drain energy attack (trunk only)

During some recent newsgroup discussion, <Someone> posted an entry from
his personal bug list:  energy draining damage from ordinary attacks is
implemented even though there are no monsters with that capability and it
was not implemented for engulf attacks even though energy vortices have
the capability.  This implements energy drain engulf attacks against the
hero and also both modes of energy drain attacks for monsters and poly'd
hero against spellcasting monsters.  Since monsters don't have energy,
they lose access to their special abilities (their spells, that is) for a
few turns, same as a post-3.4.3 change done for anti-magic traps.

doc/fixes35.0

@@ -275,6 +275,7 @@ secret door detection's trap finding is no longer blocked by water or clouds
 	on the Planes of Water and Air
 potion thrown by monster which hit a long worm's tail gave feedback about
 	hitting its head
+implement energy vortex's previously unused energy drain attack
 
 
 Platform- and/or Interface-Specific Fixes

include/extern.h

@@ -1099,6 +1099,7 @@ E int FDECL(mdisplacem, (struct monst *,struct monst *,BOOLEAN_P));
 E void FDECL(paralyze_monst, (struct monst *,int));
 E int FDECL(sleep_monst, (struct monst *,int,int));
 E void FDECL(slept_monst, (struct monst *));
+E void FDECL(xdrainenergym, (struct monst *,BOOLEAN_P));
 E long FDECL(attk_protection, (int));
 
 /* ### mhitu.c ### */

src/mhitm.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)mhitm.c	3.5	2007/04/02	*/
+/*	SCCS Id: @(#)mhitm.c	3.5	2007/12/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1121,6 +1121,11 @@ mdamagem(magr, mdef, mattk)
 		}
 		tmp = 0;
 		break;
+	    case AD_DREN:
+		if (!cancelled && !rn2(4))
+		    xdrainenergym(mdef, vis && mattk->aatyp != AT_ENGL);
+		tmp = 0;
+		break;
 	    case AD_DRST:
 	    case AD_DRDX:
 	    case AD_DRCO:
@@ -1449,6 +1454,19 @@ int mdead;
 	return (mdead | mhit);
 }
 
+/* hero or monster has successfully hit target mon with drain energy attack */
+void
+xdrainenergym(mon, givemsg)
+struct monst *mon;
+boolean givemsg;
+{
+    if (mon->mspec_used < 20 &&		/* limit draining */
+	  (attacktype(mon->data, AT_MAGC) || attacktype(mon->data, AT_BREA))) {
+	mon->mspec_used += d(2, 2);
+	if (givemsg) pline("%s seems lethargic.", Monnam(mon));
+    }
+}
+
 /* "aggressive defense"; what type of armor prevents specified attack
    from touching its target? */
 long

src/mhitu.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)mhitu.c	3.5	2007/06/02	*/
+/*	SCCS Id: @(#)mhitu.c	3.5	2007/12/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1802,6 +1802,12 @@ gulpmu(mtmp, mattk)	/* monster swallows you, or damage if u.uswallow */
 		case AD_DISE:
 		    if (!diseasemu(mtmp->data)) tmp = 0;
 		    break;
+		case AD_DREN:
+		    /* AC magic cancellation doesn't help when engulfed */
+		    if (!mtmp->mcan && rn2(4))
+			drain_en(tmp);
+		    tmp = 0;
+		    break;
 		default:
 		    physical_damage = TRUE;
 		    tmp = 0;

src/monst.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)monst.c	3.5	2007/04/02	*/
+/*	SCCS Id: @(#)monst.c	3.5	2007/12/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -955,7 +955,7 @@ NEARDATA struct permonst mons[] = {
 	M2_HOSTILE|M2_NEUTER, M3_INFRAVISIBLE, CLR_CYAN),
     MON("energy vortex", S_VORTEX,
 	LVL(6, 20, 2, 30, 0), (G_GENO|G_NOCORPSE|1),
-	A(ATTK(AT_ENGL, AD_ELEC, 1, 6), ATTK(AT_ENGL, AD_DREN, 0, 0),
+	A(ATTK(AT_ENGL, AD_ELEC, 1, 6), ATTK(AT_ENGL, AD_DREN, 4, 6),
 	  ATTK(AT_NONE, AD_ELEC, 0, 4), NO_ATTK, NO_ATTK, NO_ATTK),
 	SIZ(0, 0, MS_SILENT, MZ_HUGE),
 	MR_ELEC|MR_SLEEP|MR_DISINT|MR_POISON|MR_STONE, 0,

src/trap.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)trap.c	3.5	2007/08/24	*/
+/*	SCCS Id: @(#)trap.c	3.5	2007/12/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -3389,9 +3389,14 @@ drain_en(n)
 register int n;
 {
     if (!u.uenmax) {
+	/* energy is completely gone */
 	You_feel("momentarily lethargic.");
     } else {
-	You_feel("your magical energy drain away!");
+	/* throttle further loss a bit when there's not much left to lose */
+	if (n > u.uenmax || n > u.ulevel) n = rnd(n);
+
+	You_feel("your magical energy drain away%c",
+		 (n > u.uen) ? '!' : '.');
 	u.uen -= n;
 	if(u.uen < 0)  {
 		u.uenmax -= rnd(-u.uen);

src/uhitm.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)uhitm.c	3.5	2007/05/16	*/
+/*	SCCS Id: @(#)uhitm.c	3.5	2007/12/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1566,6 +1566,11 @@ register struct attack *mattk;
 		hurtmarmor(mdef, AD_DCAY);
 		tmp = 0;
 		break;
+	    case AD_DREN:
+		if (!negated && !rn2(4))
+		    xdrainenergym(mdef, TRUE);
+		tmp = 0;
+		break;
 	    case AD_DRST:
 	    case AD_DRDX:
 	    case AD_DRCO:
@@ -1958,6 +1963,11 @@ register struct attack *mattk;
 			    golemeffects(mdef,(int)mattk->adtyp,dam);
 			} else dam = 0;
 			break;
+		    case AD_DREN:
+			if (!rn2(4))
+			    xdrainenergym(mdef, TRUE);
+			dam = 0;
+			break;
 		}
 		end_engulf();
 		if ((mdef->mhp -= dam) <= 0) {