Implement the returning brand for ammunition. This mostly uses the same

code as weapons of returning, but such ammunition has the same chance of 
being randomly destroyed when thrown as non-returning ammunition.  Note 
that the brand is not actually generated anywhere yet.


git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@3024 c06c8d41-db1a-0410-9941-cceddc491573

1 files changed, 64 insertions, 2 deletions

diff --git a/crawl-ref/source/item_use.cc b/crawl-ref/source/item_use.cc
index 3e62c8f41f..6abc5a71ea 100644
--- a/crawl-ref/source/item_use.cc
+++ b/crawl-ref/source/item_use.cc
@@ -2068,8 +2068,10 @@ bool throw_it(bolt &pbolt, int throw_2, bool teleport, int acc_bonus,
     // CALCULATIONS FOR THROWN WEAPONS
     if (projected == LRET_THROWN)
     {
-        returning = (get_weapon_brand(item) == SPWPN_RETURNING && !teleport &&
-                     !one_chance_in(1 + skill_bump(SK_THROWING)));
+        returning = ((get_weapon_brand(item) == SPWPN_RETURNING ||
+                      get_ammo_brand(item) == SPMSL_RETURNING) &&
+                          !teleport &&
+                          !one_chance_in(1 + skill_bump(SK_THROWING)));
         baseHit = 0;
 
         // missiles only use inv_plus
@@ -2348,6 +2350,13 @@ bool throw_it(bolt &pbolt, int throw_2, bool teleport, int acc_bonus,
     {
         // Dropping item copy, since the launched item might be different.
         fire_beam(pbolt, returning ? NULL : &item);
+
+        // The item can be destroyed before returning.
+        if (returning && thrown_object_destroyed(&item, pbolt.target_x,
+                                                 pbolt.target_y, true))
+        {
+            returning = false;
+        }
     }
 
     if ( returning )
@@ -2379,6 +2388,59 @@ bool throw_it(bolt &pbolt, int throw_2, bool teleport, int acc_bonus,
     return (hit);
 }                               // end throw_it()
 
+bool thrown_object_destroyed( item_def *item, int x, int y, bool returning )
+{
+    ASSERT( item != NULL );
+
+    int chance = 0;
+    bool destroyed = false;
+    bool hostile_grid = false;
+
+    if (item->base_type == OBJ_MISSILES)
+    {
+        // [dshaligram] Removed influence of Throwing on ammo preservation.
+        // The effect is nigh impossible to perceive.
+        switch (item->sub_type)
+        {
+        case MI_NEEDLE:
+            chance = (get_ammo_brand(*item) == SPMSL_CURARE ? 3 : 6);
+            break;
+        case MI_SLING_BULLET:
+        case MI_STONE:  chance = 4; break;
+        case MI_DART:   chance = 3; break;
+        case MI_ARROW:  chance = 4; break;
+        case MI_BOLT:   chance = 4; break;
+        case MI_JAVELIN: chance = 10; break;
+        case MI_THROWING_NET: break; // doesn't get destroyed by throwing
+
+        case MI_LARGE_ROCK:
+        default:
+            chance = 25;
+            break;
+        }
+    }
+
+    destroyed = (chance == 0) ? false : one_chance_in(chance);
+    hostile_grid = grid_destroys_items(grd[x][y]);
+
+    // Non-returning items thrown into item-destroying grids are always
+    // destroyed.  Returning items are only destroyed if they would have
+    // been randomly destroyed anyway.
+    if (returning && !destroyed)
+        hostile_grid = false;
+
+    if (hostile_grid)
+    {
+        if (player_can_hear(x, y))
+            mprf(MSGCH_SOUND, grid_item_destruction_message(grd[x][y]));
+
+        item_was_destroyed(*item, NON_MONSTER);
+        destroyed = true;
+    }
+
+    return destroyed;
+}
+
 void jewellery_wear_effects(item_def &item)
 {
     item_type_id_state_type ident        = ID_TRIED_TYPE;