Fix 1974137: Stat-lowering transformations resulting in death by stat

loss. Now take to-be-removed equipment in account and don't transform 
in the removed equipment or the stat loss or both in combination would 
decrease one of your stats to (below) 0.
For the vampire bat transformation, this check only happens after the
ability failure check, so this could be improved. In any case, it's 
better than dying.

Also, fix wrongly treating armour as worn when checking for stat loss 
by wearing.


git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@5294 c06c8d41-db1a-0410-9941-cceddc491573

1 files changed, 154 insertions, 43 deletions

diff --git a/crawl-ref/source/transfor.cc b/crawl-ref/source/transfor.cc
index 6931400de3..d2f7bd9051 100644
--- a/crawl-ref/source/transfor.cc
+++ b/crawl-ref/source/transfor.cc
@@ -27,6 +27,7 @@
 #include "misc.h"
 #include "output.h"
 #include "player.h"
+#include "randart.h"
 #include "skills2.h"
 #include "stuff.h"
 #include "traps.h"
@@ -34,10 +35,67 @@
 void drop_everything(void);
 void extra_hp(int amount_extra);
 
+static void _init_equipment_removal(std::set<equipment_type> &rem_stuff,
+                                    int which_trans)
+{
+    switch (which_trans)
+    {
+    case TRAN_SPIDER:
+        // Spiders CAN wear soft helmets
+        if (you.equip[EQ_HELMET] == -1
+            || !is_hard_helmet(you.inv[you.equip[EQ_HELMET]]))
+        {
+            rem_stuff.erase(EQ_HELMET);
+        }
+        break;
+
+    case TRAN_BAT:
+        // Bats CAN wear soft helmets.
+        if (you.equip[EQ_HELMET] == -1
+            || !is_hard_helmet(you.inv[you.equip[EQ_HELMET]]))
+        {
+            rem_stuff.erase(EQ_HELMET);
+        }
+        break;
+
+    case TRAN_ICE_BEAST:
+        rem_stuff.erase(EQ_CLOAK);
+        // Ice beasts CAN wear soft helmets.
+        if (you.equip[EQ_HELMET] == -1
+            || !is_hard_helmet(you.inv[you.equip[EQ_HELMET]]))
+        {
+            rem_stuff.erase(EQ_HELMET);
+        }
+        break;
+
+    case TRAN_BLADE_HANDS:
+        rem_stuff.erase(EQ_CLOAK);
+        rem_stuff.erase(EQ_HELMET);
+        rem_stuff.erase(EQ_BOOTS);
+        rem_stuff.erase(EQ_BODY_ARMOUR);
+        break;
+
+    case TRAN_STATUE:
+        rem_stuff.erase(EQ_WEAPON); // can still hold a weapon
+        rem_stuff.erase(EQ_CLOAK);
+        rem_stuff.erase(EQ_HELMET);
+        break;
+
+    case TRAN_AIR:
+        // Can't wear anything at all!
+        rem_stuff.insert(EQ_LEFT_RING);
+        rem_stuff.insert(EQ_RIGHT_RING);
+        rem_stuff.insert(EQ_AMULET);
+        break;
+    default:
+        break;
+    }
+}
+
 bool remove_equipment(std::set<equipment_type> removed)
 {
-    if ( removed.find(EQ_WEAPON) != removed.end() &&
-         you.equip[EQ_WEAPON] != -1)
+    if (removed.find(EQ_WEAPON) != removed.end()
+        && you.equip[EQ_WEAPON] != -1)
     {
         unwield_item();
         canned_msg(MSG_EMPTY_HANDED);
@@ -45,10 +103,10 @@ bool remove_equipment(std::set<equipment_type> removed)
 
     // Remove items in order (std::set is a sorted container)
     std::set<equipment_type>::const_iterator iter;
-    for ( iter = removed.begin(); iter != removed.end(); ++iter )
+    for (iter = removed.begin(); iter != removed.end(); ++iter)
     {
         const equipment_type e = *iter;
-        if ( e == EQ_WEAPON || you.equip[e] == -1 )
+        if (e == EQ_WEAPON || you.equip[e] == -1)
             continue;
 
         mprf("%s falls away.",
@@ -58,7 +116,7 @@ bool remove_equipment(std::set<equipment_type> removed)
         you.equip[e] = -1;
     }
 
-    return true;
+    return (true);
 }                               // end remove_equipment()
 
 bool remove_one_equip(equipment_type eq)
@@ -76,7 +134,7 @@ static bool check_for_cursed_equipment(const std::set<equipment_type> &remove)
     for (iter = remove.begin(); iter != remove.end(); ++iter )
     {
         equipment_type e = *iter;
-        if ( you.equip[e] == -1 )
+        if (you.equip[e] == -1)
             continue;
 
         if (item_cursed( you.inv[ you.equip[e] ] ))
@@ -91,6 +149,78 @@ static bool check_for_cursed_equipment(const std::set<equipment_type> &remove)
     return (false);
 }                               // end check_for_cursed_equipment()
 
+// Count the stat boosts yielded by all items to be removed, and count
+// future losses (caused by the transformation) like a current stat boost,
+// as well. If the sum of all bosts of a stat is equal to or greater than
+// the current stat, give a message and return true.
+bool check_transformation_stat_loss(const std::set<equipment_type> &remove,
+                                    int str_loss, int dex_loss, int int_loss,
+                                    bool quiet)
+{
+    // Initialize with additional losses, if any.
+    int prop_str = str_loss;
+    int prop_dex = dex_loss;
+    int prop_int = int_loss;
+
+    // Check over all items to be removed.
+    std::set<equipment_type>::const_iterator iter;
+    for (iter = remove.begin(); iter != remove.end(); ++iter)
+    {
+        equipment_type e = *iter;
+        if (you.equip[e] == -1)
+            continue;
+
+        item_def item = you.inv[you.equip[e]];
+        if (item.base_type == OBJ_JEWELLERY)
+        {
+            if (!item_ident( item, ISFLAG_KNOW_PLUSES ))
+                continue;
+
+            switch (item.sub_type)
+            {
+            case RING_STRENGTH:
+                if (item.plus != 0)
+                    prop_str += item.plus;
+                break;
+            case RING_DEXTERITY:
+                if (item.plus != 0)
+                    prop_dex += item.plus;
+                break;
+            case RING_INTELLIGENCE:
+                if (item.plus != 0)
+                    prop_int += item.plus;
+                break;
+            default:
+                break;
+            }
+        }
+
+        if (is_random_artefact( item ))
+        {
+            prop_str += randart_known_wpn_property(item, RAP_STRENGTH);
+            prop_int += randart_known_wpn_property(item, RAP_INTELLIGENCE);
+            prop_dex += randart_known_wpn_property(item, RAP_DEXTERITY);
+        }
+
+        // Since there might be multiple items whose effects cancel each other
+        // out while worn, if at any point in the order of checking this list
+        // (which is the same order as when removing items) one of your stats
+        // would reach 0, return true.
+        if (prop_str >= you.strength || prop_int >= you.intel
+            || prop_dex >= you.dex)
+        {
+            if (!quiet)
+            {
+                mpr("This transformation would result in fatal stat loss!",
+                    MSGCH_WARN);
+            }
+            return (true);
+        }
+    }
+
+    return (false);
+}
+
 // FIXME: Switch to 4.1 transforms handling.
 size_type transform_size(int psize)
 {
@@ -163,10 +293,10 @@ bool transform(int pow, transformation_type which_trans)
         return (false);
     }
 
-    //jmf: silently discard this enchantment
+    //jmf: Silently discard this enchantment
     you.duration[DUR_STONESKIN] = 0;
 
-    // We drop everything except jewellery by default
+    // We drop everything except jewellery by default.
     equipment_type default_rem[] = {
         EQ_WEAPON, EQ_CLOAK, EQ_HELMET, EQ_GLOVES, EQ_BOOTS,
         EQ_SHIELD, EQ_BODY_ARMOUR
@@ -174,6 +304,7 @@ bool transform(int pow, transformation_type which_trans)
 
     std::set<equipment_type> rem_stuff(default_rem,
                                        default_rem + ARRAYSZ(default_rem));
+    _init_equipment_removal(rem_stuff, which_trans);
 
     you.redraw_evasion = true;
     you.redraw_armour_class = true;
@@ -183,13 +314,6 @@ bool transform(int pow, transformation_type which_trans)
     switch (which_trans)
     {
     case TRAN_SPIDER:           // also AC +3, ev +3, fast_run
-        // spiders CAN wear soft helmets
-        if ( you.equip[EQ_HELMET] == -1
-             || !is_hard_helmet(you.inv[you.equip[EQ_HELMET]]))
-        {
-             rem_stuff.erase(EQ_HELMET);
-        }
-
         if (check_for_cursed_equipment( rem_stuff ))
             return (false);
 
@@ -210,16 +334,11 @@ bool transform(int pow, transformation_type which_trans)
         return (true);
 
     case TRAN_BAT:
-        // bats CAN wear soft helmets
-        if ( you.equip[EQ_HELMET] == -1
-             || !is_hard_helmet(you.inv[you.equip[EQ_HELMET]]))
-        {
-             rem_stuff.erase(EQ_HELMET);
-        }
+        if (check_for_cursed_equipment(rem_stuff))
+            return (false);
 
-        // high ev, low ac, high speed
-        if (check_for_cursed_equipment( rem_stuff ))
-            return false;
+        if (check_transformation_stat_loss(rem_stuff, 5)) // Str loss = 5
+            return (false);
 
         mprf("You turn into a %sbat.",
              you.species == SP_VAMPIRE ? "vampire " : "");
@@ -232,6 +351,7 @@ bool transform(int pow, transformation_type which_trans)
         if (you.duration[DUR_TRANSFORMATION] > 100)
             you.duration[DUR_TRANSFORMATION] = 100;
 
+        // high ev, low ac, high speed
        modify_stat( STAT_DEXTERITY, 5, true,
                     "gaining the bat transformation");
        modify_stat( STAT_STRENGTH, -5, true,
@@ -242,16 +362,8 @@ bool transform(int pow, transformation_type which_trans)
        return (true);
 
     case TRAN_ICE_BEAST:  // also AC +3, cold +3, fire -1, pois +1
-        rem_stuff.erase(EQ_CLOAK);
-        // ice beasts CAN wear soft helmets
-        if ( you.equip[EQ_HELMET] == -1
-             || !is_hard_helmet(you.inv[you.equip[EQ_HELMET]]))
-        {
-             rem_stuff.erase(EQ_HELMET);
-        }
-
         if (check_for_cursed_equipment( rem_stuff ))
-            return false;
+            return (false);
 
         mpr( "You turn into a creature of crystalline ice." );
 
@@ -292,12 +404,11 @@ bool transform(int pow, transformation_type which_trans)
         return (true);
 
     case TRAN_STATUE: // also AC +20, ev -5, elec +1, pois +1, neg +1, slow
-        rem_stuff.erase(EQ_WEAPON); // can still hold a weapon
-        rem_stuff.erase(EQ_CLOAK);
-        rem_stuff.erase(EQ_HELMET);
-
         if (check_for_cursed_equipment( rem_stuff ))
-            return false;
+            return (false);
+
+        if (check_transformation_stat_loss(rem_stuff, 0, 2)) // Dex loss = 2
+            return (false);
 
         if (you.species == SP_GNOME && coinflip())
             mpr( "Look, a garden gnome.  How cute!" );
@@ -306,7 +417,7 @@ bool transform(int pow, transformation_type which_trans)
         else
             mpr( "You turn into a living statue of rough stone." );
 
-        // too stiff to make use of shields, gloves, or armour -- bwr
+        // Too stiff to make use of shields, gloves, or armour -- bwr
         remove_equipment( rem_stuff );
 
         you.attribute[ATTR_TRANSFORMATION] = TRAN_STATUE;
@@ -333,8 +444,10 @@ bool transform(int pow, transformation_type which_trans)
             return false;
 
         if (you.species == SP_MERFOLK && player_is_swimming())
+        {
             mpr("You fly out of the water as you turn into "
                 "a fearsome dragon!");
+        }
         else
             mpr("You turn into a fearsome dragon!");
 
@@ -364,6 +477,8 @@ bool transform(int pow, transformation_type which_trans)
         return (true);
 
     case TRAN_LICH:
+        // Don't need to remove anything.
+
         // also AC +3, cold +1, neg +3, pois +1, is_undead, res magic +50,
         // spec_death +1, and drain attack (if empty-handed)
         if (you.duration[DUR_DEATHS_DOOR])
@@ -403,10 +518,6 @@ bool transform(int pow, transformation_type which_trans)
         return (true);
 
     case TRAN_AIR:
-        rem_stuff.insert(EQ_LEFT_RING);
-        rem_stuff.insert(EQ_RIGHT_RING);
-        rem_stuff.insert(EQ_AMULET);
-
         if (check_for_cursed_equipment( rem_stuff ))
             return false;