Function mcast_spell

src/mcastu.c:800–897

If dmg is zero, then the monster is not casting at you. If the monster is intentionally not casting at you, we have previously called spell_would_be_useless() and spellnum should always be a valid undirected spell. If you modify either of these, be sure to change is_undirected_spell() and spell_would_be_useless(). */

   and spell_would_be_useless().
 */
staticfn void
mcast_spell(struct monst *mtmp, int dmg, int spellnum)
{
    if (dmg < 0) {
        impossible("monster cast spell (%d) with negative dmg (%d)?",
                   spellnum, dmg);
        return;
    }
    if (dmg == 0 && !is_undirected_spell(spellnum)) {
        impossible("cast directed wizard spell (%d) with dmg=0?", spellnum);
        return;
    }

    switch (spellnum) {
    case MCAST_DEATH_TOUCH:
        mcast_death_touch(mtmp);
        dmg = 0;
        break;
    case MCAST_CLONE_WIZ:
        mcast_clone_wiz(mtmp);
        dmg = 0;
        break;
    case MCAST_SUMMON_MONS:
        mcast_summon_mons(mtmp);
        dmg = 0;
        break;
    case MCAST_AGGRAVATION:
        You_feel("that monsters are aware of your presence.");
        aggravate();
        dmg = 0;
        break;
    case MCAST_CURSE_ITEMS:
        You_feel("as if you need some help.");
        rndcurse();
        dmg = 0;
        break;
    case MCAST_DESTRY_ARMR:
        mcast_destroy_armor();
        dmg = 0;
        break;
    case MCAST_WEAKEN_YOU: /* drain strength */
        mcast_weaken_you(mtmp, dmg);
        dmg = 0;
        break;
    case MCAST_DISAPPEAR: /* makes self invisible */
        mcast_disappear(mtmp);
        dmg = 0;
        break;
    case MCAST_STUN_YOU:
        mcast_stun_you(dmg);
        dmg = 0;
        break;
    case MCAST_HASTE_SELF:
        mon_adjust_speed(mtmp, 1, (struct obj *) 0);
        dmg = 0;
        break;
    case MCAST_CURE_SELF:
        dmg = m_cure_self(mtmp, dmg);