Function magic_map_background

src/display.c:232–258

* magic_map_background() * * This function is similar to map_background (see below) except we pay * attention to and correct unexplored, lit ROOM and CORR spots. */

 * attention to and correct unexplored, lit ROOM and CORR spots.
 */
void
magic_map_background(coordxy x, coordxy y, int show)
{
    int glyph = back_to_glyph(x, y); /* assumes hero can see x,y */
    struct rm *lev = &levl[x][y];

    /*
     * Correct for out of sight lit corridors and rooms that the hero
     * doesn't remember as lit.
     */
    if (!cansee(x, y) && !lev->waslit) {
        /* Floor spaces are dark if unlit.  Corridors are dark if unlit. */
        if (lev->typ == ROOM && glyph == cmap_to_glyph(S_room))
            glyph = (flags.dark_room && iflags.use_color)
                        ? cmap_to_glyph(DARKROOMSYM)
                        : GLYPH_NOTHING;
        else if (lev->typ == CORR && glyph == cmap_to_glyph(S_litcorr))
            glyph = cmap_to_glyph(S_corr);
    }
    if (svl.level.flags.hero_memory
        && (glyph_is_unexplored(lev->glyph) || glyph_is_cmap(lev->glyph)))
        lev->glyph = glyph;
    if (show)
        show_glyph(x, y, glyph);

    update_lastseentyp(x, y);
}

/*
 * The routines map_background(), map_object(), and map_trap() could just