Make mimics hold the item they're mimicking, instead of fragile hacks with saving RNG state.

10 files changed, 81 insertions, 93 deletions

diff --git a/crawl-ref/source/describe.cc b/crawl-ref/source/describe.cc
index e77ff17982..83ea1d2e2b 100644
--- a/crawl-ref/source/describe.cc
+++ b/crawl-ref/source/describe.cc
@@ -2802,9 +2802,7 @@ void get_monster_db_desc(const monsters& mons, describe_info &inf,
     // For undetected mimics describe mimicked item instead.
     if (!force_seen && mons_is_unknown_mimic(&mons))
     {
-        item_def item;
-        get_mimic_item(&mons, item);
-        get_item_desc(item, inf);
+        get_item_desc(get_mimic_item(&mons), inf);
         return;
     }
 
@@ -2812,12 +2810,6 @@ void get_monster_db_desc(const monsters& mons, describe_info &inf,
         inf.title = mons.full_name(DESC_CAP_A, true);
 
     std::string db_name = mons.base_name(DESC_DBNAME, force_seen);
-    if (mons_is_mimic(mons.type) && mons.type != MONS_GOLD_MIMIC)
-    {
-        db_name   = "mimic";
-        if (inf.title.empty())
-            inf.title = "A mimic";
-    }
 
     // This is somewhat hackish, but it's a good way of over-riding monsters'
     // descriptions in Lua vaults by using MonPropsMarker. This is also the
diff --git a/crawl-ref/source/directn.cc b/crawl-ref/source/directn.cc
index 34cef9c9f9..66d3b94f96 100644
--- a/crawl-ref/source/directn.cc
+++ b/crawl-ref/source/directn.cc
@@ -521,11 +521,7 @@ void full_describe_view()
         const bool unknown_mimic = (mon && mons_is_unknown_mimic(mon));
 
         if (unknown_mimic)      // It'll be on top.
-        {
-            item_def item;
-            get_mimic_item(mon, item);
-            list_items.push_back(item);
-        }
+            list_items.push_back(get_mimic_item(mon));
 
         const int oid = igrd(*ri);
         if (oid == NON_ITEM)
@@ -1754,11 +1750,7 @@ std::string get_terse_square_desc(const coord_def &gc)
         const monsters& mons = *monster_at(gc);
 
         if (mons_is_mimic(mons.type) && !(mons.flags & MF_KNOWN_MIMIC))
-        {
-            item_def item;
-            get_mimic_item(&mons, item);
-            desc = item.name(DESC_PLAIN);
-        }
+            desc = get_mimic_item(&mons).name(DESC_PLAIN);
         else
             desc = mons.full_name(DESC_PLAIN, true);
     }
@@ -3361,9 +3353,7 @@ static void _describe_cell(const coord_def& where, bool in_range)
                 _describe_monster(mon);
             else
             {
-                item_def item;
-                get_mimic_item( mon, item );
-                std::string name = get_menu_colour_prefix_tags(item,
+                std::string name = get_menu_colour_prefix_tags(get_mimic_item(mon),
                                                                DESC_NOCAP_A);
                 mprf(MSGCH_FLOOR_ITEMS, "You see %s here.", name.c_str());
             }
diff --git a/crawl-ref/source/mon-place.cc b/crawl-ref/source/mon-place.cc
index 6629b8acf1..a4273c6a7c 100644
--- a/crawl-ref/source/mon-place.cc
+++ b/crawl-ref/source/mon-place.cc
@@ -1116,6 +1116,17 @@ static int _place_monster_aux(const mgen_data &mg,
     int id = mon->mindex();
     env.mgrid(fpos) = id;
 
+    if (mons_is_mimic(mg.cls))
+    {
+        // Mimics who mimic thin air get the axe.
+        if (!give_mimic_item(mon))
+        {
+            mon->reset();
+            mgrd(fpos) = NON_MONSTER;
+            return (-1);
+        }
+    }
+
     // Generate a brand shiny new monster, or zombie.
     if (mons_class_is_zombified(mg.cls))
         _define_zombie(id, mg.base_type, mg.cls, mg.power, fpos);
diff --git a/crawl-ref/source/mon-stuff.cc b/crawl-ref/source/mon-stuff.cc
index 4f9fa50ac8..2288d753db 100644
--- a/crawl-ref/source/mon-stuff.cc
+++ b/crawl-ref/source/mon-stuff.cc
@@ -62,13 +62,14 @@
 
 static bool _wounded_damaged(monster_type mon_type);
 
-// This function creates an artificial item to represent a mimic's
-// appearance.  Eventually, mimics could be redone to be more like
-// dancing weapons: there'd only be one type and it would look like the
-// item it carries. - bwr
-void get_mimic_item( const monsters *mimic, item_def &item )
+int _make_mimic_item(monster_type type)
 {
-    ASSERT(mimic != NULL && mons_is_mimic( mimic->type));
+    int it = items(0, OBJ_UNASSIGNED, 0, true, 0, 0);
+
+    if (it == NON_ITEM)
+        return NON_ITEM;
+
+    item_def &item = mitm[it];
 
     item.base_type = OBJ_UNASSIGNED;
     item.sub_type  = 0;
@@ -78,22 +79,16 @@ void get_mimic_item( const monsters *mimic, item_def &item )
     item.quantity  = 1;
     item.plus      = 0;
     item.plus2     = 0;
-    item.pos       = mimic->pos();
     item.link      = NON_ITEM;
 
-    int prop = 127 * mimic->pos().x + 269 * mimic->pos().y;
-
-    rng_save_excursion exc;
-    seed_rng( prop );
-
-    switch (mimic->type)
+    int prop;
+    switch (type)
     {
     case MONS_WEAPON_MIMIC:
         item.base_type = OBJ_WEAPONS;
-        item.sub_type = (59 * mimic->pos().x + 79 * mimic->pos().y)
-                            % (WPN_MAX_NONBLESSED + 1);
+        item.sub_type = random2(WPN_MAX_NONBLESSED + 1);
 
-        prop %= 100;
+        prop = random2(100);
 
         if (prop < 20)
             make_item_randart(item);
@@ -111,10 +106,9 @@ void get_mimic_item( const monsters *mimic, item_def &item )
 
     case MONS_ARMOUR_MIMIC:
         item.base_type = OBJ_ARMOUR;
-        item.sub_type = (59 * mimic->pos().x + 79 * mimic->pos().y)
-                            % NUM_ARMOURS;
+        item.sub_type = random2(NUM_ARMOURS);
 
-        prop %= 100;
+        prop = random2(100);
 
         if (prop < 20)
             make_item_randart(item);
@@ -134,39 +128,55 @@ void get_mimic_item( const monsters *mimic, item_def &item )
 
     case MONS_SCROLL_MIMIC:
         item.base_type = OBJ_SCROLLS;
-        item.sub_type = prop % NUM_SCROLLS;
+        item.sub_type = random2(NUM_SCROLLS);
         break;
 
     case MONS_POTION_MIMIC:
         item.base_type = OBJ_POTIONS;
-        item.sub_type = prop % NUM_POTIONS;
+        item.sub_type = random2(NUM_POTIONS);
         break;
 
     case MONS_GOLD_MIMIC:
     default:
         item.base_type = OBJ_GOLD;
-        item.quantity = 5 + prop % 30;
+        item.quantity = 5 + random2(1000);
         break;
     }
 
     item_colour(item); // also sets special vals for scrolls/potions
+
+    return (it);
+}
+
+item_def *give_mimic_item(monsters *mimic)
+{
+    ASSERT(mimic != NULL && mons_is_mimic(mimic->type));
+
+    mimic->destroy_inventory();
+    int it = _make_mimic_item(mimic->type);
+    if (it == NON_ITEM)
+        return 0;
+    if (!mimic->pickup_misc(mitm[it], 0))
+        ASSERT("Mimic failed to pickup its item.");
+    return (&mitm[mimic->inv[MSLOT_MISCELLANY]]);
+}
+
+item_def &get_mimic_item(const monsters *mimic)
+{
+    ASSERT(mimic != NULL && mons_is_mimic(mimic->type));
+
+    ASSERT(mimic->inv[MSLOT_MISCELLANY] != NON_ITEM);
+
+    return (mitm[mimic->inv[MSLOT_MISCELLANY]]);
 }
 
 // Sets the colour of a mimic to match its description... should be called
 // whenever a mimic is created or teleported. -- bwr
 int get_mimic_colour( const monsters *mimic )
 {
-    ASSERT( mimic != NULL && mons_is_mimic( mimic->type ) );
+    ASSERT(mimic != NULL);
 
-    if (mimic->type == MONS_SCROLL_MIMIC)
-        return (LIGHTGREY);
-    else if (mimic->type == MONS_GOLD_MIMIC)
-        return (YELLOW);
-
-    item_def  item;
-    get_mimic_item( mimic, item );
-
-    return (item.colour);
+    return (get_mimic_item(mimic).colour);
 }
 
 // Monster curses a random player inventory item.
@@ -2126,6 +2136,8 @@ int monster_die(monsters *monster, killer_type killer,
     {
         _elven_twin_died(monster, in_transit);
     }
+    else if (mons_is_mimic(monster->type))
+        monster->destroy_inventory();
     else if (!monster->is_summoned())
     {
         if (mons_genus(monster->type) == MONS_MUMMY)
@@ -3733,7 +3745,10 @@ void monster_teleport(monsters *monster, bool instan, bool silent)
         monster_type old_type = monster->type;
         monster->type   = static_cast<monster_type>(
                                          MONS_GOLD_MIMIC + random2(5));
+        monster->destroy_inventory();
+        give_mimic_item(monster);
         monster->colour = get_mimic_colour(monster);
+        was_seen = false;
 
         // If it's changed form, you won't recognise it.
         // This assumes that a non-gold mimic turning into another item of
diff --git a/crawl-ref/source/mon-stuff.h b/crawl-ref/source/mon-stuff.h
index 97acee430f..8455c89ecb 100644
--- a/crawl-ref/source/mon-stuff.h
+++ b/crawl-ref/source/mon-stuff.h
@@ -61,7 +61,8 @@ public:
 // for definition of type monsters {dlb}
 #include "externs.h"
 
-void get_mimic_item( const monsters *mimic, item_def & item );
+item_def *give_mimic_item(monsters *mimic);
+item_def &get_mimic_item(const monsters *mimic);
 int  get_mimic_colour( const monsters *mimic );
 
 void alert_nearby_monsters(void);
diff --git a/crawl-ref/source/monster.cc b/crawl-ref/source/monster.cc
index 4aff1df1c1..d31935af61 100644
--- a/crawl-ref/source/monster.cc
+++ b/crawl-ref/source/monster.cc
@@ -2065,12 +2065,8 @@ static std::string _str_monam(const monsters& mon, description_level_type desc,
 
     // Various special cases:
     // non-gold mimics, dancing weapons, ghosts, Pan demons
-    if (mons_is_mimic(mon.type) && mon.type != MONS_GOLD_MIMIC)
-    {
-        item_def item;
-        get_mimic_item(&mon, item);
-        return (item.name(desc));
-    }
+    if (mons_is_mimic(mon.type))
+        return (get_mimic_item(&mon).name(desc));
 
     if (mon.type == MONS_DANCING_WEAPON && mon.inv[MSLOT_WEAPON] != NON_ITEM)
     {
diff --git a/crawl-ref/source/show.cc b/crawl-ref/source/show.cc
index 0d12f7f0ad..9ef5c303b9 100644
--- a/crawl-ref/source/show.cc
+++ b/crawl-ref/source/show.cc
@@ -218,19 +218,19 @@ static show_item_type _item_to_show_code(const item_def &item)
 
 void show_def::_update_item_at(const coord_def &gp, const coord_def &ep)
 {
-    item_def eitem;
+    item_def *eitem;
     // Check for mimics.
     const monsters* m = monster_at(gp);
     if (m && mons_is_unknown_mimic(m))
-        get_mimic_item(m, eitem);
+        eitem = &get_mimic_item(m);
     else if (igrd(gp) != NON_ITEM)
-        eitem = mitm[igrd(gp)];
+        eitem = &mitm[igrd(gp)];
     else
         return;
 
     unsigned short &ecol  = grid(ep).colour;
 
-    glyph g = get_item_glyph(&eitem);
+    glyph g = get_item_glyph(eitem);
 
     const dungeon_feature_type feat = grd(gp);
     if (Options.feature_item_brand && is_critical_feature(feat))
@@ -242,10 +242,13 @@ void show_def::_update_item_at(const coord_def &gp, const coord_def &ep)
         const unsigned short gcol = env.grid_colours(gp);
         ecol = (feat == DNGN_SHALLOW_WATER) ?
                (gcol != BLACK ? gcol : CYAN) : g.col;
-        if (eitem.link != NON_ITEM && !crawl_state.arena)
+        // monster(mimic)-owned items have link = NON_ITEM+1+midx
+        if (eitem->link > NON_ITEM && igrd(gp) != NON_ITEM)
+            ecol |= COLFLAG_ITEM_HEAP;
+        else if (eitem->link == NON_ITEM && !crawl_state.arena)
             ecol |= COLFLAG_ITEM_HEAP;
         grid(ep).cls = SH_ITEM;
-        grid(ep).item = _item_to_show_code(eitem);
+        grid(ep).item = _item_to_show_code(*eitem);
     }
 
 #ifdef USE_TILE
diff --git a/crawl-ref/source/stash.cc b/crawl-ref/source/stash.cc
index 9eb534b0ff..cb3a461b61 100644
--- a/crawl-ref/source/stash.cc
+++ b/crawl-ref/source/stash.cc
@@ -380,21 +380,16 @@ void Stash::update()
 
         // There's something on this square. Take a squint at it.
         const item_def *pitem;
-        item_def mimic_item;
         if (_grid_has_mimic_item(p))
-        {
-            get_mimic_item(monster_at(p), mimic_item);
-            pitem = &mimic_item;
-        }
+            pitem = &get_mimic_item(monster_at(p));
         else
         {
             pitem = &mitm[igrd(p)];
+            tutorial_first_item(*pitem);
         }
 
         const item_def& item = *pitem;
 
-        tutorial_first_item(item);
-
         if (!_grid_has_perceived_multiple_items(p))
             items.clear();
 
diff --git a/crawl-ref/source/tilepick.cc b/crawl-ref/source/tilepick.cc
index 0e95c17d07..b8ac8a5941 100644
--- a/crawl-ref/source/tilepick.cc
+++ b/crawl-ref/source/tilepick.cc
@@ -769,12 +769,7 @@ int tileidx_monster_base(const monsters *mon, bool detected)
     case MONS_ARMOUR_MIMIC:
     case MONS_SCROLL_MIMIC:
     case MONS_POTION_MIMIC:
-    {
-        // Use item tile.
-        item_def  item;
-        get_mimic_item( mon, item );
-        return tileidx_item(item);
-    }
+        return tileidx_item(get_mimic_item(mon));
 
     case MONS_DANCING_WEAPON:
     {
@@ -4696,9 +4691,7 @@ void tile_place_monster(int gx, int gy, int idx, bool foreground, bool detected)
                     t0 |= TILE_FLAG_S_UNDER;
             }
 
-            item_def item;
-            get_mimic_item( mon, item );
-            if (item_needs_autopickup(item))
+            if (item_needs_autopickup(get_mimic_item(mon))
             {
                 if (foreground)
                     env.tile_bg[ep.x][ep.y] |= TILE_FLAG_CURSOR3;
diff --git a/crawl-ref/source/travel.cc b/crawl-ref/source/travel.cc
index f8e4eb55cb..6da7bc6ee0 100644
--- a/crawl-ref/source/travel.cc
+++ b/crawl-ref/source/travel.cc
@@ -546,11 +546,7 @@ inline static void _check_interesting_square(int x, int y,
         if (const monsters *mons = monster_at(pos))
         {
             if (mons_is_unknown_mimic(mons))
-            {
-                item_def item;
-                get_mimic_item(mons, item);
-                ed.found_item(pos, item);
-            }
+                ed.found_item(pos, get_mimic_item(mons));
         }
 
         if (igrd(pos) != NON_ITEM)
@@ -1084,12 +1080,8 @@ static bool _is_greed_inducing_square(const LevelStashes *ls,
     if (const monsters *mons = monster_at(c))
     {
         if (mons_is_unknown_mimic(mons) && mons_was_seen(mons))
-        {
-            item_def mimic_item;
-            get_mimic_item(mons, mimic_item);
-            if (item_needs_autopickup(mimic_item))
+            if (item_needs_autopickup(get_mimic_item(mons)))
                 return (true);
-        }
     }
     return (false);
 }