Another use for patrolling:

Hostile monsters wandering across a grid they consider "interesting"
may note it down as patrolling point to return to. There's currently
no way of deleting such a patrol point short of enslaving the 
monster. As before, patrolling only applies while wandering. Other
behaviour modes (chasing the player etc.) take precedence.

For now interesting grids are:
* altar to one of the good gods for holy beings
* altar to Beogh, or entrance to/return from Orcish Mines for orcs
* entrance to/return from Elven Halls for elves
* entrance to the Hive for killer bees

To test these changes, I've modified the stealth checks for wizard mode:
If you set the Stealth skill to a value greater than 27 (possible in
wizmode) hostile monsters will ignore you, i.e. not set MHITYOU if 
you are nearby.
Noises will still wake monsters, and they'll hit you if they walk
into you (or vice versa), but they won't target you.


git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@5313 c06c8d41-db1a-0410-9941-cceddc491573

5 files changed, 94 insertions, 20 deletions

diff --git a/crawl-ref/source/debug.cc b/crawl-ref/source/debug.cc
index 39d194001b..d7b040207c 100644
--- a/crawl-ref/source/debug.cc
+++ b/crawl-ref/source/debug.cc
@@ -220,7 +220,7 @@ static int debug_prompt_for_skill( const char *prompt )
         {
             if (ptr == sk_name && strlen(specs) > 0)
             {
-                // we prefer prefixes over partial matches
+                // We prefer prefixes over partial matches.
                 skill = i;
                 break;
             }
diff --git a/crawl-ref/source/misc.cc b/crawl-ref/source/misc.cc
index 868db37481..3cec070520 100644
--- a/crawl-ref/source/misc.cc
+++ b/crawl-ref/source/misc.cc
@@ -2511,9 +2511,15 @@ std::string cloud_name(cloud_type type)
 
 bool mons_is_safe(const struct monsters *mon, bool want_move)
 {
+    int  dist   = grid_distance(you.x_pos, you.y_pos, mon->x, mon->y);
+
     bool is_safe = (mons_wont_attack(mon)
                     || mons_class_flag(mon->type, M_NO_EXP_GAIN)
-                       // only seen through glass walls
+#ifdef WIZARD
+                    // Wizmode skill setting enforces hiddenness.
+                    || you.skills[SK_STEALTH] > 27 && dist > 2
+#endif
+                       // Only seen through glass walls?
                     || !see_grid_no_trans(mon->x, mon->y)
                        && !mons_has_ranged_spell(mon)
                        && !mons_has_los_ability(mon->type));
@@ -2525,8 +2531,6 @@ bool mons_is_safe(const struct monsters *mon, bool want_move)
                    || you.running < RMODE_NOT_RUNNING
                    || want_move);
 
-    int  dist   = grid_distance(you.x_pos, you.y_pos,
-                                mon->x, mon->y);
     bool result = is_safe;
 
     if (clua.callfn("ch_mon_is_safe", "Mbbd>b",
diff --git a/crawl-ref/source/monstuff.cc b/crawl-ref/source/monstuff.cc
index 3f46f0d00e..bd820eb618 100644
--- a/crawl-ref/source/monstuff.cc
+++ b/crawl-ref/source/monstuff.cc
@@ -2248,6 +2248,12 @@ static void _handle_behaviour(monsters *mon)
     bool isNeutral  = mons_neutral(mon);
     bool wontAttack = mons_wont_attack(mon);
     bool proxPlayer = mons_near(mon);
+#ifdef WIZARD
+    // If stealth is greater than actually possible (wizmode level)
+    // pretend the player isn't there, but only for hostile monsters.
+    if (proxPlayer && you.skills[SK_STEALTH] > 27 && !mons_wont_attack(mon))
+        proxPlayer = false;
+#endif
     bool proxFoe;
     bool isHurt     = (mon->hit_points <= mon->max_hit_points / 4 - 1);
     bool isHealthy  = (mon->hit_points > mon->max_hit_points / 2);
@@ -2277,9 +2283,8 @@ static void _handle_behaviour(monsters *mon)
     {
         if (!mons_player_visible( mon ))
             proxPlayer = false;
-
-        // must be able to see each other
-        if (!see_grid(mon->x, mon->y))
+        // Must be able to see each other.
+        else if (!see_grid(mon->x, mon->y))
             proxPlayer = false;
 
         const int intel = mons_intel(mon->type);
@@ -2710,8 +2715,8 @@ bool choose_any_monster(const monsters* mon)
 // Find a nearby monster and return its index, including you as a
 // possibility with probability weight.  suitable() should return true
 // for the type of monster wanted.
-// If prefer_named is true, named monsters (including uniques) are twice as
-// likely to get chosen compared with non-named ones.
+// If prefer_named is true, named monsters (including uniques) are twice
+// as likely to get chosen compared to non-named ones.
 monsters *choose_random_nearby_monster(int weight,
                                        bool (*suitable)(const monsters* mon),
                                        bool in_sight, bool prefer_named)
@@ -2765,7 +2770,7 @@ monsters *choose_random_monster_on_level(int weight,
                     if (prefer_named && mon->is_named())
                     {
                         mons_count += 2;
-                        // named monsters have doubled chances
+                        // Named monsters have doubled chances.
                         if (random2(mons_count) < 2)
                             chosen = mon;
                     }
@@ -2805,6 +2810,63 @@ bool simple_monster_message(const monsters *monster, const char *event,
     return (false);
 }                               // end simple_monster_message()
 
+// Altars as well as branch entrances are considered interesting
+// for some monster types.
+static bool _mon_on_interesting_grid(monsters *mon)
+{
+    // Patrolling shouldn't happen all the time.
+    if (one_chance_in(4))
+        return (false);
+
+    const dungeon_feature_type feat = grd[mon->x][mon->y];
+
+    switch (feat)
+    {
+    // Holy beings will tend to patrol around altars to the good gods.
+    case DNGN_ALTAR_ELYVILON:
+        if (!one_chance_in(3))
+            return (false);
+        // else fall through
+    case DNGN_ALTAR_ZIN:
+    case DNGN_ALTAR_SHINING_ONE:
+        return (mons_holiness(mon) == MH_HOLY);
+
+    // Orcs will tend to patrol around altars to Beogh, and guard the
+    // stairway from and to the Orcish Mines.
+    case DNGN_ALTAR_BEOGH:
+    case DNGN_ENTER_ORCISH_MINES:
+    case DNGN_RETURN_FROM_ORCISH_MINES:
+        return (mons_species(mon->type) == MONS_ORC);
+
+    // Same for elves and the Elven Halls.
+    case DNGN_ENTER_ELVEN_HALLS:
+    case DNGN_RETURN_FROM_ELVEN_HALLS:
+        return (mons_species(mon->type) == MONS_ELF);
+
+    // Killer bees always return to their hive.
+    case DNGN_ENTER_HIVE:
+        return (mons_species(mon->type == MONS_KILLER_BEE)
+                || mons_species(mon->type == MONS_KILLER_BEE_LARVA));
+
+    default:
+        return (false);
+    }
+}
+
+// If a hostile monster finds itself on a grid of an "interesting" feature,
+// while unoccupied, it will remain in that area, and try to return to it
+// if it left it for fighting, seeking etc.
+static void _maybe_set_patrol_route(monsters *monster)
+{
+    if (monster->behaviour == BEH_WANDER
+        && !mons_friendly(monster)
+        && !monster->is_patrolling()
+        && _mon_on_interesting_grid(monster))
+    {
+        monster->patrol_point = coord_def(monster->x, monster->y);
+    }
+}
+
 //---------------------------------------------------------------
 //
 // handle_movement
@@ -2816,6 +2878,8 @@ static void _handle_movement(monsters *monster)
 {
     int dx, dy;
 
+    _maybe_set_patrol_route(monster);
+
     // Monsters will try to flee out of a sanctuary.
     if (is_sanctuary(monster->x, monster->y) && !mons_friendly(monster)
         && !mons_is_fleeing(monster)
@@ -2846,7 +2910,7 @@ static void _handle_movement(monsters *monster)
         dy = monster->target_y - monster->y;
     }
 
-    // move the monster:
+    // Move the monster.
     mmov_x = (dx > 0) ? 1 : ((dx < 0) ? -1 : 0);
     mmov_y = (dy > 0) ? 1 : ((dy < 0) ? -1 : 0);
 
@@ -6772,7 +6836,7 @@ bool message_current_target()
     if (crawl_state.is_replaying_keys())
     {
         if (you.prev_targ == MHITNOT || you.prev_targ == MHITYOU)
-            return false;
+            return (false);
 
         const monsters *montarget = &menv[you.prev_targ];
         return (you.prev_targ != MHITNOT && you.prev_targ != MHITYOU
diff --git a/crawl-ref/source/player.cc b/crawl-ref/source/player.cc
index e0b7e6ac79..be84bed2a0 100644
--- a/crawl-ref/source/player.cc
+++ b/crawl-ref/source/player.cc
@@ -3480,11 +3480,17 @@ void level_change(bool skip_attribute_increase)
 
 }                               // end level_change()
 
-// here's a question for you: does the ordering of mods make a difference?
+// Here's a question for you: does the ordering of mods make a difference?
 // (yes) -- are these things in the right order of application to stealth?
 // - 12mar2000 {dlb}
 int check_stealth(void)
 {
+#ifdef WIZARD
+    // Extreme stealthiness can be enforced by wizmode stealth setting.
+    if (you.skills[SK_STEALTH] > 27)
+        return (1000);
+#endif
+
     if (you.special_wield == SPWLD_SHADOW || you.duration[DUR_BERSERKER])
         return (0);
 
diff --git a/crawl-ref/source/view.cc b/crawl-ref/source/view.cc
index b44b8588e5..a0cc13a032 100644
--- a/crawl-ref/source/view.cc
+++ b/crawl-ref/source/view.cc
@@ -1183,7 +1183,7 @@ bool check_awaken(monsters* monster)
     if (monster->has_ench(ENCH_SLEEPY))
         return (false);
 
-    // berserkers aren't really concerned about stealth
+    // Berserkers aren't really concerned about stealth.
     if (you.duration[DUR_BERSERKER])
         return (true);
 
@@ -1194,16 +1194,16 @@ bool check_awaken(monsters* monster)
     if (you.duration[DUR_REPEL_UNDEAD] && mons_is_unholy(monster))
         return (true);
 
-    // I assume that creatures who can sense invisible are very perceptive
+    // I assume that creatures who can sense invisible are very perceptive.
     mons_perc = 10 + (mons_intel(monster->type) * 4) + monster->hit_dice
                    + mons_sense_invis(monster) * 5;
 
     bool unnatural_stealthy = false; // "stealthy" only because of invisibility?
 
-    // critters that are wandering still have MHITYOU as their foe are
-    // still actively on guard for the player, even if they can't see
-    // him.  Give them a large bonus (handle_behaviour() will nuke 'foe'
-    // after a while, removing this bonus.
+    // Critters that are wandering but still have MHITYOU as their foe are
+    // still actively on guard for the player, even if they can't see you.
+    // Give them a large bonus -- handle_behaviour() will nuke 'foe' after
+    // a while, removing this bonus.
     if (monster->behaviour == BEH_WANDER && monster->foe == MHITYOU)
         mons_perc += 15;
 
@@ -1217,7 +1217,7 @@ bool check_awaken(monsters* monster)
     {
         if (mon_holy == MH_NATURAL)
         {
-            // monster is "hibernating"... reduce chance of waking
+            // Monster is "hibernating"... reduce chance of waking.
             if (monster->has_ench(ENCH_SLEEP_WARY))
                 mons_perc -= 10;
         }