Function do_vicinity_map

src/detect.c:1447–1585

clairvoyance */

/* clairvoyance */
void
do_vicinity_map(
    struct obj *sobj) /* scroll--actually fake spellbook--object */
{
    int zx, zy;
    struct monst *mtmp;
    struct obj *otmp;
    long save_EDetect_mons;
    char save_viz_uyux;
    boolean unconstrained, refresh = FALSE,
            mdetected = FALSE, odetected = FALSE,
            /* fake spellbook 'sobj' implies hero has cast the spell;
               when book is blessed, casting is skilled or expert level;
               if already clairvoyant, non-skilled spell acts like skilled */
            extended = (sobj && (sobj->blessed || Clairvoyant)),
            random_farsight = !sobj;
    int newglyph, oldglyph,
        lo_y = ((u.uy - 5 < 0) ? 0 : u.uy - 5),
        hi_y = ((u.uy + 6 >= ROWNO) ? ROWNO - 1 : u.uy + 6),
        lo_x = ((u.ux - 9 < 1) ? 1 : u.ux - 9), /* avoid column 0 */
        hi_x = ((u.ux + 10 >= COLNO) ? COLNO - 1 : u.ux + 10),
        ter_typ = TER_DETECT | TER_MAP | TER_TRP | TER_OBJ;

    /*
     * 3.6.0 attempted to emphasize terrain over transient map
     * properties (monsters and objects) but that led to problems.
     * Notably, known trap would be displayed instead of a monster
     * on or in it and then the display remained that way after the
     * clairvoyant snapshot finished.  That could have been fixed by
     * issuing --More-- and then regular vision update, but we want
     * to avoid that when having a clairvoyant episode every N turns
     * (from donating to a temple priest or by carrying the Amulet).
     * Unlike when casting the spell, it is much too intrusive when
     * in the midst of walking around or combatting monsters.
     *
     * As of 3.6.2, show terrain, then object, then monster like regular
     * map updating, except in this case the map locations get marked
     * as seen from every direction rather than just from direction of
     * hero.  Skilled spell marks revealed objects as 'seen up close'
     * (but for piles, only the top item) and shows monsters as if
     * detected.  Non-skilled and timed clairvoyance reveals non-visible
     * monsters as 'remembered, unseen'.
     */

    /* if hero is engulfed, show engulfer at <u.ux,u.uy> */
    save_viz_uyux = gv.viz_array[u.uy][u.ux];
    if (u.uswallow)
        gv.viz_array[u.uy][u.ux] |= IN_SIGHT; /* <x,y> are reversed, [y][x] */
    save_EDetect_mons = EDetect_monsters;
    /* for skilled spell, getpos() scanning of the map will display all
       monsters within range; otherwise, "unseen creature" will be shown */
    EDetect_monsters |= I_SPECIAL;
    unconstrained = unconstrain_map();
    for (zx = lo_x; zx <= hi_x; zx++)
        for (zy = lo_y; zy <= hi_y; zy++) {
            oldglyph = glyph_at(zx, zy);
            /* this will remove 'remembered, unseen mon' (and objects) */
            show_map_spot(zx, zy, Confusion);