting glyphs & put cursor on hero */
1255 }
1256
1257 int
1258 doredraw()
1259 {
1260     docrt();
1261     return 0;
1262 }
1263
1264 void
1265 docrt()
1266 {
1267     register int x, y;
1268     register struct rm *lev;
1269
1270     if (!u.ux)
1271         return; /* display isn't ready yet */
1272
1273     if (u.uswallow) {
1274         swallowed(1);
1275         return;
1276     }
1277     if (Underwater && !Is_waterlevel(&u.uz)) {
1278         under_water(1);
1279         return;
1280     }
1281     if (u.uburied) {
1282         under_ground(1);
1283         return;
1284     }
1285
1286     /* shut down vision */
1287     vision_recalc(2);
1288
1289     /*
1290      * This routine assumes that cls() does the following:
1291      *      + fills the physical screen with the symbol for rock
1292      *      + clears the glyph buffer
1293      */
1294     cls();
1295
1296     /* display memory */
1297     for (x = 1; x < COLNO; x++) {
1298         lev = &levl[x][0];
1299         for (y = 0; y < ROWNO; y++, lev++)
1300             if (lev->glyph != cmap_to_glyph(S_stone))
1301                 show_glyph(x, y, lev->glyph);
1302     }
1303
1304     /* see what is to be seen */
1305     vision_recalc(0);
1306
1307     /* overlay with monsters */
1308     see_monsters();
1309
1310     context.botlx = 1; /* force a redraw of the bottom line */
1311 }
1312
1313 /* =========================================================================
1314  */
1315 /* Glyph Buffering (3rd screen) ============================================
1316  */
1317
1318 typedef struct {
1319     xchar new; /* perhaps move this bit into the rm structure. */
1320     int glyph;
1321 } gbuf_entry;
1322
1323 static gbuf_entry gbuf[ROWNO][COLNO];
1324 static char gbuf_start[ROWNO];
1325 static char gbuf_stop[ROWNO];
1326
1327 /* FIXME: This is a dirty hack, because newsym() doesn't distinguish
1328  * between object piles and single objects, it doesn't mark the location
1329  * for update. */
1330 void
1331 newsym_force(x, y)
1332 register int x, y;
1333 {
1334     newsym(x,y);
1335     gbuf[y][x].new = 1;
1336     if (gbuf_start[y] > x)
1337         gbuf_start[y] = x;
1338     if (gbuf_stop[y] < x)
1339         gbuf_stop[y] = x;
1340 }
1341
1342 /*
1343  * Store the glyph in the 3rd screen for later flushing.
1344  */
1345 void
1346 show_glyph(x, y, glyph)
1347 int x, y, glyph;
1348 {
1349     /*
1350      * Check for bad positions and glyphs.
1351      */
1352     if (!isok(x, y)) {
1353         const char *text;
1354         int offset;
1355
1356         /* column 0 is invalid, but it's often used as a flag, so ignore it */
1357         if (x == 0)
1358             return;
1359
1360         /*
1361          *  This assumes an ordering of the offsets.  See display.h for
1362          *  the definition.
1363          */
1364
1365         if (glyph >= GLYPH_WARNING_OFF
1366             && glyph < GLYPH_STATUE_OFF) { /* a warning */
1367             text = "warning";
1368             offset = glyph - GLYPH_WARNING_OFF;
1369         } else if (glyph >= GLYPH_SWALLOW_OFF) { /* swallow border */
1370             text = "swallow border";
1371             offset = glyph - GLYPH_SWALLOW_OFF;
1372         } else if (glyph >= GLYPH_ZAP_OFF) { /* zap beam */
1373             text = "zap beam";
1374             offset = glyph - GLYPH_ZAP_OFF;
1375         } else if (glyph >= GLYPH_EXPLODE_OFF) { /* explosion */
1376             text = "explosion";
1377             offset = glyph - GLYPH_EXPLODE_OFF;
1378         } else if (glyph >= GLYPH_CMAP_OFF) { /* cmap */
1379             text = "cmap_index";
1380             offset = glyph - GLYPH_CMAP_OFF;
1381         } else if (glyph >= GLYPH_OBJ_OFF) { /* object */
1382             text = "object";
1383             offset = glyph - GLYPH_OBJ_OFF;
1384         } else if (glyph >= GLYPH_RIDDEN_OFF) { /* ridden mon */
1385             text = "ridden mon";
1386             offset = glyph - GLYPH_RIDDEN_OFF;
1387         } else if (glyph >= GLYPH_BODY_OFF) { /* a corpse */
1388             text = "corpse";
1389             offset = glyph - GLYPH_BODY_OFF;
1390         } else if (glyph >= GLYPH_DETECT_OFF) { /* detected mon */
1391             text = "detected mon";
1392             offset = glyph - GLYPH_DETECT_OFF;
1393         } else if (glyph >= GLYPH_INVIS_OFF) { /* invisible mon */
1394             text = "invisible mon";
1395             offset = glyph - GLYPH_INVIS_OFF;
1396         } else if (glyph >= GLYPH_PET_OFF) { /* a pet */
1397             text = "pet";
1398             offset = glyph - GLYPH_PET_OFF;
1399         } else { /* a monster */
1400             text = "monster";
1401             offset = glyph;
1402         }
1403
1404         impossible("show_glyph:  bad pos %d %d with glyph %d [%s %d].", x, y,
1405                    glyph, text, offset);
1406         return;
1407     }
1408
1409     if (glyph >= MAX_GLYPH) {
1410         impossible("show_glyph:  bad glyph %d [max %d] at (%d,%d).", glyph,
1411                    MAX_GLYPH, x, y);
1412         return;
1413     }
1414
1415     if (gbuf[y][x].glyph != glyph || iflags.use_background_glyph) {
1416         gbuf[y][x].glyph = glyph;
1417         gbuf[y][x].new = 1;
1418         if (gbuf_start[y] > x)
1419             gbuf_start[y] = x;
1420         if (gbuf_stop[y] < x)
1421             gbuf_stop[y] = x;
1422     }
1423 }
1424
1425 /*
1426  * Reset the changed glyph borders so that none of the 3rd screen has
1427  * changed.
1428  */
1429 #define reset_glyph_bbox()             \
1430     {                                  \
1431         int i;                         \
1432                                        \
1433         for (i = 0; i < ROWNO; i++) {  \
1434             gbuf_start[i] = COLNO - 1; \
1435             gbuf_stop[i] = 0;          \
1436         }                              \
1437     }
1438
1439 static gbuf_entry nul_gbuf = { 0, cmap_to_glyph(S_stone) };
1440 /*
1441  * Turn the 3rd screen into stone.
1442  */
1443 void
1444 clear_glyph_buffer()
1445 {
1446     register int x, y;
1447     register gbuf_entry *gptr;
1448
1449     for (y = 0; y < ROWNO; y++) {
1450         gptr = &gbuf[y][0];
1451         for (x = COLNO; x; x--) {
1452             *gptr++ = nul_gbuf;
1453         }
1454     }
1455     reset_glyph_bbox();
1456 }
1457
1458 /*
1459  * Assumes that the indicated positions are filled with S_stone glyphs.
1460  */
1461 void
1462 row_refresh(start, stop, y)
1463 int start, stop, y;
1464 {
1465     register int x;
1466
1467     for (x = start; x <= stop; x++)
1468         if (gbuf[y][x].glyph != cmap_to_glyph(S_stone))
1469             print_glyph(WIN_MAP, x, y, gbuf[y][x].glyph, get_bk_glyph(x,y));
1470 }
1471
1472 void
1473 cls()
1474 {
1475     static boolean in_cls = 0;
1476
1477     if (in_cls)
1478         return;
1479     in_cls = TRUE;
1480     display_nhwindow(WIN_MESSAGE, FALSE); /* flush messages */
1481     context.botlx = 1;                    /* force update of botl window */
1482     clear_nhwindow(WIN_MAP);              /* clear physical screen */
1483
1484     clear_glyph_buffer(); /* this is sort of an extra effort, but OK */
1485     in_cls = FALSE;
1486 }
1487
1488 /*
1489  * Synch the third screen with the display.
1490  */
1491 void
1492 flush_screen(cursor_on_u)
1493 int cursor_on_u;
1494 {
1495     /* Prevent infinite loops on errors:
1496      *      flush_screen->print_glyph->impossible->pline->flush_screen
1497      */
1498     static boolean flushing = 0;
1499     static boolean delay_flushing = 0;
1500     register int x, y;
1501
1502     if (cursor_on_u == -1)
1503         delay_flushing = !delay_flushing;
1504     if (delay_flushing)
1505         return;
1506     if (flushing)
1507         return; /* if already flushing then return */
1508     flushing = 1;
1509 #ifdef HANGUPHANDLING
1510     if (program_state.done_hup)
1511         return;
1512 #endif
1513
1514     for (y = 0; y < ROWNO; y++) {
1515         register gbuf_entry *gptr = &gbuf[y][x = gbuf_start[y]];
1516         for (; x <= gbuf_stop[y]; gptr++, x++)
1517             if (gptr->new) {
1518                 print_glyph(WIN_MAP, x, y, gptr->glyph, get_bk_glyph(x, y));
1519                 gptr->new = 0;
1520             }
1521     }
1522
1523     if (cursor_on_u)
1524         curs(WIN_MAP, u.ux, u.uy); /* move cursor to the hero */
1525     display_nhwindow(WIN_MAP, FALSE);
1526     reset_glyph_bbox();
1527     flushing = 0;
1528     if (context.botl || context.botlx)
1529         bot();
1530 }
1531
1532 /* =========================================================================
1533  */
1534
1535 /*
1536  * back_to_glyph()
1537  *
1538  * Use the information in the rm structure at the given position to create
1539  * a glyph of a background.
1540  *
1541  * I had to add a field in the rm structure (horizontal) so that we knew
1542  * if open doors and secret doors were horizontal or vertical.  Previously,
1543  * the screen symbol had the horizontal/vertical information set at
1544  * level generation time.
1545  *
1546  * I used the 'ladder' field (really doormask) for deciding if stairwells
1547  * were up or down.  I didn't want to check the upstairs and dnstairs
1548  * variables.
1549  */
1550 int
1551 back_to_glyph(x, y)
1552 xchar x, y;
1553 {
1554     int idx;
1555     struct rm *ptr = &(levl[x][y]);
1556
1557     switch (ptr->typ) {
1558     case SCORR:
1559     case STONE:
1560         idx = level.flags.arboreal ? S_tree : S_stone;
1561         break;
1562     case ROOM:
1563         idx = S_room;
1564         break;
1565     case CORR:
1566         idx = (ptr->waslit || flags.lit_corridor) ? S_litcorr : S_corr;
1567         break;
1568     case HWALL:
1569     case VWALL:
1570     case TLCORNER:
1571     case TRCORNER:
1572     case BLCORNER:
1573     case BRCORNER:
1574     case CROSSWALL:
1575     case TUWALL:
1576     case TDWALL:
1577     case TLWALL:
1578     case TRWALL:
1579     case SDOOR:
1580         idx = ptr->seenv ? wall_angle(ptr) : S_stone;
1581         break;
1582     case DOOR:
1583         if (ptr->doormask) {
1584             if (ptr->doormask & D_BROKEN)
1585                 idx = S_ndoor;
1586             else if (ptr->doormask & D_ISOPEN)
1587                 idx = (ptr->horizontal) ? S_hodoor : S_vodoor;
1588             else /* else is closed */
1589                 idx = (ptr->horizontal) ? S_hcdoor : S_vcdoor;
1590         } else
1591             idx = S_ndoor;
1592         break;
1593     case IRONBARS:
1594         idx = S_bars;
1595         break;
1596     case TREE:
1597         idx = S_tree;
1598         break;
1599     case POOL:
1600     case MOAT:
1601         idx = S_pool;
1602         break;
1603     case STAIRS:
1604         idx = (ptr->ladder & LA_DOWN) ? S_dnstair : S_upstair;
1605         break;
1606     case LADDER:
1607         idx = (ptr->ladder & LA_DOWN) ? S_dnladder : S_upladder;
1608         break;
1609     case FOUNTAIN:
1610         idx = S_fountain;
1611         break;
1612     case SINK:
1613         idx = S_sink;
1614         break;
1615     case ALTAR:
1616         idx = S_altar;
1617         break;
1618     case GRAVE:
1619         idx = S_grave;
1620         break;
1621     case THRONE:
1622         idx = S_throne;
1623         break;
1624     case LAVAPOOL:
1625         idx = S_lava;
1626         break;
1627     case ICE:
1628         idx = S_ice;
1629         break;
1630     case AIR:
1631         idx = S_air;
1632         break;
1633     case CLOUD:
1634         idx = S_cloud;
1635         break;
1636     case WATER:
1637         idx = S_water;
1638         break;
1639     case DBWALL:
1640         idx = (ptr->horizontal) ? S_hcdbridge : S_vcdbridge;
1641         break;
1642     case DRAWBRIDGE_UP:
1643         switch (ptr->drawbridgemask & DB_UNDER) {
1644         case DB_MOAT:
1645             idx = S_pool;
1646             break;
1647         case DB_LAVA:
1648             idx = S_lava;
1649             break;
1650         case DB_ICE:
1651             idx = S_ice;
1652             break;
1653         case DB_FLOOR:
1654             idx = S_room;
1655             break;
1656         default:
1657             impossible("Strange db-under: %d",
1658                        ptr->drawbridgemask & DB_UNDER);
1659             idx = S_room; /* something is better than nothing */
1660             break;
1661         }
1662         break;
1663     case DRAWBRIDGE_DOWN:
1664         idx = (ptr->horizontal) ? S_hodbridge : S_vodbridge;
1665         break;
1666     default:
1667         impossible("back_to_glyph:  unknown level type [ = %d ]", ptr->typ);
1668         idx = S_room;
1669         break;
1670     }
1671
1672     return cmap_to_glyph(idx);
1673 }
1674
1675 /*
1676  * swallow_to_glyph()
1677  *
1678  * Convert a monster number and a swallow location into the correct glyph.
1679  * If you don't want a patchwork monster while hallucinating, decide on
1680  * a random monster in swallowed() and don't use what_mon() here.
1681  */
1682 STATIC_OVL int
1683 swallow_to_glyph(mnum, loc)
1684 int mnum;
1685 int loc;
1686 {
1687     if (loc < S_sw_tl || S_sw_br < loc) {
1688         impossible("swallow_to_glyph: bad swallow location");
1689         loc = S_sw_br;
1690     }
1691     return ((int) (what_mon(mnum) << 3) | (loc - S_sw_tl)) + GLYPH_SWALLOW_OFF;
1692 }
1693
1694 /*
1695  * zapdir_to_glyph()
1696  *
1697  * Change the given zap direction and beam type into a glyph.  Each beam
1698  * type has four glyphs, one for each of the symbols below.  The order of
1699  * the zap symbols [0-3] as defined in rm.h are:
1700  *
1701  *      |  S_vbeam      ( 0, 1) or ( 0,-1)
1702  *      -  S_hbeam      ( 1, 0) or (-1, 0)
1703  *      \  S_lslant     ( 1, 1) or (-1,-1)
1704  *      /  S_rslant     (-1, 1) or ( 1,-1)
1705  */
1706 int
1707 zapdir_to_glyph(dx, dy, beam_type)
1708 register int dx, dy;
1709 int beam_type;
1710 {
1711     if (beam_type >= NUM_ZAP) {
1712         impossible("zapdir_to_glyph:  illegal beam type");
1713         beam_type = 0;
1714     }
1715     dx = (dx == dy) ? 2 : (dx && dy) ? 3 : dx ? 1 : 0;
1716
1717     return ((int) ((beam_type << 2) | dx)) + GLYPH_ZAP_OFF;
1718 }
1719
1720 /*
1721  * Utility routine for dowhatis() used to find out the glyph displayed at
1722  * the location.  This isn't necessarily the same as the glyph in the levl
1723  * structure, so we must check the "third screen".
1724  */
1725 int
1726 glyph_at(x, y)
1727 xchar x, y;
1728 {
1729     if (x < 0 || y < 0 || x >= COLNO || y >= ROWNO)
1730         return cmap_to_glyph(S_room); /* XXX */
1731     return gbuf[y][x].glyph;
1732 }
1733
1734 /*
1735  * This will be used to get the glyph for the background so that
1736  * it can potentially be merged into graphical window ports
1737  * to improve the appearance of stuff on dark room
1738  * squares and the plane of air etc.
1739  *
1740  * Until that is working correctly in the branch, however, for now
1741  * we just return NO_GLYPH as an indicator to ignore it.
1742  */
1743
1744 STATIC_OVL int
1745 get_bk_glyph(x,y)
1746 xchar x, y;
1747 {
1748     int idx, bkglyph = NO_GLYPH;
1749     struct rm *lev = &levl[x][y];
1750
1751     if (iflags.use_background_glyph && lev->seenv != 0
1752             && gbuf[y][x].glyph != cmap_to_glyph(S_stone)) {
1753         switch (lev->typ) {
1754         case SCORR:
1755         case STONE:
1756             idx = level.flags.arboreal ? S_tree : S_stone;
1757             break;
1758         case ROOM:
1759            idx = S_room;
1760            break;
1761         case CORR:
1762            idx = (lev->waslit || flags.lit_corridor) ? S_litcorr : S_corr;
1763            break;
1764         case ICE:
1765            idx = S_ice;
1766            break;
1767         case AIR:
1768            idx = S_air;
1769            break;
1770         case CLOUD:
1771            idx = S_cloud;
1772            break;
1773         case POOL:
1774         case MOAT:
1775            idx = S_pool;
1776            break;
1777         case WATER:
1778            idx = S_water;
1779            break;
1780         case LAVAPOOL:
1781            idx = S_lava;
1782            break;
1783         default:
1784            idx = S_room;
1785            break;
1786         }
1787
1788         if (!cansee(x, y) && (!lev->waslit || flags.dark_room)) {
1789             /* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
1790             if (lev->typ == CORR && idx == S_litcorr)
1791                 idx = S_corr;
1792             else if (idx == S_room)
1793                 idx = (flags.dark_room && iflags.use_color)
1794                          ? DARKROOMSYM : S_stone;
1795         }
1796
1797         if (idx != S_room)
1798             bkglyph = cmap_to_glyph(idx);
1799     }
1800     return bkglyph;
1801 }
1802
1803 /* -------------------------------------------------------------------------
1804  */
1805 /* Wall Angle --------------------------------------------------------------
1806  */
1807
1808 #ifdef WA_VERBOSE
1809
1810 static const char *FDECL(type_to_name, (int));
1811 static void FDECL(error4, (int, int, int, int, int, int));
1812
1813 static int bad_count[MAX_TYPE]; /* count of positions flagged as bad */
1814 static const char *type_names[MAX_TYPE] = {
1815     "STONE", "VWALL", "HWALL", "TLCORNER", "TRCORNER", "BLCORNER", "BRCORNER",
1816     "CROSSWALL", "TUWALL", "TDWALL", "TLWALL", "TRWALL", "DBWALL", "TREE",
1817     "SDOOR", "SCORR", "POOL", "MOAT", "WATER", "DRAWBRIDGE_UP", "LAVAPOOL",
1818     "IRON_BARS", "DOOR", "CORR", "ROOM", "STAIRS", "LADDER", "FOUNTAIN",
1819     "THRONE", "SINK", "GRAVE", "ALTAR", "ICE", "DRAWBRIDGE_DOWN", "AIR",
1820     "CLOUD"
1821 };
1822
1823 static const char *
1824 type_to_name(type)
1825 int type;
1826 {
1827     return (type < 0 || type >= MAX_TYPE) ? "unknown" : type_names[type];
1828 }
1829
1830 static void
1831 error4(x, y, a, b, c, dd)
1832 int x, y, a, b, c, dd;
1833 {
1834     pline("set_wall_state: %s @ (%d,%d) %s%s%s%s",
1835           type_to_name(levl[x][y].typ), x, y,
1836           a ? "1" : "", b ? "2" : "", c ? "3" : "", dd ? "4" : "");
1837     bad_count[levl[x][y].typ]++;
1838 }
1839 #endif /* WA_VERBOSE */
1840
1841 /*
1842  * Return 'which' if position is implies an unfinished exterior.  Return
1843  * zero otherwise.  Unfinished implies outer area is rock or a corridor.
1844  *
1845  * Things that are ambiguous: lava
1846  */
1847 STATIC_OVL int
1848 check_pos(x, y, which)
1849 int x, y, which;
1850 {
1851     int type;
1852     if (!isok(x, y))
1853         return which;
1854     type = levl[x][y].typ;
1855     if (IS_ROCK(type) || type == CORR || type == SCORR)
1856         return which;
1857     return 0;
1858 }
1859
1860 /* Return TRUE if more than one is non-zero. */
1861 /*ARGSUSED*/
1862 #ifdef WA_VERBOSE
1863 STATIC_OVL boolean
1864 more_than_one(x, y, a, b, c)
1865 int x, y, a, b, c;
1866 {
1867     if ((a && (b | c)) || (b && (a | c)) || (c && (a | b))) {
1868         error4(x, y, a, b, c, 0);
1869         return TRUE;
1870     }
1871     return FALSE;
1872 }
1873 #else
1874 #define more_than_one(x, y, a, b, c) \
1875     (((a) && ((b) | (c))) || ((b) && ((a) | (c))) || ((c) && ((a) | (b))))
1876 #endif
1877
1878 /* Return the wall mode for a T wall. */
1879 STATIC_OVL int
1880 set_twall(x0, y0, x1, y1, x2, y2, x3, y3)
1881 int x0, y0; /* used #if WA_VERBOSE */
1882 int x1, y1, x2, y2, x3, y3;
1883 {
1884     int wmode, is_1, is_2, is_3;
1885
1886     nhUse(x0);
1887     nhUse(y0);
1888
1889     is_1 = check_pos(x1, y1, WM_T_LONG);
1890     is_2 = check_pos(x2, y2, WM_T_BL);
1891     is_3 = check_pos(x3, y3, WM_T_BR);
1892     if (more_than_one(x0, y0, is_1, is_2, is_3)) {
1893         wmode = 0;
1894     } else {
1895         wmode = is_1 + is_2 + is_3;
1896     }
1897     return wmode;
1898 }
1899
1900 /* Return wall mode for a horizontal or vertical wall. */
1901 STATIC_OVL int
1902 set_wall(x, y, horiz)
1903 int x, y, horiz;
1904 {
1905     int wmode, is_1, is_2;
1906
1907     if (horiz) {
1908         is_1 = check_pos(x, y - 1, WM_W_TOP);
1909         is_2 = check_pos(x, y + 1, WM_W_BOTTOM);
1910     } else {
1911         is_1 = check_pos(x - 1, y, WM_W_LEFT);
1912         is_2 = check_pos(x + 1, y, WM_W_RIGHT);
1913     }
1914     if (more_than_one(x, y, is_1, is_2, 0)) {
1915         wmode = 0;
1916     } else {
1917         wmode = is_1 + is_2;
1918     }
1919     return wmode;
1920 }
1921
1922 /* Return a wall mode for a corner wall. (x4,y4) is the "inner" position. */
1923 STATIC_OVL int
1924 set_corn(x1, y1, x2, y2, x3, y3, x4, y4)
1925 int x1, y1, x2, y2, x3, y3, x4, y4;
1926 {
1927     int wmode, is_1, is_2, is_3, is_4;
1928
1929     is_1 = check_pos(x1, y1, 1);
1930     is_2 = check_pos(x2, y2, 1);
1931     is_3 = check_pos(x3, y3, 1);
1932     is_4 = check_pos(x4, y4, 1); /* inner location */
1933
1934     /*
1935      * All 4 should not be true.  So if the inner location is rock,
1936      * use it.  If all of the outer 3 are true, use outer.  We currently
1937      * can't cover the case where only part of the outer is rock, so
1938      * we just say that all the walls are finished (if not overridden
1939      * by the inner section).
1940      */
1941     if (is_4) {
1942         wmode = WM_C_INNER;
1943     } else if (is_1 && is_2 && is_3)
1944         wmode = WM_C_OUTER;
1945     else
1946         wmode = 0; /* finished walls on all sides */
1947
1948     return wmode;
1949 }
1950
1951 /* Return mode for a crosswall. */
1952 STATIC_OVL int
1953 set_crosswall(x, y)
1954 int x, y;
1955 {
1956     int wmode, is_1, is_2, is_3, is_4;
1957
1958     is_1 = check_pos(x - 1, y - 1, 1);
1959     is_2 = check_pos(x + 1, y - 1, 1);
1960     is_3 = check_pos(x + 1, y + 1, 1);
1961     is_4 = check_pos(x - 1, y + 1, 1);
1962
1963     wmode = is_1 + is_2 + is_3 + is_4;
1964     if (wmode > 1) {
1965         if (is_1 && is_3 && (is_2 + is_4 == 0)) {
1966             wmode = WM_X_TLBR;
1967         } else if (is_2 && is_4 && (is_1 + is_3 == 0)) {
1968             wmode = WM_X_BLTR;
1969         } else {
1970 #ifdef WA_VERBOSE
1971             error4(x, y, is_1, is_2, is_3, is_4);
1972 #endif
1973             wmode = 0;
1974         }
1975     } else if (is_1)
1976         wmode = WM_X_TL;
1977     else if (is_2)
1978         wmode = WM_X_TR;
1979     else if (is_3)
1980         wmode = WM_X_BR;
1981     else if (is_4)
1982         wmode = WM_X_BL;
1983
1984     return wmode;
1985 }
1986
1987 /* Called from mklev.  Scan the level and set the wall modes. */
1988 void
1989 set_wall_state()
1990 {
1991     int x, y;
1992     int wmode;
1993     struct rm *lev;
1994
1995 #ifdef WA_VERBOSE
1996     for (x = 0; x < MAX_TYPE; x++)
1997         bad_count[x] = 0;
1998 #endif
1999
2000     for (x = 0; x < COLNO; x++)
2001         for (lev = &levl[x][0], y = 0; y < ROWNO; y++, lev++) {
2002             switch (lev->typ) {
2003             case SDOOR:
2004                 wmode = set_wall(x, y, (int) lev->horizontal);
2005                 break;
2006             case VWALL:
2007                 wmode = set_wall(x, y, 0);
2008                 break;
2009             case HWALL:
2010                 wmode = set_wall(x, y, 1);
2011                 break;
2012             case TDWALL:
2013                 wmode = set_twall(x, y, x, y - 1, x - 1, y + 1, x + 1, y + 1);
2014                 break;
2015             case TUWALL:
2016                 wmode = set_twall(x, y, x, y + 1, x + 1, y - 1, x - 1, y - 1);
2017                 break;
2018             case TLWALL:
2019                 wmode = set_twall(x, y, x + 1, y, x - 1, y - 1, x - 1, y + 1);
2020                 break;
2021             case TRWALL:
2022                 wmode = set_twall(x, y, x - 1, y, x + 1, y + 1, x + 1, y - 1);
2023                 break;
2024             case TLCORNER:
2025                 wmode =
2026                     set_corn(x - 1, y - 1, x, y - 1, x - 1, y, x + 1, y + 1);
2027                 break;
2028             case TRCORNER:
2029                 wmode =
2030                     set_corn(x, y - 1, x + 1, y - 1, x + 1, y, x - 1, y + 1);
2031                 break;
2032             case BLCORNER:
2033                 wmode =
2034                     set_corn(x, y + 1, x - 1, y + 1, x - 1, y, x + 1, y - 1);
2035                 break;
2036             case BRCORNER:
2037                 wmode =
2038                     set_corn(x + 1, y, x + 1, y + 1, x, y + 1, x - 1, y - 1);
2039                 break;
2040             case CROSSWALL:
2041                 wmode = set_crosswall(x, y);
2042                 break;
2043
2044             default:
2045                 wmode = -1; /* don't set wall info */
2046                 break;
2047             }
2048
2049             if (wmode >= 0)
2050                 lev->wall_info = (lev->wall_info & ~WM_MASK) | wmode;
2051         }
2052
2053 #ifdef WA_VERBOSE
2054     /* check if any bad positions found */
2055     for (x = y = 0; x < MAX_TYPE; x++)
2056         if (bad_count[x]) {
2057             if (y == 0) {
2058                 y = 1; /* only print once */
2059                 pline("set_wall_type: wall mode problems with: ");
2060             }
2061             pline("%s %d;", type_names[x], bad_count[x]);
2062         }
2063 #endif /* WA_VERBOSE */
2064 }
2065
2066 /* -------------------------------------------------------------------------
2067  */
2068 /* This matrix is used here and in vision.c. */
2069 unsigned char seenv_matrix[3][3] = { { SV2, SV1, SV0 },
2070                                      { SV3, SVALL, SV7 },
2071                                      { SV4, SV5, SV6 } };
2072
2073 #define sign(z) ((z) < 0 ? -1 : ((z) > 0 ? 1 : 0))
2074
2075 /* Set the seen vector of lev as if seen from (x0,y0) to (x,y). */
2076 STATIC_OVL void
2077 set_seenv(lev, x0, y0, x, y)
2078 struct rm *lev;
2079 int x0, y0, x, y; /* from, to */
2080 {
2081     int dx = x - x0, dy = y0 - y;
2082
2083     lev->seenv |= seenv_matrix[sign(dy) + 1][sign(dx) + 1];
2084 }
2085
2086 /* Called by blackout(vault.c) when vault guard removes temporary corridor,
2087    turning spot <x0,y0> back into stone; <x1,y1> is an adjacent spot. */
2088 void
2089 unset_seenv(lev, x0, y0, x1, y1)
2090 struct rm *lev;     /* &levl[x1][y1] */
2091 int x0, y0, x1, y1; /* from, to; abs(x1-x0)==1 && abs(y0-y1)==1 */
2092 {
2093     int dx = x1 - x0, dy = y0 - y1;
2094
2095     lev->seenv &= ~seenv_matrix[dy + 1][dx + 1];
2096 }
2097
2098 /* -------------------------------------------------------------------------
2099  */
2100
2101 /* T wall types, one for each row in wall_matrix[][]. */
2102 #define T_d 0
2103 #define T_l 1
2104 #define T_u 2
2105 #define T_r 3
2106
2107 /*
2108  * These are the column names of wall_matrix[][].  They are the "results"
2109  * of a tdwall pattern match.  All T walls are rotated so they become
2110  * a tdwall.  Then we do a single pattern match, but return the
2111  * correct result for the original wall by using different rows for
2112  * each of the wall types.
2113  */
2114 #define T_stone 0
2115 #define T_tlcorn 1
2116 #define T_trcorn 2
2117 #define T_hwall 3
2118 #define T_tdwall 4
2119
2120 static const int wall_matrix[4][5] = {
2121     { S_stone, S_tlcorn, S_trcorn, S_hwall, S_tdwall }, /* tdwall */
2122     { S_stone, S_trcorn, S_brcorn, S_vwall, S_tlwall }, /* tlwall */
2123     { S_stone, S_brcorn, S_blcorn, S_hwall, S_tuwall }, /* tuwall */
2124     { S_stone, S_blcorn, S_tlcorn, S_vwall, S_trwall }, /* trwall */
2125 };
2126
2127 /* Cross wall types, one for each "solid" quarter.  Rows of cross_matrix[][].
2128  */
2129 #define C_bl 0
2130 #define C_tl 1
2131 #define C_tr 2
2132 #define C_br 3
2133
2134 /*
2135  * These are the column names for cross_matrix[][].  They express results
2136  * in C_br (bottom right) terms.  All crosswalls with a single solid
2137  * quarter are rotated so the solid section is at the bottom right.
2138  * We pattern match on that, but return the correct result depending
2139  * on which row we'ere looking at.
2140  */
2141 #define C_trcorn 0
2142 #define C_brcorn 1
2143 #define C_blcorn 2
2144 #define C_tlwall 3
2145 #define C_tuwall 4
2146 #define C_crwall 5
2147
2148 static const int cross_matrix[4][6] = {
2149     { S_brcorn, S_blcorn, S_tlcorn, S_tuwall, S_trwall, S_crwall },
2150     { S_blcorn, S_tlcorn, S_trcorn, S_trwall, S_tdwall, S_crwall },
2151     { S_tlcorn, S_trcorn, S_brcorn, S_tdwall, S_tlwall, S_crwall },
2152     { S_trcorn, S_brcorn, S_blcorn, S_tlwall, S_tuwall, S_crwall },
2153 };
2154
2155 /* Print out a T wall warning and all interesting info. */
2156 STATIC_OVL void
2157 t_warn(lev)
2158 struct rm *lev;
2159 {
2160     static const char warn_str[] = "wall_angle: %s: case %d: seenv = 0x%x";
2161     const char *wname;
2162
2163     if (lev->typ == TUWALL)
2164         wname = "tuwall";
2165     else if (lev->typ == TLWALL)
2166         wname = "tlwall";
2167     else if (lev->typ == TRWALL)
2168         wname = "trwall";
2169     else if (lev->typ == TDWALL)
2170         wname = "tdwall";
2171     else
2172         wname = "unknown";
2173     impossible(warn_str, wname, lev->wall_info & WM_MASK,
2174                (unsigned int) lev->seenv);
2175 }
2176
2177 /*
2178  * Return the correct graphics character index using wall type, wall mode,
2179  * and the seen vector.  It is expected that seenv is non zero.
2180  *
2181  * All T-wall vectors are rotated to be TDWALL.  All single crosswall
2182  * blocks are rotated to bottom right.  All double crosswall are rotated
2183  * to W_X_BLTR.  All results are converted back.
2184  *
2185  * The only way to understand this is to take out pen and paper and
2186  * draw diagrams.  See rm.h for more details on the wall modes and
2187  * seen vector (SV).
2188  */
2189 STATIC_OVL int
2190 wall_angle(lev)
2191 struct rm *lev;
2192 {
2193     register unsigned int seenv = lev->seenv & 0xff;
2194     const int *row;
2195     int col, idx;
2196
2197 #define only(sv, bits) (((sv) & (bits)) && !((sv) & ~(bits)))
2198     switch (lev->typ) {
2199     case TUWALL:
2200         row = wall_matrix[T_u];
2201         seenv = (seenv >> 4 | seenv << 4) & 0xff; /* rotate to tdwall */
2202         goto do_twall;
2203     case TLWALL:
2204         row = wall_matrix[T_l];
2205         seenv = (seenv >> 2 | seenv << 6) & 0xff; /* rotate to tdwall */
2206         goto do_twall;
2207     case TRWALL:
2208         row = wall_matrix[T_r];
2209         seenv = (seenv >> 6 | seenv << 2) & 0xff; /* rotate to tdwall */
2210         goto do_twall;
2211     case TDWALL:
2212         row = wall_matrix[T_d];
2213     do_twall:
2214         switch (lev->wall_info & WM_MASK) {
2215         case 0:
2216             if (seenv == SV4) {
2217                 col = T_tlcorn;
2218             } else if (seenv == SV6) {
2219                 col = T_trcorn;
2220             } else if (seenv & (SV3 | SV5 | SV7)
2221                        || ((seenv & SV4) && (seenv & SV6))) {
2222                 col = T_tdwall;
2223             } else if (seenv & (SV0 | SV1 | SV2)) {
2224                 col = (seenv & (SV4 | SV6) ? T_tdwall : T_hwall);
2225             } else {
2226                 t_warn(lev);
2227                 col = T_stone;
2228             }
2229             break;
2230         case WM_T_LONG:
2231             if (seenv & (SV3 | SV4) && !(seenv & (SV5 | SV6 | SV7))) {
2232                 col = T_tlcorn;
2233             } else if (seenv & (SV6 | SV7) && !(seenv & (SV3 | SV4 | SV5))) {
2234                 col = T_trcorn;
2235             } else if ((seenv & SV5)
2236                        || ((seenv & (SV3 | SV4)) && (seenv & (SV6 | SV7)))) {
2237                 col = T_tdwall;
2238             } else {
2239                 /* only SV0|SV1|SV2 */
2240                 if (!only(seenv, SV0 | SV1 | SV2))
2241                     t_warn(lev);
2242                 col = T_stone;
2243             }
2244             break;
2245         case WM_T_BL:
2246 #if 0  /* older method, fixed */
2247             if (only(seenv, SV4|SV5)) {
2248                 col = T_tlcorn;
2249             } else if ((seenv & (SV0|SV1|SV2))
2250                        && only(seenv, SV0|SV1|SV2|SV6|SV7)) {
2251                 col = T_hwall;
2252             } else if ((seenv & SV3)
2253                        || ((seenv & (SV0|SV1|SV2)) && (seenv & (SV4|SV5)))) {
2254                 col = T_tdwall;
2255             } else {
2256                 if (seenv != SV6)
2257                     t_warn(lev);
2258                 col = T_stone;
2259             }
2260 #endif /* 0 */
2261             if (only(seenv, SV4 | SV5))
2262                 col = T_tlcorn;
2263             else if ((seenv & (SV0 | SV1 | SV2 | SV7))
2264                      && !(seenv & (SV3 | SV4 | SV5)))
2265                 col = T_hwall;
2266             else if (only(seenv, SV6))
2267                 col = T_stone;
2268             else
2269                 col = T_tdwall;
2270             break;
2271         case WM_T_BR:
2272 #if 0  /* older method, fixed */
2273             if (only(seenv, SV5|SV6)) {
2274                 col = T_trcorn;
2275             } else if ((seenv & (SV0|SV1|SV2))
2276                        && only(seenv, SV0|SV1|SV2|SV3|SV4)) {
2277                 col = T_hwall;
2278             } else if ((seenv & SV7)
2279                        || ((seenv & (SV0|SV1|SV2)) && (seenv & (SV5|SV6)))) {
2280                 col = T_tdwall;
2281             } else {
2282                 if (seenv != SV4)
2283                     t_warn(lev);
2284                 col = T_stone;
2285             }
2286 #endif /* 0 */
2287             if (only(seenv, SV5 | SV6))
2288                 col = T_trcorn;
2289             else if ((seenv & (SV0 | SV1 | SV2 | SV3))
2290                      && !(seenv & (SV5 | SV6 | SV7)))
2291                 col = T_hwall;
2292             else if (only(seenv, SV4))
2293                 col = T_stone;
2294             else
2295                 col = T_tdwall;
2296
2297             break;
2298         default:
2299             impossible("wall_angle: unknown T wall mode %d",
2300                        lev->wall_info & WM_MASK);
2301             col = T_stone;
2302             break;
2303         }
2304         idx = row[col];
2305         break;
2306
2307     case SDOOR:
2308         if (lev->horizontal)
2309             goto horiz;
2310     /* fall through */
2311     case VWALL:
2312         switch (lev->wall_info & WM_MASK) {
2313         case 0:
2314             idx = seenv ? S_vwall : S_stone;
2315             break;
2316         case 1:
2317             idx = seenv & (SV1 | SV2 | SV3 | SV4 | SV5) ? S_vwall : S_stone;
2318             break;
2319         case 2:
2320             idx = seenv & (SV0 | SV1 | SV5 | SV6 | SV7) ? S_vwall : S_stone;
2321             break;
2322         default:
2323             impossible("wall_angle: unknown vwall mode %d",
2324                        lev->wall_info & WM_MASK);
2325             idx = S_stone;
2326             break;
2327         }
2328         break;
2329
2330     case HWALL:
2331     horiz:
2332         switch (lev->wall_info & WM_MASK) {
2333         case 0:
2334             idx = seenv ? S_hwall : S_stone;
2335             break;
2336         case 1:
2337             idx = seenv & (SV3 | SV4 | SV5 | SV6 | SV7) ? S_hwall : S_stone;
2338             break;
2339         case 2:
2340             idx = seenv & (SV0 | SV1 | SV2 | SV3 | SV7) ? S_hwall : S_stone;
2341             break;
2342         default:
2343             impossible("wall_angle: unknown hwall mode %d",
2344                        lev->wall_info & WM_MASK);
2345             idx = S_stone;
2346             break;
2347         }
2348         break;
2349
2350 #define set_corner(idx, lev, which, outer, inner, name)    \
2351     switch ((lev)->wall_info & WM_MASK) {                  \
2352     case 0:                                                \
2353         idx = which;                                       \
2354         break;                                             \
2355     case WM_C_OUTER:                                       \
2356         idx = seenv & (outer) ? which : S_stone;           \
2357         break;                                             \
2358     case WM_C_INNER:                                       \
2359         idx = seenv & ~(inner) ? which : S_stone;          \
2360         break;                                             \
2361     default:                                               \
2362         impossible("wall_angle: unknown %s mode %d", name, \
2363                    (lev)->wall_info &WM_MASK);             \
2364         idx = S_stone;                                     \
2365         break;                                             \
2366     }
2367
2368     case TLCORNER:
2369         set_corner(idx, lev, S_tlcorn, (SV3 | SV4 | SV5), SV4, "tlcorn");
2370         break;
2371     case TRCORNER:
2372         set_corner(idx, lev, S_trcorn, (SV5 | SV6 | SV7), SV6, "trcorn");
2373         break;
2374     case BLCORNER:
2375         set_corner(idx, lev, S_blcorn, (SV1 | SV2 | SV3), SV2, "blcorn");
2376         break;
2377     case BRCORNER:
2378         set_corner(idx, lev, S_brcorn, (SV7 | SV0 | SV1), SV0, "brcorn");
2379         break;
2380
2381     case CROSSWALL:
2382         switch (lev->wall_info & WM_MASK) {
2383         case 0:
2384             if (seenv == SV0)
2385                 idx = S_brcorn;
2386             else if (seenv == SV2)
2387                 idx = S_blcorn;
2388             else if (seenv == SV4)
2389                 idx = S_tlcorn;
2390             else if (seenv == SV6)
2391                 idx = S_trcorn;
2392             else if (!(seenv & ~(SV0 | SV1 | SV2))
2393                      && (seenv & SV1 || seenv == (SV0 | SV2)))
2394                 idx = S_tuwall;
2395             else if (!(seenv & ~(SV2 | SV3 | SV4))
2396                      && (seenv & SV3 || seenv == (SV2 | SV4)))
2397                 idx = S_trwall;
2398             else if (!(seenv & ~(SV4 | SV5 | SV6))
2399                      && (seenv & SV5 || seenv == (SV4 | SV6)))
2400                 idx = S_tdwall;
2401             else if (!(seenv & ~(SV0 | SV6 | SV7))
2402                      && (seenv & SV7 || seenv == (SV0 | SV6)))
2403                 idx = S_tlwall;
2404             else
2405                 idx = S_crwall;
2406             break;
2407
2408         case WM_X_TL:
2409             row = cross_matrix[C_tl];
2410             seenv = (seenv >> 4 | seenv << 4) & 0xff;
2411             goto do_crwall;
2412         case WM_X_TR:
2413             row = cross_matrix[C_tr];
2414             seenv = (seenv >> 6 | seenv << 2) & 0xff;
2415             goto do_crwall;
2416         case WM_X_BL:
2417             row = cross_matrix[C_bl];
2418             seenv = (seenv >> 2 | seenv << 6) & 0xff;
2419             goto do_crwall;
2420         case WM_X_BR:
2421             row = cross_matrix[C_br];
2422         do_crwall:
2423             if (seenv == SV4)
2424                 idx = S_stone;
2425             else {
2426                 seenv = seenv & ~SV4; /* strip SV4 */
2427                 if (seenv == SV0) {
2428                     col = C_brcorn;
2429                 } else if (seenv & (SV2 | SV3)) {
2430                     if (seenv & (SV5 | SV6 | SV7))
2431                         col = C_crwall;
2432                     else if (seenv & (SV0 | SV1))
2433                         col = C_tuwall;
2434                     else
2435                         col = C_blcorn;
2436                 } else if (seenv & (SV5 | SV6)) {
2437                     if (seenv & (SV1 | SV2 | SV3))
2438                         col = C_crwall;
2439                     else if (seenv & (SV0 | SV7))
2440                         col = C_tlwall;
2441                     else
2442                         col = C_trcorn;
2443                 } else if (seenv & SV1) {
2444                     col = seenv & SV7 ? C_crwall : C_tuwall;
2445                 } else if (seenv & SV7) {
2446                     col = seenv & SV1 ? C_crwall : C_tlwall;
2447                 } else {
2448                     impossible("wall_angle: bottom of crwall check");
2449                     col = C_crwall;
2450                 }
2451
2452                 idx = row[col];
2453             }
2454             break;
2455
2456         case WM_X_TLBR:
2457             if (only(seenv, SV1 | SV2 | SV3))
2458                 idx = S_blcorn;
2459             else if (only(seenv, SV5 | SV6 | SV7))
2460                 idx = S_trcorn;
2461             else if (only(seenv, SV0 | SV4))
2462                 idx = S_stone;
2463             else
2464                 idx = S_crwall;
2465             break;
2466
2467         case WM_X_BLTR:
2468             if (only(seenv, SV0 | SV1 | SV7))
2469                 idx = S_brcorn;
2470             else if (only(seenv, SV3 | SV4 | SV5))
2471                 idx = S_tlcorn;
2472             else if (only(seenv, SV2 | SV6))
2473                 idx = S_stone;
2474             else
2475                 idx = S_crwall;
2476             break;
2477
2478         default:
2479             impossible("wall_angle: unknown crosswall mode");
2480             idx = S_stone;
2481             break;
2482         }
2483         break;
2484
2485     default:
2486         impossible("wall_angle: unexpected wall type %d", lev->typ);
2487         idx = S_stone;
2488     }
2489     return idx;
2490 }
2491
2492 /*display.c*/