Apply 1895318, with some cleanup.

This patch implements dploog's suggestion of hysteresis on piety.
gain/lose_piety() adjust you.piety_hysteresis first; you.piety is
modified with the leftovers (if any) once the hysteresis reaches its
limit.

Players start out at the upper end of the hysteresis region, meaning
there is no lag on piety increase, but a lag on piety decrease.

Hysteresis value set by "#define PIETY_HYSTERESIS_LIMIT 1"

Does not break old saves.



git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@3562 c06c8d41-db1a-0410-9941-cceddc491573

5 files changed, 44 insertions, 10 deletions

diff --git a/crawl-ref/source/externs.h b/crawl-ref/source/externs.h
index 0832dc7c9c..2e98e3fc99 100644
--- a/crawl-ref/source/externs.h
+++ b/crawl-ref/source/externs.h
@@ -703,6 +703,7 @@ public:
 
   god_type religion;
   unsigned char piety;
+  unsigned char piety_hysteresis;       // amount of stored-up docking
   unsigned char gift_timeout;
   FixedVector<unsigned char, MAX_NUM_GODS>  penance;
   FixedVector<unsigned char, MAX_NUM_GODS>  worshipped;
diff --git a/crawl-ref/source/files.cc b/crawl-ref/source/files.cc
index c656e2f596..0c4d6d4aa0 100644
--- a/crawl-ref/source/files.cc
+++ b/crawl-ref/source/files.cc
@@ -106,7 +106,10 @@ void save_level(int level_saved, level_area_type lt,
 
 #define GHOST_MINOR_VERSION 1
 #define LEVEL_MINOR_VERSION 1
-#define YOU_MINOR_VERSION   1
+
+// 1: starting version
+// 2: append piety_hysteresis to TAG_YOU
+#define YOU_MINOR_VERSION   2
 
 const short GHOST_SIGNATURE = static_cast<short>( 0xDC55 );
 
diff --git a/crawl-ref/source/player.cc b/crawl-ref/source/player.cc
index 2e0d3968fd..850030f30f 100644
--- a/crawl-ref/source/player.cc
+++ b/crawl-ref/source/player.cc
@@ -5208,6 +5208,7 @@ void player::init()
 
     religion = GOD_NO_GOD;
     piety = 0;
+    piety_hysteresis = 0;
 
     gift_timeout = 0;
 
diff --git a/crawl-ref/source/religion.cc b/crawl-ref/source/religion.cc
index 8052321cee..440244a305 100644
--- a/crawl-ref/source/religion.cc
+++ b/crawl-ref/source/religion.cc
@@ -85,6 +85,8 @@
 #    define DEBUG_PIETY       1
 #endif
 
+#define PIETY_HYSTERESIS_LIMIT 1
+
 // Item offer messages for the gods:
 // & is replaced by "is" or "are" as appropriate for the item.
 // % is replaced by "s" or "" as appropriate.
@@ -1093,7 +1095,7 @@ void pray()
         do_god_gift(true);
 
 #if DEBUG_DIAGNOSTICS
-    mprf(MSGCH_DIAGNOSTICS, "piety: %d", you.piety );
+    mprf(MSGCH_DIAGNOSTICS, "piety: %d (-%d)", you.piety, you.piety_hysteresis );
 #endif
 
 }                               // end pray()
@@ -1756,10 +1758,6 @@ void gain_piety(int pgn)
         }
     }
 
-#if DEBUG_PIETY
-    mprf(MSGCH_DIAGNOSTICS, "Piety increasing by %d", pgn);
-#endif
-
     // slow down gain at upper levels of piety
     if (you.religion != GOD_SIF_MUNA)
     {
@@ -1783,6 +1781,20 @@ void gain_piety(int pgn)
         }
     }
 
+    // Apply hysteresis
+    {
+        // piety_hysteresis is the amount of _loss_ stored up, so this
+        // may look backwards.
+        const int old_hysteresis = you.piety_hysteresis;
+        you.piety_hysteresis = (unsigned char)std::max<int>(
+            0, you.piety_hysteresis - pgn);
+        const int pgn_borrowed = (old_hysteresis - you.piety_hysteresis);
+        pgn -= pgn_borrowed;
+#if DEBUG_PIETY
+mprf(MSGCH_DIAGNOSTICS, "Piety increasing by %d (and %d taken from hysteresis)", pgn, pgn_borrowed);
+#endif
+    }
+
     int old_piety = you.piety;
 
     you.piety += pgn;
@@ -1971,8 +1983,8 @@ bool trog_burn_books()
         const int next = mitm[i].link;  // in case we can't get it later.
 
         if (mitm[i].base_type == OBJ_BOOKS
-            && mitm[i].sub_type != BOOK_MANUAL
-	    && mitm[i].sub_type != BOOK_DESTRUCTION)
+           && mitm[i].sub_type != BOOK_MANUAL
+           && mitm[i].sub_type != BOOK_DESTRUCTION)
         {
             mpr("Burning your own feet might not be such a smart idea!");
             return (false);
@@ -2011,7 +2023,7 @@ bool trog_burn_books()
 
                  if (mitm[i].base_type != OBJ_BOOKS
                      || mitm[i].sub_type == BOOK_MANUAL
-		     || mitm[i].sub_type == BOOK_DESTRUCTION)
+                     || mitm[i].sub_type == BOOK_DESTRUCTION)
                  {
                      i = next;
                      continue;
@@ -2078,9 +2090,18 @@ void lose_piety(int pgn)
 {
     const int old_piety = you.piety;
 
+    // Apply hysteresis
+    {
+        const int old_hysteresis = you.piety_hysteresis;
+        you.piety_hysteresis = (unsigned char)std::min<int>(
+            PIETY_HYSTERESIS_LIMIT, you.piety_hysteresis + pgn);
+        const int pgn_borrowed = (you.piety_hysteresis - old_hysteresis);
+        pgn -= pgn_borrowed;
 #if DEBUG_PIETY
-    mprf(MSGCH_DIAGNOSTICS, "Piety decreasing by %d", pgn);
+        mprf(MSGCH_DIAGNOSTICS, "Piety decreasing by %d (and %d added to hysteresis)", pgn, pgn_borrowed);
 #endif
+    }
+
 
     if (you.piety - pgn < 0)
         you.piety = 0;
@@ -3257,6 +3278,7 @@ void excommunication(void)
     you.duration[DUR_PIETY_POOL] = 0; // your loss
     you.religion = GOD_NO_GOD;
     you.piety = 0;
+    you.piety_hysteresis = 0;
     redraw_skill( you.your_name, player_title() );
 
     mpr("You have lost your religion!");
@@ -3840,6 +3862,7 @@ void god_pitch(god_type which_god)
     else
     {
         you.piety = 15;             // to prevent near instant excommunication
+        you.piety_hysteresis = 0;
         you.gift_timeout = 0;
     }
     
diff --git a/crawl-ref/source/tags.cc b/crawl-ref/source/tags.cc
index 7e54a35bef..3ab4284782 100644
--- a/crawl-ref/source/tags.cc
+++ b/crawl-ref/source/tags.cc
@@ -1004,6 +1004,9 @@ static void tag_construct_you(tagHeader &th)
     marshallByte(th, you.beheld_by.size());
     for (unsigned int k = 0; k < you.beheld_by.size(); k++)
          marshallByte(th, you.beheld_by[k]);
+
+    // minorVersion 2 starts here
+    marshallByte(th, you.piety_hysteresis);
 }
 
 static void tag_construct_you_items(tagHeader &th)
@@ -1380,6 +1383,9 @@ static void tag_read_you(tagHeader &th, char minorVersion)
     count_c = unmarshallByte(th);
     for (i = 0; i < count_c; i++)
          you.beheld_by.push_back(unmarshallByte(th));
+
+    if (minorVersion >= 2)
+        you.piety_hysteresis = unmarshallByte(th);
 }
 
 static void tag_read_you_items(tagHeader &th, char minorVersion)