Function zap_map

src/zap.c:3627–3801

zap_map() occurs before hitting monsters or objects and handles wands or spells that don't dish out 'elemental' damage */

/* zap_map() occurs before hitting monsters or objects and handles wands or
   spells that don't dish out 'elemental' damage */
staticfn void
zap_map(
    coordxy x, coordxy y,
    struct obj *obj) /* zapped wand, or book for cast spell */
{
    struct trap *ttmp = t_at(x, y);
    coordxy dbx = x, dby = y; /* might be changed by drawbridge handling */
    boolean learn_it = FALSE;

    /*
     * We handle drawbridge for lateral zaps; zap_updown() handles up/down.
     * Engravings only get hit by down zaps and we handle that here.
     */

    /* cancellation */
    maybe_explode_trap(ttmp, obj, &learn_it);
    ttmp = t_at(x, y); /* refresh in case trap was altered or is gone */

    if (u.dz > 0) { /* zapping down */
        char ebuf[BUFSZ], pristinebuf[BUFSZ], *etxt;
        struct engr *e = engr_at(x, y);

        /* subset of engraving effects; none sets `disclose' */
        if (e && e->engr_type != HEADSTONE) {
            switch (obj->otyp) {
            case WAN_POLYMORPH:
            case SPE_POLYMORPH:
                del_engr(e);
                etxt = random_engraving(ebuf, pristinebuf);
                make_engr_at(x, y, etxt, pristinebuf, svm.moves, 0);
                break;
            case WAN_CANCELLATION:
            case SPE_CANCELLATION:
            case WAN_MAKE_INVISIBLE:
                del_engr(e);
                break;
            case WAN_TELEPORTATION:
            case SPE_TELEPORT_AWAY:
                rloc_engr(e);
                break;
            case SPE_STONE_TO_FLESH:
                if (e->engr_type == ENGRAVE) {
                    /* only affects things in stone */
                    pline_The(Hallucination
                                  ? "floor runs like butter!"
                                  : "edges on the floor get smoother.");
                    wipe_engr_at(x, y, d(2, 4), TRUE);
                }
                break;
            case WAN_STRIKING:
            case SPE_FORCE_BOLT:
                wipe_engr_at(x, y, d(2, 4), TRUE);
                break;
            default:
                break;
            }
        }