Function blackout

src/vault.c:122–141

as a temporary corridor is removed, set stone locations and adjacent spots to unlit; if player used scroll/wand/spell of light while inside the corridor, we don't want the light to reappear if/when a new tunnel goes through the same area */

   the corridor, we don't want the light to reappear if/when a new tunnel
   goes through the same area */
staticfn void
blackout(coordxy x, coordxy y)
{
    struct rm *lev;
    int i, j;

    for (i = x - 1; i <= x + 1; ++i)
        for (j = y - 1; j <= y + 1; ++j) {
            if (!isok(i, j))
                continue;
            lev = &levl[i][j];
            /* [possible bug: when (i != x || j != y), perhaps we ought
               to check whether the spot on the far side is lit instead
               of doing a blanket blackout of adjacent locations] */
            if (lev->typ == STONE)
                lev->lit = lev->waslit = 0;
            /* mark <i,j> as not having been seen from <x,y> */
            unset_seenv(lev, x, y, i, j);
        }
}

staticfn void
restfakecorr(struct monst *grd)