magicbane tweaks

Update the comments to [try to] more accurately describe the behavior.
Also add hallucination handling and make the probe effect be more likely
to occur (or to put it another way, make the stun effect be less likely
since one or the other always takes place--except when stun is superseded
by something more severe).

src/artifact.c

@@ -727,11 +727,24 @@ winid tmpwin;		/* supplied by dodiscover() */
 	 * dependence on spe.  Against low mr victims, it typically
 	 * does "double athame" damage, 2d4.  Occasionally, it will
 	 * cast unbalancing magic which effectively averages out to
-	 * 4d4 damage (2.5d4 against high mr victims), for spe = 0.
+	 * 4d4 damage (3d4 against high mr victims), for spe = 0.
+	 *
+	 * Prior to 3.4.1, the cancel (aka purge) effect always
+	 * included the scare effect too; now it's one or the other.
+	 * Likewise, the stun effect won't be combined with either
+	 * of those two; it will be chosen separately or possibly
+	 * used as a fallback when scare or cancel fails.
+	 *
+	 * [Historical note: a change to artifact_hit() for 3.4.0
+	 * unintentionally made all of Magicbane's special effects
+	 * be blocked if the defender successfully saved against a
+	 * stun attack.  As of 3.4.1, those effects can occur but
+	 * will be slightly less likely than they were in 3.3.x.]
 	 */
 #define MB_MAX_DIEROLL		8	/* rolls above this aren't magical */
-static const char * const mb_verb[4] = {
-	"probe", "stun", "scare", "cancel"
+static const char * const mb_verb[2][4] = {
+	{ "probe", "stun", "scare", "cancel" },
+	{ "prod", "amaze", "tickle", "purge" },
 };
 #define MB_INDEX_PROBE		0
 #define MB_INDEX_STUN		1
@@ -749,6 +762,7 @@ boolean vis;			/* whether the action can be seen */
 char *hittee;			/* target's name: "you" or mon_nam(mdef) */
 {
     struct permonst *old_uasmon;
+    const char *verb;
     boolean youattack = (magr == &youmonst),
 	    youdefend = (mdef == &youmonst),
 	    resisted = FALSE, do_stun, do_confuse, result;
@@ -758,35 +772,44 @@ char *hittee;			/* target's name: "you" or mon_nam(mdef) */
     /* the most severe effects are less likely at higher enchantment */
     if (mb->spe >= 3)
 	scare_dieroll /= (1 << (mb->spe / 3));
+    /* if target successfully resisted the artifact damage bonus,
+       reduce overall likelihood of the assorted special effects */
+    if (!spec_dbon_applies) dieroll += 1;
 
     /* might stun even when attempting a more severe effect, but
        in that case it will only happen if the other effect fails;
-       extra damage will apply regardless */
-    do_stun = (mb->spe <= rn2(10));
+       extra damage will apply regardless; 3.4.1: sometimes might
+       just probe even when it hasn't been enchanted */
+    do_stun = (max(mb->spe,0) < rn2(spec_dbon_applies ? 11 : 7));
 
-    /* the special effects also boost physical damage (base 2d4 assumed);
-       increments are generally cumulative, but since the stun effect is
-       based on a different criterium its damage might not be included */
+    /* the special effects also boost physical damage; increments are
+       generally cumulative, but since the stun effect is based on a
+       different criterium its damage might not be included; the base
+       damage is either 1d4 (athame) or 2d4 (athame+spec_dbon) depending
+       on target's resistance check against AD_STUN (handled by caller)
+       [note that a successful save against AD_STUN doesn't actually
+       prevent the target from ending up stunned] */
     attack_indx = MB_INDEX_PROBE;
-    *dmgptr += rnd(4);			/* 3d4 */
+    *dmgptr += rnd(4);			/* (2..3)d4 */
     if (do_stun) {
 	attack_indx = MB_INDEX_STUN;
-	*dmgptr += rnd(4);		/* 4d4 */
+	*dmgptr += rnd(4);		/* (3..4)d4 */
     }
     if (dieroll <= scare_dieroll) {
 	attack_indx = MB_INDEX_SCARE;
-	*dmgptr += rnd(4);		/* 5d4; actually (4 or 5)d4 */
+	*dmgptr += rnd(4);		/* (3..5)d4 */
     }
     if (dieroll <= (scare_dieroll / 2)) {
 	attack_indx = MB_INDEX_CANCEL;
-	*dmgptr += rnd(4);		/* 6d4; actually (5 or 6)d4 */
+	*dmgptr += rnd(4);		/* (4..6)d4 */
     }
 
     /* give the hit message prior to inflicting the effects */
+    verb = mb_verb[!!Hallucination][attack_indx];
     if (youattack || youdefend || vis) {
 	result = TRUE;
 	pline_The("magic-absorbing blade %s %s!",
-		  vtense((const char *)0, mb_verb[attack_indx]), hittee);
+		  vtense((const char *)0, verb), hittee);
 	/* assume probing has some sort of noticeable feedback
 	   even if it is being done by one monster to another */
 	if (attack_indx == MB_INDEX_PROBE && !canspotmon(mdef))
@@ -849,10 +872,8 @@ char *hittee;			/* target's name: "you" or mon_nam(mdef) */
 	break;
 
     case MB_INDEX_PROBE:
-	/* note: can't get probe result unless mb->spe >= 1, but
-	   guard against passing bad argument to rn2() anyway */
-	if (youattack && (mb->spe < 1 || !rn2(4 * mb->spe))) {
-	    pline_The("probe is insightful.");
+	if (youattack && (mb->spe == 0 || !rn2(3 * abs(mb->spe)))) {
+	    pline_The("%s is insightful.", verb);
 	    /* pre-damage status */
 	    probe_monster(mdef);
 	}