Function impact_drop

src/dokick.c:1510–1632

player or missile impacts location, causing objects to fall down */

/* player or missile impacts location, causing objects to fall down */
void
impact_drop(
    struct obj *missile,  /* caused impact, won't drop itself */
    coordxy x, coordxy y, /* location affected */
    xint16 dlev)          /* if !0 send to dlev near player */
{
    schar toloc;
    struct obj *obj, *obj2;
    struct monst *shkp;
    long oct, dct, price, debit, robbed;
    boolean angry, costly, isrock;
    coord cc;

    if (!OBJ_AT(x, y))
        return;

    toloc = down_gate(x, y);
    drop_to(&cc, toloc, x, y);
    if (!cc.y)
        return;

    if (dlev) {
        /* send objects next to player falling through trap door.
         * checked in obj_delivery().
         */
        toloc = MIGR_WITH_HERO;
        cc.y = dlev;
    }

    costly = costly_spot(x, y);
    price = debit = robbed = 0L;
    angry = FALSE;
    shkp = (struct monst *) 0;
    /* if 'costly', we must keep a record of ESHK(shkp) before
     * it undergoes changes through the calls to stolen_value.
     * the angry bit must be reset, if needed, in this fn, since
     * stolen_value is called under the 'silent' flag to avoid
     * unsavory pline repetitions.
     */
    if (costly) {
        if ((shkp = shop_keeper(*in_rooms(x, y, SHOPBASE))) != 0) {
            debit = ESHK(shkp)->debit;
            robbed = ESHK(shkp)->robbed;
            angry = !shkp->mpeaceful;
        }
    }

    isrock = (missile && missile->otyp == ROCK);
    oct = dct = 0L;
    for (obj = svl.level.objects[x][y]; obj; obj = obj2) {
        obj2 = obj->nexthere;
        if (obj == missile)
            continue;
        /* number of objects in the pile */
        oct += obj->quan;
        if (obj == uball || obj == uchain)
            continue;
        /* boulders can fall too, but rarely & never due to rocks */